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mariadb Regular Expressions Functions Regular Expressions Functions ============================== MariaDB includes a number of functions for dealing with regular expressions. | Title | Description | | --- | --- | | [Regular Expressions Overview](../regular-expressions-overview/index) | Regular Expressions allow MariaDB to perform complex pattern matching on a string. | | [PCRE - Perl Compatible Regular Expressions](../pcre/index) | PCRE (Perl Compatible Regular Expressions) for enhanced regular expressions. | | [NOT REGEXP](../not-regexp/index) | Same as NOT (expr REGEXP pat). | | [REGEXP](../regexp/index) | Performs pattern matching | | [REGEXP\_INSTR](../regexp_instr/index) | Position of the first appearance of a regex. | | [REGEXP\_REPLACE](../regexp_replace/index) | Replaces all occurrences of a pattern. | | [REGEXP\_SUBSTR](../regexp_substr/index) | Returns the matching part of a string. | | [RLIKE](../rlike/index) | Synonym for REGEXP | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Instant ADD COLUMN for InnoDB Instant ADD COLUMN for InnoDB ============================= **MariaDB starting with [10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/)**Instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) for InnoDB was introduced in [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/). The `INSTANT` option for the [ALGORITHM](../alter-table/index#algorithm) clause was introduced in [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/). Normally, adding a column to a table requires the full table to be rebuilt. The complexity of the operation is proportional to the size of the table, or O(n·m) where n is the number of rows in the table and m is the number of indexes. In [MariaDB 10.0](../what-is-mariadb-100/index) and later, the [ALTER TABLE](../alter-table/index) statement supports [online DDL](../alter-table/index#online-ddl) for storage engines that have implemented the relevant online DDL [algorithms](../alter-table/index#algorithm) and [locking strategies](../alter-table/index#lock). The [InnoDB](../innodb/index) storage engine has implemented online DDL for many operations. These online DDL optimizations allow concurrent DML to the table in many cases, even if the table needs to be rebuilt. See [InnoDB Online DDL Overview](../innodb-online-ddl-overview/index) for more information about online DDL with InnoDB. Allowing concurrent DML during the operation does not solve all problems. When a column was added to a table with the older in-place optimization, the resulting table rebuild could still significantly increase the I/O and memory consumption and cause replication lag. In contrast, with the new instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column), all that is needed is an O(log n) operation to insert a special hidden record into the table, and an update of the data dictionary. For a large table, instead of taking several hours, the operation would be completed in the blink of an eye. The [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) operation is only slightly more expensive than a regular [INSERT](../insert/index), due to locking constraints. In the past, some developers may have implemented a kind of "instant add column" in the application by encoding multiple columns in a single [TEXT](../text/index) or [BLOB](../blob/index) column. MariaDB [Dynamic Columns](../dynamic-columns/index) was an early example of that. A more recent example is [JSON](../json-functions/index) and related string manipulation functions. Adding real columns has the following advantages over encoding columns into a single "expandable" column: * Efficient storage in a native binary format * Data type safety * Indexes can be built natively * Constraints are available: UNIQUE, CHECK, FOREIGN KEY * DEFAULT values can be specified * Triggers can be written more easily With instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column), you can enjoy all the benefits of structured storage without the drawback of having to rebuild the table. Instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) is available for both old and new InnoDB tables. Basically you can just upgrade from MySQL 5.x or MariaDB and start adding columns instantly. Columns instantly added to a table exist in a separate data structure from the main table definition, similar to how InnoDB separates `BLOB` columns. If the table ever becomes empty, (such as from [TRUNCATE](../truncate/index) or [DELETE](../delete/index) statements), InnoDB incorporates the instantly added columns into the main table definition. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Non-canonical Storage Format Caused by Some Operations](../innodb-online-ddl-operations-with-algorithminstant/index#non-canonical-storage-format-caused-by-some-operations) for more information. The operation is also crash safe. If the server is killed while executing an instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column), when the table is restored InnoDB integrates the new column, flattening the table definition. Limitations ----------- * In [MariaDB 10.3](../what-is-mariadb-103/index), instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) only applies when the added columns appear last in the table. The place specifier `LAST` is the default. If `AFTER` col is specified, then col must be the last column, or the operation will require the table to be rebuilt. In [MariaDB 10.4](../what-is-mariadb-104/index), this restriction has been lifted. * If the table contains a hidden `FTS_DOC_ID` column due to a [FULLTEXT INDEX](../full-text-indexes/index), then instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) will not be possible. * InnoDB data files after instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) cannot be imported to older versions of MariaDB or MySQL without first being rebuilt. * After using Instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column), any table-rebuilding operation such as [ALTER TABLE … FORCE](../alter-table/index#force) will incorporate instantaneously added columns into the main table body. * Instant [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) is not available for [ROW\_FORMAT=COMPRESSED](../innodb-storage-formats/index#compressed-row-format). * In [MariaDB 10.3](../what-is-mariadb-103/index), [ALTER TABLE … DROP COLUMN](../alter-table/index#drop-column) requires the table to be rebuilt. In [MariaDB 10.4](../what-is-mariadb-104/index), this restriction has been lifted. Example ------- ``` CREATE TABLE t(id INT PRIMARY KEY, u INT UNSIGNED NOT NULL UNIQUE) ENGINE=InnoDB; INSERT INTO t(id,u) VALUES(1,1),(2,2),(3,3); ALTER TABLE t ADD COLUMN (d DATETIME DEFAULT current_timestamp(), p POINT NOT NULL DEFAULT ST_GeomFromText('POINT(0 0)'), t TEXT CHARSET utf8 DEFAULT 'The quick brown fox jumps over the lazy dog'); UPDATE t SET t=NULL WHERE id=3; SELECT id,u,d,ST_AsText(p),t FROM t; SELECT variable_value FROM information_schema.global_status WHERE variable_name = 'innodb_instant_alter_column'; ``` The above example illustrates that when the added columns are declared NOT NULL, a DEFAULT value must be available, either implied by the data type or set explicitly by the user. The expression need not be constant, but it must not refer to the columns of the table, such as DEFAULT u+1 (a MariaDB extension). The DEFAULT current\_timestamp() would be evaluated at the time of the ALTER TABLE and apply to each row, like it does for non-instant ALTER TABLE. If a subsequent ALTER TABLE changes the DEFAULT value for subsequent INSERT, the values of the columns in existing records will naturally be unaffected. The design was brainstormed in April by engineers from MariaDB Corporation, Alibaba and Tencent. A prototype was developed by Vin Chen (陈福荣) from the Tencent Game DBA Team. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql-test Auxiliary Files mysql-test Auxiliary Files ========================== The mysql-test framework utilizes many other files that affect the testing process, in addition to test and result files. --- `disabled.def` file -------------------- This file can be used to disable certain tests temporarily. For example, if one test fails and you are working on that, you may want to push the changeset that disables the test into the test suite so that other tests won't be disturbed by this failure. The file contains test names and a comment (that should explain why the test was disabled), separated by a colon. Lines that start with a hash sign (`#`) are ignored. A typical `disabled.def` may look like this (note that a hash sign in the middle of a line does not start a comment): ``` # List of disabled tests # test name : comment rpl_redirect : Fails due to bug#49978 events_time_zone : need to fix the timing ``` During testing, mtr will print disabled tests like this: ``` ... rpl.rpl_redirect [ disabled ] Fails due to bug#49978 rpl.events_time_zone [ disabled ] need to fix the timing ... ``` This file should be located in the suite directory. --- `suite.opt` file ----------------- This file lists server options that will be added to the `mysqld` command line for every test of this suite. It can refer to environment variables with the `$NAME` syntax. Shell meta-characters should be quoted. For example ``` --plugin-load=$AUTH_PAM_SO --max-connections=40 --net_read_timeout=5 "--replicate-rewrite-db=test->rewrite" ``` Note that options may be put either on one line or on separate lines. It is a good idea to start an option name with the `--loose-` prefix if the server may or may not recognize the option depending on the configuration. An unknown option in the `.opt` file will stop the server from starting, and the test will be aborted. This file should be located in the suite directory. --- other `*.opt` files ------------------- For every test or include file `somefile.test` or `somefile.inc`, mtr will look for `somefile.opt`, `somefile-master.opt` and `somefile-slave.opt`. These files have exactly the same syntax as the `suite.opt` above. Options from these files will also be added to the server command line (all servers started for this test, only master, or only slave respectively) for all affected tests, for example, for all tests that include `somefile.inc` directly or indirectly. A typical usage example is `include/have_blackhole.inc` and `include/have_blackhole.opt`. The latter contains the necessary command-line options to load the Blackhole storage engine, while the former verifies that the engine was really loaded. Any test that needs the Blackhole engine needs only to start from `source include/have_blackhole.inc;` and the engine will be automatically loaded for the test. --- `my.cnf` file -------------- This is not the `my.cnf` file that tests from this suite will use, but rather a *template* of it. It will be converted later to an actual `my.cnf`. If a suite contains no `my.cnf` template, a default template, — `include/default_my.cnf` — will be used. Or `suite/rpl/my.cnf` if the test includes `master-slave.inc` (it's one of the few bits of the old MySQL `mysql-test-run` magic that we have not removed yet). Typically a suite template will not contain a complete server configuration, but rather start from ``` !include include/default_my.cnf ``` and then add the necessary modifications. The syntax of `my.cnf` template is the same of a normal `my.cnf` file, with a few extensions and assumptions. They are: * For any group with the name `[mysqld.**N**]`, where **N** is a number, mtr will start one `mysqld` process. Usually one needs to have only `[mysqld.1]` group, and `[mysqld.2]` group for replication tests. * There can be groups with non-standard names (`[foo]`, `[bar]`, whatever), not used by `mysqld`. The `suite.pm` files (see below) may use them somehow. * Values can refer to each other using the syntax `@groupname.optionname` — these references be expanded as needed. For example ``` [mysqld.2] master-port= @mysqld.1.port ``` * it sets the value of the `master-port` in the `[mysqld.2]` group to the value of `port` in the `[mysqld.1]` group. * An option name may start with a hash sign `#`. In the resulting `my.cnf` it will look like a comment, but it still can be referred to. For example: ``` [example] #location = localhost:@mysqld.1.port bar = server:@example.#location/data ``` * There is the `[ENV]` group. It sets values for the environment variables. For example ``` [ENV] MASTER_MYPORT = @mysqld.1.port ``` * Also, one can refer to values of environment variables via this group: ``` [mysqld.1] user = @ENV.LOGNAME ``` * There is the `[OPT]` group. It allows to invoke functions and generate values. Currently it contains only one option — `@OPT.port`. Every time this option is referred to in some other group in the `my.cnf` template, a new unique port number is generated. It will not match any other port number used by this test run. For example ``` [ENV] SPHINXSEARCH_PORT = @OPT.port ``` This file should be located in the suite directory. --- other `*.cnf` files ------------------- For every test file `somefile.test` (but for not included files) mtr will look for `somefile.cnf` file. If such a file exists, it will be used as a template instead of suite `my.cnf` or a default `include/default_my.cnf` templates. --- `combinations` file -------------------- The `combinations` file defines few sets of alternative configurations, and every test in this suite will be run many times - once for every configuration. This can be used, for example, to run all replication tests in the *rpl* suite for all three binlog format modes (row, statement, and mixed). A corresponding `combinations` file would look as following: ``` [row] binlog-format=row [stmt] binlog-format=statement [mix] binlog-format=mixed ``` It uses `my.cnf` file syntax, with groups (where group names define combination names) and options. But, despite the similarity, it is not a `my.cnf` template, and it cannot use the templating extentions. Instead, options from the `combinations` file are added to the server command line. In this regard, combination file is closer to `suite.opt` file. And just like it, combination file can use environment variables using the `$NAME` syntax. Not all tests will necessarily run for all combinations. A particular test may require to be run only in one specific combination. For example, in replication, if a test can only be run with the row binlog format, it will have `--binlog-format=row` in one of the `.opt` files. In this case, mtr will notice that server command line already has an option that matches one of the combinations, and will skip all other combinations for this particular test. The `combinations` file should be located in the suite directory. --- other `*.combinations` files ---------------------------- Just like with the `*.opt` files, mtr will use `somefile.combinations` file for any `somefile.test` and `somefile.inc` that is used in testing. These files have exactly the same format as a suite `combinations` file. This can cause many combination files affecting one test file (if a test includes two `.inc` files, and both of them have corresponding `.combinations` files). In this case, mtr will run the test for all combinations of combinations from both files. In [MariaDB 5.5](../what-is-mariadb-55/index), for example, `rpl_init.inc` adds combinations for row/statement/mixed, and `have_innodb.inc` adds combinations for innodb/xtradb. Thus any replication test that uses innodb will be run six times. --- `suite.pm` file ---------------- This (optional) file is a perl module. It must declare a package that inherits from `My::Suite`. This file must normally end with `bless {}` — that is it must return an object of that class. It can also return a string — in this case all tests in the suite will be skipped, with this string being printed as a reason (for example "PBXT engine was not compiled"). A suite class can define the following methods: * `config_files()` * `is_default()` * `list_cases()` * `servers()` * `skip_combinations()` * `start_test()` A `config_files()` method returns a list of additional config files (besides `my.cnf`), that this suite needs to be created. For every file it specifies a function that will create it, when given a `My::Config` object. For example: ``` sub config_files {( 'config.ini' => \&write_ini, 'new.conf' => \&do_new )} ``` A `servers()` method returns a list of processes that needs to be started for this suite. A process is specified as a [regex, hash] pair. The regular expression must match a section in the `my.cnf` template (for example, `qr/mysqld\./` corresponds to all `mysqld` processes), the hash contains these options: | | | | --- | --- | | `SORT` | a number. Processes are started in the order of increasing `SORT` values (and stopped in the reverse order). `mysqld` has number 300. | | `START` | a function to start a process. It takes two arguments, `My::Config::Group` and `My::Test`. If `START` is undefined a process will not be started. | | `WAIT` | a function to wait for the process to be started. It takes `My::Config::Group` as an argument. Internally mtr first invokes `START` for all processes, then `WAIT` for all started processes. | ``` sub servers {( qr/^foo$/ => { SORT => 200, # start foo before mysqld START => \&start_foo, WAIT => \&wait_foo } )} ``` See the *sphinx* suite for a working example. A `list_cases()` method returns a complete list of tests for this suite. By default it will be the list of files that have `.test` extension, but without the extension. This list will be filtered by mtr, subject to different mtr options (`--big-test`, `--start-from`, etc), the suite object does not have to do it. A `start_test()` method starts one test process, by default it will be `mysqltest`. See the *unit* suite for a working example of `list_cases()` and `start_test()` methods. A `skip_combinations()` method returns a hash that maps file names (where combinations are defined) to a list of combinations that should be skipped. As a special case, it can disable a complete file by using a string instead of a hash. For example ``` sub skip_combinations {( 'combinations' => [ 'mix', 'rpl' ], 'inc/many.combinations' => [ 'a', 'bb', 'c' ], 'windows.inc' => "Not on windows", )} ``` The last line will cause all tests of this suite that include `windows.inc` to be skipped with the reason being "Not on windows". An `is_default()` method returns 1 if this particular suite should be run by default, when the `mysql-test-run.pl` script is run without explicitly specified test suites or test cases. --- `*.sh` files ------------- For every test file `sometest.test` mtr looks for `sometest-master.sh` and `sometest-slave.sh`. If either of these files is found, it will be run before the test itself. --- `*.require` files ------------------ These files are obsolete. Do not use them anymore. If you need to skip a test use the `skip` command instead. --- `*.rdiff` files ---------------- These files also define what the test result should be. But unlike `*.result` files, they contain a patch that should be applied to one result file to create a new result file. This is very useful when a result of some test in one combination differs slightly from the result of the same test, but in another combination. Or when a result of a test in an overlay differs from the test result in the overlayed suite. It is quite difficult to edit `.rdiff` files to update them after the test file has changed. But luckily, it is never needed. When a test fails, mtr creates a `.reject` file. Having it, one can create `.rdiff` file as easy as (for example) ``` diff -u main/foo.result main/foo.reject > main/foo,comb.rdiff or diff -u main/foo.result main/foo,comb.reject > main/foo,comb.rdiff ``` Some example: ``` diff -u main/innodb_ext_key.result main/innodb_ext_key,off.reject > main/innodb_ext_key,off.rdiff diff -u suite/sys_vars/r/sysvars_server_notembedded.result suite/sys_vars/r/sysvars_server_notembedded,32bit.reject > suite/sys_vars/r/sysvars_server_notembedded,32bit.rdiff ``` Note: This will also add a timestamp in the .rdiff file, so if you are submitting a patch you could remove it manually. If the same .rdiff file is used for multiple combinations, then it would be good to omit in the header that would identify the combination, to allow git to pack the repository better. Example: ``` --- testname.result +++ testname.reject ``` Because a combination can be part of the `.result` or `.rdiff` file name, mtr has to look in many different places for a test result. For example, consider a test `foo.test` in the combination pair `aa,bb`, that is run in the overlay *rty* of the suite *qwe*, in other words, for the test that mtr prints as ``` qwe-rty.foo 'aa,bb' [ pass ] ``` For this test a result can be in * either `.rdiff` or `.result` file * either in the overlay "`rty/`" or in the overlayed suite "`qwe/`" * with or without combinations in the file name ("`,a`", "`,b`", "`,a,b`", or nothing) which means any of the following 15 file names can be used: 1. `rty/r/foo,aa,bb.result` 2. `rty/r/foo,aa,bb.rdiff` 3. `qwe/r/foo,aa,bb.result` 4. `qwe/r/foo,aa,bb.rdiff` 5. `rty/r/foo,aa.result` 6. `rty/r/foo,aa.rdiff` 7. `qwe/r/foo,aa.result` 8. `qwe/r/foo,aa.rdiff` 9. `rty/r/foo,bb.result` 10. `rty/r/foo,bb.rdiff` 11. `qwe/r/foo,bb.result` 12. `qwe/r/foo,bb.rdiff` 13. `rty/r/foo.result` 14. `rty/r/foo.rdiff` 15. `qwe/r/foo.result` They are listed, precisely, in the order of preference, and mtr will walk that list from top to bottom and the first file that is found will be used. If this found file is a `.rdiff`, mtr continues walking down the list until the first `.result` file is found. A `.rdiff` is applied to that `.result`. --- `valgrind.supp` file --------------------- This file defines valgrind suppressions, and it is used when mtr is started with a `--valgrind` option. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Mariabackup Options Mariabackup Options =================== There are a number of options available in `Mariabackup`. List of Options --------------- ### `--apply-log` Prepares an existing backup to restore to the MariaDB Server. This is only valid in `innobackupex` mode, which can be enabled with the `[--innobackupex](#-innobackupex)` option. Files that Mariabackup generates during `[--backup](#-backup)` operations in the target directory are not ready for use on the Server. Before you can restore the data to MariaDB, you first need to prepare the backup. In the case of full backups, the files are not point in time consistent, since they were taken at different times. If you try to restore the database without first preparing the data, InnoDB rejects the new data as corrupt. Running Mariabackup with the `--prepare` command readies the data so you can restore it to MariaDB Server. When working with incremental backups, you need to use the `--prepare` command and the `[--incremental-dir](#-incremental-dir)` option to update the base backup with the deltas from an incremental backup. ``` $ mariabackup --innobackupex --apply-log ``` Once the backup is ready, you can use the `[--copy-back](#-copy-back)` or the `[--move-back](#-move-back)` commands to restore the backup to the server. ### `--apply-log-only` If this option is used when preparing a backup, then only the redo log apply stage will be performed, and other stages of crash recovery will be ignored. This option is used with [incremental backups](../incremental-backup-and-restore-with-mariabackup/index). This option is only supported in [MariaDB 10.1](../what-is-mariadb-101/index). In [MariaDB 10.2](../what-is-mariadb-102/index) and later, this option is not needed or supported. ### `--backup` Backs up your databases. Using this command option, Mariabackup performs a backup operation on your database or databases. The backups are written to the target directory, as set by the `[--target-dir](#-target-dir)` option. ``` $ mariabackup --backup --target-dir /path/to/backup \ --user user_name --password user_passwd ``` Mariabackup can perform full and incremental backups. A full backup creates a snapshot of the database in the target directory. An incremental backup checks the database against a previously taken full backup, (defined by the `[--incremental-basedir](#-incremental-basedir)` option) and creates delta files for these changes. In order to restore from a backup, you first need to run Mariabackup with the `[--prepare](#-prepare)` command option, to make a full backup point-in-time consistent or to apply incremental backup deltas to base. Then you can run Mariabackup again with either the `[--copy-back](#-copy-back)` or `[--move-back](#-move-back)` commands to restore the database. For more information, see [Full Backup and Restore](../full-backup-and-restore-with-mariadb-backup/index) and [Incremental Backup and Restore](../incremental-backup-and-restore-with-mariadb-backup/index). ### `--binlog-info` Defines how Mariabackup retrieves the binary log coordinates from the server. ``` --binlog-info[=OFF | ON | LOCKLESS | AUTO] ``` The `--binlog-info` option supports the following retrieval methods. When no retrieval method is provided, it defaults to `AUTO`. | Option | Description | | --- | --- | | `OFF` | Disables the retrieval of binary log information | | `ON` | Enables the retrieval of binary log information, performs locking where available to ensure consistency | | `LOCKLESS` | Unsupported option | | `AUTO` | Enables the retrieval of binary log information using `ON` or `LOCKLESS` where supported | Using this option, you can control how Mariabackup retrieves the server's binary log coordinates corresponding to the backup. When enabled, whether using `ON` or `AUTO`, Mariabackup retrieves information from the binlog during the backup process. When disabled with `OFF`, Mariabackup runs without attempting to retrieve binary log information. You may find this useful when you need to copy data without metadata like the binlog or replication coordinates. ``` $ mariabackup --binlog-info --backup ``` Currently, the `LOCKLESS` option depends on features unsupported by MariaDB Server. See the description of the `[xtrabackup\_binlog\_pos\_innodb](../files-created-by-mariabackup/index#xtrabackup_binlog_pos_innodb)` file for more information. If you attempt to run Mariabackup with this option, then it causes the utility to exit with an error. ### `--close-files` Defines whether you want to close file handles. Using this option, you can tell Mariabackup that you want to close file handles. Without this option, Mariabackup keeps files open in order to manage DDL operations. When working with particularly large tablespaces, closing the file can make the backup more manageable. However, it can also lead to inconsistent backups. Use at your own risk. ``` $ mariabackup --close-files --prepare ``` ### `--compress` **MariaDB starting with [10.1.31](https://mariadb.com/kb/en/mariadb-10131-release-notes/)** This option is deprecated staring with [MariaDB 10.1.31](https://mariadb.com/kb/en/mariadb-10131-release-notes/) and 10.2.13 as relies on the no longer maintained [QuickLZ](http://www.quicklz.com/) library. It is recommended to instead backup to a stream (stdout), and use a 3rd party compression library to compress the stream, as described in [Using Encryption and Compression Tools With Mariabackup](../using-encryption-and-compression-tools-with-mariabackup/index). Defines the compression algorithm for backup files. ``` --compress[=compression_algorithm] ``` The `--compress` option only supports the now deprecated `quicklz` algorithm. | Option | Description | | --- | --- | | `quicklz` | Uses the QuickLZ compression algorithm | ``` $ mariabackup --compress --backup ``` If a backup is compressed using this option, then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--compress-chunk-size` Deprecated, for details see the `[--compress](#compress)` option. Defines the working buffer size for compression threads. ``` --compress-chunk-size=# ``` Mariabackup can perform compression operations on the backup files before writing them to disk. It can also use multiple threads for parallel data compression during this process. Using this option, you can set the chunk size each thread uses during compression. It defaults to 64K. ``` $ mariabackup --backup --compress \ --compress-threads=12 --compress-chunk-size=5M ``` To further configure backup compression, see the `[--compress](#-compress)` and `[--compress-threads](#-compress-threads)` options. ### `--compress-threads` Deprecated, for details see the `[--compress](#compress)` option. Defines the number of threads to use in compression. ``` --compress-threads=# ``` Mariabackup can perform compression operations on the backup files before writing them to disk. Using this option, you can define the number of threads you want to use for this operation. You may find this useful in speeding up the compression of particularly large databases. It defaults to single-threaded. ``` $ mariabackup --compress --compress-threads=12 --backup ``` To further configure backup compression, see the `[--compress](#-compress)` and `[--compress-chunk-size](#-compress-chunk-size)` options. ### `--copy-back` Restores the backup to the data directory. Using this command, Mariabackup copies the backup from the target directory to the data directory, as defined by the `[--datadir](#-h-datadir)` option. You must stop the MariaDB Server before running this command. The data directory must be empty. If you want to overwrite the data directory with the backup, use the `[--force-non-empty-directories](#-force-non-empty-directories)` option. Bear in mind, before you can restore a backup, you first need to run Mariabackup with the `[--prepare](#-prepare)` option. In the case of full backups, this makes the files point-in-time consistent. With incremental backups, this applies the deltas to the base backup. Once the backup is prepared, you can run `--copy-back` to apply it to MariaDB Server. ``` $ mariabackup --copy-back --force-non-empty-directories ``` Running the `--copy-back` command copies the backup files to the data directory. Use this command if you want to save the backup for later. If you don't want to save the backup for later, use the `[--move-back](#-move-back)` command. ### `--core-file` Defines whether to write a core file. Using this option, you can configure Mariabackup to dump its core to file in the event that it encounters fatal signals. You may find this useful for review and debugging purposes. ``` $ mariabackup --core-file --backup ``` ### `--databases` Defines the databases and tables you want to back up. ``` --databases="database[.table][ database[.table] ...]" ``` Using this option, you can define the specific database or databases you want to back up. In cases where you have a particularly large database or otherwise only want to back up a portion of it, you can optionally also define the tables on the database. ``` $ mariabackup --backup \ --databases="example.table1 example.table2" ``` In cases where you want to back up most databases on a server or tables on a database, but not all, you can set the specific databases or tables you don't want to back up using the `[--databases-exclude](#-databases-exclude)` option. If a backup is a [partial backup](../partial-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. In `innobackupex` mode, which can be enabled with the `[--innobackupex](#-innobackupex)` option, the `--databases` option can be used as described above, or it can be used to refer to a file, just as the `[--databases-file](-databases-file)` option can in the normal mode. ### `--databases-exclude` Defines the databases you don't want to back up. ``` --databases-exclude="database[.table][ database[.table] ...]" ``` Using this option, you can define the specific database or databases you want to exclude from the backup process. You may find it useful when you want to back up most databases on the server or tables on a database, but would like to exclude a few from the process. ``` $ mariabackup --backup \ --databases="example" \ --databases-exclude="example.table1 example.table2" ``` To include databases in the backup, see the `[--databases](#-databases)` option option If a backup is a [partial backup](../partial-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--databases-file` Defines the path to a file listing databases and/or tables you want to back up. ``` --databases-file="/path/to/database-file" ``` Format the databases file to list one element per line, with the following syntax: ``` database[.table] ``` In cases where you need to back up a number of databases or specific tables in a database, you may find the syntax for the `[--databases](#-databases)` and `[--databases-exclude](#-databases-exclude)` options a little cumbersome. Using this option you can set the path to a file listing the databases or databases and tables you want to back up. For instance, imagine you list the databases and tables for a backup in a file called `main-backup`. ``` $ cat main-backup example1 example2.table1 example2.table2 $ mariabackup --backup --databases-file=main-backup ``` If a backup is a [partial backup](../partial-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `-h, --datadir` Defines the path to the database root. ``` --datadir=PATH ``` Using this option, you can define the path to the source directory. This is the directory that Mariabackup reads for the data it backs up. It should be the same as the MariaDB Server `[datadir](../server-system-variables/index#datadir)` system variable. ``` $ mariabackup --backup -h /var/lib64/mysql ``` ### `--debug-sleep-before-unlock` This is a debug-only option used by the Xtrabackup test suite. ### `--decompress` Deprecated, for details see the `[--compress](#compress)` option. This option requires that you have the `qpress` utility installed on your system. Defines whether you want to decompress previously compressed backup files. When you run Mariabackup with the `[--compress](#-compress)` option, it compresses the subsequent backup files, using the QuickLZ algorithm. Using this option, Mariabackup decompresses the compressed files from a previous backup. For instance, run a backup with compression, ``` $ mariabackup --compress --backup ``` Then decompress the backup, ``` $ mariabackup --decompress ``` You can enable the decryption of multiple files at a time using the `[--parallel](#-parallel)` option. By default, Mariabackup does not remove the compressed files from the target directory. If you want to delete these files, use the `[--remove-original](#-remove-original)` option. ### `--debug-sync` Defines the debug sync point. This option is only used by the Mariabackup test suite. ### `--defaults-extra-file` Defines the path to an extra default [option file](../configuring-mariadb-with-option-files/index). ``` --defaults-extra-file=/path/to/config ``` Using this option, you can define an extra default [option file](../configuring-mariadb-with-option-files/index) for Mariabackup. Unlike `[--defaults-file](#-defaults-file)`, this file is read after the default [option files](../configuring-mariadb-with-option-files/index) are read, allowing you to only overwrite the existing defaults. ``` $ mariabackup --backup \ --defaults-file-extra=addition-config.cnf \ --defaults-file=config.cnf ``` ### `--defaults-file` Defines the path to the default [option file](../configuring-mariadb-with-option-files/index). ``` --defaults-file=/path/to/config ``` Using this option, you can define a default [option file](../configuring-mariadb-with-option-files/index) for Mariabackup. Unlike the `[--defaults-extra-file](#-defaults-extra-file)` option, when this option is provided, it completely replaces all default [option files](../configuring-mariadb-with-option-files/index). ``` $ mariabackup --backup \ --defaults-file="config.cnf ``` ### `--defaults-group` Defines the [option group](../configuring-mariadb-with-option-files/index#option-groups) to read in the [option file](../configuring-mariadb-with-option-files/index). ``` --defaults-group="name" ``` In situations where you find yourself using certain Mariabackup options consistently every time you call it, you can set the options in an [option file](../configuring-mariadb-with-option-files/index). The `--defaults-group` option defines what option group Mariabackup reads for its options. Options you define from the command-line can be set in the configuration file using minor formatting changes. For instance, if you find yourself perform compression operations frequently, you might set `[--compress-threads](#-compress-threads)` and `[--compress-chunk-size](#-compress-chunk-size)` options in this way: ``` [mariabackup] compress_threads = 12 compress_chunk_size = 64K ``` Now whenever you run a backup with the `[--compress](#-compress)` option, it always performs the compression using 12 threads and 64K chunks. ``` $ mariabackup --compress --backup ``` See [Mariabackup Overview: Server Option Groups](../mariabackup-overview/index#server-option-groups) and [Mariabackup Overview: Client Option Groups](../mariabackup-overview/index#client-option-groups) for a list of the option groups read by Mariabackup by default. ### `--encrypted-backup` When this option is used with `--backup`, if Mariabackup encounters a page that has a non-zero `key_version` value, then Mariabackup assumes that the page is encrypted. Use `--skip-encrypted-backup` instead to allow Mariabackup to copy unencrypted tables that were originally created before MySQL 5.1.48. This option was added in [MariaDB 10.2.22](https://mariadb.com/kb/en/mariadb-10222-release-notes/), [MariaDB 10.3.13](https://mariadb.com/kb/en/mariadb-10313-release-notes/), and [MariaDB 10.4.2](https://mariadb.com/kb/en/mariadb-1042-release-notes/). ### `--export` If this option is provided during the `--prepare` stage, then it tells Mariabackup to create `.cfg` files for each [InnoDB file-per-table tablespace](../innodb-file-per-table-tablespaces/index). These `.cfg` files are used to [import transportable tablespaces](../innodb-file-per-table-tablespaces/index#copying-transportable-tablespaces) in the process of [restoring partial backups](../partial-backup-and-restore-with-mariabackup/index) and [restoring individual tables and partitions](../restoring-individual-tables-and-partitions-with-mariabackup/index). . ``` $ mariabackup --prepare --export ``` **MariaDB until [10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/)**In [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/) and before, Mariabackup did not support the `[--export](index#-export)` option. See [MDEV-13466](https://jira.mariadb.org/browse/MDEV-13466) about that. In earlier versions of MariaDB, this means that Mariabackup could not create `.cfg` files for [InnoDB file-per-table tablespaces](../innodb-file-per-table-tablespaces/index) during the `--prepare` stage. You can still [import file-per-table tablespaces](../innodb-file-per-table-tablespaces/index#copying-transportable-tablespaces) without the `.cfg` files in many cases, so it may still be possible in those versions to [restore partial backups](../partial-backup-and-restore-with-mariabackup/index) or to [restore individual tables and partitions](../restoring-individual-tables-and-partitions-with-mariabackup/index) with just the `.ibd` files. If you have a [full backup](../full-backup-and-restore-with-mariabackup/index) and you need to create `.cfg` files for [InnoDB file-per-table tablespaces](../innodb-file-per-table-tablespaces/index), then you can do so by preparing the backup as usual without the `--export` option, and then restoring the backup, and then starting the server. At that point, you can use the server's built-in features to [copy the transportable tablespaces](../innodb-file-per-table-tablespaces/index#copying-transportable-tablespaces). ### `--extra-lsndir` Saves an extra copy of the `[xtrabackup\_checkpoints](../files-created-by-mariabackup/index#xtrabackup_checkpoints)` and `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` files into the given directory. ``` --extra-lsndir=PATH ``` When using the `[--backup](#-backup)` command option, Mariabackup produces a number of backup files in the target directory. Using this option, you can have Mariabackup produce additional copies of the `[xtrabackup\_checkpoints](../files-created-by-mariabackup/index#xtrabackup_checkpoints)` and `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` files in the given directory. ``` $ mariabackup --extra-lsndir=extras/ --backup ``` This is especially usefull when using `[--stream](#-stream)` for streaming output, e.g. for [compression and/or encryption using external tools](../using-encryption-and-compression-tools-with-mariabackup/index) in combination with [incremental backups](../incremental-backup-and-restore-with-mariabackup/index), as the `[xtrabackup\_checkpoints](../files-created-by-mariabackup/index#xtrabackup_checkpoints)` file necessary to determine the LSN to continue the incremental backup from is still accessible without uncompressing / decrypting the backup file first. Simply pass in the `--extra-lsndir` of the previous backup as `[--incremental-basedir](#-incremental-basedir)` ### `--force-non-empty-directories` Allows `[--copy-back](#-copy-back)` or `[--move-back](#-move-back)` command options to use non-empty target directories. When using Mariabackup with the `[--copy-back](#-copy-back)` or `[--move-back](#-move-back)` command options, they normally require a non-empty target directory to avoid conflicts. Using this option with either of command allows Mariabackup to use a non-empty directory. ``` $ mariabackup --force-on-empty-directories --copy-back ``` Bear in mind that this option does not enable overwrites. When copying or moving files into the target directory, if Mariabackup finds that the target file already exists, it fails with an error. ### `--ftwrl-wait-query-type` Defines the type of query allowed to complete before Mariabackup issues the global lock. ``` --ftwrl-wait-query-type=[ALL | UPDATE | SELECT] ``` The `--ftwrl-wait-query-type` option supports the following query types. The default value is `ALL`. | Option | Description | | --- | --- | | `ALL` | Waits until all queries complete before issuing the global lock | | `SELECT` | Waits until `[SELECT](../select/index)` statements complete before issuing the global lock | | `UPDATE` | Waits until `[UPDATE](../update/index)` statements complete before issuing the global lock | When Mariabackup runs, it issues a global lock to prevent data from changing during the backup process. When it encounters a statement in the process of executing, it waits until the statement is finished before issuing the global lock. Using this option, you can modify this default behavior to ensure that it waits only for certain query types, such as for `[SELECT](../select/index)` and `[UPDATE](../update/index)` statements. ``` $ mariabackup --backup \ --ftwrl-wait-query-type=UPDATE ``` ### `--ftwrl-wait-threshold` Defines the minimum threshold for identifying long-running queries for FTWRL. ``` --ftwrl-wait-threshold=# ``` When Mariabackup runs, it issues a global lock to prevent data from changing during the backup process and ensure a consistent record. If it encounters statements still in the process of executing, it waits until they complete before setting the lock. Using this option, you can set the threshold at which Mariabackup engages FTWRL. When it `[--ftwrl-wait-timeout](#-ftwrl-wait-timeout)` is not 0 and a statement has run for at least the amount of time given this argument, Mariabackup waits until the statement completes or until the `[--ftwrl-wait-timeout](#-ftwrl-wait-timeout)` expires before setting the global lock and starting the backup. ``` $ mariabackup --backup \ --ftwrl-wait-timeout=90 \ --ftwrl-wait-threshold=30 ``` ### `--ftwrl-wait-timeout` Defines the timeout to wait for queries before trying to acquire the global lock. In [MariaDB 10.4](../what-is-mariadb-104/index) and later, the global lock refers to `[BACKUP STAGE BLOCK\_COMMIT](../backup-stage/index#backup-stage-block_commit)`. In [MariaDB 10.3](../what-is-mariadb-103/index) and before, the global lock refers to `[FLUSH TABLES WITH READ LOCK (FTWRL)](../flush/index#the-purpose-of-flush-tables-table_list-with-read-lock)`. ``` --ftwrl-wait-timeout=# ``` When Mariabackup runs, it acquires a global lock to prevent data from changing during the backup process and ensure a consistent record. If it encounters statements still in the process of executing, it can be configured to wait until the statements complete before trying to acquire the global lock. If the `--ftwrl-wait-timeout` is set to 0, then Mariabackup tries to acquire the global lock immediately without waiting. This is the default value. If the `--ftwrl-wait-timeout` is set to a non-zero value, then Mariabackup waits for the configured number of seconds until trying to acquire the global lock. Starting in [MariaDB 10.5.3](https://mariadb.com/kb/en/mariadb-1053-release-notes/), [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/), [MariaDB 10.3.23](https://mariadb.com/kb/en/mariadb-10323-release-notes/), and [MariaDB 10.2.32](https://mariadb.com/kb/en/mariadb-10232-release-notes/), Mariabackup will exit if it can't acquire the global lock after waiting for the configured number of seconds. In earlier versions, it could wait for the global lock indefinitely, even if `--ftwrl-wait-timeout` was set to a non-zero value. ``` $ mariabackup --backup \ --ftwrl-wait-query-type=UPDATE \ --ftwrl-wait-timeout=5 ``` ### `--galera-info` Defines whether you want to back up information about a [Galera Cluster](../galera/index) node's state. When this option is used, Mariabackup creates an additional file called `[xtrabackup\_galera\_info](../files-created-by-mariabackup/index#xtrabackup_galera_info)`, which records information about a [Galera Cluster](../galera/index) node's state. It records the values of the `[wsrep\_local\_state\_uuid](../galera-cluster-status-variables/index#wsrep_local_state_uuid)` and `[wsrep\_last\_committed](../galera-cluster-status-variables/index#wsrep_last_committed)` status variables. You should only use this option when backing up a [Galera Cluster](../galera/index) node. If the server is not a [Galera Cluster](../galera/index) node, then this option has no effect. ``` $ mariabackup --backup --galera-info ``` ### `--history` Defines whether you want to track backup history in the `PERCONA_SCHEMA.xtrabackup_history` table. ``` --history[=name] ``` When using this option, Mariabackup records its operation in a table on the MariaDB Server. Passing a name to this option allows you group backups under arbitrary terms for later processing and analysis. ``` $ mariabackup --backup --history=backup_all ``` Currently, the table it uses is named `PERCONA_SCHEMA.xtrabackup_history`, but expect that name to change in future releases. See [MDEV-19246](https://jira.mariadb.org/browse/MDEV-19246) for more information. Mariabackup will also record this in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `-H, --host` Defines the host for the MariaDB Server you want to backup. ``` --host=name ``` Using this option, you can define the host to use when connecting to a MariaDB Server over TCP/IP. By default, Mariabackup attempts to connect to the local host. ``` $ mariabackup --backup \ --host="example.com" ``` ### `--include` This option is a regular expression to be matched against table names in databasename.tablename format. It is equivalent to the `[--tables](#-tables)` option. This is only valid in `innobackupex` mode, which can be enabled with the `[--innobackupex](#-innobackupex)` option. ### `--incremental` Defines whether you want to take an increment backup, based on another backup. This is only valid in `innobackupex` mode, which can be enabled with the `[--innobackupex](#-innobackupex)` option. ``` mariabackup --innobackupex --incremental ``` Using this option with the `[--backup](#-backup)` command option makes the operation incremental rather than a complete overwrite. When this option is specified, either the `[--incremental-lsn](#-incremental-lsn) or` [--incremental-basedir](#-incremental-basedir) `options can also be given. If neither option is given, option` [--incremental-basedir](#-incremental-basedir) `is used by default, set to the first timestamped backup directory in the backup base directory.` ``` $ mariabackup --innobackupex --backup --incremental \ --incremental-basedir=/data/backups \ --target-dir=/data/backups ``` If a backup is a [incremental backup](../incremental-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--incremental-basedir` Defines whether you want to take an incremental backup, based on another backup. ``` --incremental-basedir=PATH ``` Using this option with the `[--backup](#-backup)` command option makes the operation incremental rather than a complete overwrite. Mariabackup will only copy pages from `.ibd` files if they are newer than the backup in the specified directory. ``` $ mariabackup --backup \ --incremental-basedir=/data/backups \ --target-dir=/data/backups ``` If a backup is a [incremental backup](../incremental-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--incremental-dir` Defines whether you want to take an incremental backup, based on another backup. ``` --increment-dir=PATH ``` Using this option with `[--prepare](#-prepare)` command option makes the operation incremental rather than a complete overwrite. Mariabackup will apply `.delta` files and log files into the target directory. ``` $ mariabackup --prepare \ --increment-dir=backups/ ``` If a backup is a [incremental backup](../incremental-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--incremental-force-scan` Defines whether you want to force a full scan for incremental backups. When using Mariabackup to perform an incremental backup, this option forces it to also perform a full scan of the data pages being backed up, even when there's bitmap data on the changes. [MariaDB 10.2](../what-is-mariadb-102/index) and later does not support changed page bitmaps, so this option is useless in those versions. See [MDEV-18985](https://jira.mariadb.org/browse/MDEV-18985) for more information. ``` $ mariabackup --backup \ --incremental-basedir=/path/to/target \ --incremental-force-scan ``` ### `--incremental-history-name` Defines a logical name for the backup. ``` --incremental-history-name=name ``` Mariabackup can store data about its operations on the MariaDB Server. Using this option, you can define the logical name it uses in identifying the backup. ``` $ mariabackup --backup \ --incremental-history-name=morning_backup ``` Currently, the table it uses is named `PERCONA_SCHEMA.xtrabackup_history`, but expect that name to change in future releases. See [MDEV-19246](https://jira.mariadb.org/browse/MDEV-19246) for more information. Mariabackup will also record this in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--incremental-history-uuid` Defines a UUID for the backup. ``` --incremental-history-uuid=name ``` Mariabackup can store data about its operations on the MariaDB Server. Using this option, you can define the UUID it uses in identifying a previous backup to increment from. It checks `[--incremental-history-name](#-incremental-history-name)`, `[--incremental-basedir](#-incremental-basedir)`, and `[--incremental-lsn](#-incremental-lsn)`. If Mariabackup fails to find a valid lsn, it generates an error. ``` $ mariabackup --backup \ --incremental-history-uuid=main-backup012345678 ``` Currently, the table it uses is named `PERCONA_SCHEMA.xtrabackup_history`, but expect that name to change in future releases. See [MDEV-19246](https://jira.mariadb.org/browse/MDEV-19246) for more information. Mariabackup will also record this in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--incremental-lsn` Defines the sequence number for incremental backups. ``` --incremental-lsn=name ``` Using this option, you can define the sequence number (LSN) value for `[--backup](#-backup)` operations. During backups, Mariabackup only copies `.ibd` pages newer than the specified values. **WARNING**: Incorrect LSN values can make the backup unusable. It is impossible to diagnose this issue. ### `--innobackupex` Enables `innobackupex` mode, which is a compatibility mode. ``` $ mariabackup --innobackupex ``` In `innobackupex` mode, Mariabackup has the following differences: * To prepare a backup, the `[--apply-log](#-apply-log)` option is used instead of the `[--prepare](#-prepare)` option. * To create an [incremental backup](../incremental-backup-and-restore-with-mariabackup/index), the `[--incremental](#-incremental)` option is supported. * The `[--no-timestamp](#-no-timestamp)` option is supported. * To create a [partial backup](../partial-backup-and-restore-with-mariabackup/index), the `[--include](#--include)` option is used instead of the `[--tables](#-tables)` option. * To create a [partial backup](../partial-backup-and-restore-with-mariabackup/index), the `[--databases](#--databases)` option can still be used, but it's behavior changes slightly. * The `[--target-dir](#-target-dir)` option is not used to specify the backup directory. The backup directory should instead be specified as a standalone argument. The primary purpose of `innobackupex` mode is to allow scripts and tools to more easily migrate to Mariabackup if they were originally designed to use the `innobackupex` utility that is included with [Percona XtraBackup](../percona-xtrabackup-overview/index). It is not recommended to use this mode in new scripts, since it is not guaranteed to be supported forever. See [MDEV-20552](https://jira.mariadb.org/browse/MDEV-20552) for more information. ### `--innodb` This option has no effect. Set only for MySQL option compatibility. ### `--innodb-adaptive-hash-index` Enables InnoDB Adaptive Hash Index. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option you can explicitly enable the InnoDB Adaptive Hash Index. This feature is enabled by default for Mariabackup. If you want to disable it, use `[--skip-innodb-adaptive-hash-index](#-skip-innodb-adaptive-hash-index)`. ``` $ mariabackup --backup \ --innodb-adaptive-hash-index ``` ### `--innodb-autoextend-increment` Defines the increment in megabytes for auto-extending the size of tablespace file. ``` --innodb-autoextend-increment=36 ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can set the increment in megabytes for automatically extending the size of tablespace data file in InnoDB. ``` $ mariabackup --backup \ --innodb-autoextend-increment=35 ``` ### `--innodb-buffer-pool-filename` Using this option has no effect. It is available to provide compatibility with the MariaDB Server. ### `--innodb-buffer-pool-size` Defines the memory buffer size InnoDB uses the cache data and indexes of the table. ``` --innodb-buffer-pool-size=124M ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can configure the buffer pool for InnoDB operations. ``` $ mariabackup --backup \ --innodb-buffer-pool-size=124M ``` ### `--innodb-checksum-algorithm` Defines the checksum algorithm. ``` --innodb-checksum-algorithm=crc32 | strict_crc32 | innodb | strict_innodb | none | strict_none ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can specify the algorithm Mariabackup uses when checksumming on InnoDB tables. Currently, MariaDB supports the following algorithms `CRC32`, `STRICT_CRC32`, `INNODB`, `STRICT_INNODB`, `NONE`, `STRICT_NONE`. ``` $ mariabackup --backup \ ---innodb-checksum-algorithm=strict_innodb ``` ### `--innodb-data-file-path` Defines the path to individual data files. ``` --innodb-data-file-path=/path/to/file ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option you can define the path to InnoDB data files. Each path is appended to the `[--innodb-data-home-dir](#-innodb-data-home-dir)` option. ``` $ mariabackup --backup \ --innodb-data-file-path=ibdata1:13M:autoextend \ --innodb-data-home-dir=/var/dbs/mysql/data ``` ### `--innodb-data-home-dir` Defines the home directory for InnoDB data files. ``` --innodb-data-home-dir=PATH ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option you can define the path to the directory containing InnoDB data files. You can specific the files using the `[--innodb-data-file-path](#-innodb-data-file-path)` option. ``` $ mariabackup --backup \ --innodb-data-file-path=ibdata1:13M:autoextend \ --innodb-data-home-dir=/var/dbs/mysql/data ``` ### `--innodb-doublewrite` Enables doublewrites for InnoDB tables. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. When using this option, Mariabackup improves fault tolerance on InnoDB tables with a doublewrite buffer. By default, this feature is enabled. Use this option to explicitly enable it. To disable doublewrites, use the `[--skip-innodb-doublewrite](#-skip-innodb-doublewrite)` option. ``` $ mariabackup --backup \ --innodb-doublewrite ``` ### `--innodb-encrypt-log` Defines whether you want to encrypt InnoDB logs. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can tell Mariabackup that you want to encrypt logs from its InnoDB activity. ### `--innodb-file-io-threads` Defines the number of file I/O threads in InnoDB. ``` --innodb-file-io-threads=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can define the number of file I/O threads Mariabackup uses on InnoDB tables. ``` $ mariabackup --backup \ --innodb-file-io-threads=5 ``` ### `--innodb-file-per-table` Defines whether you want to store each InnoDB table as an `.ibd` file. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option causes Mariabackup to store each InnoDB table as an `.ibd` file in the target directory. ### `--innodb-flush-method` Defines the data flush method. ``` --innodb-flush-method=fdatasync | O_DSYNC | O_DIRECT | O_DIRECT_NO_FSYNC | ALL_O_DIRECT ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can define the data flush method Mariabackup uses with InnoDB tables. ``` $ mariabackup --backup \ --innodb-flush-method==_DIRECT_NO_FSYNC ``` Note, the `0_DIRECT_NO_FSYNC` method is only available with [MariaDB 10.0](../what-is-mariadb-100/index) and later. The `ALL_O_DIRECT` method available with version 5.5 and later, but only with tables using the XtraDB storage engine. ### `--innodb-io-capacity` Defines the number of IOP's the utility can perform. ``` --innodb-io-capacity=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can limit the I/O activity for InnoDB background tasks. It should be set around the number of I/O operations per second that the system can handle, based on drive or drives being used. ``` $ mariabackup --backup \ --innodb-io-capacity=200 ``` ### `--innodb-log-checksums` Defines whether to include checksums in the InnoDB logs. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can explicitly set Mariabackup to include checksums in the InnoDB logs. The feature is enabled by default. To disable it, use the `[--skip-innodb-log-checksums](#-skip-innodb-log-checksums)` option. ``` $ mariabackup --backup \ --innodb-log-checksums ``` ### `--innodb-log-buffer-size` This option has no functionality in Mariabackup. It exists for MariaDB Server compatibility. ### `--innodb-log-files-in-group` This option has no functionality in Mariabackup. It exists for MariaDB Server compatibility. ### `--innodb-log-group-home-dir` Defines the path to InnoDB log files. ``` --innodb-log-group-home-dir=PATH ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can define the path to InnoDB log files. ``` $ mariabackup --backup \ --innodb-log-group-home-dir=/path/to/logs ``` ### `--innodb-max-dirty-pages-pct` Defines the percentage of dirty pages allowed in the InnoDB buffer pool. ``` --innodb-max-dirty-pages-pct=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can define the maximum percentage of dirty, (that is, unwritten) pages that Mariabackup allows in the InnoDB buffer pool. ``` $ mariabackup --backup \ --innodb-max-dirty-pages-pct=80 ``` ### `--innodb-open-files` Defines the number of files kept open at a time. ``` --innodb-open-files=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can set the maximum number of files InnoDB keeps open at a given time during backups. ``` $ mariabackup --backup \ --innodb-open-files=10 ``` ### `--innodb-page-size` Defines the universal page size. ``` --innodb-page-size=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can define the universal page size in bytes for Mariabackup. ``` $ mariabackup --backup \ --innodb-page-size=16k ``` ### `--innodb-read-io-threads` Defines the number of background read I/O threads in InnoDB. ``` --innodb-read-io-threads=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can set the number of I/O threads MariaDB uses when reading from InnoDB. ``` $ mariabackup --backup \ --innodb-read-io-threads=4 ``` ### `--innodb-undo-directory` Defines the directory for the undo tablespace files. ``` --innodb-undo-directory=PATH ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can define the path to the directory where you want MariaDB to store the undo tablespace on InnoDB tables. The path can be absolute. ``` $ mariabackup --backup \ --innodb-undo-directory=/path/to/innodb_undo ``` ### `--innodb-undo-tablespaces` Defines the number of undo tablespaces to use. ``` --innodb-undo-tablespaces=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can define the number of undo tablespaces you want to use during the backup. ``` $ mariabackup --backup \ --innodb-undo-tablespaces=10 ``` ### `--innodb-use-native-aio` Defines whether you want to use native AI/O. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can enable the use of the native asynchronous I/O subsystem. It is only available on Linux operating systems. ``` $ mariabackup --backup \ --innodb-use-native-aio ``` ### `--innodb-write-io-threads` Defines the number of background write I/O threads in InnoDB. ``` --innodb-write-io-threads=# ``` Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can set the number of background write I/O threads Mariabackup uses. ``` $ mariabackup --backup \ --innodb-write-io-threads=4 ``` ### `--kill-long-queries-timeout` Defines the timeout for blocking queries. ``` --kill-long-queries-timeout=# ``` When Mariabackup runs, it issues a `FLUSH TABLES WITH READ LOCK` statement. It then identifies blocking queries. Using this option you can set a timeout in seconds for these blocking queries. When the time runs out, Mariabackup kills the queries. The default value is 0, which causes Mariabackup to not attempt killing any queries. ``` $ mariabackup --backup \ --kill-long-queries-timeout=10 ``` ### `--kill-long-query-type` Defines the query type the utility can kill to unblock the global lock. ``` --kill-long-query-type=ALL | UPDATE | SELECT ``` When Mariabackup encounters a query that sets a global lock, it can kill the query in order to free up MariaDB Server for the backup. Using this option, you can choose the types of query it kills: `[SELECT](../select/index)`, `[UPDATE](../update/index)`, or both set with `ALL`. The default is `ALL`. ``` $ mariabackup --backup \ --kill-long-query-type=UPDATE ``` ### `--lock-ddl-per-table` Prevents DDL for each table to be backed up by acquiring MDL lock on that. NOTE: Unless --no-lock option was also specified, conflicting DDL queries , will be killed at the end of backup This is done avoid deadlock between "FLUSH TABLE WITH READ LOCK", user's DDL query (ALTER, RENAME), and MDL lock on table. Only available in [MariaDB 10.2.9](https://mariadb.com/kb/en/mariadb-1029-release-notes/) and later. ### `--log` This option has no functionality. It is set to ensure compatibility with MySQL. ### `--log-bin` Defines the base name for the log sequence. ``` --log-bin[=name] ``` Using this option you, you can set the base name for Mariabackup to use in log sequences. ### `--log-copy-interval` Defines the copy interval between checks done by the log copying thread. ``` --log-copy-interval=# ``` Using this option, you can define the copy interval Mariabackup uses between checks done by the log copying thread. The given value is in milliseconds. ``` $ mariabackup --backup \ --log-copy-interval=50 ``` ### `--log-innodb-page-corruption` Continue backup if InnoDB corrupted pages are found. The pages are logged in `innodb_corrupted_pages` and backup is finished with error. [--prepare](#-prepare) will try to fix corrupted pages. If `innodb_corrupted_pages` exists after [--prepare](#-prepare) in base backup directory, backup still contains corrupted pages and can not be considered as consistent. Added in [MariaDB 10.2.37](https://mariadb.com/kb/en/mariadb-10237-release-notes/), [MariaDB 10.3.28](https://mariadb.com/kb/en/mariadb-10328-release-notes/), [MariaDB 10.4.18](https://mariadb.com/kb/en/mariadb-10418-release-notes/), [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/) ### `--move-back` Restores the backup to the data directory. Using this command, Mariabackup moves the backup from the target directory to the data directory, as defined by the `[--datadir](#-h-datadir)` option. You must stop the MariaDB Server before running this command. The data directory must be empty. If you want to overwrite the data directory with the backup, use the `[--force-non-empty-directories](#-force-non-empty-directories)` option. Bear in mind, before you can restore a backup, you first need to run Mariabackup with the `[--prepare](#-prepare)` option. In the case of full backups, this makes the files point-in-time consistent. With incremental backups, this applies the deltas to the base backup. Once the backup is prepared, you can run `--move-back` to apply it to MariaDB Server. ``` $ mariabackup --move-back \ --datadir=/var/mysql ``` Running the `--move-back` command moves the backup files to the data directory. Use this command if you don't want to save the backup for later. If you do want to save the backup for later, use the `[--copy-back](#-copy-back)` command. ### `--mysqld` Used internally to prepare a backup. ### `--no-backup-locks` Mariabackup locks the database by default when it runs. This option disables support for Percona Server's backup locks. When backing up Percona Server, Mariabackup would use backup locks by default. To be specific, backup locks refers to the `LOCK TABLES FOR BACKUP` and `LOCK BINLOG FOR BACKUP` statements. This option can be used to disable support for Percona Server's backup locks. This option has no effect when the server does not support Percona's backup locks. This option may eventually be removed. See [MDEV-19753](https://jira.mariadb.org/browse/MDEV-19753) for more information. ``` $ mariabackup --backup --no-backup-locks ``` ### `--no-lock` Disables table locks with the `FLUSH TABLE WITH READ LOCK` statement. Using this option causes Mariabackup to disable table locks with the `FLUSH TABLE WITH READ LOCK` statement. Only use this option if: * You are not executing DML statements on non-InnoDB tables during the backup. This includes the `mysql` database system tables (which are MyISAM). * You are not executing any DDL statements during the backup. * You **do not care** if the binary log position included with the backup in `[xtrabackup\_binlog\_info](../files-created-by-mariabackup/index#xtrabackup_binlog_info)` is consistent with the data. * **All** tables you're backing up use the InnoDB storage engine. ``` $ mariabackup --backup --no-lock ``` If you're considering `--no-lock` due to backups failing to acquire locks, this may be due to incoming replication events preventing the lock. Consider using the `[--safe-slave-backup](#-safe-slave-backup)` option to momentarily stop the replication slave thread. This alternative may help the backup to succeed without resorting to `--no-lock`. Do not use this option. This option may cause data consistency issues. This option is not supported. ### `--no-timestamp` This option prevents creation of a time-stamped subdirectory of the BACKUP-ROOT-DIR given on the command line. When it is specified, the backup is done in BACKUP-ROOT-DIR instead. This is only valid in `innobackupex` mode, which can be enabled with the `[--innobackupex](#-innobackupex)` option. ### `--no-version-check` Disables version check. Using this option, you can disable Mariabackup version check. ``` $ mariabackup --backup --no-version-check ``` ### `--open-files-limit` Defines the maximum number of file descriptors. ``` --open-files-limit=# ``` Using this option, you can define the maximum number of file descriptors Mariabackup reserves with `setrlimit()`. ``` $ mariabackup --backup \ --open-files-limit= ``` ### `--parallel` Defines the number of threads to use for parallel data file transfer. ``` --parallel=# ``` Using this option, you can set the number of threads Mariabackup uses for parallel data file transfers. By default, it is set to 1. ### `-p, --password` Defines the password to use to connect to MariaDB Server. ``` --password=passwd ``` When you run Mariabackup, it connects to MariaDB Server in order to access and back up the databases and tables. Using this option, you can set the password Mariabackup uses to access the server. To set the user, use the `[--user](#-u-user)` option. ``` $ mariabackup --backup \ --user=root \ --password=root_password ``` ### `--plugin-dir` Defines the directory for server plugins. ``` --plugin-dir=PATH ``` Using this option, you can define the path Mariabackup reads for MariaDB Server plugins. It only uses it during the `[--prepare](#-prepare)` phase to load the encryption plugin. It defaults to the `[plugin\_dir](../server-system-variables/index#plugin_dir)` server system variable. ``` $ mariabackup --backup \ --plugin-dir=/var/mysql/lib/plugin ``` ### `--plugin-load` Defines the encryption plugins to load. ``` --plugin-load=name ``` Using this option, you can define the encryption plugin you want to load. It is only used during the `[--prepare](#-prepare)` phase to load the encryption plugin. It defaults to the server `--plugin-load` option. The option was removed starting from [MariaDB 10.2.18](https://mariadb.com/kb/en/mariadb-10218-release-notes/) ### `-P, --port` Defines the server port to connect to. ``` --port=# ``` When you run Mariabackup, it connects to MariaDB Server in order to access and back up your databases and tables. Using this option, you can set the port the utility uses to access the server over TCP/IP. To set the host, see the `[--host](#-h-host)` option. Use `mysql --help` for more details. ``` $ mariabackup --backup \ --host=192.168.11.1 \ --port=3306 ``` ### `--prepare` Prepares an existing backup to restore to the MariaDB Server. Files that Mariabackup generates during `[--backup](#-backup)` operations in the target directory are not ready for use on the Server. Before you can restore the data to MariaDB, you first need to prepare the backup. In the case of full backups, the files are not point in time consistent, since they were taken at different times. If you try to restore the database without first preparing the data, InnoDB rejects the new data as corrupt. Running Mariabackup with the `--prepare` command readies the data so you can restore it to MariaDB Server. When working with incremental backups, you need to use the `--prepare` command and the `[--incremental-dir](#-incremental-dir)` option to update the base backup with the deltas from an incremental backup. ``` $ mariabackup --prepare ``` Once the backup is ready, you can use the `[--copy-back](#-copy-back)` or the `[--move-back](#-move-back)` commands to restore the backup to the server. ### `--print-defaults` Prints the utility argument list, then exits. Using this argument, MariaDB prints the argument list to stdout and then exits. You may find this useful in debugging to see how the options are set for the utility. ``` $ mariabackup --print-defaults ``` ### `--print-param` Prints the MariaDB Server options needed for copyback. Using this option, Mariabackup prints to stdout the MariaDB Server options that the utility requires to run the `[--copy-back](#-copy-back)` command option. ``` $ mariabackup --print-param ``` ### `--rollback-xa` By default, Mariabackup will not commit or rollback uncommitted XA transactions, and when the backup is restored, any uncommitted XA transactions must be manually committed using `XA COMMIT` or manually rolled back using `XA ROLLBACK`. In [MariaDB 10.2](../what-is-mariadb-102/index), [MariaDB 10.3](../what-is-mariadb-103/index), and [MariaDB 10.4](../what-is-mariadb-104/index), Mariabackup's `--rollback-xa` option can be used to rollback uncommitted XA transactions while performing a `--prepare` operation, so that they do not need to be manually committed or rolled back when the backup is restored. This option is not present from [MariaDB 10.5](../what-is-mariadb-105/index), because the server has more robust ways of handling uncommitted XA transactions in later versions. This is an experimental option. Do not use this option in versions older than [MariaDB 10.2.33](https://mariadb.com/kb/en/mariadb-10233-release-notes/), [MariaDB 10.3.24](https://mariadb.com/kb/en/mariadb-10324-release-notes/), and [MariaDB 10.4.14](https://mariadb.com/kb/en/mariadb-10414-release-notes/). Older implementation can cause corruption of InnoDB data. ### `--rsync` Defines whether to use rsync. During normal operation, Mariabackup transfers local non-InnoDB files using a separate call to `cp` for each file. Using this option, you can optimize this process by performing this transfer with rsync, instead. ``` $ mariabackup --backup --rsync ``` This option is not compatible with the `[--stream](#-stream)` option. ### `--safe-slave-backup` Stops slave SQL threads for backups. When running Mariabackup on a server that uses replication, you may occasionally encounter locks that block backups. Using this option, it stops slave SQL threads and waits until the `Slave_open_temp_tables` in the `SHOW STATUS` statement is zero. If there are no open temporary tables, the backup runs, otherwise the SQL thread starts and stops until there are no open temporary tables. ``` $ mariabackup --backup \ --safe-slave-backup \ --safe-slave-backup-timeout=500 ``` The backup fails if the `Slave_open_temp_tables` doesn't reach zero after the timeout period set by the `[--safe-slave-backup-timeout](#-safe-slave-backup-timeout)` option. ### `--safe-slave-backup-timeout` Defines the timeout for slave backups. ``` --safe-slave-backup-timeout=# ``` When running Mariabackup on a server that uses replication, you may occasionally encounter locks that block backups. With the `[--safe-slave-backup](#-safe-slave-backup)` option, it waits until the `Slave_open_temp_tables` in the `SHOW STATUS` statement reaches zero. Using this option, you set how long it waits. It defaults to 300. ``` $ mariabackup --backup \ --safe-slave-backup \ --safe-slave-backup-timeout=500 ``` ### `--secure-auth` Refuses client connections to servers using the older protocol. Using this option, you can set it explicitly to refuse client connections to the server when using the older protocol, from before 4.1.1. This feature is enabled by default. Use the `[--skip-secure-auth](#-skip-secure-auth)` option to disable it. ``` $ mariabackup --backup --secure-auth ``` ### `--skip-innodb-adaptive-hash-index` Disables InnoDB Adaptive Hash Index. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option you can explicitly disable the InnoDB Adaptive Hash Index. This feature is enabled by default for Mariabackup. If you want to explicitly enable it, use `[--innodb-adaptive-hash-index](#-innodb-adaptive-hash-index)`. ``` $ mariabackup --backup \ --skip-innodb-adaptive-hash-index ``` ### `--skip-innodb-doublewrite` Disables doublewrites for InnoDB tables. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. When doublewrites are enabled, InnoDB improves fault tolerance with a doublewrite buffer. By default this feature is turned on. Using this option you can disable it for Mariabackup. To explicitly enable doublewrites, use the `[--innodb-doublewrite](#-innodb-doublewrite)` option. ``` $ mariabackup --backup \ --skip-innodb-doublewrite ``` ### `--skip-innodb-log-checksums` Defines whether to exclude checksums in the InnoDB logs. Mariabackup initializes its own embedded instance of InnoDB using the same configuration as defined in the configuration file. Using this option, you can set Mariabackup to exclude checksums in the InnoDB logs. The feature is enabled by default. To explicitly enable it, use the `[--innodb-log-checksums](#-innodb-log-checksums)` option. ### `--skip-secure-auth` Refuses client connections to servers using the older protocol. Using this option, you can set it accept client connections to the server when using the older protocol, from before 4.1.1. By default, it refuses these connections. Use the `[--secure-auth](#-secure-auth)` option to explicitly enable it. ``` $ mariabackup --backup --skip-secure-auth ``` ### `--slave-info` Prints the binary log position and the name of the master server. If the server is a [replication slave](../replication/index), then this option causes Mariabackup to print the hostname of the slave's replication master and the [binary log](../binary-log/index) file and position of the [slave's SQL thread](../replication-threads/index#slave-sql-thread) to `stdout`. This option also causes Mariabackup to record this information as a `[CHANGE MASTER](../change-master-to/index)` command that can be used to set up a new server as a slave of the original server's master after the backup has been restored. This information will be written to to the `[xtrabackup\_slave\_info](../files-created-by-mariabackup/index#xtrabackup_slave_info)` file. Mariabackup does **not** check if [GTIDs](../gtid/index) are being used in replication. It takes a shortcut and assumes that if the `[gtid\_slave\_pos](../gtid/index#gtid_slave_pos)` system variable is non-empty, then it writes the `[CHANGE MASTER](../change-master-to/index)` command with the `[MASTER\_USE\_GTID](../change-master-to/index#master_use_gtid)` option set to `slave_pos`. Otherwise, it writes the `[CHANGE MASTER](../change-master-to/index)` command with the `[MASTER\_LOG\_FILE](../change-master-to/index#master_log_file)` and `[MASTER\_LOG\_POS](../change-master-to/index#master_log_pos)` options using the master's [binary log](../binary-log/index) file and position. See [MDEV-19264](https://jira.mariadb.org/browse/MDEV-19264) for more information. ``` $ mariabackup --slave-info ``` ### `-S, --socket` Defines the socket for connecting to local database. ``` --socket=name ``` Using this option, you can define the UNIX domain socket you want to use when connecting to a local database server. The option accepts a string argument. For more information, see the `mysql --help` command. ``` $ mariabackup --backup \ --socket=/var/mysql/mysql.sock ``` ### `--ssl` Enables [TLS](../data-in-transit-encryption/index). By using this option, you can explicitly configure Mariabackup to to encrypt its connection with [TLS](../data-in-transit-encryption/index) when communicating with the server. You may find this useful when performing backups in environments where security is extra important or when operating over an insecure network. TLS is also enabled even without setting this option when certain other TLS options are set. For example, see the descriptions of the following options: * `[--ssl-ca](#-ssl-ca)` * `[--ssl-capath](#-ssl-capath)` * `[--ssl-cert](#-ssl-cert)` * `[--ssl-cipher](#-ssl-cipher)` * `[--ssl-key](#-ssl-key)` ### `--ssl-ca` Defines a path to a PEM file that should contain one or more X509 certificates for trusted Certificate Authorities (CAs) to use for [TLS](../data-in-transit-encryption/index). This option requires that you use the absolute path, not a relative path. For example: ``` --ssl-ca=/etc/my.cnf.d/certificates/ca.pem ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem ``` See [Secure Connections Overview: Certificate Authorities (CAs)](../secure-connections-overview/index#certificate-authorities-cas) for more information. This option implies the `[--ssl](#-ssl)` option. ### `--ssl-capath` Defines a path to a directory that contains one or more PEM files that should each contain one X509 certificate for a trusted Certificate Authority (CA) to use for [TLS](../data-in-transit-encryption/index). This option requires that you use the absolute path, not a relative path. For example: ``` --ssl-capath=/etc/my.cnf.d/certificates/ca/ ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem \ --ssl-capath=/etc/my.cnf.d/certificates/ca/ ``` The directory specified by this option needs to be run through the `[openssl rehash](https://www.openssl.org/docs/man1.1.1/man1/rehash.html)` command. See [Secure Connections Overview: Certificate Authorities (CAs)](../secure-connections-overview/index#certificate-authorities-cas) for more information This option implies the `[--ssl](#-ssl)` option. ### `--ssl-cert` Defines a path to the X509 certificate file to use for [TLS](../data-in-transit-encryption/index). This option requires that you use the absolute path, not a relative path. For example: ``` --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem ``` This option implies the `[--ssl](#-ssl)` option. ### `--ssl-cipher` Defines the list of permitted ciphers or cipher suites to use for [TLS](../data-in-transit-encryption/index). For example: ``` --ssl-cipher=name ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem --ssl-cipher=TLSv1.2 ``` To determine if the server restricts clients to specific ciphers, check the `[ssl\_cipher](../ssltls-system-variables/index#ssl_cipher)` system variable. This option implies the `[--ssl](#-ssl)` option. ### `--ssl-crl` Defines a path to a PEM file that should contain one or more revoked X509 certificates to use for [TLS](../data-in-transit-encryption/index). This option requires that you use the absolute path, not a relative path. For example: ``` --ssl-crl=/etc/my.cnf.d/certificates/crl.pem ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem \ --ssl-crl=/etc/my.cnf.d/certificates/crl.pem ``` See [Secure Connections Overview: Certificate Revocation Lists (CRLs)](../secure-connections-overview/index#certificate-revocation-lists-crls) for more information. This option is only supported if Mariabackup was built with OpenSSL. If Mariabackup was built with yaSSL, then this option is not supported. See [TLS and Cryptography Libraries Used by MariaDB](../tls-and-cryptography-libraries-used-by-mariadb/index) for more information about which libraries are used on which platforms. ### `--ssl-crlpath` Defines a path to a directory that contains one or more PEM files that should each contain one revoked X509 certificate to use for [TLS](../data-in-transit-encryption/index). This option requires that you use the absolute path, not a relative path. For example: ``` --ssl-crlpath=/etc/my.cnf.d/certificates/crl/ ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem \ --ssl-crlpath=/etc/my.cnf.d/certificates/crl/ ``` The directory specified by this option needs to be run through the `[openssl rehash](https://www.openssl.org/docs/man1.1.1/man1/rehash.html)` command. See [Secure Connections Overview: Certificate Revocation Lists (CRLs)](../secure-connections-overview/index#certificate-revocation-lists-crls) for more information. This option is only supported if Mariabackup was built with OpenSSL. If Mariabackup was built with yaSSL, then this option is not supported. See [TLS and Cryptography Libraries Used by MariaDB](../tls-and-cryptography-libraries-used-by-mariadb/index) for more information about which libraries are used on which platforms. ### `--ssl-key` Defines a path to a private key file to use for [TLS](../data-in-transit-encryption/index). This option requires that you use the absolute path, not a relative path. For example: ``` --ssl-key=/etc/my.cnf.d/certificates/client-key.pem ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem ``` This option implies the `[--ssl](#-ssl)` option. ### `--ssl-verify-server-cert` Enables [server certificate verification](../secure-connections-overview/index#server-certificate-verification). This option is disabled by default. This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem \ --ssl-verify-server-cert ``` ### `--stream` Streams backup files to stdout. ``` --stream=xbstream ``` Using this command option, you can set Mariabackup to stream the backup files to stdout in the given format. Currently, the supported format is `xbstream`. ``` $ mariabackup --stream=xbstream > backup.xb ``` To extract all files from the xbstream archive into a directory use the `mbstream` utility ``` $ mbstream -x < backup.xb ``` If a backup is streamed, then Mariabackup will record the format in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--tables` Defines the tables you want to include in the backup. ``` --tables=REGEX ``` Using this option, you can define what tables you want Mariabackup to back up from the database. The table values are defined using Regular Expressions. To define the tables you want to exclude from the backup, see the `[--tables-exclude](#-tables-exclude)` option. ``` $ mariabackup --backup \ --databases=example --tables=nodes_* \ --tables-exclude=nodes_tmp ``` If a backup is a [partial backup](../partial-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--tables-exclude` Defines the tables you want to exclude from the backup. ``` --tables-exclude=REGEX ``` Using this option, you can define what tables you want Mariabackup to exclude from the backup. The table values are defined using Regular Expressions. To define the tables you want to include from the backup, see the `[--tables](#-tables)` option. ``` $ mariabackup --backup \ --databases=example --tables=nodes_* \ --tables-exclude=nodes_tmp ``` If a backup is a [partial backup](../partial-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--tables-file` Defines path to file with tables for backups. ``` --tables-file=/path/to/file ``` Using this option, you can set a path to a file listing the tables you want to back up. Mariabackup iterates over each line in the file. The format is `database.table`. ``` $ mariabackup --backup \ --databases=example \ --tables-file=/etc/mysql/backup-file ``` If a backup is a [partial backup](../partial-backup-and-restore-with-mariabackup/index), then Mariabackup will record that detail in the `[xtrabackup\_info](../files-created-by-mariabackup/index#xtrabackup_info)` file. ### `--target-dir` Defines the destination directory. ``` --target-dir=/path/to/target ``` Using this option you can define the destination directory for the backup. Mariabackup writes all backup files to this directory. Mariabackup will create the directory, if it does not exist (but it will not create the full path recursively, i.e. at least parent directory if the --target-dir must exist= ``` $ mariabackup --backup \ --target-dir=/data/backups ``` ### `--throttle` Defines the limit for I/O operations per second in IOS values. ``` --throttle=# ``` Using this option, you can set a limit on the I/O operations Mariabackup performs per second in IOS values. It is only used during the `[--backup](#-backup)` command option. ### `--tls-version` This option accepts a comma-separated list of TLS protocol versions. A TLS protocol version will only be enabled if it is present in this list. All other TLS protocol versions will not be permitted. For example: ``` --tls-version="TLSv1.2,TLSv1.3" ``` This option is usually used with other TLS options. For example: ``` $ mariabackup --backup \ --ssl-cert=/etc/my.cnf.d/certificates/client-cert.pem \ --ssl-key=/etc/my.cnf.d/certificates/client-key.pem \ --ssl-ca=/etc/my.cnf.d/certificates/ca.pem \ --tls-version="TLSv1.2,TLSv1.3" ``` This option was added in [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/). See [Secure Connections Overview: TLS Protocol Versions](../secure-connections-overview/index#tls-protocol-versions) for more information. ### `-t, --tmpdir` Defines path for temporary files. ``` --tmpdir=/path/tmp[;/path/tmp...] ``` Using this option, you can define the path to a directory Mariabackup uses in writing temporary files. If you want to use more than one, separate the values by a semicolon (that is, `;`). When passing multiple temporary directories, it cycles through them using round-robin. ``` $ mariabackup --backup \ --tmpdir=/data/tmp;/tmp ``` ### `--use-memory` Defines the buffer pool size that is used during the prepare stage. ``` --use-memory=124M ``` Using this option, you can define the buffer pool size for Mariabackup. Use it instead of `buffer_pool_size`. ``` $ mariabackup --prepare \ --use-memory=124M ``` ### `--user` Defines the username for connecting to the MariaDB Server. ``` --user=name -u name ``` When Mariabackup runs it connects to the specified MariaDB Server to get its backups. Using this option, you can define the database user uses for authentication. ``` $ mariabackup --backup \ --user=root \ --password=root_passwd ``` ### `--version` Prints version information. Using this option, you can print the Mariabackup version information to stdout. ``` $ mariabackup --version ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Embedded MariaDB Interface Embedded MariaDB Interface ========================== The embedded MariaDB server, `libmysqld` has the identical interface as the [C client library](../client-library-for-c/index)`libmysqclient`. The normal usage of the embedded server is to use the normal `mysql.h` include file in your application and link with `libmysqld` instead of `libmysqlclient`. The intention is that one should be able to move from a server/client version of MariaDB to a single server version of MariaDB by just changing which library you link with. This means that the embedded C client API only changes when the normal C API changes, usually only between major releases. The only major change required in your application if you are going to use the embedded server is that you have to call the following functions from your application: ``` int mysql_library_init(int argc, char **argv, char **groups) void mysql_library_end(void); ``` This is also safe to do when using the standard C library. Notes ----- * libmysqld.so has many more exported symbols than the C library to allow one to expose and use more parts of MariaDB. In normal applications one should not use them, as they may change between every release. * Before [MariaDB 5.5.60](https://mariadb.com/kb/en/mariadb-5560-release-notes/) ([MariaDB 10.0.35](https://mariadb.com/kb/en/mariadb-10035-release-notes/), [MariaDB 10.1.33](https://mariadb.com/kb/en/mariadb-10133-release-notes/), [MariaDB 10.2.15](https://mariadb.com/kb/en/mariadb-10215-release-notes/), [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/)), the embedded server library did not support SSL when it was used to connect to remote servers. * Starting with [MariaDB 10.5](../what-is-mariadb-105/index) the embedded server library and related test binaries are no longer part of binary tarball release archives. See Also -------- * [mysql\_library\_init](../mysql_library_init/index) * [mysql\_library\_init](http://dev.mysql.com/doc/refman/5.6/en/mysql-library-init.html) in the MySQL documentation. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb LineString Properties LineString Properties ====================== LineString properties | Title | Description | | --- | --- | | [ENDPOINT](../linestring-properties-endpoint/index) | Synonym for ST\_ENDPOINT. | | [GLENGTH](../glength/index) | Length of a LineString value. | | [NumPoints](../linestring-properties-numpoints/index) | Synonym for ST\_NumPoints. | | [PointN](../linestring-properties-pointn/index) | Synonym for PointN. | | [STARTPOINT](../linestring-properties-startpoint/index) | Synonym for ST\_StartPoint. | | [ST\_ENDPOINT](../st_endpoint/index) | Returns the endpoint of a LineString. | | [ST\_NUMPOINTS](../st_numpoints/index) | Returns the number of Point objects in a LineString. | | [ST\_POINTN](../st_pointn/index) | Returns the N-th Point in the LineString. | | [ST\_STARTPOINT](../st_startpoint/index) | Returns the start point of a LineString | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema THREAD_POOL_WAITS Table Information Schema THREAD\_POOL\_WAITS Table ============================================ **MariaDB starting with [10.5](../what-is-mariadb-105/index)**The [Information Schema](../information_schema/index) `THREAD_POOL_WAITS` table was introduced in [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/). The table provides wait counters for the [thread pool](../thread-pool-in-mariadb/index), and contains the following columns: | Column | Description | | --- | --- | | `REASON` | | | `COUNT` | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Storage Engine Development Storage Engine Development =========================== | Title | Description | | --- | --- | | [Storage Engine FAQ](../storage-engine-faq/index) | Are storage engines designed for MySQL compatible with MariaDB? In most cas... | | [Engine-defined New Table/Field/Index Attributes](../engine-defined-new-tablefieldindex-attributes/index) | A storage engine can allow the user to specify additional attributes per index, field, or table. | | [Table Discovery](../table-discovery/index) | Mechanism for an engine to tell the server that the table exists | | [Table Discovery (before 10.0.2)](../table-discovery-before-1002/index) | This page describes the old discovery API, created in MySQL for NDB Cluste... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb InnoDB Strict Mode InnoDB Strict Mode ================== [InnoDB](../innodb/index) strict mode is similar to [SQL strict mode](../sql-mode/index#strict-mode). When it is enabled, certain InnoDB warnings become errors instead. Configuring InnoDB Strict Mode ------------------------------ **MariaDB starting with [10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)**In [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) and later, InnoDB strict mode is enabled by default. InnoDB strict mode can be enabled or disabled by configuring the [innodb\_strict\_mode](../xtradbinnodb-server-system-variables/index#innodb_strict_mode) server system variable. Its global value can be changed dynamically with [SET GLOBAL](../set/index#global-session). For example: ``` SET GLOBAL innodb_strict_mode=ON; ``` Its value for the current session can also be changed dynamically with [SET SESSION](../set/index#global-session). For example: ``` SET SESSION innodb_strict_mode=ON; ``` It can also be set in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index) prior to starting up the server. For example: ``` [mariadb] ... innodb_strict_mode=ON ``` InnoDB Strict Mode Errors ------------------------- ### Wrong Create Options If InnoDB strict mode is enabled, and if a DDL statement is executed and invalid or conflicting [table options](../create-table/index#table-options) are specified, then an error is raised. The error will only be a generic error that says the following: ``` ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") ``` However, more details about the error can be found by executing [SHOW WARNINGS](../show-warnings/index). For example, the error is raised in the following cases: * The [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is set to a non-zero value, but the [ROW\_FORMAT](../create-table/index#row_format) table option is set to some row format other than the [COMPRESSED](../innodb-compressed-row-format/index) row format. For example: ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) KEY_BLOCK_SIZE=4 ROW_FORMAT=DYNAMIC; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: cannot specify ROW_FORMAT = DYNAMIC with KEY_BLOCK_SIZE. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is set to a non-zero value, but the configured value is larger than either `16` or the value of the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) system variable, whichever is smaller. ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) KEY_BLOCK_SIZE=16; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: KEY_BLOCK_SIZE=16 cannot be larger than 8. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is set to a non-zero value, but the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable is not set to `ON`. ``` SET GLOBAL innodb_file_per_table=OFF; SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) KEY_BLOCK_SIZE=4; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: KEY_BLOCK_SIZE requires innodb_file_per_table. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is set to a non-zero value, but it is not set to one of the supported values: [1, 2, 4, 8, 16]. ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) KEY_BLOCK_SIZE=5; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+-----------------------------------------------------------------------+ | Level | Code | Message | +---------+------+-----------------------------------------------------------------------+ | Warning | 1478 | InnoDB: invalid KEY_BLOCK_SIZE = 5. Valid values are [1, 2, 4, 8, 16] | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+-----------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [ROW\_FORMAT](../create-table/index#row_format) table option is set to the [COMPRESSED](../innodb-compressed-row-format/index) row format, but the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable is not set to `ON`. ``` SET GLOBAL innodb_file_per_table=OFF; SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) ROW_FORMAT=COMPRESSED; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: ROW_FORMAT=COMPRESSED requires innodb_file_per_table. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [ROW\_FORMAT](../create-table/index#row_format) table option is set to a value, but it is not set to one of the values supported by InnoDB: [REDUNDANT](../innodb-redundant-row-format/index), [COMPACT](../innodb-compact-row-format/index), [DYNAMIC](../innodb-dynamic-row-format/index), and [COMPRESSED](../innodb-compressed-row-format/index). ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) ROW_FORMAT=PAGE; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: invalid ROW_FORMAT specifier. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * Either the [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is set to a non-zero value or the [ROW\_FORMAT](../create-table/index#row_format) table option is set to the [COMPRESSED](../innodb-compressed-row-format/index) row format, but the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) system variable is set to a value greater than `16k`. ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) ROW_FORMAT=COMPRESSED; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+-----------------------------------------------------------------------+ | Level | Code | Message | +---------+------+-----------------------------------------------------------------------+ | Warning | 1478 | InnoDB: Cannot create a COMPRESSED table when innodb_page_size > 16k. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+-----------------------------------------------------------------------+ 3 rows in set (0.00 sec) ``` * The [DATA DIRECTORY](../create-table/index#data-directoryindex-directory) table option is set, but the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable is not set to `ON`. ``` SET GLOBAL innodb_file_per_table=OFF; SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) DATA DIRECTORY='/mariadb'; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: DATA DIRECTORY requires innodb_file_per_table. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [DATA DIRECTORY](../create-table/index#data-directoryindex-directory) table option is set, but the table is a [temporary table](../create-table/index#create-temporary-table). ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TEMPORARY TABLE tab ( id int PRIMARY KEY, str varchar(50) ) DATA DIRECTORY='/mariadb'; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: DATA DIRECTORY cannot be used for TEMPORARY tables. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [INDEX DIRECTORY](../create-table/index#data-directoryindex-directory) table option is set. ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) INDEX DIRECTORY='/mariadb'; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: INDEX DIRECTORY is not supported | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [PAGE\_COMPRESSED](#page_compressed) table option is set to `1`, so [InnoDB page compression](../compression/index) is enabled, but the [ROW\_FORMAT](../create-table/index#row_format) table option is set to some row format other than the [COMPACT](../innodb-compact-row-format/index) or [DYNAMIC](../innodb-dynamic-row-format/index) row formats. ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) PAGE_COMPRESSED=1 ROW_FORMAT=COMPRESSED; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 140 | InnoDB: PAGE_COMPRESSED table can't have ROW_TYPE=COMPRESSED | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [PAGE\_COMPRESSED](#page_compressed) table option is set to `1`, so [InnoDB page compression](../compression/index) is enabled, but the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable is not set to `ON`. ``` SET GLOBAL innodb_file_per_table=OFF; SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) PAGE_COMPRESSED=1; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 140 | InnoDB: PAGE_COMPRESSED requires innodb_file_per_table. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [PAGE\_COMPRESSED](#page_compressed) table option is set to `1`, so [InnoDB page compression](../compression/index) is enabled, but the [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is also specified. ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) PAGE_COMPRESSED=1 KEY_BLOCK_SIZE=4; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 140 | InnoDB: PAGE_COMPRESSED table can't have key_block_size | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` * The [PAGE\_COMPRESSION\_LEVEL](../create-table/index#page_compression_level) table option is set, but the [PAGE\_COMPRESSED](#page_compressed) table option is set to `0`, so [InnoDB page compression](../compression/index) is disabled. ``` SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) PAGE_COMPRESSED=0 PAGE_COMPRESSION_LEVEL=9; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 140 | InnoDB: PAGE_COMPRESSION_LEVEL requires PAGE_COMPRESSED | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.000 sec) ``` **MariaDB until [10.2](../what-is-mariadb-102/index)**In [MariaDB 10.2](../what-is-mariadb-102/index) and before, the error is raised in the following additional cases: * The [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is set to a non-zero value, but the [innodb\_file\_format](../innodb-system-variables/index#innodb_file_format) system variable is not set to `Barracuda`. ``` SET GLOBAL innodb_file_format='Antelope'; SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) KEY_BLOCK_SIZE=4; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 1478 | InnoDB: KEY_BLOCK_SIZE requires innodb_file_format > Antelope. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.00 sec) ``` * The [ROW\_FORMAT](../create-table/index#row_format) table option is set to either the [COMPRESSED](../innodb-compressed-row-format/index) or the [DYNAMIC](../innodb-dynamic-row-format/index) row format, but the [innodb\_file\_format](../innodb-system-variables/index#innodb_file_format) system variable is not set to `Barracuda`. ``` SET GLOBAL innodb_file_format='Antelope'; SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) ROW_FORMAT=COMPRESSED; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+-----------------------------------------------------------------------+ | Level | Code | Message | +---------+------+-----------------------------------------------------------------------+ | Warning | 1478 | InnoDB: ROW_FORMAT=COMPRESSED requires innodb_file_format > Antelope. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+-----------------------------------------------------------------------+ 3 rows in set (0.00 sec) ``` * The [PAGE\_COMPRESSED](#page_compressed) table option is set to `1`, so [InnoDB page compression](../compression/index) is enabled, but the [innodb\_file\_format](../innodb-system-variables/index#innodb_file_format) system variable is not set to `Barracuda`. ``` SET GLOBAL innodb_file_format='Antelope'; SET SESSION innodb_strict_mode=ON; CREATE OR REPLACE TABLE tab ( id int PRIMARY KEY, str varchar(50) ) PAGE_COMPRESSED=1; SHOW WARNINGS; ERROR 1005 (HY000): Can't create table `db1`.`tab` (errno: 140 "Wrong create options") SHOW WARNINGS; +---------+------+--------------------------------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------------------------------+ | Warning | 140 | InnoDB: PAGE_COMPRESSED requires innodb_file_format > Antelope. | | Error | 1005 | Can't create table `db1`.`tab` (errno: 140 "Wrong create options") | | Warning | 1030 | Got error 140 "Wrong create options" from storage engine InnoDB | +---------+------+--------------------------------------------------------------------+ 3 rows in set (0.00 sec) ``` ### COMPRESSED Row Format If InnoDB strict mode is enabled, and if a table uses the [COMPRESSED](../innodb-compressed-row-format/index) row format, and if the table's [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) is too small to contain a row, then an error is returned by the statement. ### Row Size Too Large If InnoDB strict mode is enabled, and if a table exceeds its row format's [maximum row size](../innodb-row-formats-overview/index#maximum-row-size), then InnoDB will return an error. ``` ERROR 1118 (42000): Row size too large (> 8126). Changing some columns to TEXT or BLOB may help. In current row format, BLOB prefix of 0 bytes is stored inline. ``` See [Troubleshooting Row Size Too Large Errors with InnoDB](../troubleshooting-row-size-too-large-errors-with-innodb/index) for more information. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Encryption Key Management Encryption Key Management ========================= MariaDB's [data-at-rest encryption](../data-at-rest-encryption/index) requires the use of a key management and encryption plugin. These plugins are responsible both for the management of encryption keys and for the actual encryption and decryption of data. MariaDB supports the use of multiple encryption keys. Each encryption key uses a 32-bit integer as a key identifier. If the specific plugin supports key rotation, then encryption keys can also be rotated, which creates a new version of the encryption key. Choosing an Encryption Key Management Solution ---------------------------------------------- How MariaDB manages encryption keys depends on which encryption key management solution you choose. Currently, MariaDB has three options: ### File Key Management Plugin The File Key Management plugin that ships with MariaDB is a basic key management and encryption plugin that reads keys from a plain-text file. It can also serve as example and as a starting point when developing a key management plugin. For more information, see [File Key Management Plugin](../file-key-management-encryption-plugin/index). ### AWS Key Management Plugin The AWS Key Management plugin is a key management and encryption plugin that uses the Amazon Web Services (AWS) Key Management Service (KMS). The AWS Key Management plugin depends on the [AWS SDK for C++](https://github.com/aws/aws-sdk-cpp), which uses the [Apache License, Version 2.0](https://github.com/aws/aws-sdk-cpp/blob/master/LICENSE). This license is not compatible with MariaDB Server's [GPL 2.0 license](../mariadb-license/index), so we are not able to distribute packages that contain the AWS Key Management plugin. Therefore, the only way to currently obtain the plugin is to install it from source. For more information, see [AWS Key Management Plugin](../aws-key-management-encryption-plugin/index). ### Eperi Key Management Plugin The Eperi Key Management plugin is a key management and encryption plugin that uses the [eperi Gateway for Databases](https://eperi.com/database-encryption/). The [eperi Gateway for Databases](https://eperi.com/database-encryption/) stores encryption keys on the key server outside of the database server itself, which provides an extra level of security. The [eperi Gateway for Databases](https://eperi.com/database-encryption/) also supports performing all data encryption operations on the key server as well, but this is optional. For more information, see [Eperi Key Management Plugin](../eperi-key-management-encryption-plugin/index). Using Multiple Encryption Keys ------------------------------ Key management and encryption plugins support using multiple encryption keys. Each encryption key can be defined with a different 32-bit integer as a key identifier. The support for multiple keys opens up some potential use cases. For example, let's say that a hypothetical key management and encryption plugin is configured to provide two encryption keys. One encryption key might be intended for "low security" tables. It could use short keys, which might not be rotated, and data could be encrypted with a fast encryption algorithm. Another encryption key might be intended for "high security" tables. It could use long keys, which are rotated often, and data could be encrypted with a slower, but more secure encryption algorithm. The user would specify the identifier of the key that they want to use for different tables, only using high level security where it's needed. There are two encryption key identifiers that have special meanings in MariaDB. Encryption key `1` is intended for encrypting system data, such as InnoDB redo logs, binary logs, and so on. It must always exist when [data-at-rest encryption](../data-at-rest-encryption/index) is enabled. Encryption key `2` is intended for encrypting temporary data, such as temporary files and temporary tables. It is optional. If it doesn't exist, then MariaDB uses encryption key `1` for these purposes instead. When [encrypting InnoDB tables](../innodb-encryption/index), the key that is used to encrypt tables [can be changed](../innodb-xtradb-encryption-keys/index). When [encrypting Aria tables](../aria-encryption/index), the key that is used to encrypt tables [cannot currently be changed](../aria-encryption-keys/index). Key Rotation ------------ Encryption key rotation is optional in MariaDB Server. Key rotation is only supported if the backend key management service (KMS) supports key rotation, and if the corresponding key management and encryption plugin for MariaDB also supports key rotation. When a key management and encryption plugin supports key rotation, users can opt to rotate one or more encryption keys, which creates a new version of each rotated encryption key. Key rotation allows users to improve data security in the following ways: * If the server is configured to automatically re-encrypt table data with the newer version of the encryption key after the key is rotated, then that prevents an encryption key from being used for long periods of time. * If the server is configured to simultaneously encrypt table data with multiple versions of the encryption key after the key is rotated, then that prevents all data from being leaked if a single encryption key version is compromised. The [InnoDB storage engine](../innodb/index) has [background encryption threads](../innodb-background-encryption-threads/index) that can [automatically re-encrypt pages when key rotations occur](../innodb-background-encryption-threads/index#background-operations). The [Aria storage engine](../aria/index) does [not currently have a similar mechanism to re-encrypt pages in the background when key rotations occur](../aria-encryption-keys/index#key-rotation). ### Support for Key Rotation in Encryption Plugins #### Encryption Plugins with Key Rotation Support * The [AWS Key Management Service (KMS)](https://aws.amazon.com/kms/) supports encryption key rotation, and the corresponding [AWS Key Management Plugin](../aws-key-management-encryption-plugin/index) also supports encryption key rotation. * The [eperi Gateway for Databases](https://eperi.com/database-encryption/) supports encryption key rotation, and the corresponding [Eperi Key Management Plugin](../eperi-key-management-encryption-plugin/index) also supports encryption key rotation. #### Encryption Plugins without Key Rotation Support * The [File Key Management Plugin](../file-key-management-encryption-plugin/index) does not support encryption key rotation, because it does not use a backend key management service (KMS). Encryption Plugin API --------------------- New key management and encryption plugins can be developed using the [encryption plugin API](../encryption-plugin-api/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema TABLES Table Information Schema TABLES Table =============================== The [Information Schema](../information_schema/index) table shows information about the various non-`TEMPORARY` tables (except tables from the `Information Schema` database) and [views](../views/index) on the server. It contains the following columns: | Column | Description | | --- | --- | | `TABLE_CATALOG` | Always `def`. | | `TABLE_SCHEMA` | Database name. | | `TABLE_NAME` | Table name. | | `TABLE_TYPE` | One of `BASE TABLE` for a regular table, `VIEW` for a [view](../views/index), `SYSTEM VIEW` for [Information Schema](../information_schema/index) tables, `SYSTEM VERSIONED` for [system-versioned tables](../system-versioned-tables/index) or `SEQUENCE` for [sequences](../sequences/index). | | `ENGINE` | [Storage Engine](../storage-engines/index). | | `VERSION` | Version number from the table's .frm file | | `ROW_FORMAT` | Row format (see [InnoDB](../xtradbinnodb-storage-formats/index), [Aria](../aria-storage-formats/index) and [MyISAM](../myisam-storage-formats/index) row formats). | | `TABLE_ROWS` | Number of rows in the table. Some engines, such as [XtraDB and InnoDB](../xtradb-and-innodb/index) may store an estimate. | | `AVG_ROW_LENGTH` | Average row length in the table. | | `DATA_LENGTH` | For [InnoDB/XtraDB](../innodb/index), the index size, in pages, multiplied by the page size. For [Aria](../aria/index) and [MyISAM](../myisam/index), length of the data file, in bytes. For [MEMORY](../memory-storage-engine/index), the approximate allocated memory. | | `MAX_DATA_LENGTH` | Maximum length of the data file, ie the total number of bytes that could be stored in the table. Not used in [XtraDB and InnoDB](../innodb/index). | | `INDEX_LENGTH` | Length of the index file. | | `DATA_FREE` | Bytes allocated but unused. For [InnoDB](../xtradb-and-innodb/index) tables in a shared tablespace, the free space of the shared tablespace with small safety margin. An estimate in the case of partitioned tables - see the `[PARTITIONS](../information-schema-partitions-table/index)` table. | | `AUTO_INCREMENT` | Next [AUTO\_INCREMENT](../auto_increment/index) value. | | `CREATE_TIME` | Time the table was created. Some engines just return the `ctime` information from the file system layer here, in that case the value is not necessarily the table creation time but rather the time the file system metadata for it had last changed. | | `UPDATE_TIME` | Time the table was last updated. On Windows, the timestamp is not updated on update, so MyISAM values will be inaccurate. In [InnoDB](../xtradb-and-innodb/index), if shared tablespaces are used, will be NULL, while buffering can also delay the update, so the value will differ from the actual time of the last `UPDATE`, `INSERT` or `DELETE`. | | `CHECK_TIME` | Time the table was last checked. Not kept by all storage engines, in which case will be `NULL`. | | `TABLE_COLLATION` | [Character set and collation](../data-types-character-sets-and-collations/index). | | `CHECKSUM` | Live checksum value, if any. | | `CREATE_OPTIONS` | Extra `[CREATE TABLE](../create-table/index)` options. | | `TABLE_COMMENT` | Table comment provided when MariaDB created the table. | | `MAX_INDEX_LENGTH` | Maximum index length (supported by MyISAM and Aria tables). Added in [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/). | | `TEMPORARY` | Placeholder to signal that a table is a temporary table. Currently always "N", except "Y" for generated information\_schema tables and NULL for [views](../views/index). Added in [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/). | Although the table is standard in the Information Schema, all but `TABLE_CATALOG`, `TABLE_SCHEMA`, `TABLE_NAME`, `TABLE_TYPE`, `ENGINE` and `VERSION` are MySQL and MariaDB extensions. [SHOW TABLES](../show-tables/index) lists all tables in a database. Examples -------- From [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/): ``` SELECT * FROM information_schema.tables WHERE table_schema='test'\G *************************** 1. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: test TABLE_NAME: xx5 TABLE_TYPE: BASE TABLE ENGINE: InnoDB VERSION: 10 ROW_FORMAT: Dynamic TABLE_ROWS: 0 AVG_ROW_LENGTH: 0 DATA_LENGTH: 16384 MAX_DATA_LENGTH: 0 INDEX_LENGTH: 0 DATA_FREE: 0 AUTO_INCREMENT: NULL CREATE_TIME: 2020-11-18 15:57:10 UPDATE_TIME: NULL CHECK_TIME: NULL TABLE_COLLATION: latin1_swedish_ci CHECKSUM: NULL CREATE_OPTIONS: TABLE_COMMENT: MAX_INDEX_LENGTH: 0 TEMPORARY: N *************************** 2. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: test TABLE_NAME: xx4 TABLE_TYPE: BASE TABLE ENGINE: MyISAM VERSION: 10 ROW_FORMAT: Fixed TABLE_ROWS: 0 AVG_ROW_LENGTH: 0 DATA_LENGTH: 0 MAX_DATA_LENGTH: 1970324836974591 INDEX_LENGTH: 1024 DATA_FREE: 0 AUTO_INCREMENT: NULL CREATE_TIME: 2020-11-18 15:56:57 UPDATE_TIME: 2020-11-18 15:56:57 CHECK_TIME: NULL TABLE_COLLATION: latin1_swedish_ci CHECKSUM: NULL CREATE_OPTIONS: TABLE_COMMENT: MAX_INDEX_LENGTH: 17179868160 TEMPORARY: N ... ``` Example with temporary = 'y', from [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/): ``` SELECT * FROM information_schema.tables WHERE temporary='y'\G *************************** 1. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: information_schema TABLE_NAME: INNODB_FT_DELETED TABLE_TYPE: SYSTEM VIEW ENGINE: MEMORY VERSION: 11 ROW_FORMAT: Fixed TABLE_ROWS: NULL AVG_ROW_LENGTH: 9 DATA_LENGTH: 0 MAX_DATA_LENGTH: 9437184 INDEX_LENGTH: 0 DATA_FREE: 0 AUTO_INCREMENT: NULL CREATE_TIME: 2020-11-17 21:54:02 UPDATE_TIME: NULL CHECK_TIME: NULL TABLE_COLLATION: utf8_general_ci CHECKSUM: NULL CREATE_OPTIONS: max_rows=1864135 TABLE_COMMENT: MAX_INDEX_LENGTH: 0 TEMPORARY: Y ... ``` ### View Tables in Order of Size Returns a list of all tables in the database, ordered by size: ``` SELECT table_schema as `DB`, table_name AS `Table`, ROUND(((data_length + index_length) / 1024 / 1024), 2) `Size (MB)` FROM information_schema.TABLES ORDER BY (data_length + index_length) DESC; +--------------------+---------------------------------------+-----------+ | DB | Table | Size (MB) | +--------------------+---------------------------------------+-----------+ | wordpress | wp_simple_history_contexts | 7.05 | | wordpress | wp_posts | 6.59 | | wordpress | wp_simple_history | 3.05 | | wordpress | wp_comments | 2.73 | | wordpress | wp_commentmeta | 2.47 | | wordpress | wp_simple_login_log | 2.03 | ... ``` See Also -------- * [mysqlshow](../mysqlshow/index) * [SHOW TABLE STATUS](../show-table-status/index) * [Finding Tables Without Primary Keys](../getting-started-with-indexes/index#finding-tables-without-primary-keys) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb TIMESTAMPADD TIMESTAMPADD ============ Syntax ------ ``` TIMESTAMPADD(unit,interval,datetime_expr) ``` Description ----------- Adds the integer expression interval to the date or datetime expression datetime\_expr. The unit for interval is given by the unit argument, which should be one of the following values: MICROSECOND, SECOND, MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER, or YEAR. The unit value may be specified using one of keywords as shown, or with a prefix of SQL\_TSI\_. For example, DAY and SQL\_TSI\_DAY both are legal. Before [MariaDB 5.5](../what-is-mariadb-55/index), FRAC\_SECOND was permitted as a synonym for MICROSECOND. Examples -------- ``` SELECT TIMESTAMPADD(MINUTE,1,'2003-01-02'); +-------------------------------------+ | TIMESTAMPADD(MINUTE,1,'2003-01-02') | +-------------------------------------+ | 2003-01-02 00:01:00 | +-------------------------------------+ SELECT TIMESTAMPADD(WEEK,1,'2003-01-02'); +-----------------------------------+ | TIMESTAMPADD(WEEK,1,'2003-01-02') | +-----------------------------------+ | 2003-01-09 | +-----------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.user Table mysql.user Table ================ **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, the [mysql.global\_priv table](../mysqlglobal_priv-table/index) has replaced the `mysql.user` table, and `mysql.user` should be considered obsolete. It is now a [view](../views/index) into `mysql.global_priv` created for compatibility with older applications and monitoring scripts. New tools are supposed to use `INFORMATION_SCHEMA` tables. From [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/), the dedicated `mariadb.sys` user is created as the definer of the view. Previously, `root` was the definer, which resulted in privilege problems when this username was changed ([MDEV-19650](https://jira.mariadb.org/browse/MDEV-19650)). The `mysql.user` table contains information about users that have permission to access the MariaDB server, and their global privileges. The table can be queried and although it is possible to directly update it, it is best to use [GRANT](../grant/index) and [CREATE USER](../create-user/index) for adding users and privileges. Note that the MariaDB privileges occur at many levels. A user may not be granted `create` privilege at the user level, but may still have `create` permission on certain tables or databases, for example. See [privileges](../grant/index) for a more complete view of the MariaDB privilege system. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. The `mysql.user` table contains the following fields: | Field | Type | Null | Key | Default | Description | Introduced | | --- | --- | --- | --- | --- | --- | --- | | `Host` | `char(60)` | NO | PRI | | Host (together with `User` makes up the unique identifier for this account. | | | `User` | `char(80)` | NO | PRI | | User (together with `Host` makes up the unique identifier for this account. | | | `Password` | `longtext` (>= [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/)), `char(41)` (<= [MariaDB 10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/)) | NO | | | Hashed password, generated by the [PASSWORD()](../password/index) function. | | | `Select_priv` | `enum('N','Y')` | NO | | N | Can perform [SELECT](../select/index) statements. | | | `Insert_priv` | `enum('N','Y')` | NO | | N | Can perform [INSERT](../insert/index) statements. | | | `Update_priv` | `enum('N','Y')` | NO | | N | Can perform [UPDATE](../update/index) statements. | | | `Delete_priv` | `enum('N','Y')` | NO | | N | Can perform [DELETE](../delete/index) statements. | | | `Create_priv` | `enum('N','Y')` | NO | | N | Can [CREATE DATABASE's](../create-database/index) or [CREATE TABLE's](../create-table/index). | | | `Drop_priv` | `enum('N','Y')` | NO | | N | Can [DROP DATABASE's](../drop-database/index) or [DROP TABLE's](../drop-table/index). | | | `Reload_priv` | `enum('N','Y')` | NO | | N | Can execute [FLUSH](../flush/index) statements or equivalent [mysqladmin](../mysqladmin/index) commands. | | | `Shutdown_priv` | `enum('N','Y')` | NO | | N | Can shut down the server with [SHUTDOWN](../shutdown/index) or [mysqladmin shutdown](../mysqladmin/index). | | | `Process_priv` | `enum('N','Y')` | NO | | N | Can show information about active processes, via [SHOW PROCESSLIST](../show-processlist/index) or [mysqladmin processlist](../mysqladmin/index). | | | `File_priv` | `enum('N','Y')` | NO | | N | Read and write files on the server, using statements like [LOAD DATA INFILE](../load-data-infile/index) or functions like [LOAD\_FILE()](../load_file/index). Also needed to create [CONNECT](../connect/index) outward tables. MariaDB server must have permission to access those files. | | | `Grant_priv` | `enum('N','Y')` | NO | | N | User can [grant](../grant/index) privileges they possess. | | | `References_priv` | `enum('N','Y')` | NO | | N | Unused | | | `Index_priv` | `enum('N','Y')` | NO | | N | Can create an index on a table using the [CREATE INDEX](../create-index/index) statement. Without the `INDEX` privilege, user can still create indexes when creating a table using the [CREATE TABLE](../create-table/index) statement if the user has have the `CREATE` privilege, and user can create indexes using the [ALTER TABLE](../alter-table/index) statement if they have the `ALTER` privilege. | | | `Alter_priv` | `enum('N','Y')` | NO | | N | Can perform [ALTER TABLE](../alter-table/index) statements. | | | `Show_db_priv` | `enum('N','Y')` | NO | | N | Can list all databases using the [SHOW DATABASES](../show-databases/index) statement. Without the `SHOW DATABASES` privilege, user can still issue the `SHOW DATABASES` statement, but it will only list databases containing tables on which they have privileges. | | | `Super_priv` | `enum('N','Y')` | NO | | N | Can execute superuser statements: [CHANGE MASTER TO](../change-master-to/index), [KILL](../data-manipulation-kill-connection-query/index) (users who do not have this privilege can only `KILL` their own threads), [PURGE LOGS](../sql-commands-purge-logs/index), [SET global system variables](../set/index), or the [mysqladmin debug](../mysqladmin/index) command. Also, this permission allows the user to write data even if the [read\_only](../server-system-variables/index#read_only) startup option is set, enable or disable logging, enable or disable replication on slaves, specify a `DEFINER` for statements that support that clause, connect once after reaching the `MAX_CONNECTIONS`. If a statement has been specified for the [init-connect](../server-system-variables/index#init_connect) mysqld option, that command will not be executed when a user with `SUPER` privileges connects to the server. | | | `Create_tmp_table_priv` | `enum('N','Y')` | NO | | N | Can create temporary tables with the [CREATE TEMPORARY TABLE](../create-table/index) statement. | | | `Lock_tables_priv` | `enum('N','Y')` | NO | | N | Acquire explicit locks using the [LOCK TABLES](../transactions-lock/index) statement; user also needs to have the `SELECT` privilege on a table in order to lock it. | | | `Execute_priv` | `enum('N','Y')` | NO | | N | Can execute [stored procedure](../stored-procedures/index) or functions. | | | `Repl_slave_priv` | `enum('N','Y')` | NO | | N | Accounts used by slave servers on the master need this privilege. This is needed to get the updates made on the master. | | | `Repl_client_priv` | `enum('N','Y')` | NO | | N | Can execute [SHOW MASTER STATUS](../show-master-status/index) and [SHOW SLAVE STATUS](../show-slave-status/index) statements. | | | `Create_view_priv` | `enum('N','Y')` | NO | | N | Can create a view using the [CREATE\_VIEW](../create-view/index) statement. | | | `Show_view_priv` | `enum('N','Y')` | NO | | N | Can show the [CREATE VIEW](../create-view/index) statement to create a view using the [SHOW CREATE VIEW](../show-create-view/index) statement. | | | `Create_routine_priv` | `enum('N','Y')` | NO | | N | Can create stored programs using the [CREATE PROCEDURE](../create-procedure/index) and [CREATE FUNCTION](../create-function/index) statements. | | | `Alter_routine_priv` | `enum('N','Y')` | NO | | N | Can change the characteristics of a stored function using the [ALTER FUNCTION](../alter-function/index) statement. | | | `Create_user_priv` | `enum('N','Y')` | NO | | N | Can create a user using the [CREATE USER](../create-user/index) statement, or implicitly create a user with the [GRANT](../grant/index) statement. | | | `Event_priv` | `enum('N','Y')` | NO | | N | Create, drop and alter [events](../stored-programs-and-views-events/index). | | | `Trigger_priv` | `enum('N','Y')` | NO | | N | Can execute [triggers](../triggers/index) associated with tables the user updates, execute the [CREATE TRIGGER](../create-trigger/index) and [DROP TRIGGER](../drop-trigger/index) statements. | | | `Create_tablespace_priv` | `enum('N','Y')` | NO | | N | | | | `Delete_history_priv` | `enum('N','Y')` | NO | | N | Can delete rows created through [system versioning](../system-versioned-tables/index). | [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/) | | `ssl_type` | `enum('', 'ANY', 'X509', 'SPECIFIED')` | NO | | | TLS type - see [TLS options](../grant/index#per-account-tls-options). | | | `ssl_cipher` | `blob` | NO | | NULL | TLS cipher - see [TLS options](../grant/index#per-account-tls-options). | | | `x509_issuer` | `blob` | NO | | NULL | X509 cipher - see [TLS options](../grant/index#per-account-tls-options). | | | `x509_subject` | `blob` | NO | | NULL | SSL subject - see [TLS options](../grant/index#per-account-tls-options). | | | `max_questions` | `int(11) unsigned` | NO | | 0 | Number of queries the user can perform per hour. Zero is unlimited. See [per-account resource limits](../grant/index#setting-per-account-resources-limits). | | | `max_updates` | `int(11) unsigned` | NO | | 0 | Number of updates the user can perform per hour. Zero is unlimited. See [per-account resource limits](../grant/index#setting-per-account-resources-limits). | | | `max_connections` | `int(11) unsigned` | NO | | 0 | Number of connections the account can start per hour. Zero is unlimited. See [per-account resource limits](../grant/index#setting-per-account-resources-limits). | | | `max_user_connections` | `int(11)` | NO | | 0 | Number of simultaneous connections the account can have. Zero is unlimited. See [per-account resource limits](../grant/index#setting-per-account-resources-limits). | | | `plugin` | `char(64)` | NO | | | Authentication plugin used on connection. If empty, uses the [default](#authentication-plugin). | | | `authentication_string` | `text` | NO | | NULL | Authentication string for the authentication plugin. | | | `password_expired` | `enum('N','Y')` | NO | | N | MySQL-compatibility option, not implemented in MariaDB. | | | `is_role` | `enum('N','Y')` | NO | | N | Whether the user is a [role](../roles/index). | | | `default_role` | `char(80)` | NO | | N | Role which will be enabled on user login automatically. | | | `max_statement_time` | `decimal(12,6)` | NO | | 0.000000 | If non-zero, how long queries can run before being killed automatically. | | | Field | Type | Null | Key | Default | Description | Introduced | The [Acl\_roles](../server-status-variables/index#acl_roles) status variable indicates how many rows the `mysql.user` table contains where `is_role='Y'`. The [Acl\_users](../server-status-variables/index#acl_users) status variable, indicates how many rows the `mysql.user` table contains where `is_role='N'`. ### Authentication Plugin When the `plugin` column is empty, MariaDB defaults to authenticating accounts with either the `[mysql\_native\_password](../authentication-plugin-mysql_native_password/index)` or the `[mysql\_old\_password](../authentication-plugin-mysql_old_password/index)` plugins. It decides which based on the hash used in the value for the `Password` column. When there's no password set or when the 4.1 password hash is used, (which is 41 characters long), MariaDB uses the `[mysql\_native\_password](../authentication-plugin-mysql_native_password/index)` plugin. The `[mysql\_old\_password](../authentication-plugin-mysql_old_password/index)` plugin is used with pre-4.1 password hashes, (which are 16 characters long). MariaDB also supports the use of alternative [authentication plugins](../authentication-plugins/index). When the `plugin` column is not empty for the given account, MariaDB uses it to authenticate connection attempts. The specific plugin then uses the value of either the `Password` column or the `authentication_string` column to authenticate the user. A specific authentication plugin can be used for an account by providing the `IDENTIFIED VIA authentication_plugin` clause with the [CREATE USER](../create-user/index), [ALTER USER](../alter-user/index), or [GRANT](../grant/index) statements. For example, the following statement would create an account that authenticates with the [PAM authentication plugin](../authentication-plugin-pam/index): ``` CREATE USER foo2@test IDENTIFIED VIA pam; ``` If the specific authentication plugin uses the `authentication_string` column, then this value for the account can be specified after a `USING` or `AS` keyword. For example, the [PAM authentication plugin](../authentication-plugin-pam/index) accepts a [service name](../authentication-plugin-pam/index#configuring-the-pam-service) that would go into the `authentication_string` column for the account: ``` CREATE USER foo2@test IDENTIFIED VIA pam USING 'mariadb'; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Moving Data Between SQL Server and MariaDB Moving Data Between SQL Server and MariaDB ========================================== There are several ways to move data between SQL Server and MariaDB. Here we will discuss them and we will highlight some caveats. Moving Data Definition from SQL Server to MariaDB ------------------------------------------------- To copy SQL Server data structures to MariaDB, one has to: 1. Generate a CSV file from SQL Server data. 2. Modify the syntax so that it works in MariaDB. 3. Run the file in MariaDB. ### Variables That Affect DDL Statements DDL statements are affected by some server system variables. [sql\_mode](../sql-mode/index) determines the behavior of some SQL statements and expressions, including how strict error checking is, and some details regarding the syntax. Objects like [stored procedures](../stored-procedures/index), [stored functions](../stored-functions/index) [triggers](../triggers/index) and [views](../views/index), are always executed with the sql\_mode that was in effect during their creation. [sql\_mode='MSSQL'](../sql_modemssql/index) can be used to have MariaDB behaving as close to SQL Server as possible. [innodb\_strict\_mode](../innodb-system-variables/index#innodb_strict_mode) enables the so-called InnoDB strict mode. Normally some errors in the [CREATE TABLE](../create-table/index) options are ignored. When InnoDB strict mode is enabled, the creation of InnoDB tables will fail with an error when certain mistakes are made. [updatable\_views\_with\_limit](../server-system-variables/index#updatable_views_with_limit) determines whether view updates can be made with an [UPDATE](../update/index) or [DELETE](../delete/index) statement with a `LIMIT` clause if the view does not contain all primary or not null unique key columns from the underlying table. ### Dumps and sys.sql\_modules SQL Server Management Studio allows one to create a working SQL script to recreate a database - something that MariaDB users refer to as a *dump*. Several options allow fine-tuning the generated syntax. It could be necessary to adjust some of these options to make the output compatible with MariaDB. It is possible to export schemas, data or both. One can create a single global file, or one file for each exported object. Normally, producing a single file is more practical. Alternatively, the [sp\_helptext()](https://docs.microsoft.com/en-us/sql/relational-databases/system-stored-procedures/sp-helptext-transact-sql) procedure returns information about how to recreate a certain object. Similar information is also present in the [sql\_modules](https://docs.microsoft.com/en-us/sql/relational-databases/system-catalog-views/sys-sql-modules-transact-sql) table (`definition` column), in the `sys` schema. Such information, however, is not a ready-to-use set of SQL statements. Remember however that [MariaDB does not support schemas](../understanding-mariadb-architecture/index#databases). An SQL Server schema is approximately a MariaDB database. To execute a dump, we can pass the file to [mysql](../mysql-command-line-client/index), the MariaDB command-line client. Provided that a dump file contains syntax that is valid in MariaDB, it can be executed in this way: ``` mysql --show-warnings < dump.sql ``` `--show-warnings` tells MariaDB to output any warnings produced by the statements contained in the dump. Without this option, warnings will not appear on screen. Warnings don't stop the dump execution. Errors will appear on screen. Errors will stop the dump execution, unless the `--force` option (or just `-f`) is specified. For other `mysql` options, see [mysql Command-line Client Options](../mysql-command-line-client/index#options). Another way to achieve the same purpose is to start the `mysql` client in interactive mode first, and then run the `source` command. For example: ``` root@d5a54a082d1b:/# mysql -uroot -psecret Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 22 Server version: 10.4.7-MariaDB-1:10.4.7+maria~bionic mariadb.org binary distribution Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> \W Show warnings enabled. MariaDB [(none)]> source dump.sql ``` In this case, to show warnings we used the `\W` command, where "w" is uppercase. To hide warnings (which is the default), we can use `\w` (lowercase). For other `mysql` commands, see [mysql Commands](../mysql-command-line-client/index#mysql-commands). ### CSV Data If the table structures are already in MariaDB, we need only to import table data. While this can still be done as explained above, it may be more practical to export CSV files from SQL Server and import them into MariaDB. SQL Server Management Studio and several other Microsoft tools allow one to export CSV files. MariaDB allows importing CSV files with the [LOAD DATA INFILE](../load-data-infile/index) statement, which is essentially the MariaDB equivalent of `BULK INSERT`. It can happen that we don't want to import the whole data, but some filtered or transformed version of it. In that case, we may prefer to use the [CONNECT](../connect/index) storage engine to access CSV files and query them. The results of a query can be inserted into a table using [INSERT SELECT](../insert-select/index). Moving Data from MariaDB to SQL Server -------------------------------------- There are several ways to move data from MariaDB to SQL Server: * If the tables don't exist at all in SQL Server, we need to generate a dump first. The dump can include data or not. * If the tables are already in SQL Server, we can use CSV files instead of dumps to move the rows. CSV files are the most concise format to move data between different technologies. * With the tables already in SQL Server, another way to move data is to insert the rows into [CONNECT](../connect/index) tables that "point" to remote SQL Server tables. ### Using a Dump (Structure) [mysqldump](../mysqldump/index) can be used to generate dumps of all databases, a specified database, or a set of tables. It is even possible to only dump a set of rows by specifying the `WHERE` clause. By specifying the `--no-data` option we can dump the table structures without data. `--compatible=mssql` will produce an output that should be usable in SQL Server. ### Using a Dump (Data) mysqldump by default produces an output with both data and structure. `--no-create-info` can be used to skip the [CREATE TABLE](../create-table/index) statements. `--compatible=mssql` will produce an output that should be usable in SQL Server. `--single-transaction` should be specified to select the source data in a single transaction, so that a consistent dump is produced. `--quick` speeds up the dump process when dumping big tables. ### Using a CSV File CSV files can also be used to export data to SQL Server. There are several ways to produce CSV files from MariaDB: * The [SELECT INTO OUTFILE](../select-into-outfile/index) statement. * The [CONNECT](../connect/index) storage engine, with the [CSV table type](../connect-csv-and-fmt-table-types/index). * The [CSV](../csv/index) storage engine (note that it doesn't support `NULL` and indexes). ### Using CONNECT Tables The [CONNECT](../connect/index) storage engine allows one to access external data, in many forms: * [Data files](../connect-table-types-data-files/index) ([CSV](../connect-csv-and-fmt-table-types/index), [JSON](../connect-json-table-type/index), [XML](../connect-xml-table-type/index), HTML and more). * Remote databases, using the [ODBC](../connect-odbc-table-type-accessing-tables-from-another-dbms/index) or [JDBC](../connect-jdbc-table-type-accessing-tables-from-another-dbms/index) standards, or [MariaDB/MySQL native protocol](../connect-mysql-table-type-accessing-mysqlmariadb-tables/index). * Some [special data sources](../connect-table-types-special-virtual-tables/index). `CONNECT` was mentioned previously because it could allow one to read a CSV file and query it in SQL, filtering and transforming the data that we want to move into regular MariaDB tables. However, `CONNECT` can also access remote SQL Server tables. We can read data from it, or even write data. To enable `CONNECT` to work with SQL Server, we need to fulfill these requirements: * Install the ODBC driver, downloadable form [Microsoft](https://microsoft.com/) website. The driver is also available for Linux and MacOS. * Install [unixODBC](http://www.unixodbc.org/). * [Install `CONNECT`](../installing-the-connect-storage-engine/index) (unless it is already installed). Here is an example of a `CONNECT` table that points to a SQL Server table: ``` CREATE TABLE city ( id INT PRIMARY KEY, city_name VARCHAR(100), province_id INT NOT NULL ) ENGINE=CONNECT, TABLE_TYPE=ODBC, TABNAME='city' CONNECTION='Driver=SQL Server Native Client 13.0;Server=sql-server-hostname;Database=world;UID=mariadb_connect;PWD=secret'; ``` The key points here are: * `ENGINE=CONNECT` tells MariaDB that we want to create a `CONNECT` table. * `TABLE_TYPE` must be 'ODBC', so `CONNECT` knows what type of data source it has to use. * `CONNECTION` is the connection string to use, including server address, username and password. * `TABNAME` tells `CONNECT` what the remote table is called. The local name could be different. `CONNECT` is able to query SQL Server to find out the remote table structure. We can use this feature to avoid specifying the column names and types: ``` CREATE TABLE city ENGINE=CONNECT, TABLE_TYPE=ODBC, TABNAME='city' CONNECTION='Driver=SQL Server Native Client 13.0;Server=sql-server-hostname;Database=world;UID=mariadb_connect;PWD=secret'; ``` However, we may prefer to manually specify the MariaDB types, sizes and character sets to use. ### Linked Server Instead of using MariaDB `CONNECT`, it is possible to use SQL Server Linked Server functionality. This will allow one to read data from a remote MariaDB database and copy it into local SQL Server tables. However, note that `CONNECT` allows more control on [types and character sets](../sql-server-and-mariadb-types-comparison/index) mapping. Refer to [Linked Servers](https://docs.microsoft.com/en-us/sql/relational-databases/linked-servers/linked-servers-database-engine?view=sql-server-ver15) section in Microsoft documentation. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Environment Variables MariaDB Environment Variables ============================= MariaDB makes use of numerous environment variables that may be set on your system. Environment variables have the lowest precedence, so any options set on the command line or in an option file will take precedence. It's usually better not to rely on environment variables, and to rather set the options you need directly, as this makes the system a little more robust and easy to administer. Here is a list of environment variables used by MariaDB. | Environment Variable | Description | | --- | --- | | CXX | Name of the C++ compiler, used for running CMake. | | CC | Name of the C compiler, used for running CMake. | | DBI\_USER | Perl DBI default username. | | DBI\_TRACE | Perl DBI trace options. | | HOME | Default directory for the [mysql\_history file](../mysql-command-line-client/index#the-mysql_history-file). | | MYSQL\_DEBUG | Debug trace options used when debugging. | | MYSQL\_GROUP\_SUFFIX | In addition to the given option groups, also read groups with this suffix. | | MYSQL\_HISTFILE | Path to the [mysql\_history file](../mysql-command-line-client/index#the-mysql_history-file), overriding the $HOME/.mysql\_history setting. | | MYSQL\_HOME | Path to the directory containing the [my.cnf file](../configuring-mariadb-with-mycnf/index) used by the server. | | MYSQL\_HOST | Default host name used by the [mysql command line client](../mysql-client/index). | | MYSQL\_PS1 | Command prompt for use by the [mysql command line client](../mysql-client/index). | | MYSQL\_PWD | Default password when connecting to mysqld. It is strongly recommended to use a more secure method of sending the password to the server. | | MYSQL\_TCP\_PORT | Default TCP/IP port number. | | MYSQL\_UNIX\_PORT | On Unix, default socket file used for localhost connections. | | PATH | Path to directories that hold executable programs (such as the [mysql client](../mysql-client/index), [mysqladmin](../mysqladmin/index)), so that these can be run from any location. | | TMPDIR | Directory where temporary files are created. | | TZ | Local [time zone](../time-zones/index). | | UMASK | Creation mode when creating files. See [Specifying Permissions for Schema (Data) Directories and Tables](../specifying-permissions-for-schema-data-directories-and-tables/index). | | UMASK\_DIR | Creation mode when creating directories. See [Specifying Permissions for Schema (Data) Directories and Tables](../specifying-permissions-for-schema-data-directories-and-tables/index). | | USER | On Windows, up to [MariaDB 5.5](../what-is-mariadb-55/index), the default user name when connecting to the mysqld server. API GetUserName() is used in later versions. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHOW OPEN TABLES SHOW OPEN TABLES ================ Syntax ------ ``` SHOW OPEN TABLES [FROM db_name] [LIKE 'pattern' | WHERE expr] ``` Description ----------- `SHOW OPEN TABLES` lists the non-`TEMPORARY` tables that are currently open in the table cache. See <http://dev.mysql.com/doc/refman/5.1/en/table-cache.html>. The `FROM` and `LIKE` clauses may be used. The `FROM` clause, if present, restricts the tables shown to those present in the `db_name` database. The `LIKE` clause, if present on its own, indicates which table names to match. The `WHERE` and `LIKE` clauses can be given to select rows using more general conditions, as discussed in [Extended SHOW](../extended-show/index). The following information is returned: | Column | Description | | --- | --- | | Database | Database name. | | Name | Table name. | | In\_use | Number of table instances being used. | | Name\_locked | `1` if the table is name-locked, e.g. if it is being dropped or renamed, otherwise `0`. | Before [MariaDB 5.5](../what-is-mariadb-55/index), each use of, for example, [LOCK TABLE ... WRITE](../lock-tables-and-unlock-tables/index) would increment `In_use` for that table. With the implementation of the metadata locking improvements in [MariaDB 5.5](../what-is-mariadb-55/index), `LOCK TABLE... WRITE` acquires a strong MDL lock, and concurrent connections will wait on this MDL lock, so any subsequent `LOCK TABLE... WRITE` will not increment `In_use`. Example ------- ``` SHOW OPEN TABLES; +----------+---------------------------+--------+-------------+ | Database | Table | In_use | Name_locked | +----------+---------------------------+--------+-------------+ ... | test | xjson | 0 | 0 | | test | jauthor | 0 | 0 | | test | locks | 1 | 0 | ... +----------+---------------------------+--------+-------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHOW PROFILES SHOW PROFILES ============= Syntax ------ ``` SHOW PROFILES ``` Description ----------- The `SHOW PROFILES` statement displays profiling information that indicates resource usage for statements executed during the course of the current session. It is used together with `[SHOW PROFILE](../show-profile/index)`. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Upgrading from MariaDB 5.5 to MariaDB 10.0 Upgrading from MariaDB 5.5 to MariaDB 10.0 ========================================== What You Need to Know --------------------- There are no changes in table or index formats between [MariaDB 5.5](../what-is-mariadb-55/index) and [MariaDB 10.0](../what-is-mariadb-100/index), so on most servers the upgrade should be painless. ### How to Upgrade For Windows, see [Upgrading MariaDB on Windows](../upgrading-mariadb-on-windows/index) instead. For MariaDB Galera Cluster, see [Upgrading from MariaDB Galera Cluster 5.5 to MariaDB Galera Cluster 10.0](../upgrading-from-mariadb-galera-cluster-55-to-mariadb-galera-cluster-100/index) instead. Before you upgrade, it would be best to take a backup of your database. This is always a good idea to do before an upgrade. We would recommend [Percona XtraBackup](../backup-restore-and-import-clients-percona-xtrabackup/index). The suggested upgrade procedure is: 1. Modify the repository configuration, so the system's package manager installs [MariaDB 10.0](../what-is-mariadb-100/index). For example, * On Debian, Ubuntu, and other similar Linux distributions, see [Updating the MariaDB APT repository to a New Major Release](../installing-mariadb-deb-files/index#updating-the-mariadb-apt-repository-to-a-new-major-release) for more information. * On RHEL, CentOS, Fedora, and other similar Linux distributions, see [Updating the MariaDB YUM repository to a New Major Release](../yum/index#updating-the-mariadb-yum-repository-to-a-new-major-release) for more information. * On SLES, OpenSUSE, and other similar Linux distributions, see [Updating the MariaDB ZYpp repository to a New Major Release](../installing-mariadb-with-zypper/index#updating-the-mariadb-zypp-repository-to-a-new-major-release) for more information. 2. Set `[innodb\_fast\_shutdown](../xtradbinnodb-server-system-variables/index#innodb_fast_shutdown)` to `0`. It can be changed dynamically with `[SET GLOBAL](../set/index#global-session)`. For example: `SET GLOBAL innodb_fast_shutdown=0;` 3. [Stop MariaDB](../starting-and-stopping-mariadb-automatically/index). 4. Uninstall the old version of MariaDB. * On Debian, Ubuntu, and other similar Linux distributions, execute the following: `sudo apt-get remove mariadb-server` * On RHEL, CentOS, Fedora, and other similar Linux distributions, execute the following: `sudo yum remove MariaDB-server` * On SLES, OpenSUSE, and other similar Linux distributions, execute the following: `sudo zypper remove MariaDB-server` 5. Install the new version of MariaDB. * On Debian, Ubuntu, and other similar Linux distributions, see [Installing MariaDB Packages with APT](../installing-mariadb-deb-files/index#installing-mariadb-packages-with-apt) for more information. * On RHEL, CentOS, Fedora, and other similar Linux distributions, see [Installing MariaDB Packages with YUM](../yum/index#installing-mariadb-packages-with-yum) for more information. * On SLES, OpenSUSE, and other similar Linux distributions, see [Installing MariaDB Packages with ZYpp](../installing-mariadb-with-zypper/index#installing-mariadb-packages-with-zypp) for more information. 6. Make any desired changes to configuration options in [option files](../configuring-mariadb-with-option-files/index), such as `my.cnf`. This includes removing any options that are no longer supported. 7. [Start MariaDB](../starting-and-stopping-mariadb-automatically/index). 8. Run `[mysql\_upgrade](../mysql_upgrade/index)`. * `mysql_upgrade` does two things: 1. Ensures that the system tables in the `[mysq](../the-mysql-database-tables/index)l` database are fully compatible with the new version. 2. Does a very quick check of all tables and marks them as compatible with the new version of MariaDB . ### Incompatible Changes Between 5.5 and 10.0 As mentioned previously, on most servers upgrading from 5.5 should be painless. However, there are some things that have changed which could affect an upgrade: #### Options That Have Changed Default Values Most of the following options have increased a bit in value to give better performance. They should not use much additional memory, but some of them a do use a bit more disk space. [[1](#_note-0)] | Option | Old default value | New default value | | --- | --- | --- | | `[aria-sort-buffer-size](../aria-system-variables/index#aria_sort_buffer_size)` | `128M` | `256M` | | `[back\_log](../server-system-variables/index#back_log)` | `50` | `150` | | `[innodb-buffer-pool-instances](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_instances)` | `1` | `8` (except on 32-bit Windows) | | `[innodb-concurrency-tickets](../xtradbinnodb-server-system-variables/index#innodb_concurrency_tickets)` | `500` | `5000` | | `[innodb-log-file-size](../xtradbinnodb-server-system-variables/index#innodb_log_file_size)` | `5M` | `48M` | | `[innodb-old-blocks-time](../xtradbinnodb-server-system-variables/index#innodb_old_blocks_time)` | `0` | `1000` | | `[innodb-open-files](../xtradbinnodb-server-system-variables/index#innodb_open_files)` | `300` | `400` [[2]](#_note-1) | | `[innodb-purge-batch-size](../xtradbinnodb-server-system-variables/index#innodb_purge_batch_size)` | `20` | `300` | | `[innodb-undo-logs](../xtradbinnodb-server-system-variables/index#innodb_undo_logs)` | `ON` | `20` | | `[max-connect-errors](../server-system-variables/index#max_connect_errors)` | `10` | `100` | | `[max-relay-log-size](../server-system-variables/index#max_relay_log_size)` | `0` | `1024M` | | `[myisam-sort-buffer-size](../myisam-server-system-variables/index#myisam_sort_buffer_size)` | `8M` | `128M` | | `[optimizer-switch](../server-system-variables/index#optimizer_switch)` | ... | Added `extended_keys=on, exists_to_in=on` | #### Options That Have Been Removed or Renamed The following options should be removed or renamed if you use them in your config files: | Option | Reason | | --- | --- | | `engine-condition-pushdown` | Replaced with `[set optimizer\_switch='engine\_condition\_pushdown=on'](../index-condition-pushdown/index)` | | `innodb-adaptive-flushing-method` | Removed by [XtraDB](../xtradb/index) | | `innodb-autoextend-increment` | Removed by [XtraDB](../xtradb/index) | | `innodb-blocking-buffer-pool-restore` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-pages` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-pages-blob` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-pages-index` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-restore-at-startup` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-shm-checksum` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-shm-key` | Removed by [XtraDB](../xtradb/index) | | `innodb-checkpoint-age-target` | Removed by [XtraDB](../xtradb/index) | | `innodb-dict-size-limit` | Removed by [XtraDB](../xtradb/index) | | `innodb-doublewrite-file` | Removed by [XtraDB](../xtradb/index) | | `innodb-fast-checksum` | Renamed to [innodb-checksum-algorithm](../xtradbinnodb-server-system-variables/index#innodb_checksum_algorithm) | | `innodb-flush-neighbor-pages` | Renamed to [innodb-flush-neighbors](../xtradbinnodb-server-system-variables/index#innodb_flush_neighbors) | | `innodb-ibuf-accel-rate` | Removed by [XtraDB](../xtradb/index) | | `innodb-ibuf-active-contract` | Removed by [XtraDB](../xtradb/index) | | `innodb-ibuf-max-size` | Removed by [XtraDB](../xtradb/index) | | `innodb-import-table-from-xtrabackup` | Removed by [XtraDB](../xtradb/index) | | `innodb-index-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-lazy-drop-table` | Removed by [XtraDB](../xtradb/index) | | `innodb-merge-sort-block-size` | Removed by [XtraDB](../xtradb/index) | | `innodb-persistent-stats-root-page` | Removed by [XtraDB](../xtradb/index) | | `innodb-read-ahead` | Removed by [XtraDB](../xtradb/index) | | `innodb-recovery-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-recovery-update-relay-log` | Removed by [XtraDB](../xtradb/index) | | `innodb-stats-auto-update` | Renamed to `innodb-stats-auto-recalc` | | `innodb-stats-update-need-lock` | Removed by [XtraDB](../xtradb/index) | | `innodb-sys-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-table-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-thread-concurrency-timer-based` | Removed by [XtraDB](../xtradb/index) | | `innodb-use-sys-stats-table` | Removed by [XtraDB](../xtradb/index) | | `xtradb-admin-command` | Removed by [XtraDB](../xtradb/index) | #### Reserved Words New reserved word: RETURNING. This can no longer be used as an identifier without being quoted. #### Other The `SET OPTION` syntax is deprecated in [MariaDB 10.0](../what-is-mariadb-100/index). Use `[SET](../set/index)` instead. ### New Major Features To Consider You should consider using the following new major features in [MariaDB 10.0](../what-is-mariadb-100/index): #### For Master / Slave Setups * [Global transaction id](../global-transaction-id/index) is enabled by default. This makes it easier to change a slave to a master. * [MariaDB 10.0](../what-is-mariadb-100/index) supports [parallel applying of queries on slaves](../parallel-replication/index). You can enable this with [slave-parallel-threads=#](../replication-and-binary-log-server-system-variables/index#slave_parallel_threads). Note that this works only if your master is [MariaDB 10.0](../what-is-mariadb-100/index) or later. * [Multi source replication](../multi-source-replication/index) #### Galera See [Upgrading from MariaDB Galera Cluster 5.5 to MariaDB Galera Cluster 10.0](../upgrading-from-mariadb-galera-cluster-55-to-mariadb-galera-cluster-100/index) for more details on [Galera](../what-is-mariadb-galera-cluster/index) upgrades. #### Variables * [System Variables Added in MariaDB 10.0](../system-variables-added-in-mariadb-100/index) * [Status Variables Added in MariaDB 10.0](../status-variables-added-in-mariadb-100/index) Notes ----- 1. [↑](#_ref-0) The `innodb-open-files` variable defaults to the value of `table-open-cache` (`400` is the default) if it is set to any value less than `10` so long as `innodb-file-per-table` is set to `1` or `TRUE` (the default). If `innodb_file_per_table` is set to `0` or `FALSE` **and** `innodb-open-files` is set to a value less than `10`, the default is `300` See Also -------- * [The features in MariaDB 10.0](../what-is-mariadb-100/index) * [Upgrading from MariaDB Galera Cluster 5.5 to MariaDB Galera Cluster 10.0](../upgrading-from-mariadb-galera-cluster-55-to-mariadb-galera-cluster-100/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Upgrading to MariaDB From MySQL 5.0 or Older Upgrading to MariaDB From MySQL 5.0 or Older ============================================ If you upgrade to [MariaDB 5.1](../what-is-mariadb-51/index) from MySQL 5.1 you [don't have to do anything](../how-can-i-upgrade-from-mysql-to-mariadb/index) with your data or MySQL clients. Things should "just work". When upgrading between different major versions of MariaDB or MySQL you need to run the [mysql\_upgrade](../mysql_upgrade/index) program to convert data that are incompatible between versions. This will also update your privilege tables in the mysql database to the latest format. In almost all cases [mysql\_upgrade](../mysql_upgrade/index) should be able to convert your tables, without you having to dump and restore your data. After installing MariaDB, just do: ``` mysql_upgrade --verbose ``` If you want to run with a specific TCP/IP port do: ``` mysql_upgrade --host=127.0.0.1 --port=3308 --protocol=tcp ``` If you want to connect with a socket do: ``` mysql_upgrade --socket=127.0.0.1 --protocol=socket ``` To see other options, use [--help](../mysql_upgrade/index). "mysql\_upgrade" reads the [my.cnf](../mysqld-configuration-files-and-groups/index) sections [mysql\_upgrade] and [client] for default values. There are a variety of reasons tables need to be converted; they could be any of the following: * The collation (sorting order) for an index column has changed * A field type has changed storage format + `[DECIMAL](../decimal/index)` and `[VARCHAR](../varchar/index)` changed format between MySQL 4.1 and MySQL 5.0 * An engine has a new storage format + [ARCHIVE](../archive/index) changed storage format between 5.0 and 5.1 * The format for storing [table names](../identifier-names/index) has changed + In MySQL 5.1 table names are encoded so that the file names are identical on all computers. Old table names that contains forbidden file name characters will show up prefixed with #mysql50# in `SHOW TABLES` until you convert them. If you don't convert the tables, one of the following things may happen: * You will get warnings in the error log every time you access a table with an invalid (old) file name. * When searching on key values you may not find all rows * You will get an error "ERROR 1459 (HY000): Table upgrade required" when accessing the table. * You may get crashes "mysql\_upgrade" works by calling mysqlcheck with different options and running the "mysql\_fix\_privileges" script. If you have trouble with "mysql\_upgrade", you can run these commands separately to get more information of what is going on. Most of the things in the [MySQL 5.1 manual](http://dev.mysql.com/doc/refman/5.1/en/upgrading.html) section also applies to MariaDB. The following differences exists between "mysql\_upgrade" in MariaDB and MySQL (as of [MariaDB 5.1.50](https://mariadb.com/kb/en/mariadb-5150-release-notes/)): * MariaDB will convert long table names properly. * MariaDB will convert [InnoDB](../xtradb-and-innodb/index) tables (no need to do a dump/restore or `[ALTER TABLE](../alter-table/index)`). * MariaDB will convert old archive tables to the new 5.1 format (note: new feature in testing). * "mysql\_upgrade --verbose" will run "mysqlcheck --verbose" so that you get more information of what is happening. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb VARIANCE VARIANCE ======== Syntax ------ ``` VARIANCE(expr) ``` Description ----------- Returns the population standard variance of `expr`. This is an extension to standard SQL. The standard SQL function [VAR\_POP()](../var_pop/index) can be used instead. Variance is calculated by * working out the mean for the set * for each number, subtracting the mean and squaring the result * calculate the average of the resulting differences It is an [aggregate function](../aggregate-functions/index), and so can be used with the [GROUP BY](../group-by/index) clause. From [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/), VARIANCE() can be used as a [window function](../window-functions/index). VARIANCE() returns `NULL` if there were no matching rows. Examples -------- ``` CREATE TABLE v(i tinyint); INSERT INTO v VALUES(101),(99); SELECT VARIANCE(i) FROM v; +-------------+ | VARIANCE(i) | +-------------+ | 1.0000 | +-------------+ INSERT INTO v VALUES(120),(80); SELECT VARIANCE(i) FROM v; +-------------+ | VARIANCE(i) | +-------------+ | 200.5000 | +-------------+ ``` As an [aggregate function](../aggregate-functions/index): ``` CREATE OR REPLACE TABLE stats (category VARCHAR(2), x INT); INSERT INTO stats VALUES ('a',1),('a',2),('a',3), ('b',11),('b',12),('b',20),('b',30),('b',60); SELECT category, STDDEV_POP(x), STDDEV_SAMP(x), VAR_POP(x) FROM stats GROUP BY category; +----------+---------------+----------------+------------+ | category | STDDEV_POP(x) | STDDEV_SAMP(x) | VAR_POP(x) | +----------+---------------+----------------+------------+ | a | 0.8165 | 1.0000 | 0.6667 | | b | 18.0400 | 20.1693 | 325.4400 | +----------+---------------+----------------+------------+ ``` As a [window function](../window-functions/index): ``` CREATE OR REPLACE TABLE student_test (name CHAR(10), test CHAR(10), score TINYINT); INSERT INTO student_test VALUES ('Chun', 'SQL', 75), ('Chun', 'Tuning', 73), ('Esben', 'SQL', 43), ('Esben', 'Tuning', 31), ('Kaolin', 'SQL', 56), ('Kaolin', 'Tuning', 88), ('Tatiana', 'SQL', 87); SELECT name, test, score, VAR_POP(score) OVER (PARTITION BY test) AS variance_results FROM student_test; +---------+--------+-------+------------------+ | name | test | score | variance_results | +---------+--------+-------+------------------+ | Chun | SQL | 75 | 287.1875 | | Chun | Tuning | 73 | 582.0000 | | Esben | SQL | 43 | 287.1875 | | Esben | Tuning | 31 | 582.0000 | | Kaolin | SQL | 56 | 287.1875 | | Kaolin | Tuning | 88 | 582.0000 | | Tatiana | SQL | 87 | 287.1875 | +---------+--------+-------+------------------+ ``` See Also -------- * [VAR\_POP](../var_pop/index) (equivalent, standard SQL) * [STDDEV\_POP](../stddev_pop/index) (population standard deviation) * [STDDEV\_SAMP](../stddev_samp/index) (sample standard deviation) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Subqueries and ANY Subqueries and ANY ================== [Subqueries](../subqueries/index) using the ANY keyword will return `true` if the comparison returns `true` for at least one row returned by the subquery. Syntax ------ The required syntax for an `ANY` or `SOME` quantified comparison is: ``` scalar_expression comparison_operator ANY <Table subquery> ``` Or: ``` scalar_expression comparison_operator SOME <Table subquery> ``` * `scalar_expression` may be any expression that evaluates to a single value. * `comparison_operator` may be any one of `=`, `>`, `<`, `>=`, `<=`, `<>` or `!=`. `ANY` returns: * `TRUE` if the comparison operator returns `TRUE` for at least one row returned by the Table subquery. * `FALSE` if the comparison operator returns `FALSE` for all rows returned by the Table subquery, or Table subquery has zero rows. * `NULL` if the comparison operator returns `NULL` for at least one row returned by the Table subquery and doesn't returns `TRUE` for any of them, or if scalar\_expression returns `NULL`. `SOME` is a synmonym for `ANY`, and `IN` is a synonym for `= ANY` Examples -------- ``` CREATE TABLE sq1 (num TINYINT); CREATE TABLE sq2 (num2 TINYINT); INSERT INTO sq1 VALUES(100); INSERT INTO sq2 VALUES(40),(50),(120); SELECT * FROM sq1 WHERE num > ANY (SELECT * FROM sq2); +------+ | num | +------+ | 100 | +------+ ``` `100` is greater than two of the three values, and so the expression evaluates as true. SOME is a synonym for ANY: ``` SELECT * FROM sq1 WHERE num < SOME (SELECT * FROM sq2); +------+ | num | +------+ | 100 | +------+ ``` `IN` is a synonym for `= ANY`, and here there are no matches, so no results are returned: ``` SELECT * FROM sq1 WHERE num IN (SELECT * FROM sq2); Empty set (0.00 sec) ``` ``` INSERT INTO sq2 VALUES(100); Query OK, 1 row affected (0.05 sec) SELECT * FROM sq1 WHERE num <> ANY (SELECT * FROM sq2); +------+ | num | +------+ | 100 | +------+ ``` Reading this query, the results may be counter-intuitive. It may seem to read as "SELECT \* FROM sq1 WHERE num does not match any results in sq2. Since it does match 100, it could seem that the results are incorrect. However, the query returns a result if the match does not match any *of* sq2. Since `100` already does not match `40`, the expression evaluates to true immediately, regardless of the 100's matching. It may be more easily readable to use SOME in a case such as this: ``` SELECT * FROM sq1 WHERE num <> SOME (SELECT * FROM sq2); +------+ | num | +------+ | 100 | +------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Encryption Encryption =========== | Title | Description | | --- | --- | | [Data-in-Transit Encryption](../data-in-transit-encryption/index) | Data can be encrypted in transit using the Transport Layer Security (TLS) protocol. | | [Data-at-Rest Encryption](../encryption-data-at-rest-encryption/index) | MariaDB supports the use of data-at-rest encryption for tables and tablespa... | | [TLS and Cryptography Libraries Used by MariaDB](../tls-and-cryptography-libraries-used-by-mariadb/index) | MariaDB supports several different TLS and cryptography libraries. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb GeometryCollectionFromText GeometryCollectionFromText ========================== A synonym for [ST\_GeomCollFromText](../st_geomcollfromtext/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb IS NOT IS NOT ====== Syntax ------ ``` IS NOT boolean_value ``` Description ----------- Tests a value against a boolean value, where boolean\_value can be TRUE, FALSE, or UNKNOWN. Examples -------- ``` SELECT 1 IS NOT UNKNOWN, 0 IS NOT UNKNOWN, NULL IS NOT UNKNOWN; +------------------+------------------+---------------------+ | 1 IS NOT UNKNOWN | 0 IS NOT UNKNOWN | NULL IS NOT UNKNOWN | +------------------+------------------+---------------------+ | 1 | 1 | 0 | +------------------+------------------+---------------------+ ``` ``` SELECT NULL IS NOT TRUE, NULL IS NOT FALSE; +------------------+-------------------+ | NULL IS NOT TRUE | NULL IS NOT FALSE | +------------------+-------------------+ | 1 | 1 | +------------------+-------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mariadb_schema mariadb\_schema =============== `mariadb_schema` is a data type qualifier that allows one to create MariaDB native date types in an [SQL\_MODE](../sql-mode/index) that has conflicting data type translations. `mariadb_schema` was introduced in [MariaDB 10.3.24](https://mariadb.com/kb/en/mariadb-10324-release-notes/), [MariaDB 10.4.14](https://mariadb.com/kb/en/mariadb-10414-release-notes/) and [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/). For example, in [SQL\_MODE=ORACLE](../sql_modeoracle/index), if one creates a table with the [DATE](../date/index) type, it will actually create a [DATETIME](../datetime/index#oracle-mode) column to match what an Oracle user is expecting. To be able to create a MariaDB DATE in Oracle mode one would have to use `mariadb_schema`: ``` CREATE TABLE t1 (d mariadb_schema.DATE); ``` `mariadb_schema` is also shown if one creates a table with `DATE` in MariaDB native mode and then does a [SHOW CREATE TABLE](../show-create-table/index) in `ORACLE` mode: ``` SET sql_mode=DEFAULT; CREATE OR REPLACE TABLE t1 ( d DATE ); SET SQL_mode=ORACLE; SHOW CREATE TABLE t1; +-------+--------------------------------------------------------------+ | Table | Create Table | +-------+--------------------------------------------------------------+ | t1 | CREATE TABLE "t1" ( "d" mariadb_schema.date DEFAULT NULL ) | +-------+--------------------------------------------------------------+ ``` When the server sees the `mariadb_schema` qualifier, it disables sql\_mode-specific data type translation and interprets the data type literally, so for example `mariadb_schema.DATE` is interpreted as the traditional MariaDB `DATE` data type, no matter what the current sql\_mode is. The `mariadb_schema` prefix is displayed only when the data type name would be ambiguous otherwise. The prefix is displayed together with MariaDB `DATE` when [SHOW CREATE TABLE](../show-create-table/index) is executed in [SQL\_MODE=ORACLE](../sql_modeoracle/index). The prefix is not displayed when [SHOW CREATE TABLE](../show-create-table/index) is executed in SQL\_MODE=DEFAULT, or when a non-ambiguous data type is displayed. Note, the `mariadb_schema` prefix can be used with any data type, including non-ambiguous ones: ``` CREATE OR REPLACE TABLE t1 (a mariadb_schema.INT); SHOW CREATE TABLE t1; +-------+--------------------------------------------------+ | Table | Create Table | +-------+--------------------------------------------------+ | t1 | CREATE TABLE "t1" ( "a" int(11) DEFAULT NULL ) | +-------+--------------------------------------------------+ ``` Currently the `mariadb_schema` prefix is only used in the following case: * For a MariaDB native [DATE](../date/index) type when running [SHOW CREATE TABLE](../show-create-table/index) in [Oracle mode](../sql_modeoracle/index). History ------- When running with [SQL\_MODE=ORACLE](../sql_modeoracle/index), MariaDB server translates the data type `DATE` to `DATETIME`, for better Oracle compatibility: ``` SET SQL_mode=ORACLE; CREATE OR REPLACE TABLE t1 ( d DATE ); SHOW CREATE TABLE t1; +-------+---------------------------------------------------+ | Table | Create Table | +-------+---------------------------------------------------+ | t1 | CREATE TABLE "t1" ( "d" datetime DEFAULT NULL ) | +-------+---------------------------------------------------+ ``` Notice, `DATE` was translated to `DATETIME`. This translation may cause some ambiguity. Suppose a user creates a table with a column of the traditional MariaDB `DATE` data type using the default sql\_mode, but then switches to [SQL\_MODE=ORACLE](../sql_modeoracle/index) and runs a [SHOW CREATE TABLE](../show-create-table/index) statement: ``` SET sql_mode=DEFAULT; CREATE OR REPLACE TABLE t1 ( d DATE ); SET SQL_mode=ORACLE; SHOW CREATE TABLE t1; ``` Before `mariadb_schema` was introduced, the above script displayed: ``` CREATE TABLE "t1" ( "d" date DEFAULT NULL ); ``` which had two problems: * It was confusing for the reader: its not clear if it is the traditional MariaDB `DATE`, or is it Oracle-alike date (which is actually `DATETIME`); * It broke replication and caused data type mismatch on the master and on the slave (see [MDEV-19632](https://jira.mariadb.org/browse/MDEV-19632)). To address this problem, starting from the mentioned versions, MariaDB uses the idea of qualified data types: ``` SET sql_mode=DEFAULT; CREATE OR REPLACE TABLE t1 ( d DATE ); SET SQL_mode=ORACLE; SHOW CREATE TABLE t1; +-------+--------------------------------------------------------------+ | Table | Create Table | +-------+--------------------------------------------------------------+ | t1 | CREATE TABLE "t1" ( "d" mariadb_schema.date DEFAULT NULL ) | +-------+--------------------------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Authentication from MariaDB 10.4 Authentication from MariaDB 10.4 ================================ **MariaDB starting with [10.4](../what-is-mariadb-104/index)**[MariaDB 10.4](../what-is-mariadb-104/index) introduces a number of changes to the authentication process, intended to make things easier and more intuitive. Overview -------- There are four **new main features in 10.4** relating to authentication: * It is possible to use more than one [authentication plugin](../authentication-plugins/index) for each user account. For example, this can be useful to slowly migrate users to the more secure [ed25519](../authentication-plugin-ed25519/index) authentication plugin over time, while allowing the old [mysql\_native\_password](../authentication-plugin-mysql_native_password/index) authentication plugin as an alternative for the transitional period. * The `root@localhost` user account created by [mysql\_install\_db](../mysql_install_db/index) is created with the ability to use two [authentication plugins](../authentication-plugins/index). + First, it is configured to try to use the [unix\_socket](../authentication-plugin-unix-socket/index) authentication plugin. This allows the `root@localhost` user to login without a password via the local Unix socket file defined by the [socket](../server-system-variables/index#socket) system variable, as long as the login is attempted from a process owned by the operating system `root` user account. + Second, if authentication fails with the [unix\_socket](../authentication-plugin-unix-socket/index) authentication plugin, then it is configured to try to use the [mysql\_native\_password](../authentication-plugin-mysql_native_password/index) authentication plugin. However, an invalid password is initially set, so in order to authenticate this way, a password must be set with [SET PASSWORD](../set-password/index). + However, just using the [unix\_socket](../authentication-plugin-unix-socket/index) authentication plugin may be fine for many users, and it is very secure. You may want to try going without password authentication to see how well it works for you. Remember, the best way to keep your password safe is not to have one! * All user accounts, passwords, and global privileges are now stored in the [mysql.global\_priv](../mysqlglobal_priv-table/index) table. The [mysql.user](../mysqluser-table/index) table still exists and has exactly the same set of columns as before, but it’s now a view that references the [mysql.global\_priv](../mysqlglobal_priv-table/index) table. Tools that analyze the [mysql.user](../mysqluser-table/index) table should continue to work as before. From [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/), the dedicated `mariadb.sys` user is created as the definer of this view. Previously `root` was the definer, which resulted in privilege problems when this username was changed. * [MariaDB 10.4](../what-is-mariadb-104/index) adds supports for [User Password Expiry](../user-password-expiry/index), which is not active by default. Description ----------- As a result of the above changes, the open-for-everyone all-powerful root account is finally gone. And installation scripts will no longer demand that you “PLEASE REMEMBER TO SET A PASSWORD FOR THE MariaDB root USER !”, because the root account is securely created automatically. Two all-powerful accounts are created by default — root and the OS user that owns the data directory, typically mysql. They are created as: ``` CREATE USER root@localhost IDENTIFIED VIA unix_socket OR mysql_native_password USING 'invalid' CREATE USER mysql@localhost IDENTIFIED VIA unix_socket OR mysql_native_password USING 'invalid' ``` Using unix\_socket means that if you are the system root user, you can login as root@locahost without a password. This technique was pioneered by Otto Kekäläinen in Debian MariaDB packages and has been successfully [used in Debian](../differences-in-mariadb-in-debian-and-ubuntu/index) since as early as [MariaDB 10.0](../what-is-mariadb-100/index). It is based on a simple fact that asking the system root for a password adds no extra security — root has full access to all the data files and all process memory anyway. But not asking for a password means, there is no root password to forget (no need for the numerous tutorials on “how to reset MariaDB root password”). And if you want to script some tedious database work, there is no need to store the root password in plain text for the script to use (no need for debian-sys-maint user). Still, some users may wish to log in as MariaDB root without using sudo. Hence the old authentication method — conventional MariaDB password — is still available. By default it is disabled (“invalid” is not a valid password hash), but one can set the password with a usual [SET PASSWORD](../set-password/index) statement. And still retain the password-less access via sudo. If you install MariaDB locally (say from a tarball), you would not want to use sudo to be able to login. This is why MariaDB creates a second all-powerful user with the same name as a system user that owns the data directory. In local (not system-wide) installations, this will be the user who installed MariaDB — they automatically get convenient password-less root-like access, because they can access all the data files anyway. Even if MariaDB is installed system-wide, you may not want to run your database maintenance scripts as system root — now you can run them as system mysql user. And you will know that they will never destroy your entire system, even if you make a typo in a shell script. However, seasoned MariaDB DBAs who are used to the old ways do need to makes some changes. See the examples below for common tasks. Cookbook -------- After installing MariaDB system-wide the first thing you’ve got used to doing is logging in into the unprotected root account and protecting it, that is, setting the root password: ``` $ sudo dnf install MariaDB-server $ mysql -uroot ... MariaDB> set password = password("XH4VmT3_jt"); ``` This is not only unnecessary now, it will simply not work — there is no unprotected root account. To login as root use ``` $ sudo dnf install MariaDB-server $ sudo mysql ``` Note that it implies you are connecting via the unix socket, not tcp. If you happen to have `protocol=tcp` in a system-wide `/etc/my.cnf` file, use `sudo mysql --protocol=socket`. After installing MariaDB locally you’ve also used to connect to the unprotected root account using `mysql -uroot`. This will not work either, simply use `mysql` without specifying a username. If you've forgotten your root password, no problem — you can still connect using sudo and change the password. And if you've also removed unix\_socket authentication, to restore access do as follows: * restart MariaDB with [--skip-grant-tables](../mysqld-options/index#-skip-grant-tables) * login into the unprotected server * run [FLUSH PRIVILEGES](../flush/index) (note, before 10.4 this would’ve been the last step, not anymore). This disables `--skip-grant-tables` and allows you to change the stored authentication method * run [SET PASSWORD](../set-password/index) FOR root@localhost to change the root password. To view inside privilege tables, the old mysql.user table still exists. You can select from it as before, although you cannot update it anymore. It doesn’t show alternative authentication plugins and this was one of the reasons for switching to the mysql.global\_priv table — complex authentication rules did not fit into rigid structure of a relational table. You can select from the new table, for example: ``` select concat(user, '@', host, ' => ', json_detailed(priv)) from mysql.global_priv; ``` Reverting to the Previous Authentication Method for root@localhost ------------------------------------------------------------------ If you don't want the `root@localhost` user account created by [mysql\_install\_db](../mysql_install_db/index) to use [unix\_socket](../authentication-plugin-unix-socket/index) authentication by default, then there are a few ways to revert to the previous [mysql\_native\_password](../authentication-plugin-mysql_native_password/index) authentication method for this user account. ### Configuring `mysql_install_db` to Revert to the Previous Authentication Method One way to revert to the previous [mysql\_native\_password](../authentication-plugin-mysql_native_password/index) authentication method for the `root@localhost` user account is to execute [mysql\_install\_db](../mysql_install_db/index) with a special option. If [mysql\_install\_db](../mysql_install_db/index) is executed while `--auth-root-authentication-method=normal` is specified, then it will create the default user accounts using the default behavior of [MariaDB 10.3](../what-is-mariadb-103/index) and before. This means that the `root@localhost` user account will use [mysql\_native\_password](../authentication-plugin-mysql_native_password/index) authentication by default. There are some other differences as well. See [mysql\_install\_db: User Accounts Created by Default](../mysql_install_db/index#user-accounts-created-by-default) for more information. For example, the option can be set on the command-line while running [mysql\_install\_db](../mysql_install_db/index): ``` mysql_install_db --user=mysql --datadir=/var/lib/mysql --auth-root-authentication-method=normal ``` The option can also be set in an [option file](../configuring-mariadb-with-option-files/index) in an [option group](../configuring-mariadb-with-option-files/index#option-groups) supported by [mysql\_install\_db](../mysql_install_db/index). For example: ``` [mysql_install_db] auth_root_authentication_method=normal ``` If the option is set in an [option file](../configuring-mariadb-with-option-files/index) and if [mysql\_install\_db](../mysql_install_db/index) is executed, then [mysql\_install\_db](../mysql_install_db/index) will read this option from the [option file](../configuring-mariadb-with-option-files/index), and it will automatically set this option. ### Altering the User Account to Revert to the Previous Authentication Method If you have already installed MariaDB, and if the `root@localhost` user account is already using [unix\_socket](../authentication-plugin-unix-socket/index) authentication, then you can revert to the old [mysql\_native\_password](../authentication-plugin-mysql_native_password/index) authentication method for the user account by executing the following: ``` ALTER USER root@localhost IDENTIFIED VIA mysql_native_password USING PASSWORD("verysecret") ``` See Also -------- * [Authentication from MariaDB 10 4 video tutorial](https://www.youtube.com/watch?v=aWFG4uLbimM) * [Authentication in MariaDB 10.4 — understanding the changes (mariadb.org)](https://mariadb.org/authentication-in-mariadb-10-4/) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Useful MariaDB Queries Useful MariaDB Queries ====================== This page is intended to be a quick reference of commonly-used and/or useful queries in MariaDB. Creating a Table ---------------- ``` CREATE TABLE t1 ( a INT ); CREATE TABLE t2 ( b INT ); CREATE TABLE student_tests ( name CHAR(10), test CHAR(10), score TINYINT, test_date DATE ); ``` See [CREATE TABLE](../create-table/index) for more. Inserting Records ----------------- ``` INSERT INTO t1 VALUES (1), (2), (3); INSERT INTO t2 VALUES (2), (4); INSERT INTO student_tests (name, test, score, test_date) VALUES ('Chun', 'SQL', 75, '2012-11-05'), ('Chun', 'Tuning', 73, '2013-06-14'), ('Esben', 'SQL', 43, '2014-02-11'), ('Esben', 'Tuning', 31, '2014-02-09'), ('Kaolin', 'SQL', 56, '2014-01-01'), ('Kaolin', 'Tuning', 88, '2013-12-29'), ('Tatiana', 'SQL', 87, '2012-04-28'), ('Tatiana', 'Tuning', 83, '2013-09-30'); ``` See [INSERT](../insert/index) for more. Using AUTO\_INCREMENT --------------------- The AUTO\_INCREMENT attribute is used to automatically generate a unique identity for new rows. ``` CREATE TABLE student_details ( id INT NOT NULL AUTO_INCREMENT, name CHAR(10), date_of_birth DATE, PRIMARY KEY (id) ); ``` When inserting, the id field can be omitted, and is automatically created. ``` INSERT INTO student_details (name,date_of_birth) VALUES ('Chun', '1993-12-31'), ('Esben','1946-01-01'), ('Kaolin','1996-07-16'), ('Tatiana', '1988-04-13'); SELECT * FROM student_details; +----+---------+---------------+ | id | name | date_of_birth | +----+---------+---------------+ | 1 | Chun | 1993-12-31 | | 2 | Esben | 1946-01-01 | | 3 | Kaolin | 1996-07-16 | | 4 | Tatiana | 1988-04-13 | +----+---------+---------------+ ``` See [AUTO\_INCREMENT](../auto_increment/index) for more. Querying from two tables on a common value ------------------------------------------ ``` SELECT * FROM t1 INNER JOIN t2 ON t1.a = t2.b; ``` This kind of query is called a join - see [JOINS](../joins/index) for more. Finding the Maximum Value ------------------------- ``` SELECT MAX(a) FROM t1; +--------+ | MAX(a) | +--------+ | 3 | +--------+ ``` See the [MAX() function](../max/index) for more, as well as [Finding the maximum value and grouping the results](#finding-the-maximum-value-and-grouping-the-results) below for a more practical example. Finding the Minimum Value ------------------------- ``` SELECT MIN(a) FROM t1; +--------+ | MIN(a) | +--------+ | 1 | +--------+ ``` See the [MIN() function](../min/index) for more. Finding the Average Value ------------------------- ``` SELECT AVG(a) FROM t1; +--------+ | AVG(a) | +--------+ | 2.0000 | +--------+ ``` See the [AVG() function](../avg/index) for more. Finding the Maximum Value and Grouping the Results -------------------------------------------------- ``` SELECT name, MAX(score) FROM student_tests GROUP BY name; +---------+------------+ | name | MAX(score) | +---------+------------+ | Chun | 75 | | Esben | 43 | | Kaolin | 88 | | Tatiana | 87 | +---------+------------+ ``` See the [MAX() function](../max/index) for more. Ordering Results ---------------- ``` SELECT name, test, score FROM student_tests ORDER BY score DESC; +---------+--------+-------+ | name | test | score | +---------+--------+-------+ | Kaolin | Tuning | 88 | | Tatiana | SQL | 87 | | Tatiana | Tuning | 83 | | Chun | SQL | 75 | | Chun | Tuning | 73 | | Kaolin | SQL | 56 | | Esben | SQL | 43 | | Esben | Tuning | 31 | +---------+--------+-------+ ``` See [ORDER BY](../order-by/index) for more. Finding the Row with the Minimum of a Particular Column ------------------------------------------------------- In this example, we want to find the lowest test score for any student. ``` SELECT name,test, score FROM student_tests WHERE score=(SELECT MIN(score) FROM student); +-------+--------+-------+ | name | test | score | +-------+--------+-------+ | Esben | Tuning | 31 | +-------+--------+-------+ ``` Finding Rows with the Maximum Value of a Column by Group -------------------------------------------------------- This example returns the best test results of each student: ``` SELECT name, test, score FROM student_tests st1 WHERE score = ( SELECT MAX(score) FROM student st2 WHERE st1.name = st2.name ); +---------+--------+-------+ | name | test | score | +---------+--------+-------+ | Chun | SQL | 75 | | Esben | SQL | 43 | | Kaolin | Tuning | 88 | | Tatiana | SQL | 87 | +---------+--------+-------+ ``` Calculating Age --------------- The [TIMESTAMPDIFF](../timestampdiff/index) function can be used to calculate someone's age: ``` SELECT CURDATE() AS today; +------------+ | today | +------------+ | 2014-02-17 | +------------+ SELECT name, date_of_birth, TIMESTAMPDIFF(YEAR,date_of_birth,'2014-08-02') AS age FROM student_details; +---------+---------------+------+ | name | date_of_birth | age | +---------+---------------+------+ | Chun | 1993-12-31 | 20 | | Esben | 1946-01-01 | 68 | | Kaolin | 1996-07-16 | 18 | | Tatiana | 1988-04-13 | 26 | +---------+---------------+------+ ``` See [TIMESTAMPDIFF()](../timestampdiff/index) for more. Using User-defined Variables ---------------------------- This example sets a [user-defined variable](../user-defined-variables/index) with the average test score, and then uses it in a later query to return all results above the average. ``` SELECT @avg_score:= AVG(score) FROM student_tests; +-------------------------+ | @avg_score:= AVG(score) | +-------------------------+ | 67.000000000 | +-------------------------+ SELECT * FROM student_tests WHERE score > @avg_score; +---------+--------+-------+------------+ | name | test | score | test_date | +---------+--------+-------+------------+ | Chun | SQL | 75 | 2012-11-05 | | Chun | Tuning | 73 | 2013-06-14 | | Kaolin | Tuning | 88 | 2013-12-29 | | Tatiana | SQL | 87 | 2012-04-28 | | Tatiana | Tuning | 83 | 2013-09-30 | +---------+--------+-------+------------+ ``` User-defined variables can also be used to add an incremental counter to a resultset: ``` SET @count = 0; SELECT @count := @count + 1 AS counter, name, date_of_birth FROM student_details; +---------+---------+---------------+ | counter | name | date_of_birth | +---------+---------+---------------+ | 1 | Chun | 1993-12-31 | | 2 | Esben | 1946-01-01 | | 3 | Kaolin | 1996-07-16 | | 4 | Tatiana | 1988-04-13 | +---------+---------+---------------+ ``` See [User-defined Variables](../user-defined-variables/index) for more. View Tables in Order of Size ---------------------------- Returns a list of all tables in the database, ordered by size: ``` SELECT table_schema as `DB`, table_name AS `Table`, ROUND(((data_length + index_length) / 1024 / 1024), 2) `Size (MB)` FROM information_schema.TABLES ORDER BY (data_length + index_length) DESC; +--------------------+---------------------------------------+-----------+ | DB | Table | Size (MB) | +--------------------+---------------------------------------+-----------+ | wordpress | wp_simple_history_contexts | 7.05 | | wordpress | wp_posts | 6.59 | | wordpress | wp_simple_history | 3.05 | | wordpress | wp_comments | 2.73 | | wordpress | wp_commentmeta | 2.47 | | wordpress | wp_simple_login_log | 2.03 | ... ``` Removing Duplicates ------------------- **MariaDB starting with [10.3](../what-is-mariadb-103/index)**The following syntax is only valid [MariaDB 10.3](../what-is-mariadb-103/index) and beyond: This example assumes there's a unique ID, but that all other fields are identical. In the example below, there are 4 records, 3 of which are duplicates, so two of the three duplicates need to be removed. The intermediate SELECT is not necessary, but demonstrates what is being returned. ``` CREATE TABLE t (id INT, f1 VARCHAR(2)); INSERT INTO t VALUES (1,'a'), (2,'a'), (3,'b'), (4,'a'); SELECT * FROM t t1, t t2 WHERE t1.f1=t2.f1 AND t1.id<>t2.id AND t1.id=( SELECT MAX(id) FROM t tab WHERE tab.f1=t1.f1 ); +------+------+------+------+ | id | f1 | id | f1 | +------+------+------+------+ | 4 | a | 1 | a | | 4 | a | 2 | a | +------+------+------+------+ DELETE FROM t WHERE id IN ( SELECT t2.id FROM t t1, t t2 WHERE t1.f1=t2.f1 AND t1.id<>t2.id AND t1.id=( SELECT MAX(id) FROM t tab WHERE tab.f1=t1.f1 ) ); Query OK, 2 rows affected (0.120 sec) SELECT * FROM t; +------+------+ | id | f1 | +------+------+ | 3 | b | | 4 | a | +------+------ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb TRUNCATE TRUNCATE ======== This page documents the TRUNCATE function. See [TRUNCATE TABLE](../truncate-table/index) for the DDL statement. Syntax ------ ``` TRUNCATE(X,D) ``` Description ----------- Returns the number X, truncated to D decimal places. If D is 0, the result has no decimal point or fractional part. D can be negative to cause D digits left of the decimal point of the value X to become zero. Examples -------- ``` SELECT TRUNCATE(1.223,1); +-------------------+ | TRUNCATE(1.223,1) | +-------------------+ | 1.2 | +-------------------+ SELECT TRUNCATE(1.999,1); +-------------------+ | TRUNCATE(1.999,1) | +-------------------+ | 1.9 | +-------------------+ SELECT TRUNCATE(1.999,0); +-------------------+ | TRUNCATE(1.999,0) | +-------------------+ | 1 | +-------------------+ SELECT TRUNCATE(-1.999,1); +--------------------+ | TRUNCATE(-1.999,1) | +--------------------+ | -1.9 | +--------------------+ SELECT TRUNCATE(122,-2); +------------------+ | TRUNCATE(122,-2) | +------------------+ | 100 | +------------------+ SELECT TRUNCATE(10.28*100,0); +-----------------------+ | TRUNCATE(10.28*100,0) | +-----------------------+ | 1028 | +-----------------------+ ``` See Also -------- * [TRUNCATE TABLE](../truncate-table/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb RPAD RPAD ==== Syntax ------ ``` RPAD(str, len [, padstr]) ``` Description ----------- Returns the string `str`, right-padded with the string `padstr` to a length of `len` characters. If `str` is longer than `len`, the return value is shortened to `len` characters. If `padstr` is omitted, the RPAD function pads spaces. Prior to [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), the `padstr` parameter was mandatory. Returns NULL if given a NULL argument. If the result is empty (a length of zero), returns either an empty string, or, from [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/) with [SQL\_MODE=Oracle](../sql_modeoracle-from-mariadb-103/index), NULL. The Oracle mode version of the function can be accessed outside of Oracle mode by using `RPAD_ORACLE` as the function name. Examples -------- ``` SELECT RPAD('hello',10,'.'); +----------------------+ | RPAD('hello',10,'.') | +----------------------+ | hello..... | +----------------------+ SELECT RPAD('hello',2,'.'); +---------------------+ | RPAD('hello',2,'.') | +---------------------+ | he | +---------------------+ ``` From [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), with the pad string defaulting to space. ``` SELECT RPAD('hello',30); +--------------------------------+ | RPAD('hello',30) | +--------------------------------+ | hello | +--------------------------------+ ``` Oracle mode version from [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/): ``` SELECT RPAD('',0),RPAD_ORACLE('',0); +------------+-------------------+ | RPAD('',0) | RPAD_ORACLE('',0) | +------------+-------------------+ | | NULL | +------------+-------------------+ ``` See Also -------- * [LPAD](../lpad/index) - Left-padding instead of right-padding. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb EXPLAIN EXPLAIN ======= Syntax ------ ``` EXPLAIN tbl_name [col_name | wild] ``` Or ``` EXPLAIN [EXTENDED | PARTITIONS | FORMAT=JSON] {SELECT select_options | UPDATE update_options | DELETE delete_options} ``` Description ----------- The `EXPLAIN` statement can be used either as a synonym for `DESCRIBE` or as a way to obtain information about how MariaDB executes a `SELECT`, `UPDATE` or `DELETE` statement: * `'EXPLAIN tbl_name'` is synonymous with `'[DESCRIBE](../describe-command/index) tbl_name'` or `'[SHOW COLUMNS](../show-columns/index) FROM tbl_name'`. * When you precede a `SELECT`, `UPDATE` or a `DELETE` statement with the keyword `EXPLAIN`, MariaDB displays information from the optimizer about the query execution plan. That is, MariaDB explains how it would process the `SELECT`, `UPDATE` or `DELETE`, including information about how tables are joined and in which order. `EXPLAIN EXTENDED` can be used to provide additional information. * `EXPLAIN PARTITIONS` is useful only when examining queries involving partitioned tables. For details, see [Partition pruning and selection](../partition-pruning-and-selection/index). * [ANALYZE statement](../analyze-statement/index) performs the query as well as producing EXPLAIN output, and provides actual as well as estimated statistics. * `EXPLAIN` output can be printed in the [slow query log](../slow-query-log/index). See [EXPLAIN in the Slow Query Log](../explain-in-the-slow-query-log/index) for details. [SHOW EXPLAIN](../show-explain/index) shows the output of a running statement. In some cases, its output can be closer to reality than `EXPLAIN`. The [ANALYZE statement](../analyze-statement/index) runs a statement and returns information about its execution plan. It also shows additional columns, to check how much the optimizer's estimation about filtering and found rows are close to reality. There is an online [EXPLAIN Analyzer](../explain-analyzer/index) that you can use to share `EXPLAIN` and `EXPLAIN EXTENDED` output with others. `EXPLAIN` can acquire metadata locks in the same way that `SELECT` does, as it needs to know table metadata and, sometimes, data as well. ### Columns in EXPLAIN ... SELECT | Column name | Description | | --- | --- | | `id` | Sequence number that shows in which order tables are joined. | | `select_type` | What kind of `SELECT` the table comes from. | | `table` | Alias name of table. Materialized temporary tables for sub queries are named <subquery#> | | `type` | How rows are found from the table (join type). | | `possible_keys` | keys in table that could be used to find rows in the table | | `key` | The name of the key that is used to retrieve rows. `NULL` is no key was used. | | `key_len` | How many bytes of the key that was used (shows if we are using only parts of the multi-column key). | | `ref` | The reference that is used as the key value. | | `rows` | An estimate of how many rows we will find in the table for each key lookup. | | `Extra` | Extra information about this join. | Here are descriptions of the values for some of the more complex columns in `EXPLAIN ... SELECT`: #### "Select\_type" Column The `select_type` column can have the following values: | Value | Description | Comment | | --- | --- | --- | | `DEPENDENT SUBQUERY` | The `SUBQUERY` is `DEPENDENT`. | | | `DEPENDENT UNION` | The `UNION` is `DEPENDENT`. | | | `DERIVED` | The `SELECT` is `DERIVED` from the `PRIMARY`. | | | `MATERIALIZED` | The `SUBQUERY` is `[MATERIALIZED](../semi-join-materialization-strategy/index)`. | Materialized tables will be populated at first access and will be accessed by the primary key (= one key lookup). Number of rows in EXPLAIN shows the cost of populating the table | | `PRIMARY` | The `SELECT` is a `PRIMARY` one. | | | `SIMPLE` | The `SELECT` is a `SIMPLE` one. | | | `SUBQUERY` | The `SELECT` is a `SUBQUERY` of the `PRIMARY`. | | | `UNCACHEABLE SUBQUERY` | The `SUBQUERY` is `UNCACHEABLE`. | | | `UNCACHEABLE UNION` | The `UNION` is `UNCACHEABLE`. | | | `UNION` | The `SELECT` is a `UNION` of the `PRIMARY`. | | | `UNION RESULT` | The result of the `UNION`. | | | `LATERAL DERIVED` | The `SELECT` uses a [Lateral Derived optimization](../lateral-derived-optimization/index) | | #### "Type" Column This column contains information on how the table is accessed. | Value | Description | | --- | --- | | `ALL` | A full table scan is done for the table (all rows are read). This is bad if the table is large and the table is joined against a previous table! This happens when the optimizer could not find any usable index to access rows. | | `const` | There is only one possibly matching row in the table. The row is read before the optimization phase and all columns in the table are treated as constants. | | `eq_ref` | A unique index is used to find the rows. This is the best possible plan to find the row. | | `fulltext` | A fulltext index is used to access the rows. | | `index_merge` | A 'range' access is done for for several index and the found rows are merged. The key column shows which keys are used. | | `index_subquery` | This is similar as ref, but used for sub queries that are transformed to key lookups. | | `index` | A full scan over the used index. Better than ALL but still bad if index is large and the table is joined against a previous table. | | `range` | The table will be accessed with a key over one or more value ranges. | | `ref_or_null` | Like 'ref' but in addition another search for the 'null' value is done if the first value was not found. This happens usually with sub queries. | | `ref` | A non unique index or prefix of an unique index is used to find the rows. Good if the prefix doesn't match many rows. | | `system` | The table has 0 or 1 rows. | | `unique_subquery` | This is similar as eq\_ref, but used for sub queries that are transformed to key lookups | #### "Extra" Column This column consists of one or more of the following values, separated by ';' *Note that some of these values are detected after the optimization phase.* The optimization phase can do the following changes to the `WHERE` clause: * Add the expressions from the `ON` and `USING` clauses to the `WHERE` clause. * Constant propagation: If there is `column=constant`, replace all column instances with this constant. * Replace all columns from '`const`' tables with their values. * Remove the used key columns from the `WHERE` (as this will be tested as part of the key lookup). * Remove impossible constant sub expressions. For example `WHERE '(a=1 and a=2) OR b=1'` becomes `'b=1'`. * Replace columns with other columns that has identical values: Example: `WHERE` `a=b` and `a=c` may be treated as `'WHERE a=b and a=c and b=c'`. * Add extra conditions to detect impossible row conditions earlier. This happens mainly with `OUTER JOIN` where we in some cases add detection of `NULL` values in the `WHERE` (Part of '`Not exists`' optimization). This can cause an unexpected '`Using where`' in the Extra column. * For each table level we remove expressions that have already been tested when we read the previous row. Example: When joining tables `t1` with `t2` using the following `WHERE 't1.a=1 and t1.a=t2.b'`, we don't have to test `'t1.a=1'` when checking rows in `t2` as we already know that this expression is true. | Value | Description | | --- | --- | | `const row not found` | The table was a system table (a table with should exactly one row), but no row was found. | | `Distinct` | If distinct optimization (remove duplicates) was used. This is marked only for the last table in the `SELECT`. | | `Full scan on NULL key` | The table is a part of the sub query and if the value that is used to match the sub query will be `NULL`, we will do a full table scan. | | `Impossible HAVING` | The used `HAVING` clause is always false so the `SELECT` will return no rows. | | `Impossible WHERE` `noticed` `after` `reading` `const` `tables.` | The used `WHERE` clause is always false so the `SELECT` will return no rows. This case was detected after we had read all 'const' tables and used the column values as constant in the `WHERE` clause. For example: `WHERE const_column=5` and `const_column` had a value of 4. | | `Impossible WHERE` | The used `WHERE` clause is always false so the `SELECT` will return no rows. For example: `WHERE 1=2` | | `No matching min/max row` | During early optimization of `MIN()`/`MAX()` values it was detected that no row could match the `WHERE` clause. The `MIN()`/`MAX()` function will return `NULL`. | | `no matching row` `in` `const` `table` | The table was a const table (a table with only one possible matching row), but no row was found. | | `No tables used` | The `SELECT` was a sub query that did not use any tables. For example a there was no `FROM` clause or a `FROM DUAL` clause. | | `Not exists` | Stop searching after more row if we find one single matching row. This optimization is used with `LEFT JOIN` where one is explicitly searching for rows that doesn't exists in the `LEFT JOIN TABLE`. Example: `SELECT * FROM t1 LEFT JOIN t2 on (...) WHERE t2.not_null_column IS NULL`. As `t2.not_null_column` can only be `NULL` if there was no matching row for on condition, we can stop searching if we find a single matching row. | | `Open_frm_only` | For `information_schema` tables. Only the `frm` (table definition file was opened) was opened for each matching row. | | `Open_full_table` | For `information_schema` tables. A full table open for each matching row is done to retrieve the requested information. (Slow) | | `Open_trigger_only` | For `information_schema` tables. Only the trigger file definition was opened for each matching row. | | `Range checked` `for` `each` `record` `(index map: ...)` | This only happens when there was no good default index to use but there may some index that could be used when we can treat all columns from previous table as constants. For each row combination the optimizer will decide which index to use (if any) to fetch a row from this table. This is not fast, but faster than a full table scan that is the only other choice. The index map is a bitmask that shows which index are considered for each row condition. | | `Scanned 0/1/all databases` | For `information_schema` tables. Shows how many times we had to do a directory scan. | | `Select tables` `optimized` `away` | All tables in the join was optimized away. This happens when we are only using `COUNT(*)`, `MIN()` and `MAX()` functions in the `SELECT` and we where able to replace all of these with constants. | | `Skip_open_table` | For `information_schema` tables. The queried table didn't need to be opened. | | `unique row not found` | The table was detected to be a const table (a table with only one possible matching row) during the early optimization phase, but no row was found. | | `Using filesort` | Filesort is needed to resolve the query. This means an extra phase where we first collect all columns to sort, sort them with a disk based merge sort and then use the sorted set to retrieve the rows in sorted order. If the column set is small, we store all the columns in the sort file to not have to go to the database to retrieve them again. | | `Using index` | Only the index is used to retrieve the needed information from the table. There is no need to perform an extra seek to retrieve the actual record. | | `Using index condition` | Like '`Using where`' but the where condition is pushed down to the table engine for internal optimization at the index level. | | `Using index condition(BKA)` | Like '`Using index condition`' but in addition we use batch key access to retrieve rows. | | `Using index for group-by` | The index is being used to resolve a `GROUP BY` or `DISTINCT` query. The rows are not read. This is very efficient if the table has a lot of identical index entries as duplicates are quickly jumped over. | | `Using intersect(...)` | For `index_merge` joins. Shows which index are part of the intersect. | | `Using join buffer` | We store previous row combinations in a row buffer to be able to match each row against all of the rows combinations in the join buffer at one go. | | `Using sort_union(...)` | For `index_merge` joins. Shows which index are part of the union. | | `Using temporary` | A temporary table is created to hold the result. This typically happens if you are using `GROUP BY`, `DISTINCT` or `ORDER BY`. | | `Using where` | A `WHERE` expression (in additional to the possible key lookup) is used to check if the row should be accepted. If you don't have 'Using where' together with a join type of `ALL`, you are probably doing something wrong! | | `Using where` `with` `pushed` `condition` | Like '`Using where`' but the where condition is pushed down to the table engine for internal optimization at the row level. | | `Using buffer` | The `UPDATE` statement will first buffer the rows, and then run the updates, rather than do updates on the fly. See [Using Buffer UPDATE Algorithm](../using-buffer-update-algorithm/index) for a detailed explanation. | ### EXPLAIN EXTENDED The `EXTENDED` keyword adds another column, *filtered*, to the output. This is a percentage estimate of the table rows that will be filtered by the condition. An `EXPLAIN EXTENDED` will always throw a warning, as it adds extra *Message* information to a subsequent `[SHOW WARNINGS](../show-warnings/index)` statement. This includes what the `SELECT` query would look like after optimizing and rewriting rules are applied and how the optimizer qualifies columns and tables. Examples -------- As synonym for `DESCRIBE` or `SHOW COLUMNS FROM`: ``` DESCRIBE city; +------------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+----------+------+-----+---------+----------------+ | Id | int(11) | NO | PRI | NULL | auto_increment | | Name | char(35) | YES | | NULL | | | Country | char(3) | NO | UNI | | | | District | char(20) | YES | MUL | | | | Population | int(11) | YES | | NULL | | +------------+----------+------+-----+---------+----------------+ ``` A simple set of examples to see how `EXPLAIN` can identify poor index usage: ``` CREATE TABLE IF NOT EXISTS `employees_example` ( `id` int(11) NOT NULL AUTO_INCREMENT, `first_name` varchar(30) NOT NULL, `last_name` varchar(40) NOT NULL, `position` varchar(25) NOT NULL, `home_address` varchar(50) NOT NULL, `home_phone` varchar(12) NOT NULL, `employee_code` varchar(25) NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `employee_code` (`employee_code`), KEY `first_name` (`first_name`,`last_name`) ) ENGINE=Aria; INSERT INTO `employees_example` (`first_name`, `last_name`, `position`, `home_address`, `home_phone`, `employee_code`) VALUES ('Mustapha', 'Mond', 'Chief Executive Officer', '692 Promiscuous Plaza', '326-555-3492', 'MM1'), ('Henry', 'Foster', 'Store Manager', '314 Savage Circle', '326-555-3847', 'HF1'), ('Bernard', 'Marx', 'Cashier', '1240 Ambient Avenue', '326-555-8456', 'BM1'), ('Lenina', 'Crowne', 'Cashier', '281 Bumblepuppy Boulevard', '328-555-2349', 'LC1'), ('Fanny', 'Crowne', 'Restocker', '1023 Bokanovsky Lane', '326-555-6329', 'FC1'), ('Helmholtz', 'Watson', 'Janitor', '944 Soma Court', '329-555-2478', 'HW1'); SHOW INDEXES FROM employees_example; +-------------------+------------+---------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | +-------------------+------------+---------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | employees_example | 0 | PRIMARY | 1 | id | A | 7 | NULL | NULL | | BTREE | | | | employees_example | 0 | employee_code | 1 | employee_code | A | 7 | NULL | NULL | | BTREE | | | | employees_example | 1 | first_name | 1 | first_name | A | NULL | NULL | NULL | | BTREE | | | | employees_example | 1 | first_name | 2 | last_name | A | NULL | NULL | NULL | | BTREE | | | +-------------------+------------+---------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ ``` `SELECT` on a primary key: ``` EXPLAIN SELECT * FROM employees_example WHERE id=1; +------+-------------+-------------------+-------+---------------+---------+---------+-------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+-------------------+-------+---------------+---------+---------+-------+------+-------+ | 1 | SIMPLE | employees_example | const | PRIMARY | PRIMARY | 4 | const | 1 | | +------+-------------+-------------------+-------+---------------+---------+---------+-------+------+-------+ ``` The type is *const*, which means that only one possible result could be returned. Now, returning the same record but searching by their phone number: ``` EXPLAIN SELECT * FROM employees_example WHERE home_phone='326-555-3492'; +------+-------------+-------------------+------+---------------+------+---------+------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+-------------------+------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | employees_example | ALL | NULL | NULL | NULL | NULL | 6 | Using where | +------+-------------+-------------------+------+---------------+------+---------+------+------+-------------+ ``` Here, the type is *All*, which means no index could be used. Looking at the rows count, a full table scan (all six rows) had to be performed in order to retrieve the record. If it's a requirement to search by phone number, an index will have to be created. [SHOW EXPLAIN](../show-explain/index) example: ``` SHOW EXPLAIN FOR 1; +------+-------------+-------+-------+---------------+------+---------+------+---------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+-------+-------+---------------+------+---------+------+---------+-------------+ | 1 | SIMPLE | tbl | index | NULL | a | 5 | NULL | 1000107 | Using index | +------+-------------+-------+-------+---------------+------+---------+------+---------+-------------+ 1 row in set, 1 warning (0.00 sec) ``` ### Example of `ref_or_null` Optimization ``` SELECT * FROM table_name WHERE key_column=expr OR key_column IS NULL; ``` `ref_or_null` is something that often happens when you use subqueries with `NOT IN` as then one has to do an extra check for `NULL` values if the first value didn't have a matching row. See Also -------- * [SHOW EXPLAIN](../show-explain/index) * [Ignored Indexes](../ignored-indexes/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb JSON_OBJECTAGG JSON\_OBJECTAGG =============== **MariaDB starting with [10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)**JSON\_OBJECTAGG was added in [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/). Syntax ------ ``` JSON_OBJECTAGG(key, value) ``` Description ----------- `JSON_OBJECTAGG` returns a JSON object containing key-value pairs. It takes two expressions that evaluate to a single value, or two column names, as arguments, the first used as a key, and the second as a value. Returns NULL in the case of an error, or if the result contains no rows. `JSON_OBJECTAGG` cannot currently be used as a [window function](../window-functions/index). Examples -------- ``` select * from t1; +------+-------+ | a | b | +------+-------+ | 1 | Hello | | 1 | World | | 2 | This | +------+-------+ SELECT JSON_OBJECTAGG(a, b) FROM t1; +----------------------------------------+ | JSON_OBJECTAGG(a, b) | +----------------------------------------+ | {"1":"Hello", "1":"World", "2":"This"} | +----------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Configuring PAM Authentication and User Mapping with Unix Authentication Configuring PAM Authentication and User Mapping with Unix Authentication ======================================================================== In this article, we will walk through the configuration of PAM authentication using the `[pam](../authentication-plugin-pam/index)` authentication plugin and user and group mapping with the `[pam\_user\_map](../user-and-group-mapping-with-pam/index)` PAM module. The primary authentication will be handled by the `[pam\_unix](https://linux.die.net/man/8/pam_unix)` PAM module, which performs standard Unix password authentication. Hypothetical Requirements ------------------------- In this walkthrough, we are going to assume the following hypothetical requirements: * The Unix user `foo` should be mapped to the MariaDB user `bar`. (`foo: bar`) * Any Unix user in the Unix group `dba` should be mapped to the MariaDB user `dba`. (`@dba: dba`) Creating Our Unix Users and Groups ---------------------------------- Let's go ahead and create the Unix users and groups that we are using for this hypothetical scenario. First, let's create the the `foo` user and a couple users to go into the `dba` group. Note that each of these users needs a password. ``` sudo useradd foo sudo passwd foo sudo useradd alice sudo passwd alice sudo useradd bob sudo passwd bob ``` And then let's create our `dba` group and add our two users to it: ``` sudo groupadd dba sudo usermod -a -G dba alice sudo usermod -a -G dba bob ``` We also need to create Unix users with the same name as the `bar` and `dba` MariaDB users. See [here](../user-and-group-mapping-with-pam/index#pam-user-with-same-name-as-mapped-mariadb-user-must-exist) to read more about why. No one will be logging in as these users, so they do not need passwords. ``` sudo useradd bar sudo useradd dba -g dba ``` Installing the pam\_user\_map PAM Module ---------------------------------------- Next, let's [install the pam\_user\_map PAM module](../user-and-group-mapping-with-pam/index#installing-the-pam_user_map-pam-module). Before the module can be compiled from source, we may need to install some dependencies. On RHEL, CentOS, and other similar Linux distributions that use [RPM packages](../rpm/index), we need to install `gcc` and `pam-devel`: ``` sudo yum install gcc pam-devel ``` On Debian, Ubuntu, and other similar Linux distributions that use [DEB packages](../installing-mariadb-deb-files/index), we need to install `gcc` and `libpam0g-dev`: ``` sudo apt-get install gcc libpam0g-dev ``` And then we can build and install the library with the following: ``` wget https://raw.githubusercontent.com/MariaDB/server/10.4/plugin/auth_pam/mapper/pam_user_map.c gcc pam_user_map.c -shared -lpam -fPIC -o pam_user_map.so sudo install --mode=0755 pam_user_map.so /lib64/security/ ``` Configuring the pam\_user\_map PAM Module ----------------------------------------- Next, let's [configure the pam\_user\_map PAM module](../user-and-group-mapping-with-pam/index#configuring-the-pam_user_map-pam-module) based on our hypothetical requirements. The configuration file for the `pam_user_map` PAM module is `/etc/security/user_map.conf`. Based on our hypothetical requirements, ours would look like: ``` foo: bar @dba:dba ``` Installing the PAM Authentication Plugin ---------------------------------------- Next, let's [install the `pam` authentication plugin](../authentication-plugin-pam/index#installing-the-plugin). Log into the MariaDB Server and execute the following: ``` INSTALL SONAME 'auth_pam'; ``` Configuring the PAM Service --------------------------- Next, let's [configure the PAM service](../authentication-plugin-pam/index#configuring-the-pam-service). We will call our service `mariadb`, so our PAM service configuration file will be located at `/etc/pam.d/mariadb` on most systems. Since we are only doing Unix authentication with the `pam_unix` PAM module and group mapping with the `pam_user_map` PAM module, our configuration file would look like this: ``` auth required pam_unix.so audit auth required pam_user_map.so account required pam_unix.so audit ``` Configuring the pam\_unix PAM Module ------------------------------------ The `pam_unix` PAM module adds [some additional configuration steps](../authentication-plugin-pam/index#configuring-the-pam-service) on a lot of systems. We basically have to give the user that runs `mysqld` access to `/etc/shadow`. If the `mysql` user is running `mysqld`, then we can do that by executing the following: ``` sudo groupadd shadow sudo usermod -a -G shadow mysql sudo chown root:shadow /etc/shadow sudo chmod g+r /etc/shadow ``` The [server needs to be restarted](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index) for this change to take affect. Creating MariaDB Users ---------------------- Next, let's [create the MariaDB users](../authentication-plugin-pam/index#creating-users). Remember that our PAM service is called `mariadb`. First, let's create the MariaDB user for the user mapping: `foo: bar` That means that we need to create a `bar` user: ``` CREATE USER 'bar'@'%' IDENTIFIED BY 'strongpassword'; GRANT ALL PRIVILEGES ON *.* TO 'bar'@'%' ; ``` And then let's create the MariaDB user for the group mapping: `@dba: dba` That means that we need to create a `dba` user: ``` CREATE USER 'dba'@'%' IDENTIFIED BY 'strongpassword'; GRANT ALL PRIVILEGES ON *.* TO 'dba'@'%' ; ``` And then to allow for the user and group mapping, we need to [create an anonymous user that authenticates with the `pam` authentication plugin](../user-and-group-mapping-with-pam/index#creating-users) that is also able to `PROXY` as the `bar` and `dba` users. Before we can create the proxy user, we might need to [clean up some defaults](../create-user/index#fixing-a-legacy-default-anonymous-account): ``` DELETE FROM mysql.db WHERE User='' AND Host='%'; FLUSH PRIVILEGES; ``` And then let's create the anonymous proxy user: ``` CREATE USER ''@'%' IDENTIFIED VIA pam USING 'mariadb'; GRANT PROXY ON 'bar'@'%' TO ''@'%'; GRANT PROXY ON 'dba'@'%' TO ''@'%'; ``` Testing our Configuration ------------------------- Next, let's test out our configuration by [verifying that mapping is occurring](../user-and-group-mapping-with-pam/index#verifying-that-mapping-is-occurring). We can verify this by logging in as each of our users and comparing the return value of `[USER()](../user/index)`, which is the original user name and the return value of `[CURRENT\_USER()](../current_user/index)`, which is the authenticated user name. First, let's test out our `foo` user: ``` $ mysql -u foo -h 172.30.0.198 [mariadb] Password: Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 22 Server version: 10.3.10-MariaDB MariaDB Server Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> SELECT USER(), CURRENT_USER(); +------------------------------------------------+----------------+ | USER() | CURRENT_USER() | +------------------------------------------------+----------------+ | [email protected] | bar@% | +------------------------------------------------+----------------+ 1 row in set (0.000 sec) ``` We can verify that our `foo` Unix user was properly mapped to the `bar` MariaDB user by looking at the return value of `[CURRENT\_USER()](../current_user/index)`. Then let's test out our `alice` user in the `dba` group: ``` $ mysql -u alice -h 172.30.0.198 [mariadb] Password: Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 19 Server version: 10.3.10-MariaDB MariaDB Server Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> SELECT USER(), CURRENT_USER(); +--------------------------------------------------+----------------+ | USER() | CURRENT_USER() | +--------------------------------------------------+----------------+ | [email protected] | dba@% | +--------------------------------------------------+----------------+ 1 row in set (0.000 sec) ``` And then let's test out our `bob` user in the `dba` group: ``` $ mysql -u bob -h 172.30.0.198 [mariadb] Password: Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 20 Server version: 10.3.10-MariaDB MariaDB Server Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> SELECT USER(), CURRENT_USER(); +------------------------------------------------+----------------+ | USER() | CURRENT_USER() | +------------------------------------------------+----------------+ | [email protected] | dba@% | +------------------------------------------------+----------------+ 1 row in set (0.000 sec) ``` We can verify that our `alice` and `bob` Unix users in the `dba` Unix group were properly mapped to the `dba` MariaDB user by looking at the return values of `[CURRENT\_USER()](../current_user/index)`. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHA2 SHA2 ==== Syntax ------ ``` SHA2(str,hash_len) ``` Description ----------- Given a string *`str`*, calculates an SHA-2 checksum, which is considered more cryptographically secure than its [SHA-1](../sha1/index) equivalent. The SHA-2 family includes SHA-224, SHA-256, SHA-384, and SHA-512, and the *`hash_len`* must correspond to one of these, i.e. 224, 256, 384 or 512. 0 is equivalent to 256. The return value is a nonbinary string in the connection [character set and collation](../data-types-character-sets-and-collations/index), determined by the values of the [character\_set\_connection](../server-system-variables/index#character_set_connection) and [collation\_connection](../server-system-variables/index#collation_connection) system variables. NULL is returned if the hash length is not valid, or the string `str` is NULL. SHA2 will only work if MariaDB was has been configured with [TLS support](../secure-connections-overview/index). Examples -------- ``` SELECT SHA2('Maria',224); +----------------------------------------------------------+ | SHA2('Maria',224) | +----------------------------------------------------------+ | 6cc67add32286412efcab9d0e1675a43a5c2ef3cec8879f81516ff83 | +----------------------------------------------------------+ SELECT SHA2('Maria',256); +------------------------------------------------------------------+ | SHA2('Maria',256) | +------------------------------------------------------------------+ | 9ff18ebe7449349f358e3af0b57cf7a032c1c6b2272cb2656ff85eb112232f16 | +------------------------------------------------------------------+ SELECT SHA2('Maria',0); +------------------------------------------------------------------+ | SHA2('Maria',0) | +------------------------------------------------------------------+ | 9ff18ebe7449349f358e3af0b57cf7a032c1c6b2272cb2656ff85eb112232f16 | +------------------------------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Installation issues on Windows Installation issues on Windows ============================== [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/) ------------------------------------------------------------------------- [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/) may not start on Windows. See [MDEV-22555](https://jira.mariadb.org/browse/MDEV-22555). To resolve this, download, click and install <https://aka.ms/vs/16/release/vc_redist.x64.exe> and then install 10.4.13. Unsupported Versions of Windows ------------------------------- Recent versions of MariaDB may not install on unsupported Windows versions. See [Deprecated Package Platforms](../deprecation-policy/index#deprecated-package-platforms) to find the final supported versions. [MariaDB 5.2.5](https://mariadb.com/kb/en/mariadb-525-release-notes/) and earlier ---------------------------------------------------------------------------------- ### On Windows Vista/7 , changes to database or my.ini are not persistent, when mysqld.exe is run from the command line. The reason for this behavior is Vista/Win7 file system redirection. Writes to protected locations (in this case a subdirectory of Program Files) are redirected to the user's so-called "Virtual Store". Workarounds: * Run mysqld.exe as service. See answer [here](http://stackoverflow.com/questions/4962342/mariadb-on-windows-what-is-this-error-when-trying-to-start-the-database-engine) on how to create a MariaDB service. * Run mysqld.exe from the [elevated command prompt](http://www.winhelponline.com/articles/158/1/How-to-open-an-elevated-Command-Prompt-in-Windows-Vista.html). * [Change the ACL](http://technet.microsoft.com/en-us/library/bb727008.aspx) of the data directory and add full control for the current user. The Windows installer for [MariaDB 5.2.6](https://mariadb.com/kb/en/mariadb-526-release-notes/) and higher will set the data directory ACL to include full access rights for the user who runs the setup to prevent this issue from happening. Systems with User Account Control --------------------------------- Running `mysql_install_db.exe` from a standard command prompt might cause the error: ``` FATAL ERROR: OpenSCManager failed ``` To get rid of it, use the elevated command prompt, for example on Windows 7 start it via 'Run as administrator' option. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Testing the Connections to S3 Testing the Connections to S3 ============================= **MariaDB starting with [10.5](../what-is-mariadb-105/index)**The [S3 storage engine](../s3-storage-engine/index) has been available since [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/). If you can't get the S3 storage engine to work, here are some steps to help verify where the problem could be. S3 Connection Variables ----------------------- In most cases the problem is to correctly set the S3 connection variables. The variables are: * **[s3\_access\_key](../s3-storage-engine-system-variables/index#s3_access_key):** The AWS access key to access your data * **[s3\_secret\_key](../s3-storage-engine-system-variables/index#s3_secret_key):** The AWS secret key to access your data * **[s3\_bucket](../s3-storage-engine-system-variables/index#s3_bucket):** The AWS bucket where your data should be stored. All MariaDB table data is stored in this bucket. * **[s3\_region](../s3-storage-engine-system-variables/index#s3_region):** The AWS region where your data should be stored. * **[s3\_host\_name](../s3-storage-engine-system-variables/index#s3_host_name):** Hostname for the S3 service. * **[s3\_protocol\_version](../s3-storage-engine-system-variables/index#s3_protocol_version):** Protocol used to communicate with S3. One of "Amazon" or "Original" There are several ways to ensure you get them right: ### Using aria\_s3\_copy to Test the Connection [aria\_s3\_copy](../aria_s3_copy/index) is a tool that allows you to copy [aria](../aria/index) tables to and from S3. It's useful for testing the connection as it allows you to specify all s3 options on the command line. Execute the following sql commands to create a trivial sql table: ``` use test; create table s3_test (a int) engine=aria row_format=page transactional=0; insert into s3_test values (1),(2); flush tables s3_test; ``` Now you can use the [aria\_s3\_copy](../aria_s3_copy/index) tool to copy this to S3 from your shell/the command line: ``` shell> cd mariadb-data-directory/test shell> aria_s3_copy --op=to --verbose --force --**other*options* s3_test.frm Copying frm file s3_test.frm Copying aria table: test.s3_test to s3 Creating aria table information test/s3_test/aria Copying index information test/s3_test/index Copying data information test/s3_test/data ``` As you can see from the above, [aria\_s3\_copy](../aria_s3_copy/index) is using the current directory as the database name. You can also set the [aria\_s3\_copy](../aria_s3_copy/index) options in your my.cnf file to avoid some typing. ### Using mysql-test-run to Test the Connection and the S3 Storage Engine One can use the [MariaDB test system](../mysqltest/index) to run all default S3 test against your S3 storage. To do that you have to locate the `mysql-test` directory in your system and `cd` to it. The config file for the S3 test system can be found at `suite/s3/my.cnf`. To enable testing you have to edit this file and add the s3 connection options to the end of the file. It should look something like this after editing: ``` !include include/default_mysqld.cnf !include include/default_client.cnf [mysqld.1] s3=ON #s3-host-name=s3.amazonaws.com #s3-protocol-version=Amazon s3-bucket=MariaDB s3-access-key= s3-secret-key= s3-region= ``` You must give values for `s3-access-key`, `s3-secret-key` and `s3-region` that reflects your S3 provider. The `s3-bucket` name is defined by your administrator. If you are not using Amazon Web Services as your S3 provider you must also specify `s3-hostname` and possibly change `s3-protocol-version` to "Original". Now you can test the configuration: ``` shell> cd **mysql-test** directory shell> ./mysql-test-run --suite=s3 ... s3.no_s3 [ pass ] 5 s3.alter [ pass ] 11073 s3.arguments [ pass ] 2667 s3.basic [ pass ] 2757 s3.discovery [ pass ] 7851 s3.select [ pass ] 1325 s3.unsupported [ pass ] 363 ``` Note that there may be more tests in your output as we are constantly adding more tests to S3 when needed. What to Do Next --------------- When you got the connection to work, you should add the options to your global my.cnf file. Now you can start testing S3 from your [mysql command client](../mysql-command-line-client/index) by converting some existing table to S3 with [ALTER TABLE ... ENGINE=S3](../using-the-s3-storage-engine/index). See Also -------- * [Using the S3 Storage Engine](../using-the-s3-storage-engine/index) * [Using MinIO with mysql-test-run to test the S3 storage engine](../installing-minio-for-usage-with-mysql-test-run/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Information Schema INNODB_CMPMEM and INNODB_CMPMEM_RESET Tables Information Schema INNODB\_CMPMEM and INNODB\_CMPMEM\_RESET Tables ================================================================== The `INNODB_CMPMEM` and `INNODB_CMPMEM_RESET` tables contain status information on compressed pages in the [buffer pool](../innodb-buffer-pool/index) (see InnoDB [COMPRESSED](../innodb-storage-formats/index#compressed) format). The [PROCESS](../grant/index#global-privileges) privilege is required to query this table. These tables contain the following columns: | Column Name | Description | | --- | --- | | `PAGE_SIZE` | Compressed page size, in bytes. This value is unique in the table; other values are totals which refer to pages of this size. | | `BUFFER_POOL_INSTANCE` | Buffer Pool identifier. From [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/) returns a value of 0, since multiple InnoDB buffer pool instances has been removed. | | `PAGES_USED` | Number of pages of the size `PAGE_SIZE` which are currently in the buffer pool. | | `PAGES_FREE` | Number of pages of the size `PAGE_SIZE` which are currently free, and thus are available for allocation. This value represents the buffer pool's fragmentation. A totally unfragmented buffer pool has at most 1 free page. | | `RELOCATION_OPS` | How many times a page of the size `PAGE_SIZE` has been relocated. This happens when data exceeds a page (because a row must be copied into a new page) and when two pages are merged (because their data shrunk and can now be contained in one page). | | `RELOCATION_TIME` | Time (in seconds) spent in relocation operations for pages of the size `PAGE_SIZE`. This column is reset when the `INNODB_CMPMEM_RESET` table is queried. | These tables can be used to measure the effectiveness of InnoDB table compression. When you have to decide a value for `KEY_BLOCK_SIZE`, you can create more than one version of the table (one for each candidate value) and run a realistic workload on them. Then, these tables can be used to see how the operations performed with different page sizes. `INNODB_CMPMEM` and `INNODB_CMPMEM_RESET` have the same columns and always contain the same values, but when `INNODB_CMPMEM_RESET` is queried, the `RELOCATION_TIME` column from both the tables are cleared. `INNODB_CMPMEM_RESET` can be used, for example, if a script periodically logs the performances of compression in the last period of time. `INNODB_CMPMEM` can be used to see the cumulated statistics. Example ------- ``` SELECT * FROM information_schema.INNODB_CMPMEM\G ********************** 1. row ********************** page_size: 1024 buffer_pool_instance: 0 pages_used: 0 pages_free: 0 reloacation_ops: 0 relocation_time: 0 ``` See Also -------- Other tables that can be used to monitor InnoDB compressed tables: * [INNODB\_CMP and INNODB\_CMP\_RESET](../information_schemainnodb_cmp-and-innodb_cmp_reset-tables/index) * [INNODB\_CMP\_PER\_INDEX and INNODB\_CMP\_PER\_INDEX\_RESET](../information_schemainnodb_cmp_per_index-and-innodb_cmp_per_index_reset-table/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb BIGINT BIGINT ====== Syntax ------ ``` BIGINT[(M)] [SIGNED | UNSIGNED | ZEROFILL] ``` Description ----------- A large integer. The signed range is `-9223372036854775808` to `9223372036854775807`. The unsigned range is `0` to `18446744073709551615`. If a column has been set to ZEROFILL, all values will be prepended by zeros so that the BIGINT value contains a number of M digits. **Note:** If the ZEROFILL attribute has been specified, the column will automatically become UNSIGNED. For more details on the attributes, see [Numeric Data Type Overview](../numeric-data-type-overview/index). `SERIAL` is an alias for: ``` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE ``` `INT8` is a synonym for `BIGINT`. Examples -------- ``` CREATE TABLE bigints (a BIGINT,b BIGINT UNSIGNED,c BIGINT ZEROFILL); ``` With [strict\_mode](../sql-mode/index#strict-mode) set, the default from [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/): ``` INSERT INTO bigints VALUES (-10,-10,-10); ERROR 1264 (22003): Out of range value for column 'b' at row 1 INSERT INTO bigints VALUES (-10,10,-10); ERROR 1264 (22003): Out of range value for column 'c' at row 1 INSERT INTO bigints VALUES (-10,10,10); INSERT INTO bigints VALUES (9223372036854775808,9223372036854775808,9223372036854775808); ERROR 1264 (22003): Out of range value for column 'a' at row 1 INSERT INTO bigints VALUES (9223372036854775807,9223372036854775808,9223372036854775808); SELECT * FROM bigints; +---------------------+---------------------+----------------------+ | a | b | c | +---------------------+---------------------+----------------------+ | -10 | 10 | 00000000000000000010 | | 9223372036854775807 | 9223372036854775808 | 09223372036854775808 | +---------------------+---------------------+----------------------+ ``` With [strict\_mode](../sql-mode/index#strict-mode) unset, the default until [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/): ``` INSERT INTO bigints VALUES (-10,-10,-10); Query OK, 1 row affected, 2 warnings (0.08 sec) Warning (Code 1264): Out of range value for column 'b' at row 1 Warning (Code 1264): Out of range value for column 'c' at row 1 INSERT INTO bigints VALUES (-10,10,-10); Query OK, 1 row affected, 1 warning (0.08 sec) Warning (Code 1264): Out of range value for column 'c' at row 1 INSERT INTO bigints VALUES (-10,10,10); INSERT INTO bigints VALUES (9223372036854775808,9223372036854775808,9223372036854775808); Query OK, 1 row affected, 1 warning (0.07 sec) Warning (Code 1264): Out of range value for column 'a' at row 1 INSERT INTO bigints VALUES (9223372036854775807,9223372036854775808,9223372036854775808); SELECT * FROM bigints; +---------------------+---------------------+----------------------+ | a | b | c | +---------------------+---------------------+----------------------+ | -10 | 0 | 00000000000000000000 | | -10 | 10 | 00000000000000000000 | | -10 | 10 | 00000000000000000010 | | 9223372036854775807 | 9223372036854775808 | 09223372036854775808 | | 9223372036854775807 | 9223372036854775808 | 09223372036854775808 | +---------------------+---------------------+----------------------+ ``` See Also -------- * [Numeric Data Type Overview](../numeric-data-type-overview/index) * [TINYINT](../tinyint/index) * [SMALLINT](../smallint/index) * [MEDIUMINT](../mediumint/index) * [INTEGER](../int/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Oracle XE 11.2. and MariaDB 10.1 integration on Ubuntu 14.04 and Debian systems Oracle XE 11.2. and MariaDB 10.1 integration on Ubuntu 14.04 and Debian systems =============================================================================== 1) Sign up for Oracle downloads and download Oracle Express at: <http://www.oracle.com/technetwork/database/database-technologies/express-edition/downloads/index.html> - Sign up (unless already) and log in. - Accept the license agreement. - Download Oracle Database Express Edition 11g Release 2 for Linux x64 (oracle-xe-11.2.0-1.0.x86\_64.rpm.zip, version numbers may change over time) 2) Prepare apt-get on your system ``` sudo add-apt-repository ppa:webupd8team/java <press Enter to accept> sudo apt-get update sudo apt-get install oracle-java8-installer ``` 3) After Java installation, verify the version ``` java -version java version "1.8.0_121" ``` 4) Edit /etc/bash.bashrc Scroll to the bottom of the file and add the following lines. ``` export JAVA_HOME=/usr/lib/jvm/java-8-oracle export PATH=$JAVA_HOME/bin:$PATH ``` Save and check: ``` source /etc/bash.bashrc echo $JAVA_HOME /usr/lib/jvm/java-8-oracle ``` 5) Additional packages are required, unless installed already. Run the command: ``` sudo apt-get install alien libaio1 unixodbc ``` 6) ``` unzip oracle-xe-11.2.0-1.0.x86_64.rpm.zip cd Disk1/ sudo alien --scripts -d oracle-xe-11.2.0-1.0.x86_64.rpm ``` This step might take some time. You may proceed steps 7)-11) in the meanwhile in another terminal window. 7) Create a new file /sbin/chkconfig and add the following contents ``` #!/bin/bash # Oracle 11gR2 XE installer chkconfig for Ubuntu file=/etc/init.d/oracle-xe if [[ ! `tail -n1 $file | grep INIT` ]]; then echo >> $file echo '### BEGIN INIT INFO' >> $file echo '# Provides: OracleXE' >> $file echo '# Required-Start: $remote_fs $syslog' >> $file echo '# Required-Stop: $remote_fs $syslog' >> $file echo '# Default-Start: 2 3 4 5' >> $file echo '# Default-Stop: 0 1 6' >> $file echo '# Short-Description: Oracle 11g Express Edition' >> $file echo '### END INIT INFO' >> $file fi update-rc.d oracle-xe defaults 80 01 #EOF ``` 8) ``` sudo chmod 755 /sbin/chkconfig ``` 9) Create a new file /etc/sysctl.d/60-oracle.conf Copy and paste the following into the file. Kernel.shmmax is the maximum possible value of physical RAM in bytes. 536870912 / 1024 /1024 = 512 MB. ``` #Oracle 11g XE kernel parameters fs.file-max=6815744 net.ipv4.ip_local_port_range=9000 65000 kernel.sem=250 32000 100 128 kernel.shmmax=536870912 ``` 10) ``` sudo service procps start sudo sysctl -q fs.file-max ``` 1. This method should return the following: fs.file-max = 6815744 11) Some additional steps required ``` sudo ln -s /usr/bin/awk /bin/awk mkdir /var/lock/subsys touch /var/lock/subsys/listener ``` 12) Install Oracle XE (should have been converted from .rpm to .deb by now) ``` sudo dpkg --install oracle-xe_11.2.0-2_amd64.deb ``` 13) Execute the following to avoid getting a ORA-00845: MEMORY\_TARGET error. Note: replace "size=4096m" with the size of your (virtual) machine RAM in MBs. ``` sudo rm -rf /dev/shm sudo mkdir /dev/shm sudo mount -t tmpfs shmfs -o size=4096m /dev/shm ``` 14) Create the file /etc/rc2.d/S01shm\_load NOTE: replace "size=4096m" with the size of your machine RAM in MBS. ``` #!/bin/sh case "$1" in start) mkdir /var/lock/subsys 2>/dev/null touch /var/lock/subsys/listener rm /dev/shm 2>/dev/null mkdir /dev/shm 2>/dev/null mount -t tmpfs shmfs -o size=4096m /dev/shm ;; *) echo error exit 1 ;; esac ``` ``` sudo chmod 755 /etc/rc2.d/S01shm_load ``` 15) Configure Oracle 11g R2 Express Edition. Default answers are probably OK. ``` sudo /etc/init.d/oracle-xe configure ``` Specify the HTTP port that will be used for Oracle Application Express [8080]: Specify a port that will be used for the database listener [1521]: Specify a password to be used for database accounts. Note that the same password will be used for SYS and SYSTEM. Oracle recommends the use of different passwords for each database account. This can be done after initial configuration: Do you want Oracle Database 11g Express Edition to be started on boot (y/n) [y]: 16) Edit /etc/bash.bashrc. Add to the end of the file: ``` export ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe export ORACLE_SID=XE export NLS_LANG=`$ORACLE_HOME/bin/nls_lang.sh` export ORACLE_BASE=/u01/app/oracle export LD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATH export PATH=$ORACLE_HOME/bin:$PATH ``` Save. 17) Run source command and check that the output makes sense ``` source /etc/bash.bashrc echo $ORACLE_HOME /u01/app/oracle/product/11.2.0/xe ``` 18) Apply desktop icon changes and start Oracle: ``` sudo chmod a+x ~/Desktop/oraclexe-gettingstarted.desktop sudo service oracle-xe start ``` 19) Download SQL Developer package Download Oracle SQL Developer from the Oracle site. Select the Linux RPM package: <http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html> Choose the Linux RPM package. 20) Install SQL Developer ``` sudo alien --scripts -d sqldeveloper-4.1.5.21.78-1.noarch.rpm sudo dpkg --install sqldeveloper_4.1.5.21.78-2_all.deb mkdir ~/.sqldeveloper ``` 21) Run sqldeveloper: ``` sudo /opt/sqldeveloper/sqldeveloper.sh ``` 1. Tell sqldeveloper the correct Java path, if it asks for it: /usr/lib/jvm/java-8-oracle ``` - Click connections - Add new connection - Connection name: XE - username: SYSTEM - password: <your-password> - Connection type: Basic Role: Default - Hostname: localhost - Port: 1521 - SID: xe ``` MariaDB ------- 22) Install MariaDB <https://downloads.mariadb.org/mariadb/repositories/> Instructions are for Ubuntu, but choose the one that is appropriate: - Ubuntu - 14.04 LTS "trusty" - 10.1 [Stable] - choose a mirror Run the commands given for you. For example (DO NOT COPY PASTE BELOW, CHECK WHAT THE MariaDB PAGE TELLS YOU TO DO): ``` sudo apt-get install software-properties-common sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xcbcb082a1bb943db sudo add-apt-repository 'deb [arch=amd64,i386,ppc64el] http://mirror.netinch.com/pub/mariadb/repo/10.1/ubuntu trusty main' sudo apt-get update ``` 1. Install mariadb-server: ``` sudo apt-get install mariadb-server ``` 23) Install ODBC driver <https://downloads.mariadb.org/connector-odbc/> 1. MariaDB Connector/ODBC 2.0.13 Stable for Linux Download: mariadb-connector-[ODBC-2](https://jira.mariadb.org/browse/ODBC-2).0.13-ga-linux-x86\_64.tar.gz ``` tar xfz mariadb-connector-odbc-2.0.13-ga-linux-x86_64.tar.gz sudo cp -p mariadb-connector-odbc-2.0.13-ga-linux-x86_64/lib/libmaodbc.so /lib sudo ldconfig ``` 24) Install unixodbc and mariadb-connect engine ``` apt-get install unixodbc-dev apt-get install unixodbc-bin apt-get install unixodbc apt-get install libodbc1 apt-get install mariadb-connect-engine-10.1 ``` 25) Edit /etc/odbcinst.ini Add: ``` [Oracle ODBC driver for Oracle 11.2] Description = Oracle 11.2 ODBC driver Driver = /u01/app/oracle/product/11.2.0/xe/lib/libsqora.so.11.1 ``` 26) Edit /etc/odbc.ini Add (check your password): ``` [XE] Driver = Oracle ODBC driver for Oracle 11.2 ServerName = //localhost:1521/xe DSN = XE UserName = SYSTEM Password = <your-password> ``` 27) Test ODBC connection and add a table ``` isql -v XE SYSTEM <your-password> create table t1 (i int); insert into t1 (i) values (1); insert into t1 (i) values (3); insert into t1 (i) values (5); insert into t1 (i) values (8); select i from t1; ``` And you should see the rows. You can test the same with sqldeveloper, open XE connection and run select i from t1; in Worksheet. 28) Edit /etc/init.d/mysql Add: ``` export JAVA_HOME=/usr/lib/jvm/java-8-oracle export PATH=$JAVA_HOME/bin:$PATH export ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe export CLIENT_HOME=$ORACLE_HOME export ORACLE_SID=XE export NLS_LANG=`$ORACLE_HOME/bin/nls_lang.sh` export ORACLE_BASE=/u01/app/oracle export LD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATH export PATH=$ORACLE_HOME/bin:$PATH ``` Right after END INIT INFO. Otherwise mysqld will not find the Oracle ODBC driver. 28) Restart MariaDB ``` sudo /etc/init.d/mysql restart ``` 29) ``` mysql -uroot -p CREATE DATABASE mdb; USE mdb; INSTALL SONAME 'ha_connect'; CREATE TABLE t1 ENGINE=CONNECT TABLE_TYPE=ODBC tabname='T1' CONNECTION='DSN=XE;UID=SYSTEM;PWD=<your-password>'; select I from t1; ``` You should see the previously inserted values 1,3,5 and 8. Using isql or sqldeveloper, add another rows with values 9 and 11. Remember to commit, if you are using Oracle sqldeveloper. You should now see the added values via MariaDB client (mysql-client) connection. To be examined: inserting values to the t1 table from mariadb connection does not work. It gives a precision error from Oracle side. Connect to MariaDB via JDBC --------------------------- Download MySQL Connector from <https://dev.mysql.com/downloads/connector/j/5.0.html> Select Version (for example 5.0.8) Platform independent. Download mysql-connector-java-5.0.8.tar.gz ``` tar xvfz mysql-connector-java-5.0.8.tar.gz cd mysql-connector-java-5.0.8/ sudo cp -p mysql-connector-java-5.0.8-bin.jar /usr/lib/jvm/java-8-oracle/lib/mariadb/ sudo /opt/sqldeveloper/sqldeveloper.sh ``` In SQL Developer choose Tools -> Preferences Expand the "Database" option in the left hand tree Click on "Third Party JDBC Drivers" Click on "Add Entry..." Navigate to your third-party driver jar file and choose OK /usr/lib/jvm/java-8-oracle/lib/mariadb/mysql-connector-java-5.0.8-bin.jar Click Connections -> New connection. Add values. The following are examples: ``` Connection Name: MariaDB via MySQL Conn Username: root Password: ******** Save Password: [x] Choose MySQL tab Hostname: localhost Port: 3306 Click "Test Connection". It should says Status: Success. Click Save. Click Connect. ``` You are connected. You may run commands in the Worksheet. For example: use mdb; show tables; You should see the tables. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Building PBXT Building PBXT ============= As of [MariaDB 5.5](../what-is-mariadb-55/index) PBXT is not built by default any longer. The commands to use for building the [MariaDB 5.5 source](../compiling-mariadb-from-source/index) with PBXT: ``` cmake -DWITH_PBXT_STORAGE_ENGINE=1 . make make install ``` It should be noted that MariaDB still ships the engine, it just does not build it by default. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb LevelDB Storage Engine Development LevelDB Storage Engine Development ================================== Items that are considered for development of [LevelDB Storage Engine](../leveldb-storage-engine/index) after [Milestone #1](../leveldb-storage-engine-ms1/index) is complete. [DONE] AUTO\_INCREMENT ---------------------- See [MDEV-4110](https://jira.mariadb.org/browse/MDEV-4110). [DONE] Use table/index numbers as prefixes ------------------------------------------ (The Jira entry for this task is [MDEV-4122](https://jira.mariadb.org/browse/MDEV-4122)) Currently, keys are prefixed with ``` dbname.table_name$INDEX_NO\0 ``` where INDEX\_NO is one byte with the number of index, counting from 1. With this: * Renaming a table is very slow. This is a problem, because ALTER TABLE assumes table rename is a fast, O(1) operation. * DROP TABLE needs to delete every row, it is not possible to do the deletions later in the background. If one wants to run `DROP TABLE t; CREATE TABLE t; ...` then CREATE TABLE will have to wait until DROP has truly finished. * Dropping a table and creating another table with a different DDL causes deleted records of the first table to be compared with DDL of the second. This particular issue (but not others) can be avoided if we switch to keys that are compared with memcmp(). ### Proposed solution LevelDB keys should look like this (for both table records and secondary indexes): ``` [indexnr] key_data ``` where `indexnr` is an index number, which is assigned sequentially, and is not a function of dbname.tablename. The "data dictionary" will need to have two mappings: ``` index2ddl index_no -> index_ddl_data table2indexes dbname.tablename -> (index_no, index_no, ...) ``` index2ddl will be used to make comparisons when LevelDB requests them. table2indexes will tell us what to read when SQL layer requests to read (or write) records for dbname.tablename. DROP TABLE will remove table's entry from table2indexes. Actual record deletion can be done in the background. index2ddl entries can remain forever, so we will not face potential crashes when LevelDB tries to compare long-deleted records. RENAME TABLE will modify the entry in table2indexes. This is an O(1) operation. TRUNCATE TABLE will remove the entry in table2indexes and add another one, with different values of index\_no. Actual row deletion can be done in the background. memcmp'able keys ---------------- Current way to compare keys (find the table DDL in the hash, then use ha\_key\_cmp()) is likely to be slow. The advantages of current scheme are * It is possible to restore field values from index tuple, which means index-only scans are always possible. * Keys are "packed" - for example, endspace is removed from CHAR(n) fields. *not that these matter much. In the benchmark of interest, most of indexed values are integers. There is a VARCHAR column with charset=latin1*. If we switched to keys that were comparable with memcmp(), one could expect comparisons to become faster. ### Making keys comparable #### Falcon SE Falcon did use memcmp() to compare index tuples. Looking into the source (it is available for download still), one can see the comparison being somewhere around: ``` void Index::makeKey(Field *field, Value *value, int segment, IndexKey *indexKey, bool highKey) void Index::makeMultiSegmentKey(int count, Value **values, IndexKey *indexKey, bool highKey) ... void IndexKey::appendNumber(double number) ^^ makes double numbers memcmp'able... ``` unfortunately, there is no single, isolated part of code that we could copy. (Or may be there is, but we were not able to find it yet). #### Field::make\_sort\_key Found this in the source: ``` /** Writes a copy of the current value in the record buffer, suitable for sorting using byte-by-byte comparison. Integers are always in big-endian regardless of hardware architecture. At most length bytes are written into the buffer. @param buff The buffer, assumed to be at least length bytes. @param length Number of bytes to write. */ virtual void make_sort_key(uchar *buff, uint length) = 0; ``` Looks like this is exactly what we needed? Fewer mutexes ------------- Current code initializes/uses a mutex for every row lock taken. According to Monty, having lots of mutexes that are spread out all over the memory will slow things down, and we should switch to fewer mutexes (this is a basic description). Maybe, it makes sense to use mutex/condition from waiter's struct st\_my\_thread\_var. Not included in MS2 ------------------- ### Improve AUTO\_INCREMENT handling If there is no replication, then nothing is missing? The effect of ``` ALTER TABLE tbl AUTO_INCREMENT=nnn ``` does not survive the server restart for leveldb tables. But neither it does for InnoDB (at least, when replication is not in use). To our best knowledge, AUTO\_INCREMENT handling is adequate for non-replication use cases. ### Partial indexes Currently, leveldb doesn't support indexes that cover a part of the column, e.g. ``` CREATE TABLE t1 ( pk int primary key, col1 varchar(100), INDEX i1 (col1(10)) ); ``` Adding them is just a question of careful coding/testing. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb mysql.roles_mapping Table mysql.roles\_mapping Table ========================== The `mysql.roles_mapping` table contains information about mariaDB [roles](../roles/index). **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this table uses the [Aria](../aria/index) storage engine. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. The `mysql.roles_mapping` table contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | `Host` | `char(60)` | NO | PRI | | Host (together with `User` and `Role` makes up the unique identifier for this record. | | `User` | `char(80)` | NO | PRI | | User (together with `Host` and `Role` makes up the unique identifier for this record. | | `Role` | `char(80)` | NO | PRI | | Role (together with `Host` and `User` makes up the unique identifier for this record. | | `Admin_option` | `enum('N','Y')` | NO | | N | Whether the role can be granted (see the [CREATE ROLE](../create-role/index) `WITH ADMIN` clause). | The [Acl\_role\_grants](../server-status-variables/index#acl_role_grants) status variable, added in [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/), indicates how many rows the `mysql.roles_mapping` table contains. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Merging TokuDB (obsolete) Merging TokuDB (obsolete) ========================= **Note:** This page is obsolete. The information is old, outdated, or otherwise currently incorrect. We are keeping the page for historical reasons only. **Do not** rely on the information in this article. We merge TokuDB from Tokutek **git** repositories on GutHub: * <https://github.com/Tokutek/tokudb-engine> * <https://github.com/Tokutek/ft-index> Just merge normally at release points (use tag names) and don't forget to update `storage/tokudb/CMakeLists.txt`, setting `TOKUDB_VERSION` correctly. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CASE OPERATOR CASE OPERATOR ============= Syntax ------ ``` CASE value WHEN [compare_value] THEN result [WHEN [compare_value] THEN result ...] [ELSE result] END CASE WHEN [condition] THEN result [WHEN [condition] THEN result ...] [ELSE result] END ``` Description ----------- The first version returns the result where value=compare\_value. The second version returns the result for the first condition that is true. If there was no matching result value, the result after ELSE is returned, or NULL if there is no ELSE part. There is also a [CASE statement](../case-statement/index), which differs from the CASE operator described here. Examples -------- ``` SELECT CASE 1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'more' END; +------------------------------------------------------------+ | CASE 1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'more' END | +------------------------------------------------------------+ | one | +------------------------------------------------------------+ SELECT CASE WHEN 1>0 THEN 'true' ELSE 'false' END; +--------------------------------------------+ | CASE WHEN 1>0 THEN 'true' ELSE 'false' END | +--------------------------------------------+ | true | +--------------------------------------------+ SELECT CASE BINARY 'B' WHEN 'a' THEN 1 WHEN 'b' THEN 2 END; +-----------------------------------------------------+ | CASE BINARY 'B' WHEN 'a' THEN 1 WHEN 'b' THEN 2 END | +-----------------------------------------------------+ | NULL | +-----------------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CREATE SEQUENCE CREATE SEQUENCE =============== **MariaDB starting with [10.3](../what-is-mariadb-103/index)**CREATE SEQUENCE was introduced in [MariaDB 10.3](../what-is-mariadb-103/index). Syntax ------ ``` CREATE [OR REPLACE] [TEMPORARY] SEQUENCE [IF NOT EXISTS] sequence_name [ INCREMENT [ BY | = ] increment ] [ MINVALUE [=] minvalue | NO MINVALUE | NOMINVALUE ] [ MAXVALUE [=] maxvalue | NO MAXVALUE | NOMAXVALUE ] [ START [ WITH | = ] start ] [ CACHE [=] cache | NOCACHE ] [ CYCLE | NOCYCLE] [table_options] ``` The options for `CREATE SEQUENCE` can be given in any order, optionally followed by `table_options`. *table\_options* can be any of the normal table options in [CREATE TABLE](../create-table/index) but the most usable ones are `ENGINE=...` and `COMMENT=`. `NOMAXVALUE` and `NOMINVALUE` are there to allow one to create SEQUENCEs using the Oracle syntax. Description ----------- CREATE SEQUENCE will create a sequence that generates new values when called with `NEXT VALUE FOR sequence_name`. It's an alternative to [AUTO INCREMENT](../auto_increment/index) when one wants to have more control of how the numbers are generated. As the SEQUENCE caches values (up to `CACHE`) it can in some cases be much faster than [AUTO INCREMENT](../auto_increment/index). Another benefit is that one can access the last value generated by all used sequences, which solves one of the limitations with [LAST\_INSERT\_ID()](../last_insert_id/index). CREATE SEQUENCE requires the [CREATE privilege](../grant/index). [DROP SEQUENCE](../drop-sequence/index) can be used to drop a sequence, and [ALTER SEQUENCE](../alter-sequence/index) to change it. ### Arguments to Create The following options may be used: | Option | Default value | Description | | --- | --- | --- | | INCREMENT | 1 | Increment to use for values. May be negative. Setting an increment of 0 causes the sequence to use the value of the [auto\_increment\_increment](../replication-and-binary-log-server-system-variables/index#auto_increment_increment) system variable at the time of creation, which is always a positive number. (see [MDEV-16035](https://jira.mariadb.org/browse/MDEV-16035)). | | MINVALUE | 1 if INCREMENT > 0 and -9223372036854775807 if INCREMENT < 0 | Minimum value for the sequence | | MAXVALUE | 9223372036854775806 if INCREMENT > 0 and -1 if INCREMENT < 0 | Max value for sequence | | START | MINVALUE if INCREMENT > 0 and MAX\_VALUE if INCREMENT< 0 | First value that the sequence will generate | | CACHE | 1000 | Number of values that should be cached. 0 if no CACHE. The underlying table will be updated first time a new sequence number is generated and each time the cache runs out. | If `CYCLE` is used then the sequence should start again from `MINVALUE` after it has run out of values. Default value is `NOCYCLE`. ### Constraints on Create Arguments To be able to create a legal sequence, the following must hold: * MAXVALUE >= start * MAXVALUE > MINVALUE * START >= MINVALUE * MAXVALUE <= 9223372036854775806 (LONGLONG\_MAX-1) * MINVALUE >= -9223372036854775807 (LONGLONG\_MIN+1) Note that sequences can't generate the maximum/minimum 64 bit number because of the constraint of `MINVALUE` and `MAXVALUE`. ### Atomic DDL **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**[MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/) supports [Atomic DDL](../atomic-ddl/index) and `CREATE SEQUENCE` is atomic. Examples -------- ``` CREATE SEQUENCE s START WITH 100 INCREMENT BY 10; CREATE SEQUENCE s2 START WITH -100 INCREMENT BY -10; ``` The following statement fails, as the increment conflicts with the defaults ``` CREATE SEQUENCE s3 START WITH -100 INCREMENT BY 10; ERROR 4082 (HY000): Sequence 'test.s3' values are conflicting ``` The sequence can be created by specifying workable minimum and maximum values: ``` CREATE SEQUENCE s3 START WITH -100 INCREMENT BY 10 MINVALUE=-100 MAXVALUE=1000; ``` See Also -------- * [Sequence Overview](../sequence-overview/index) * [ALTER SEQUENCE](../alter-sequence/index) * [DROP SEQUENCE](../drop-sequence/index) * [NEXT VALUE FOR](../next-value-for-sequence_name/index) * [PREVIOUS VALUE FOR](../previous-value-for-sequence_name/index) * [SETVAL()](../setval/index). Set next value for the sequence. * [AUTO INCREMENT](../auto_increment/index) * [SHOW CREATE SEQUENCE](../show-create-sequence/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB String Functions MariaDB String Functions ======================== MariaDB has many built-in functions that can be used to manipulate strings of data. With these functions, one can format data, extract certain characters, or use search expressions. Good developers should be aware of the string functions that are available. Therefore, in this article we will go through several string functions, grouping them by similar features, and provide examples of how they might be used. #### Formatting There are several string functions that are used to format text and numbers for nicer display. A popular and very useful function for pasting together the contents of data fields with text is the [CONCAT()](../concat/index) function. As an example, suppose that a table called contacts has a column for each sales contact's first name and another for the last name. The following SQL statement would put them together: ``` SELECT CONCAT(name_first, ' ', name_last) AS Name FROM contacts; ``` This statement will display the first name, a space, and then the last name together in one column. The AS clause will change the column heading of the results to Name. A less used concatenating function is [CONCAT\_WS()](../concat_ws/index). It will put together columns with a separator between each. This can be useful when making data available for other programs. For instance, suppose we have a program that will import data, but it requires the fields to be separated by vertical bars. We could just export the data, or we could use a [SELECT](../select/index) statement like the one that follows in conjunction with an interface written with an API language like Perl: ``` SELECT CONCAT_WS('|', col1, col2, col3) FROM table1; ``` The first element above is the separator. The remaining elements are the columns to be strung together. If we want to format a long number with commas every three digits and a period for the decimal point (e.g., 100,000.00), we can use the function [FORMAT()](../format/index) like so: ``` SELECT CONCAT('$', FORMAT(col5, 2)) FROM table3; ``` In this statement, the [CONCAT()](../concat/index) will place a dollar sign in front of the numbers found in the `col5` column, which will be formatted with commas by [FORMAT()](../format/index). The `2` within the [FORMAT()](../format/index) stipulates two decimal places. Occasionally, one will want to convert the text from a column to either all upper-case letters or all lower-case letters. In the example that follows, the output of the first column is converted to upper-case and the second to lower-case: ``` SELECT UCASE(col1), LCASE(col2) FROM table4; ``` When displaying data in forms, it's sometimes useful to pad the data displayed with zeros or dots or some other filler. This can be necessary when dealing with [VARCHAR](../varchar/index) columns where the width varies to help the user to see the column limits. There are two functions that may be used for padding: [LPAD()](../lpad/index) and [RPAD()](../rpad/index). ``` SELECT RPAD(part_nbr, 8, '.') AS 'Part Nbr.', LPAD(description, 15, '_') AS Description FROM catalog; ``` In this SQL statement, dots are added to the right end of each part number. So a part number of "H200" will display as "H200....", but without the quotes. Each part's description will have under-scores preceding it. A part with a description of "brass hinge" will display as "brass hinge". If a column is a [CHAR](../char/index) data-type, a fixed width column, then it may be necessary to trim any leading or trailing spaces from displays. There are a few functions to accomplish this task. The [LTRIM()](../ltrim/index) function will eliminate any leading spaces to the left. So " `H200`" becomes "`H200`". For columns with trailing spaces, spaces on the right, [RTRIM()](../rtrim/index) will work: "`H500` " becomes "`H500`". A more versatile trimming function, though, is [TRIM()](../trim/index). With it one can trim left, right or both. Below are a few examples: ``` SELECT TRIM(LEADING '.' FROM col1), TRIM(TRAILING FROM col2), TRIM(BOTH '_' FROM col3), TRIM(col4) FROM table5; ``` In the first [TRIM()](../trim/index) clause, the padding component is specified; the leading dots are to be trimmed from the output of `col1`. The trailing spaces will be trimmed off of `col2`—space is the default. Both leading and trailing under-scores are trimmed from `col3` above. Unless specified, BOTH is the default. So leading and trailing spaces are trimmed from `col4` in the statement here. #### Extracting When there is a need to extract specific elements from a column, MariaDB has a few functions that can help. Suppose a column in the table contacts contains the telephone numbers of sales contacts, including the area-codes, but without any dashes or parentheses. The area-code of each could be extracted for sorting with the [LEFT()](../left/index) and the telephone number with the [RIGHT()](../right/index) function. ``` SELECT LEFT(telephone, 3) AS area_code, RIGHT(telephone, 7) AS tel_nbr FROM contacts ORDER BY area_code; ``` In the [LEFT()](../left/index) function above, the column telephone is given along with the number of characters to extract, starting from the first character on the left in the column. The [RIGHT()](../right/index) function is similar, but it starts from the last character on the right, counting left to capture, in this statement, the last seven characters. In the SQL statement above, area\_code is reused to order the results set. To reformat the telephone number, it will be necessary to use the [SUBSTRING()](../substring/index) function. ``` SELECT CONCAT('(', LEFT(telephone, 3), ') ', SUBSTRING(telephone, 4, 3), '-', MID(telephone, 7)) AS 'Telephone Number' FROM contacts ORDER BY LEFT(telephone, 3); ``` In this SQL statement, the [CONCAT()](../concat/index) function is employed to assemble some characters and extracted data to produce a common display for telephone numbers (e.g., (504) 555-1234). The first element of the [CONCAT()](../concat/index) is an opening parenthesis. Next, a [LEFT()](../left/index) is used to get the first three characters of telephone, the area-code. After that a closing parenthesis, along with a space is added to the output. The next element uses the [SUBSTRING()](../substring/index) function to extract the telephone number's prefix, starting at the fourth position, for a total of three characters. Then a dash is inserted into the display. Finally, the function [MID()](../mid/index) extracts the remainder of the telephone number, starting at the seventh position. The functions [MID()](../mid/index) and [SUBSTRING()](../substring/index) are interchangeable and their syntax are the same. By default, for both functions, if the number of characters to capture isn't specified, then it's assumed that the remaining ones are to be extracted. #### Manipulating There are a few functions in MariaDB that can help in manipulating text. One such function is [REPLACE()](../replace-function/index). With it every occurrence of a search parameter in a string can be replaced. For example, suppose we wanted to replace the title *Mrs.* with *Ms.* in a column containing the person's title, but only in the output. The following SQL would do the trick: ``` SELECT CONCAT(REPLACE(title, 'Mrs.', 'Ms.'), ' ', name_first, ' ', name_last) AS Name FROM contacts; ``` We're using the ever handy [CONCAT()](../concat/index) function to put together the contact's name with spaces. The [REPLACE()](../replace-function/index) function extracts each title and replaces *Mrs.* with *Ms.*, where applicable. Otherwise, for all other titles, it displays them unchanged. If we want to insert or replace certain text from a column (but not all of its contents), we could use the [INSERT()](../insert-function/index) function in conjunction with the [LOCATE()](../locate/index) function. For example, suppose another contacts table has the contact's title and full name in one column. To change the occurrences of Mrs. to Ms., we could not use [REPLACE()](../replace-function/index) since the title is embedded in this example. Instead, we would do the following: ``` SELECT INSERT(name, LOCATE(name, 'Mrs.'), 4, 'Ms.') FROM contacts; ``` The first element of the [INSERT()](../insert-function/index) function is the column. The second element which contains the [LOCATE()](../locate/index) is the position in the string that text is to be inserted. The third element is optional; it states the number of characters to overwrite. In this case, Mrs. which is four characters is overwritten with Ms. (the final element), which is only three. Incidentally, if 0 is specified, then nothing is overwritten, text is inserted only. As for the [LOCATE()](../locate/index) function, the first element is the column and the second the search text. It returns the position within the column where the text is found. If it's not found, then 0 is returned. A value of 0 for the position in the [INSERT()](../insert-function/index) function negates it and returns the value of name unchanged. On the odd chance that there is a need to reverse the content of a column, there's the [REVERSE()](../reverse/index) function. You would just place the column name within the function. Another minor function is the [REPEAT()](repeat) function. With it a string may be repeated in the display: ``` SELECT REPEAT(col1, 2) FROM table1; ``` The first component of the function above is the string or column to be repeated. The second component states the number of times it's to be repeated. #### Expression Aids The function [CHAR\_LENGTH()](../char_length/index) is used to determine the number of characters in a string. This could be useful in a situation where a column contains different types of information of specific lengths. For instance, suppose a column in a table for a college contains identification numbers for students, faculty, and staff. If student identification numbers have eight characters while others have less, the following will count the number of student records: ``` SELECT COUNT(school_id) AS 'Number of Students' FROM table8 WHERE CHAR_LENGTH(school_id)=8; ``` The [COUNT()](../count/index) function above counts the number of rows that meet the condition of the `WHERE` clause. In a [SELECT](../select/index) statement, an [ORDER BY](../select/index#order-by) clause can be used to sort a results set by a specific column. However, if the column contains IP addresses, a simple sort may not produce the desired results: ``` SELECT ip_address FROM computers WHERE server='Y' ORDER BY ip_address LIMIT 3; +-------------+ | ip_address | +-------------+ | 10.0.1.1 | | 10.0.11.1 | | 10.0.2.1 | +-------------+ ``` In the limited results above, the IP address 10.0.2.1 should be second. This happens because the column is being sorted lexically and not numerically. The function [INET\_ATON()](../inet_aton/index) will solve this sorting problem. ``` SELECT ip_address FROM computers WHERE server='Y' ORDER BY INET_ATON(ip_address) LIMIT 3; ``` Basically, the [INET\_ATON()](../inet_aton/index) function will convert IP addresses to regular numbers for numeric sorting. For instance, if we were to use the function in the list of columns in a [SELECT](../select/index) statement, instead of the `WHERE` clause, the address 10.0.1.1 would return 167772417, 10.0.11.1 will return 167774977, and 10.0.2.1 the number 167772673. As a complement to [INET\_ATON()](../inet_aton/index), the function [INET\_ATON()](../inet_aton/index) will translate these numbers back to their original IP addresses. MariaDB is fairly case insensitive, which usually is fine. However, to be able to check by case, the [STRCMP()](../strcmp/index) function can be used. It converts the column examined to a string and makes a comparison to the search parameter. ``` SELECT col1, col2 FROM table6 WHERE STRCMP(col3, 'text')=0; ``` If there is an exact match, the function [STRCMP()](../strcmp/index) returns 0. So if `col3` here contains "Text", it won't match. Incidentally, if `col3` alphabetically is before the string to which it's compared, a `-1` will be returned. If it's after it, a `1` is returned. When you have list of items in one string, the [SUBSTRING\_INDEX()](../substring_index/index) can be used to pull out a sub-string of data. As an example, suppose we have a column which has five elements, but we want to retrieve just the first two elements. This SQL statement will return them: ``` SELECT SUBSTRING_INDEX(col4, '|', 2) FROM table7; ``` The first component in the function above is the column or string to be picked apart. The second component is the delimiter. The third is the number of elements to return, counting from the left. If we want to grab the last two elements, we would use a negative two to instruct MariaDB to count from the right end. #### Conclusion There are more string functions available in MariaDB. A few of the functions mentioned here have aliases or close alternatives. There are also functions for converting between ASCII, binary, hexi-decimal, and octal strings. And there are also string functions related to text encryption and decryption that were not mentioned. However, this article has given you a good collection of common string functions that will assist you in building more powerful and accurate SQL statements. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Information Schema INNODB_BUFFER_PAGE_LRU Table Information Schema INNODB\_BUFFER\_PAGE\_LRU Table ================================================== The [Information Schema](../information_schema/index) `INNODB_BUFFER_PAGE_LRU` table contains information about pages in the [buffer pool](../xtradbinnodb-memory-buffer/index) and how they are ordered for eviction purposes. The `PROCESS` [privilege](../grant/index) is required to view the table. It has the following columns: | Column | Description | | --- | --- | | `POOL_ID` | Buffer Pool identifier. From [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/) returns a value of 0, since multiple InnoDB buffer pool instances has been removed. | | `LRU_POSITION` | LRU (Least recently-used), for determining eviction order from the buffer pool. | | `SPACE` | Tablespace identifier. Matches the `SPACE` value on the `[INNODB\_SYS\_TABLES](../information-schema-innodb_sys_tables-table/index)` table. | | `PAGE_NUMBER` | Buffer pool page number. | | `PAGE_TYPE` | Page type; one of `allocated` (newly-allocated page), `index` (B-tree node), `undo_log` (undo log page), `inode` (index node), `ibuf_free_list` (insert buffer free list), `ibuf_bitmap` (insert buffer bitmap), `system` (system page), `trx_system` (transaction system data), `file_space_header` (file space header), `extent_descriptor` (extent descriptor page), `blob` (uncompressed blob page), `compressed_blob` (first compressed blob page), `compressed_blob2` (subsequent compressed blob page) or `unknown`. | | `FLUSH_TYPE` | Flush type. | | `FIX_COUNT` | Count of the threads using this block in the buffer pool. When it is zero, the block can be evicted from the buffer pool. | | `IS_HASHED` | Whether or not a hash index has been built on this page. | | `NEWEST_MODIFICATION` | Most recent modification's Log Sequence Number. | | `OLDEST_MODIFICATION` | Oldest modification's Log Sequence Number. | | `ACCESS_TIME` | Abstract number representing the time the page was first accessed. | | `TABLE_NAME` | Table that the page belongs to. | | `INDEX_NAME` | Index that the page belongs to, either a clustered index or a secondary index. | | `NUMBER_RECORDS` | Number of records the page contains. | | `DATA_SIZE` | Size in bytes of all the records contained in the page. | | `COMPRESSED_SIZE` | Compressed size in bytes of the page, or `NULL` for pages that aren't compressed. | | `PAGE_STATE` | Page state; one of `FILE_PAGE` (page from a file) or `MEMORY` (page from an in-memory object) for valid data, or one of `NULL`, `READY_FOR_USE`, `NOT_USED`, `REMOVE_HASH`. | | `IO_FIX` | Whether there is I/O pending for the page; one of `IO_NONE` (no pending I/O), `IO_READ` (read pending), `IO_WRITE` (write pending). | | `IS_OLD` | Whether the page is old or not. | | `FREE_PAGE_CLOCK` | Freed\_page\_clock counter, which tracks the number of blocks removed from the end of the LRU list, at the time the block was last placed at the head of the list. | The related [INFORMATION\_SCHEMA.INNODB\_BUFFER\_PAGE](../information-schema-innodb_buffer_page/index) table contains the same information, but with a block id rather than LRU position. Example ------- ``` DESC information_schema.innodb_buffer_page_lru; +---------------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------------------+---------------------+------+-----+---------+-------+ | POOL_ID | bigint(21) unsigned | NO | | 0 | | | LRU_POSITION | bigint(21) unsigned | NO | | 0 | | | SPACE | bigint(21) unsigned | NO | | 0 | | | PAGE_NUMBER | bigint(21) unsigned | NO | | 0 | | | PAGE_TYPE | varchar(64) | YES | | NULL | | | FLUSH_TYPE | bigint(21) unsigned | NO | | 0 | | | FIX_COUNT | bigint(21) unsigned | NO | | 0 | | | IS_HASHED | varchar(3) | YES | | NULL | | | NEWEST_MODIFICATION | bigint(21) unsigned | NO | | 0 | | | OLDEST_MODIFICATION | bigint(21) unsigned | NO | | 0 | | | ACCESS_TIME | bigint(21) unsigned | NO | | 0 | | | TABLE_NAME | varchar(1024) | YES | | NULL | | | INDEX_NAME | varchar(1024) | YES | | NULL | | | NUMBER_RECORDS | bigint(21) unsigned | NO | | 0 | | | DATA_SIZE | bigint(21) unsigned | NO | | 0 | | | COMPRESSED_SIZE | bigint(21) unsigned | NO | | 0 | | | COMPRESSED | varchar(3) | YES | | NULL | | | IO_FIX | varchar(64) | YES | | NULL | | | IS_OLD | varchar(3) | YES | | NULL | | | FREE_PAGE_CLOCK | bigint(21) unsigned | NO | | 0 | | +---------------------+---------------------+------+-----+---------+-------+ ``` ``` SELECT * FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE_LRU\G ... *************************** 6. row *************************** POOL_ID: 0 LRU_POSITION: 5 SPACE: 0 PAGE_NUMBER: 11 PAGE_TYPE: INDEX FLUSH_TYPE: 1 FIX_COUNT: 0 IS_HASHED: NO NEWEST_MODIFICATION: 2046835 OLDEST_MODIFICATION: 0 ACCESS_TIME: 2585566280 TABLE_NAME: `SYS_INDEXES` INDEX_NAME: CLUST_IND NUMBER_RECORDS: 57 DATA_SIZE: 4016 COMPRESSED_SIZE: 0 COMPRESSED: NO IO_FIX: IO_NONE IS_OLD: NO FREE_PAGE_CLOCK: 0 ... ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Sequel Pro Sequel Pro ========== [Sequel Pro](https://www.sequelpro.com) is a fast, easy-to-use Mac database management application for working with MySQL and MariaDB databases. [Sequel Pro](https://www.sequelpro.com) is open source, so it's easy to be involved and enhance it for MariaDB. You can also help by donating to the project! If you have any issues with Sequel Pro on MariaDB, please use the [issue tracking](https://github.com/sequelpro/sequelpro/issues) for that! See Also -------- * [Sequal Pro home site](https://www.sequelpro.com) * [Source code](https://github.com/sequelpro) * [Issue tracking](https://github.com/sequelpro/sequelpro/issues) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MBREqual MBREqual ======== Syntax ------ ``` MBREqual(g1,g2) ``` Description ----------- Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles of the two geometries g1 and g2 are the same. Examples -------- ``` SET @g1=GEOMFROMTEXT('LINESTRING(0 0, 1 2)'); SET @g2=GEOMFROMTEXT('POLYGON((0 0, 0 2, 1 2, 1 0, 0 0))'); SELECT MbrEqual(@g1,@g2); +-------------------+ | MbrEqual(@g1,@g2) | +-------------------+ | 1 | +-------------------+ SET @g1=GEOMFROMTEXT('LINESTRING(0 0, 1 3)'); SET @g2=GEOMFROMTEXT('POLYGON((0 0, 0 2, 1 4, 1 0, 0 0))'); SELECT MbrEqual(@g1,@g2); +-------------------+ | MbrEqual(@g1,@g2) | +-------------------+ | 0 | +-------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql Client mysql Client ============= The mysql (from [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), [also called mariadb](../mariadb-command-line-client/index)) command-line client. | Title | Description | | --- | --- | | [mysql Command-line Client](../mysql-command-line-client/index) | mysql is a simple SQL shell with GNU readline capabilities. | | [Delimiters](../delimiters/index) | How to Change the Delimiter for the mysql Client. | | [mariadb Command-Line Client](../mariadb-command-line-client/index) | Symlink or new name for mysql, the command-line client. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb S3 Storage Engine System Variables S3 Storage Engine System Variables ================================== **MariaDB starting with [10.5](../what-is-mariadb-105/index)**The [S3 storage engine](../s3-storage-engine/index) has been available since [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/). This page documents system variables related to the [S3 storage engine](../s3-storage-engine/index). See [Server System Variables](../server-system-variables/index) for a complete list of system variables and instructions on setting system variables. Also see the [Full list of MariaDB options, system and status variables](../full-list-of-mariadb-options-system-and-status-variables/index) Variables --------- #### `s3_access_key` * **Description:** The AWS access key to access your data. See [mysqld startup options for S3](../using-the-s3-storage-engine/index#mysqld-startup-options-for-s3). * **Commandline:** `--s3-access-key=val` * **Scope:** Global * **Dynamic:** No * **Data Type:** String * **Default Value:** (Empty) * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_block_size` * **Description:** The default block size for a table, if not specified in [CREATE TABLE](../create-table/index). Set to 4M as default. See [mysqld startup options for S3](../using-the-s3-storage-engine/index#mysqld-startup-options-for-s3). * **Commandline:** `--s3-block-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** Numeric * **Default Value:** `4194304` * **Range:** `4194304` to `16777216` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_bucket` * **Description:** The AWS bucket where your data should be stored. All MariaDB table data is stored in this bucket. See [mysqld startup options for S3](../using-the-s3-storage-engine/index#mysqld-startup-options-for-s3). * **Commandline:** `--s3-bucket=val` * **Scope:** Global * **Dynamic:** No * **Data Type:** String * **Default Value:** `MariaDB` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_debug` * **Description:** Generates a trace file from libmarias3 on stderr (mysqld.err) for debugging the S3 protocol. * **Commandline:** `--s3-debug{=0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** Boolean * **Valid Values:** 0 or 1 * **Default Value:** `0` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_host_name` * **Description:** Hostname for the S3 service. "s3.amazonaws.com", Amazon S3 service, by default * **Commandline:** `--s3-host-name=val` * **Scope:** Globa; * **Dynamic:** No * **Data Type:** String * **Default Value:** `s3.amazonaws.com` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_pagecache_age_threshold` * **Description:** This characterizes the number of hits a hot block has to be untouched until it is considered aged enough to be downgraded to a warm block. This specifies the percentage ratio of that number of hits to the total number of blocks in the page cache. * **Commandline:** `--s3-pagecache-age-threshold=val` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** Numeric * **Default Value:** `300` * **Range:** `100` to `18446744073709551615` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_pagecache_buffer_size` * **Description:** The size of the buffer used for index blocks for S3 tables. Increase this to get better index handling (for all reads and multiple writes) to as much as you can afford. Size can be adjusted in blocks of `8192`. * **Commandline:** `--s3-pagecache-buffer-size=val` * **Scope:** Global * **Dynamic:** No * **Data Type:** Numeric * **Default Value:** `134217728` (128M) * **Range:** `33554432` to `18446744073709551615` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_pagecache_division_limit` * **Description:** The minimum percentage of warm blocks in key cache. * **Commandline:** `--s3-pagecache-division-limit=val` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** Numeric * **Default Value:** `100` * **Range:** `1` to `100` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_pagecache_file_hash_size` * **Description:** Number of hash buckets for open files. Default 512. If you have a lot of S3 files open you should increase this for faster flush of changes. A good value is probably 1/10 of number of possible open S3 files. * **Commandline:** `--s3-pagecache-file-hash-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** Numeric * **Default Value:** `512` * **Range:** `32` to `16384` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_port` * **Description:** The TCP port number on the S3 host to connect to. A values of 0 means determine automatically. * **Commandline:** `--s3-port=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** Numeric * **Default Value:** `0` * **Range:** `0` to `65535` * **Introduced:** [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/) --- #### `s3_protocol_version` * **Description:** Protocol used to communication with S3. One of "Auto", "Amazon" or "Original" where "Auto" is the default. If you get errors like "8 Access Denied" when you are connecting to another service provider, then try to change this option. The reason for this variable is that Amazon has changed some parts of the S3 protocol since they originally introduced it but other service providers are still using the original protocol. * **Commandline:** `--s3-protocol-version=val` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** Enum * **Valid Values:** `Auto`, `Amazon` or `Original` * **Default Value:** `Auto` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_region` * **Description:** The AWS region where your data should be stored. See [mysqld startup options for S3](../using-the-s3-storage-engine/index#mysqld-startup-options-for-s3). * **Commandline:** `--s3-region=val` * **Scope:** Global * **Dynamic:** No * **Data Type:** String * **Default Value:** (Empty) * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_replicate_alter_as_create_select` * **Description:** When converting S3 table to local table, log all rows in binary log. This allows the slave to replicate `CREATE TABLE .. SELECT FROM s3_table` even it the slave doesn't have access to the original `s3_table`. * **Commandline:** `--s3-replicate-alter-as-create-select{=0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** Boolean * **Default Value:** `1` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_secret_key` * **Description:** The AWS secret key to access your data. See [mysqld startup options for S3](../using-the-s3-storage-engine/index#mysqld-startup-options-for-s3). * **Commandline:** `--s3-secret-key=val` * **Scope:** Global * **Dynamic:** No * **Data Type:** String * **Default Value:** (Empty) * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_slave_ignore_updates` * **Description:** Should be set if master and slave share the same S3 instance. This tells the slave that it can ignore any updates to the S3 tables as they are already applied on the master. * **Commandline:** `--s3-slave-ignore-updates{=0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** Boolean * **Default Value:** `0` * **Introduced:** [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) --- #### `s3_use_http` * **Description:** If enabled, HTTP will be used instead of HTTPS. * **Commandline:** `--s3-use-http{=0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** Boolean * **Default Value:** `0` * **Introduced:** [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/) --- See Also -------- [Using the S3 Storage Engine](../using-the-s3-storage-engine/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Database Design Database Design ================ Articles about the database design process | Title | Description | | --- | --- | | [Database Design: Overview](../database-design-overview/index) | Databases exist because of the need to change data into information | | [Database Lifecycle](../database-lifecycle/index) | Like everything else, databases have a finite lifespan | | [Database Design Phase 1: Analysis](../database-design-phase-1-analysis/index) | Defining problems, possibilities, constraints, objectives and agreeing on the scope | | [Database Design Phase 2: Conceptual Design](../database-design-phase-2-conceptual-design/index) | Requirements identified in the previous phase are used as the basis to develop the new system | | [Database Design Phase 2: Logical and Physical Design](../database-design-phase-2-logical-and-physical-design/index) | After conceptual design, it's time to convert to the logical and physical design | | [Database Design Phase 3: Implementation](../database-design-phase-3-implementation/index) | Install the DBMS and load the data | | [Database Design Phase 4: Testing](../database-design-phase-4-testing/index) | Testing performance, security, and integrity of the data | | [Database Design Phase 5: Operation](../database-design-phase-5-operation/index) | Rolling out for everyday use | | [Database Design Phase 6: Maintenance](../database-design-phase-6-maintenance/index) | Maintaining indexes, optimizing tables, adding and removing users, changing passwords | | [Database Design Example Phase 1: Analysis](../database-design-example-phase-1-analysis/index) | Walking through the database design process with a step-by-step example | | [Database Design Example Phase 2: Design](../database-design-example-phase-2-design/index) | Poet Circle logical design and identifying the initial entities | | [Database Design Example Phase 3: Implementation](../database-design-example-phase-3-implementation/index) | Creating the Poet's Circle tables | | [Database Design Example Phases 4-6: Testing, Operation and Maintenance](../database-design-example-phases-4-6-testing-operation-and-maintenance/index) | Testing, rolling out and maintenance of the Poet's Circle database | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb DIV DIV === Syntax ------ ``` DIV ``` Description ----------- Integer division. Similar to [FLOOR()](../floor/index), but is safe with [BIGINT](../bigint/index) values. Incorrect results may occur for non-integer operands that exceed BIGINT range. If the `ERROR_ON_DIVISION_BY_ZERO` [SQL\_MODE](../sql-mode/index) is used, a division by zero produces an error. Otherwise, it returns NULL. The remainder of a division can be obtained using the [MOD](../mod/index) operator. Examples -------- ``` SELECT 300 DIV 7; +-----------+ | 300 DIV 7 | +-----------+ | 42 | +-----------+ SELECT 300 DIV 0; +-----------+ | 300 DIV 0 | +-----------+ | NULL | +-----------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Buildbot Setup for BSD Buildbot Setup for BSD ====================== Here are the steps I did when installing and configuring a buildbot slave on a PC-BSD 9 box. Add buildbot user: ``` sudo adduser buildbot /bin/sh ``` Python was already installed. Bazaar was already installed. NTP was already installed. Install Zope3 ``` cd /usr/ports/www/zope3 sudo make install clean # accepted default options cd /usr/ports/devel/py-zope.interface sudo make install clean ``` Install Twisted ``` cd /usr/ports/devel/py-twisted sudo make install clean # accepted default options ``` Install ccache ``` cd /usr/ports/devel/ccache sudo make install clean # accepted default options ``` Run a test compile of MariaDB ``` cd cd src/maria/build BUILD/compile-pentium64-max # test compile appeared to work ``` Install buildbot ``` cd /usr/ports/devel/buildbot sudo make install clean # accepted default options ``` Create the buildbot slave On the build master, add new entry to /etc/buildbot/maria-master-private.cfg ``` slave-name=bsd9 ``` Remember the ${slave-name} and ${password} configured above, they're used in the next step. Back on bsd9 ``` sudo su - buildbot buildslave create-slave --usepty=0 /home/buildbot/maria-slave \ hasky.askmonty.org:9989 ${slave-name} ${password} echo '${contact-email-address}' > /home/buildbot/maria-slave/info/admin echo 'A host running PC-BSD 9.' > /home/buildbot/maria-slave/info/host bzr init-repo maria-slave/bsd9 exit ``` Start the buildslave ``` sudo su - buildbot buildslave start maria-slave ``` Make the archive dir ``` sudo su - buildbot mkdir archive exit sudo ln -s /home/buildbot/archive /archive ``` Install Apache ``` cd /usr/ports/www/apache22 sudo make install clean # accepted default options ``` Configure apache: ``` sudo su -s echo 'apache22_enable="YES"' >> /etc/rc.conf echo 'alias /archive "/archive"\ <Directory "/archive">\ Options All Multiviews\ AllowOverride All\ Order allow,deny\ Allow from all\ </Directory>' >> /usr/local/etc/apache22/httpd.conf sudo /usr/local/etc/rc.d/apache22 start ``` Install md5sum ``` md5sum already installed at /compat/linux/usr/bin/md5sum edited /home/buildbot/.profile and added that dir to the path # That didn't work, so did the following: cd /usr/local/bin/ sudo ln -s /compat/linux/usr/bin/md5sum md5sum ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CHAR CHAR ==== This article covers the CHAR data type. See [CHAR Function](../char-function/index) for the function. Syntax ------ ``` [NATIONAL] CHAR[(M)] [CHARACTER SET charset_name] [COLLATE collation_name] ``` Description ----------- A fixed-length string that is always right-padded with spaces to the specified length when stored. `M` represents the column length in characters. The range of `M` is `0` to `255`. If `M` is omitted, the length is `1`. CHAR(0) columns can contain 2 values: an empty string or NULL. Such columns cannot be part of an index. The [CONNECT](../connect/index) storage engine does not support CHAR(0). **Note:** Trailing spaces are removed when `CHAR` values are retrieved unless the `PAD_CHAR_TO_FULL_LENGTH` [SQL mode](../sql_mode/index) is enabled. Before [MariaDB 10.2](../what-is-mariadb-102/index), all collations were of type PADSPACE, meaning that CHAR (as well as [VARCHAR](../varchar/index) and [TEXT](../text/index)) values are compared without regard for trailing spaces. This does not apply to the [LIKE](../like/index) pattern-matching operator, which takes into account trailing spaces. If a unique index consists of a column where trailing pad characters are stripped or ignored, inserts into that column where values differ only by the number of trailing pad characters will result in a duplicate-key error. Examples -------- Trailing spaces: ``` CREATE TABLE strtest (c CHAR(10)); INSERT INTO strtest VALUES('Maria '); SELECT c='Maria',c='Maria ' FROM strtest; +-----------+--------------+ | c='Maria' | c='Maria ' | +-----------+--------------+ | 1 | 1 | +-----------+--------------+ SELECT c LIKE 'Maria',c LIKE 'Maria ' FROM strtest; +----------------+-------------------+ | c LIKE 'Maria' | c LIKE 'Maria ' | +----------------+-------------------+ | 1 | 0 | +----------------+-------------------+ ``` NO PAD Collations ----------------- NO PAD collations regard trailing spaces as normal characters. You can get a list of all NO PAD collations by querying the [Information Schema Collations table](../information-schema-collations-table/index), for example: ``` SELECT collation_name FROM information_schema.collations WHERE collation_name LIKE "%nopad%"; +------------------------------+ | collation_name | +------------------------------+ | big5_chinese_nopad_ci | | big5_nopad_bin | ... ``` See Also -------- * [CHAR Function](../char-function/index) * [VARCHAR](../varchar/index) * [BINARY](../binary/index) * [Data Type Storage Requirements](../data-type-storage-requirements/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_AsBinary ST\_AsBinary ============ Syntax ------ ``` ST_AsBinary(g) AsBinary(g) ST_AsWKB(g) AsWKB(g) ``` Description ----------- Converts a value in internal geometry format to its [WKB](../well-known-binary-wkb-format/index) representation and returns the binary result. `ST_AsBinary()`, `AsBinary()`, `ST_AsWKB()` and `AsWKB()` are synonyms, Examples -------- ``` SET @poly = ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))'); SELECT ST_AsBinary(@poly); SELECT ST_AsText(ST_GeomFromWKB(ST_AsWKB(@poly))); +--------------------------------------------+ | ST_AsText(ST_GeomFromWKB(ST_AsWKB(@poly))) | +--------------------------------------------+ | POLYGON((0 0,0 1,1 1,1 0,0 0)) | +--------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema status_by_host Table Performance Schema status\_by\_host Table ========================================= **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**The `status_by_host` table was added in [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). The `status_by_host` table contains status variable information by host. The table does not collect statistics for `Com_xxx` variables. The table contains the following columns: | Column | Description | | --- | --- | | HOST | Host for which the status variable is reported. | | VARIABLE\_NAME | Status variable name. | | VARIABLE\_VALUE | Aggregated status variable value | If [TRUNCATE TABLE](../truncate-table/index) is run, will reset the aggregated host status from terminated sessions. If [FLUSH STATUS](flush-status) is run, session status from all active sessions are added to the global status variables, the status of all active sessions are reset, and values aggregated from disconnected sessions are reset. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Development Meeting - Lisbon MariaDB Development Meeting - Lisbon ===================================== 11-13 Mar 2011 - Notes and Plans from the Lisbon Developer meeting. | Title | Description | | --- | --- | | [Plans for 5.6](../plans-for-56/index) | The information on this page is obsolete. Current information can be found... | | [MariaDB Plans - GIS](../mariadb-plans-gis/index) | Old GIS plans | | [MariaDB Plans - Online Operations](../mariadb-plans-online-operations/index) | Note: This page is obsolete. The information is old, outdated, or otherwise... | | [MariaDB Plans - Replication](../mariadb-plans-replication/index) | Note: This page is obsolete. The information is old, outdated, or otherwise... | | [MariaDB Plans - Statistics and Monitoring](../mariadb-plans-statistics-and-monitoring/index) | Note: This page is obsolete. The information is old, outdated, or otherwise... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Configuring MariaDB Replication between MariaDB Galera Cluster and MariaDB Server Configuring MariaDB Replication between MariaDB Galera Cluster and MariaDB Server ================================================================================= [MariaDB replication](../high-availability-performance-tuning-mariadb-replication/index) can be used to replicate between [MariaDB Galera Cluster](../galera-cluster/index) and MariaDB Server. This article will discuss how to do that. Configuring the Cluster ----------------------- Before we set up replication, we need to ensure that the cluster is configured properly. This involves the following steps: * Set `[log\_slave\_updates=ON](../replication-and-binary-log-system-variables/index#log_slave_updates)` on all nodes in the cluster. See [Configuring MariaDB Galera Cluster: Writing Replicated Write Sets to the Binary Log](../configuring-mariadb-galera-cluster/index#writing-replicated-write-sets-to-the-binary-log) and [Using MariaDB Replication with MariaDB Galera Cluster: Configuring a Cluster Node as a Replication Master](../using-mariadb-replication-with-mariadb-galera-cluster-using-mariadb-replica/index#configuring-a-cluster-node-as-a-replication-master) for more information on why this is important. This is also needed to [enable wsrep GTID mode](../using-mariadb-gtids-with-mariadb-galera-cluster/index#enabling-wsrep-gtid-mode). * Set `[server\_id](../replication-and-binary-log-system-variables/index#server_id)` to the same value on all nodes in the cluster. See [Using MariaDB Replication with MariaDB Galera Cluster: Setting server\_id on Cluster Nodes](../using-mariadb-replication-with-mariadb-galera-cluster-using-mariadb-replica/index#setting-server_id-on-cluster-nodes) for more information on what this means. ### Configuring Wsrep GTID Mode If you want to use [GTID](../gtid/index) replication, then you also need to configure some things to [enable wsrep GTID mode](../using-mariadb-gtids-with-mariadb-galera-cluster/index#enabling-wsrep-gtid-mode). For example: * `[wsrep\_gtid\_mode=ON](../galera-cluster-system-variables/index#wsrep_gtid_mode)` needs to be set on all nodes in the cluster. * `[wsrep\_gtid\_domain\_id](../galera-cluster-system-variables/index#wsrep_gtid_domain_id)` needs to be set to the same value on all nodes in the cluster, so that each cluster node uses the same domain when assigning [GTIDs](../gtid/index) for Galera Cluster's write sets. * `[log\_slave\_updates](../replication-and-binary-log-system-variables/index#log_slave_updates)` needs to be enabled on all nodes in the cluster. See [MDEV-9855](https://jira.mariadb.org/browse/MDEV-9855) about that. * `[log\_bin](../replication-and-binary-log-server-system-variables/index#log_bin)` needs to be set to the same path on all nodes in the cluster. See [MDEV-9856](https://jira.mariadb.org/browse/MDEV-9856) about that. And as an extra safety measure: * [gtid\_domain\_id](../gtid/index#gtid_domain_id) should be set to a different value on all nodes in a given cluster, and each of these values should be different than the configured [wsrep\_gtid\_domain\_id](../galera-cluster-system-variables/index#wsrep_gtid_domain_id) value. This is to prevent a node from using the same domain used for Galera Cluster's write sets when assigning [GTIDs](../gtid/index) for non-Galera transactions, such as DDL executed with [wsrep\_sst\_method=RSU](../galera-cluster-system-variables/index#wsrep_sst_method) set or DML executed with [wsrep\_on=OFF](../galera-cluster-system-variables/index#wsrep_on) set. Configuring the Replica ----------------------- Before we set up replication, we also need to ensure that the MariaDB Server replica is configured properly. This involves the following steps: * Set [server\_id](../replication-and-binary-log-system-variables/index#server_id) to a different value than the one that the cluster nodes are using. * Set [gtid\_domain\_id](../gtid/index#gtid_domain_id) to a value that is different than the [wsrep\_gtid\_domain\_id](../galera-cluster-system-variables/index#wsrep_gtid_domain_id) and [gtid\_domain\_id](../gtid/index#gtid_domain_id) values that the cluster nodes are using. * Set [log\_bin](../replication-and-binary-log-server-system-variables/index#log_bin) and [log\_slave\_updates=ON](../replication-and-binary-log-system-variables/index#log_slave_updates) if you want the replica to log the transactions that it replicates. Setting up Replication ---------------------- Our process to set up replication is going to be similar to the process described at [Setting up a Replication Slave with Mariabackup](../setting-up-a-replication-slave-with-mariabackup/index), but it will be modified a bit to work in this context. ### Start the Cluster The very first step is to start the nodes in the first cluster. The first node will have to be [bootstrapped](../getting-started-with-mariadb-galera-cluster/index#bootstrapping-a-new-cluster). The other nodes can be [started normally](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index). Once the nodes are started, you need to pick a specific node that will act as the replication primary for the MariaDB Server. ### Backup the Database on the Cluster's Primary Node and Prepare It The first step is to simply take and prepare a fresh [full backup](../full-backup-and-restore-with-mariabackup/index) of the node that you have chosen to be the replication primary. For example: ``` $ mariabackup --backup \ --target-dir=/var/mariadb/backup/ \ --user=mariabackup --password=mypassword ``` And then you would prepare the backup as you normally would. For example: ``` $ mariabackup --prepare \ --target-dir=/var/mariadb/backup/ ``` ### Copy the Backup to the Replica Once the backup is done and prepared, you can copy it to the MariaDB Server that will be acting as replica. For example: ``` $ rsync -avrP /var/mariadb/backup dc2-dbserver1:/var/mariadb/backup ``` ### Restore the Backup on the Second Cluster's Replica At this point, you can restore the backup to the [datadir](../server-system-variables/index#datadir), as you normally would. For example: ``` $ mariabackup --copy-back \ --target-dir=/var/mariadb/backup/ ``` And adjusting file permissions, if necessary: ``` $ chown -R mysql:mysql /var/lib/mysql/ ``` ### Start the New Replica Now that the backup has been restored to the MariaDB Server replica, you can [start the MariaDB Server process](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index). ### Create a Replication User on the Cluster's Primary Before the MariaDB Server replica can begin replicating from the cluster's primary, you need to [create a user account](../create-user/index) on the primary that the replica can use to connect, and you need to [grant](../grant/index) the user account the [REPLICATION SLAVE](../grant/index#global-privileges) privilege. For example: ``` CREATE USER 'repl'@'dc2-dbserver1' IDENTIFIED BY 'password'; GRANT REPLICATION SLAVE ON *.* TO 'repl'@'dc2-dbserver1'; ``` ### Start Replication on the New Replica At this point, you need to get the replication coordinates of the primary from the original backup. The coordinates will be in the [xtrabackup\_binlog\_info](../files-created-by-mariabackup/index#xtrabackup_binlog_info) file. Mariabackup dumps replication coordinates in two forms: [GTID strings](../gtid/index) and [binary log](../binary-log/index) file and position coordinates, like the ones you would normally see from [SHOW MASTER STATUS](../show-master-status/index) output. In this case, it is probably better to use the [GTID](../gtid/index) coordinates. For example: ``` mariadb-bin.000096 568 0-1-2 ``` Regardless of the coordinates you use, you will have to set up the primary connection using [CHANGE MASTER TO](../change-master-to/index) and then start the replication threads with [START SLAVE](../start-slave/index). #### GTIDs If you want to use GTIDs, then you will have to first set [gtid\_slave\_pos](../gtid/index#gtid_slave_pos) to the [GTID](../gtid/index) coordinates that we pulled from the [xtrabackup\_binlog\_info](../files-created-by-mariabackup/index#xtrabackup_binlog_info) file, and we would set `MASTER_USE_GTID=slave_pos` in the [CHANGE MASTER TO](../change-master-to/index) command. For example: ``` SET GLOBAL gtid_slave_pos = "0-1-2"; CHANGE MASTER TO MASTER_HOST="c1dbserver1", MASTER_PORT=3310, MASTER_USER="repl", MASTER_PASSWORD="password", MASTER_USE_GTID=slave_pos; START SLAVE; ``` #### File and Position If you want to use the [binary log](../binary-log/index) file and position coordinates, then you would set `MASTER_LOG_FILE` and `MASTER_LOG_POS` in the [CHANGE MASTER TO](../change-master-to/index) command to the file and position coordinates that we pulled the [xtrabackup\_binlog\_info](../files-created-by-mariabackup/index#xtrabackup_binlog_info) file. For example: ``` CHANGE MASTER TO MASTER_HOST="c1dbserver1", MASTER_PORT=3310, MASTER_USER="repl", MASTER_PASSWORD="password", MASTER_LOG_FILE='mariadb-bin.000096', MASTER_LOG_POS=568, START SLAVE; ``` ### Check the Status of the New Replica You should be done setting up the replica now, so you should check its status with [SHOW SLAVE STATUS](../show-slave-status/index). For example: ``` SHOW SLAVE STATUS\G ``` Now that the MariaDB Server is up, ensure that it does not start accepting writes yet if you want to set up [circular replication](../replication-overview/index#ring-replication) between the cluster and the MariaDB Server. Setting up Circular Replication ------------------------------- You can also set up [circular replication](../replication-overview/index#ring-replication) between the cluster and MariaDB Server, which means that the MariaDB Server replicates from the cluster, and the cluster also replicates from the MariaDB Server. ### Create a Replication User on the MariaDB Server Primary Before circular replication can begin, you also need to [create a user account](../create-user/index) on the MariaDB Server, since it will be acting as replication primary to the cluster's replica, and you need to [grant](../grant/index) the user account the [REPLICATION SLAVE](../grant/index#global-privileges) privilege. For example: ``` CREATE USER 'repl'@'c1dbserver1' IDENTIFIED BY 'password'; GRANT REPLICATION SLAVE ON *.* TO 'repl'@'c1dbserver1'; ``` ### Start Circular Replication on the Cluster How this is done would depend on whether you want to use the [GTID](../gtid/index) coordinates or the [binary log](../binary-log/index) file and position coordinates. Regardless, you need to ensure that the second cluster is not accepting any writes other than those that it replicates from the cluster at this stage. #### GTIDs To get the GTID coordinates on the MariaDB Server you can check `[gtid\_current\_pos](../gtid/index#gtid_current_pos)` by executing: ``` SHOW GLOBAL VARIABLES LIKE 'gtid_current_pos'; ``` Then on the node acting as replica in the cluster, you can set up replication by setting [gtid\_slave\_pos](../gtid/index#gtid_slave_pos) to the GTID that was returned and then executing [CHANGE MASTER TO](../change-master-to/index): ``` SET GLOBAL gtid_slave_pos = "0-1-2"; CHANGE MASTER TO MASTER_HOST="c2dbserver1", MASTER_PORT=3310, MASTER_USER="repl", MASTER_PASSWORD="password", MASTER_USE_GTID=slave_pos; START SLAVE; ``` #### File and Position To get the [binary log](../binary-log/index) file and position coordinates on the MariaDB Server, you can execute [SHOW MASTER STATUS](../show-master-status/index): ``` SHOW MASTER STATUS ``` Then on the node acting as replica in the cluster, you would set `master_log_file` and `master_log_pos` in the [CHANGE MASTER TO](../change-master-to/index) command. For example: ``` CHANGE MASTER TO MASTER_HOST="c2dbserver1", MASTER_PORT=3310, MASTER_USER="repl", MASTER_PASSWORD="password", MASTER_LOG_FILE='mariadb-bin.000096', MASTER_LOG_POS=568; START SLAVE; ``` ### Check the Status of the Circular Replication You should be done setting up the circular replication on the node in the first cluster now, so you should check its status with [SHOW SLAVE STATUS](../show-slave-status/index). For example: ``` SHOW SLAVE STATUS\G ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Information Schema LOCALES Table Information Schema LOCALES Table ================================ Description ----------- The [Information Schema](../information_schema/index) `LOCALES` table contains a list of all compiled-in locales. It is only available if the [LOCALES plugin](../locales-plugin/index) has been installed. It contains the following columns: | Column | Description | | --- | --- | | `ID` | Row ID. | | `NAME` | Locale name, for example `en_GB`. | | `DESCRIPTION` | Locale description, for example `English - United Kingdom`. | | `MAX_MONTH_NAME_LENGTH` | Numeric length of the longest month in the locale | | `MAX_DAY_NAME_LENGTH` | Numeric length of the longest day name in the locale. | | `DECIMAL_POINT` | Decimal point character (some locales use a comma). | | `THOUSAND_SEP` | Thousand's character separator, | | `ERROR_MESSAGE_LANGUAGE` | Error message language. | The table is not a standard Information Schema table, and is a MariaDB extension. The [SHOW LOCALES](../show-locales/index) statement returns a subset of the information. Example ------- ``` SELECT * FROM information_schema.LOCALES; +-----+-------+-------------------------------------+-----------------------+---------------------+---------------+--------------+------------------------+ | ID | NAME | DESCRIPTION | MAX_MONTH_NAME_LENGTH | MAX_DAY_NAME_LENGTH | DECIMAL_POINT | THOUSAND_SEP | ERROR_MESSAGE_LANGUAGE | +-----+-------+-------------------------------------+-----------------------+---------------------+---------------+--------------+------------------------+ | 0 | en_US | English - United States | 9 | 9 | . | , | english | | 1 | en_GB | English - United Kingdom | 9 | 9 | . | , | english | | 2 | ja_JP | Japanese - Japan | 3 | 3 | . | , | japanese | | 3 | sv_SE | Swedish - Sweden | 9 | 7 | , | | swedish | | 4 | de_DE | German - Germany | 9 | 10 | , | . | german | | 5 | fr_FR | French - France | 9 | 8 | , | | french | | 6 | ar_AE | Arabic - United Arab Emirates | 6 | 8 | . | , | english | | 7 | ar_BH | Arabic - Bahrain | 6 | 8 | . | , | english | | 8 | ar_JO | Arabic - Jordan | 12 | 8 | . | , | english | ... | 106 | no_NO | Norwegian - Norway | 9 | 7 | , | . | norwegian | | 107 | sv_FI | Swedish - Finland | 9 | 7 | , | | swedish | | 108 | zh_HK | Chinese - Hong Kong SAR | 3 | 3 | . | , | english | | 109 | el_GR | Greek - Greece | 11 | 9 | , | . | greek | +-----+-------+-------------------------------------+-----------------------+---------------------+---------------+--------------+------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb TIMESTAMPDIFF TIMESTAMPDIFF ============= Syntax ------ ``` TIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2) ``` Description ----------- Returns `datetime_expr2` - `datetime_expr1`, where `datetime_expr1` and `datetime_expr2` are date or datetime expressions. One expression may be a date and the other a datetime; a date value is treated as a datetime having the time part '00:00:00' where necessary. The unit for the result (an integer) is given by the unit argument. The legal values for unit are the same as those listed in the description of the [TIMESTAMPADD()](../timestampadd/index) function, i.e MICROSECOND, SECOND, MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER, or YEAR. `TIMESTAMPDIFF` can also be used to calculate age. Examples -------- ``` SELECT TIMESTAMPDIFF(MONTH,'2003-02-01','2003-05-01'); +------------------------------------------------+ | TIMESTAMPDIFF(MONTH,'2003-02-01','2003-05-01') | +------------------------------------------------+ | 3 | +------------------------------------------------+ SELECT TIMESTAMPDIFF(YEAR,'2002-05-01','2001-01-01'); +-----------------------------------------------+ | TIMESTAMPDIFF(YEAR,'2002-05-01','2001-01-01') | +-----------------------------------------------+ | -1 | +-----------------------------------------------+ SELECT TIMESTAMPDIFF(MINUTE,'2003-02-01','2003-05-01 12:05:55'); +----------------------------------------------------------+ | TIMESTAMPDIFF(MINUTE,'2003-02-01','2003-05-01 12:05:55') | +----------------------------------------------------------+ | 128885 | +----------------------------------------------------------+ ``` Calculating age: ``` SELECT CURDATE(); +------------+ | CURDATE() | +------------+ | 2019-05-27 | +------------+ SELECT TIMESTAMPDIFF(YEAR, '1971-06-06', CURDATE()) AS age; +------+ | age | +------+ | 47 | +------+ SELECT TIMESTAMPDIFF(YEAR, '1971-05-06', CURDATE()) AS age; +------+ | age | +------+ | 48 | +------+ ``` Age as of 2014-08-02: ``` SELECT name, date_of_birth, TIMESTAMPDIFF(YEAR,date_of_birth,'2014-08-02') AS age FROM student_details; +---------+---------------+------+ | name | date_of_birth | age | +---------+---------------+------+ | Chun | 1993-12-31 | 20 | | Esben | 1946-01-01 | 68 | | Kaolin | 1996-07-16 | 18 | | Tatiana | 1988-04-13 | 26 | +---------+---------------+------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MyRocks Transactional Isolation MyRocks Transactional Isolation =============================== TODO: * MyRocks uses snapshot isolation * Support do READ-COMMITTED and REPEATABLE-READ * SERIALIZABLE is not supported + There is no "Gap Locking" which makes Statement Based Replication unsafe (See MyRocks and Replication). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Database Design Phase 2: Logical and Physical Design Database Design Phase 2: Logical and Physical Design ==================================================== This article follows on from [Database Design Phase 2: Conceptual Design](../database-design-phase-2-conceptual-design/index). Overview -------- Once the conceptual design is finalized, it's time to convert this to the logical and physical design. Usually, the DBMS is chosen at this stage, depending on the requirements and complexity of the data structures. Strictly speaking, the logical design and the physical design are two separate stages, but are often merged into one. They overlap because most current DBMSs (including MariaDB) match logical records to physical records on disk on a 1:1 basis. Each entity will become a database table, and each attribute will become a field of this table. Foreign keys can be created if the DBMS supports them and the designer decides to implement them. If the relationship is mandatory, the foreign key must be defined as *NOT NULL*, and if it's optional, the foreign key can allow nulls. For example, because of the invoice line-to-product relationship in the previous example, the product code field is a foreign key in the invoice to line table. Because the invoice line must contain a product, the field must be defined as *NOT NULL*. The default MariaDB storage engine, [XtraDB](../innodb/index), does support foreign key constraints, but some storage engines, such as [MyISAM](../myisam/index) do not. The *ON DELETE CASCADE* and *ON DELETE RESTRICT* clauses are used to support foreign keys. *ON DELETE RESTRICT* means that records cannot be deleted unless all records associated with the foreign key are also deleted. In the invoice line-to-product case, *ON DELETE RESTRICT* in the invoice line table means that if a product is deleted, the deletion will not take place unless all associated invoice lines with that product are deleted as well. This avoids the possibility of an invoice line existing that points to a non-existent product. *ON DELETE CASCADE* achieves a similar effect, but more automatically (and more dangerously!). If the foreign key was declared with *ON CASCADE DELETE*, associated invoice lines would automatically be deleted if a product was deleted. *ON UPDATE CASCADE* is similar to *ON DELETE CASCADE* in that all foreign key references to a primary key are updated when the primary key is updated. [Normalizing](../database-normalization/index) your tables is an important step when designing the database. This process helps avoid data redundancy and improves your data integrity. Novice database designers usually make a number of common errors. If you've carefully identified entities and attributes and you've normalized your data, you'll probably avoid these errors. Common errors ------------- * Keep unrelated data in different tables. People who are used to using spreadsheets often make this mistake because they are used to seeing all their data in one two-dimensional table. A relational database is much more powerful; don't 'hamstring' it in this way. * Don't store values you can calculate. Let's say you're interested three numbers: /A, B and the product of A and B (A\*B). Don't store the product. It wastes space and can easily be calculated if you need it. And it makes your database more difficult to maintain: If you change A, you also have to change all of the products as well. Why waste your database's efforts on something you can calculate when you need it? * Does your design cater to all the conditions you've analyzed? In the heady rush of creating an entity-relationship diagram, you can easily overlook a condition. Entity-relationship diagrams are usually better at getting stakeholders to spot an incorrect rule than spot a missing one. The business logic is as important as the database logic and is more likely to be overlooked. For example, it's easy to spot that you cannot have a sale without an associated customer, but have you built in that the customer cannot be approved for a sale of less than $500 if another approved customer has not recommended them? * Are your attributes, which are about to become field names, well chosen? Fields should be clearly named. For example, if you use *f1* and *f2* instead of *surname* and *first\_name*, the time saved in less typing will be lost in looking up the correct spelling of the field, or in mistakes where a developer thought *f1* was the first name, and *f2* the surname. Similarly, try to avoid the same names for different fields. If six tables have a primary key of *code*, you're making life unnecessarily difficult. Rather, use more descriptive terms, such as *sales\_code* or *customer\_code*. * Don't create too many relationships. Almost every table in a system can be related by some stretch of the imagination, but there's no need to do this. For example, a tennis player belongs to a sports club. A sports club belongs to a region. The tennis players then also belong to a region, but this relationship can be derived through the sports club, so there's no need to add another foreign key (except to achieve performance benefits for certain kinds of queries). Normalizing can help you avoid this sort of problem (and even when you're trying to optimize for speed, it's usually better to normalize and then consciously denormalize rather than not normalize at all). * Conversely, have you catered to all relations? Do all relations from your entity-relationship diagram appear as common fields in your table structures? Have you covered all relations? Are all many-to-many relationships broken up into two one-to-many relationships, with an intersection entity? * Have you listed all constraints? Constraints include a gender that can only be *m* or *f*, ages of schoolchildren that cannot exceed twenty, or email addresses that need to have an *@* sign and at least one period (*.*; don't take these limits for granted. At some stage the system you will need to implement them, and you're either going to forget to do so, or have to go back and gather more data if you don't list these up front. * Are you planning to store too much data? Should a customer be asked to supply their eye color, favorite kind of fish, and names of their grandparents if they are simply trying to register for an online newsletter? Sometimes stakeholders want too much information from their customers. If the user is outside the organization, they may not have a voice in the design process, but they should always be thought of foremost. Consider also the difficulty and time taken to capture all the data. If a telephone operator needs to take all this information down before making a sale, imagine how much slower they will be. Also consider the impact data has on database speed. Larger tables are generally slower to access, and unnecessary [BLOB](../blob/index), [TEXT](../text/index) and [VARCHAR](../varchar/index) fields lead to record and table fragmentation. * Have you combined fields that should be separate? Combining first name and surname into one field is a common beginner mistake. Later you'll realise that sorting names alphabetically is tricky if you've stored them as *John Ellis* and *Alfred Ntombela*. Keep distinct data discrete. * Has every table got a primary key? There had better be a good reason for leaving out a primary key. How else are you going to identify a unique record quickly? Consider that an index speeds up access time tremendously, and when kept small it adds very little overhead. Also, it's usually better to create a new field for the primary key rather than take existing fields. First name and surname may be unique in your current database, but they may not always be. Creating a system-defined primary key ensures it will always be unique. * Give some thought to your other indexes. What fields are likely to be used in this condition to access the table? You can always create more fields later when you test the system, but add any you think you need at this stage. * Are your foreign keys correctly placed? In a one-to-many relationship, the foreign key appears in the *many* table, and the associated primary key in the *one* table. Mixing these up can cause errors. * Do you ensure referential integrity? Foreign keys should not relate to a primary key in another table that no longer exists. * Have you covered all character sets you may need? German letters, for example, have an expanded character set, and if the database is to cater for German users it will have to take this into account. Similarly, dates and currency formats should be carefully considered if the system is to be international * Is your security sufficient? Remember to assign the minimum permissions you can. Do not allow anyone to view a table if they do not need to do so. Allowing malicious users view data, even if they cannot change it, is often the first step in for an attacker. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb version_major version\_major ============== Syntax ------ ``` sys.version_major() ``` Description ----------- `version_major` is a [stored function](../stored-functions/index) available with the [Sys Schema](../sys-schema/index). It returns the MariaDB Server major release version. Examples -------- ``` SELECT VERSION(), sys.version_major() AS major, sys.version_minor() AS minor, sys.version_patch() AS patch; +----------------+-------+-------+-------+ | VERSION() | major | minor | patch | +----------------+-------+-------+-------+ | 10.8.2-MariaDB | 10 | 8 | 2 | +----------------+-------+-------+-------+ ``` See Also -------- * [version\_minor](../version_minor/index) * [version\_patch](../version_patch/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_stages_history_long Table Performance Schema events\_stages\_history\_long Table ====================================================== The `events_stages_history_long` table by default contains the ten thousand most recent completed stage events. This number can be adjusted by setting the [performance\_schema\_events\_stages\_history\_long\_size](../performance-schema-system-variables/index#performance_schema_events_stages_history_long_size) system variable when the server starts up. The table structure is identical to the `events_stage_current` table structure, and contains the following columns: | Column | Description | | --- | --- | | `THREAD_ID` | Thread associated with the event. Together with `EVENT_ID` uniquely identifies the row. | | `EVENT_ID` | Thread's current event number at the start of the event. Together with `THREAD_ID` uniquely identifies the row. | | `END_EVENT_ID` | `NULL` when the event starts, set to the thread's current event number at the end of the event. | | `EVENT_NAME` | Event instrument name and a NAME from the `setup_instruments` table | | `SOURCE` | Name and line number of the source file containing the instrumented code that produced the event. | | `TIMER_START` | Value in picoseconds when the event timing started or NULL if timing is not collected. | | `TIMER_END` | Value in picoseconds when the event timing ended, or NULL if timing is not collected. | | `TIMER_WAIT` | Value in picoseconds of the event's duration or NULL if timing is not collected. | | `NESTING_EVENT_ID` | `EVENT_ID` of event within which this event nests. | | `NESTING_EVENT_TYPE` | Nesting event type. One of `transaction`, `statement`, `stage` or `wait`. | It is possible to empty this table with a `TRUNCATE TABLE` statement. [events\_stages\_current](../performance-schema-events_stages_current-table/index) and [events\_stages\_history](../performance-schema-events_stages_history-table/index) are related tables. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Buildbot Setup for Virtual Machines - Ubuntu 8.04, 8.10, and 9.10 Buildbot Setup for Virtual Machines - Ubuntu 8.04, 8.10, and 9.10 ================================================================= These 6 platforms were installed together (i386 and amd64). Base installs ------------- Ubuntu 8.04 "Hardy" amd64: ``` qemu-img create -f qcow2 vm-hardy-amd64-serial.qcow2 8G kvm -m 1024 -hda vm-hardy-amd64-serial.qcow2 -cdrom /kvm/ubuntu-8.04.3-server-amd64.iso -redir tcp:2228::22 -boot d -smp 2 -cpu qemu64 -net nic,model=virtio -net user # Install, picking default options mostly, only adding openssh server. kvm -m 1024 -hda vm-hardy-amd64-serial.qcow2 -cdrom /kvm/ubuntu-8.04.3-server-amd64.iso -redir tcp:2228::22 -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user -nographic ssh -p 2228 localhost # edit /boot/grub/menu.lst and visudo, see below sudo /sbin/shutdown -h now kvm -m 1024 -hda vm-hardy-amd64-serial.qcow2 -cdrom /kvm/ubuntu-8.04.3-server-amd64.iso -redir tcp:2228::22 -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user -nographic ssh -t -p 2228 localhost "mkdir .ssh; sudo addgroup $USER sudo" scp -P 2228 authorized_keys localhost:.ssh/ echo $'Buildbot\n\n\n\n\ny' | ssh -p 2228 localhost 'chmod -R go-rwx .ssh; sudo adduser --disabled-password buildbot; sudo addgroup buildbot sudo; sudo mkdir ~buildbot/.ssh; sudo cp .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -R buildbot:buildbot ~buildbot/.ssh; sudo chmod -R go-rwx ~buildbot/.ssh' scp -P 2228 ttyS0 buildbot@localhost: ssh -p 2228 buildbot@localhost 'sudo cp ttyS0 /etc/event.d; rm ttyS0; sudo shutdown -h now' ``` Ubuntu 8.04 "Hardy" i386: ``` qemu-img create -f qcow2 vm-hardy-i386-serial.qcow2 8G kvm -m 1024 -hda vm-hardy-i386-serial.qcow2 -cdrom /kvm/ubuntu-8.04.3-server-i386.iso -redir tcp:2229::22 -boot d -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user # Install, picking default options mostly, only adding openssh server. kvm -m 1024 -hda vm-hardy-i386-serial.qcow2 -cdrom /kvm/ubuntu-8.04.3-server-i386.iso -redir tcp:2229::22 -boot c -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user -nographic ssh -p 2229 localhost # edit /boot/grub/menu.lst and visudo, see below ssh -t -p 2229 localhost "mkdir .ssh; sudo addgroup $USER sudo" scp -P 2229 authorized_keys localhost:.ssh/ echo $'Buildbot\n\n\n\n\ny' | ssh -p 2229 localhost 'chmod -R go-rwx .ssh; sudo adduser --disabled-password buildbot; sudo addgroup buildbot sudo; sudo mkdir ~buildbot/.ssh; sudo cp .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -R buildbot:buildbot ~buildbot/.ssh; sudo chmod -R go-rwx ~buildbot/.ssh' scp -P 2229 ttyS0 buildbot@localhost: ssh -p 2229 buildbot@localhost 'sudo cp ttyS0 /etc/event.d; rm ttyS0; sudo shutdown -h now' ``` Ubuntu 8.10 "Intrepid" amd64: ``` qemu-img create -f qcow2 vm-intrepid-amd64-serial.qcow2 8G kvm -m 1024 -hda vm-intrepid-amd64-serial.qcow2 -cdrom /kvm/ubuntu-8.10-server-amd64.iso -redir tcp:2230::22 -boot d -smp 2 -cpu qemu64 -net nic,model=virtio -net user # Install, picking default options mostly, only adding openssh server. kvm -m 1024 -hda vm-intrepid-amd64-serial.qcow2 -cdrom /kvm/ubuntu-8.10-server-amd64.iso -redir tcp:2230::22 -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user -nographic ssh -p 2230 localhost # edit /boot/grub/menu.lst and visudo, see below ssh -t -p 2230 localhost "mkdir .ssh; sudo addgroup $USER sudo" scp -P 2230 authorized_keys localhost:.ssh/ echo $'Buildbot\n\n\n\n\ny' | ssh -p 2230 localhost 'chmod -R go-rwx .ssh; sudo adduser --disabled-password buildbot; sudo addgroup buildbot sudo; sudo mkdir ~buildbot/.ssh; sudo cp .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -R buildbot:buildbot ~buildbot/.ssh; sudo chmod -R go-rwx ~buildbot/.ssh' scp -P 2230 ttyS0 buildbot@localhost: ssh -p 2230 buildbot@localhost 'sudo cp ttyS0 /etc/event.d; rm ttyS0; sudo shutdown -h now' ``` Ubuntu 8.10 "Intrepid" i386: ``` qemu-img create -f qcow2 vm-intrepid-i386-serial.qcow2 8G kvm -m 1024 -hda vm-intrepid-i386-serial.qcow2 -cdrom /kvm/ubuntu-8.10-server-i386.iso -redir tcp:2231::22 -boot d -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user # Install, picking default options mostly, only adding openssh server. kvm -m 1024 -hda vm-intrepid-i386-serial.qcow2 -cdrom /kvm/ubuntu-8.10-server-i386.iso -redir tcp:2231::22 -boot c -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user -nographic ssh -p 2231 localhost # edit /boot/grub/menu.lst and visudo, see below ssh -t -p 2231 localhost "mkdir .ssh; sudo addgroup $USER sudo" scp -P 2231 authorized_keys localhost:.ssh/ echo $'Buildbot\n\n\n\n\ny' | ssh -p 2231 localhost 'chmod -R go-rwx .ssh; sudo adduser --disabled-password buildbot; sudo addgroup buildbot sudo; sudo mkdir ~buildbot/.ssh; sudo cp .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -R buildbot:buildbot ~buildbot/.ssh; sudo chmod -R go-rwx ~buildbot/.ssh' scp -P 2231 ttyS0 buildbot@localhost: ssh -p 2231 buildbot@localhost 'sudo cp ttyS0 /etc/event.d; rm ttyS0; sudo shutdown -h now' ``` Ubuntu 9.10 "Karmic" amd64: ``` qemu-img create -f qcow2 vm-karmic-amd64-serial.qcow2 8G kvm -m 1024 -hda vm-karmic-amd64-serial.qcow2 -cdrom /kvm/ubuntu-9.10-server-amd64.iso -redir tcp:2232::22 -boot d -smp 2 -cpu qemu64 -net nic,model=virtio -net user # Install, picking default options mostly, only adding openssh server. kvm -m 1024 -hda vm-karmic-amd64-serial.qcow2 -cdrom /kvm/ubuntu-9.10-server-amd64.iso -redir tcp:2232::22 -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user -nographic ssh -p 2232 localhost # edit /boot/grub/menu.lst and visudo, see below ssh -t -p 2232 localhost "mkdir .ssh; sudo addgroup $USER sudo" scp -P 2232 authorized_keys localhost:.ssh/ echo $'Buildbot\n\n\n\n\ny' | ssh -p 2232 localhost 'chmod -R go-rwx .ssh; sudo adduser --disabled-password buildbot; sudo addgroup buildbot sudo; sudo mkdir ~buildbot/.ssh; sudo cp .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -R buildbot:buildbot ~buildbot/.ssh; sudo chmod -R go-rwx ~buildbot/.ssh' scp -P 2232 ttyS0.conf buildbot@localhost: ssh -p 2232 buildbot@localhost 'sudo cp ttyS0.conf /etc/init/; rm ttyS0.conf; sudo shutdown -h now' ``` Ubuntu 9.10 "Karmic" i386: ``` qemu-img create -f qcow2 vm-karmic-i386-serial.qcow2 8G kvm -m 1024 -hda vm-karmic-i386-serial.qcow2 -cdrom /kvm/ubuntu-9.10-server-i386.iso -redir tcp:2233::22 -boot d -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user # Install, picking default options mostly, only adding openssh server. kvm -m 1024 -hda vm-karmic-i386-serial.qcow2 -cdrom /kvm/ubuntu-9.10-server-i386.iso -redir tcp:2233::22 -boot c -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user -nographic ssh -p 2233 localhost # edit /boot/grub/menu.lst and visudo, see below ssh -t -p 2233 localhost "mkdir .ssh; sudo addgroup $USER sudo" scp -P 2233 authorized_keys localhost:.ssh/ echo $'Buildbot\n\n\n\n\ny' | ssh -p 2233 localhost 'chmod -R go-rwx .ssh; sudo adduser --disabled-password buildbot; sudo addgroup buildbot sudo; sudo mkdir ~buildbot/.ssh; sudo cp .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -R buildbot:buildbot ~buildbot/.ssh; sudo chmod -R go-rwx ~buildbot/.ssh' scp -P 2233 ttyS0.conf buildbot@localhost: ssh -p 2233 buildbot@localhost 'sudo cp ttyS0.conf /etc/init/; rm ttyS0.conf; sudo shutdown -h now' ``` For visudo to enable passwordless sudo: ``` sudo VISUAL=vi visudo # uncomment `%sudo ALL=NOPASSWD: ALL' line in `visudo`, and move to end. ``` For 8.04/8.10/9.04, /boot/grub/menu.lst is edited as follows: ``` sudo vi /boot/grub/menu.lst # Add this: serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1 terminal --timeout=3 serial console # Also add in menu.lst to kernel line (after removing `quiet splash'): console=tty0 console=ttyS0,115200n8 ``` For 9.10, /boot/grub/menu.lst is edited as follows: ``` sudo vi /etc/default/grub # Add/edit these entries: GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8" GRUB_TERMINAL="serial" GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1" sudo update-grub ``` VMs for building .debs ---------------------- ``` for i in 'vm-hardy-amd64-serial.qcow2 2228 qemu64' 'vm-hardy-i386-serial.qcow2 2229 qemu32,-nx' 'vm-intrepid-amd64-serial.qcow2 2230 qemu64' 'vm-intrepid-i386-serial.qcow2 2231 qemu32,-nx' ; do \ set $i; \ runvm --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/build/')" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get build-dep -y mysql-server-5.0" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get install -y devscripts hardening-wrapper fakeroot doxygen texlive-latex-base ghostscript libevent-dev libssl-dev zlib1g-dev libreadline5-dev" ; \ done for i in 'vm-karmic-amd64-serial.qcow2 2232 qemu64' 'vm-karmic-i386-serial.qcow2 2233 qemu32,-nx' ; do \ set $i; \ runvm --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/build/')" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get update" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get -y build-dep mysql-server-5.1" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get install -y devscripts hardening-wrapper fakeroot doxygen texlive-latex-base ghostscript libevent-dev libssl-dev zlib1g-dev libreadline5-dev" ; \ done ``` VMs for install testing ----------------------- See the [General Principles](../buildbot-setup-for-virtual-machines-general-principles/index) article for how to make the '`my.seed`' and '`sources.append`' files. ``` for i in 'vm-hardy-amd64-serial.qcow2 2228 qemu64' 'vm-hardy-i386-serial.qcow2 2229 qemu32,-nx' 'vm-intrepid-amd64-serial.qcow2 2230 qemu64' 'vm-intrepid-i386-serial.qcow2 2231 qemu32,-nx' 'vm-karmic-amd64-serial.qcow2 2232 qemu64' 'vm-karmic-i386-serial.qcow2 2233 qemu32,-nx' ; do \ set $i; \ runvm --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/install/')" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get update" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get install -y debconf-utils" \ "= scp -P $2 my.seed sources.append buildbot@localhost:/tmp/" \ "sudo debconf-set-selections /tmp/my.seed" \ "sudo sh -c 'cat /tmp/sources.append >> /etc/apt/sources.list'"; \ done ``` VMs for upgrade testing ----------------------- ``` for i in 'vm-hardy-amd64-install.qcow2 2228 qemu64' 'vm-hardy-i386-install.qcow2 2229 qemu32,-nx' 'vm-intrepid-amd64-install.qcow2 2230 qemu64' 'vm-intrepid-i386-install.qcow2 2231 qemu32,-nx' ; do \ set $i; \ runvm --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/install/upgrade/')" \ 'sudo DEBIAN_FRONTEND=noninteractive apt-get install -y mysql-server-5.0' 'mysql -uroot -prootpass -e "create database mytest; use mytest; create table t(a int primary key); insert into t values (1); select * from t"' ; \ done for i in 'vm-karmic-amd64-install.qcow2 2232 qemu64' 'vm-karmic-i386-install.qcow2 2233 qemu32,-nx' ; do \ set $i; \ runvm --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/install/upgrade/')" \ 'sudo DEBIAN_FRONTEND=noninteractive apt-get install -y mysql-server-5.1' \ 'mysql -uroot -prootpass -e "create database mytest; use mytest; create table t(a int primary key); insert into t values (1); select * from t"' ; \ done ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SPATIAL INDEX SPATIAL INDEX ============= Description ----------- On [MyISAM](../myisam/index), [Aria](../aria/index) and [InnoDB](../innodb/index) tables, MariaDB can create spatial indexes (an R-tree index) using syntax similar to that for creating regular indexes, but extended with the `SPATIAL` keyword. Currently, columns in spatial indexes must be declared `NOT NULL`. Spatial indexes can be created when the table is created, or added after the fact like so: * with [CREATE TABLE](../create-table/index): ``` CREATE TABLE geom (g GEOMETRY NOT NULL, SPATIAL INDEX(g)); ``` * with [ALTER TABLE](../alter-table/index): ``` ALTER TABLE geom ADD SPATIAL INDEX(g); ``` * with [CREATE INDEX](../create-index/index): ``` CREATE SPATIAL INDEX sp_index ON geom (g); ``` `SPATIAL INDEX` creates an `R-tree` index. For storage engines that support non-spatial indexing of spatial columns, the engine creates a `B-tree` index. A `B-tree` index on spatial values is useful for exact-value lookups, but not for range scans. For more information on indexing spatial columns, see [CREATE INDEX](../create-index/index). To drop spatial indexes, use [ALTER TABLE](../alter-table/index) or [DROP INDEX](../drop-index/index): * with [ALTER TABLE](../alter-table/index): ``` ALTER TABLE geom DROP INDEX g; ``` * with [DROP INDEX](../drop-index/index): ``` DROP INDEX sp_index ON geom; ``` ### Data-at-Rest Encyption Before [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/), InnoDB's spatial indexes could not be [encrypted](../encryption/index). If an InnoDB table was encrypted and if it contained spatial indexes, then those indexes would be unencrypted. In [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) and later, if `[innodb\_checksum\_algorithm](../innodb-system-variables/index#innodb_checksum_algorithm)` is set to `full_crc32` or `strict_full_crc32`, and if the table does not use `[ROW\_FORMAT=COMPRESSED](../xtradbinnodb-storage-formats/index)`, then InnoDB spatial indexes will be encrypted if the table is encrypted. See [MDEV-12026](https://jira.mariadb.org/browse/MDEV-12026) for more information. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb NOT REGEXP NOT REGEXP ========== Syntax ------ ``` expr NOT REGEXP pat, expr NOT RLIKE pat ``` Description ----------- This is the same as [NOT (expr REGEXP pat)](../not/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb BIT BIT === Syntax ------ ``` BIT[(M)] ``` Description ----------- A bit-field type. `M` indicates the number of bits per value, from `1` to `64`. The default is `1` if `M` is omitted. Bit values can be inserted with `b'value'` notation, where `value` is the bit value in 0's and 1's. Bit fields are automatically zero-padded from the left to the full length of the bit, so for example in a BIT(4) field, '10' is equivalent to '0010'. Bits are returned as binary, so to display them, either add 0, or use a function such as [HEX](../hex/index), [OCT](../oct/index) or [BIN](../bin/index) to convert them. Examples -------- ``` CREATE TABLE b ( b1 BIT(8) ); ``` With [strict\_mode](../sql-mode/index#strict-mode) set, the default from [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/): ``` INSERT INTO b VALUES (b'11111111'); INSERT INTO b VALUES (b'01010101'); INSERT INTO b VALUES (b'1111111111111'); ERROR 1406 (22001): Data too long for column 'b1' at row 1 SELECT b1+0, HEX(b1), OCT(b1), BIN(b1) FROM b; +------+---------+---------+----------+ | b1+0 | HEX(b1) | OCT(b1) | BIN(b1) | +------+---------+---------+----------+ | 255 | FF | 377 | 11111111 | | 85 | 55 | 125 | 1010101 | +------+---------+---------+----------+ ``` With [strict\_mode](../sql-mode/index#strict-mode) unset, the default until [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/): ``` INSERT INTO b VALUES (b'11111111'),(b'01010101'),(b'1111111111111'); Query OK, 3 rows affected, 1 warning (0.10 sec) Records: 3 Duplicates: 0 Warnings: 1 SHOW WARNINGS; +---------+------+---------------------------------------------+ | Level | Code | Message | +---------+------+---------------------------------------------+ | Warning | 1264 | Out of range value for column 'b1' at row 3 | +---------+------+---------------------------------------------+ SELECT b1+0, HEX(b1), OCT(b1), BIN(b1) FROM b; +------+---------+---------+----------+ | b1+0 | HEX(b1) | OCT(b1) | BIN(b1) | +------+---------+---------+----------+ | 255 | FF | 377 | 11111111 | | 85 | 55 | 125 | 1010101 | | 255 | FF | 377 | 11111111 | +------+---------+---------+----------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CLOSE CLOSE ===== Syntax ------ ``` CLOSE cursor_name ``` Description ----------- This statement closes a previously [opened](../open/index) cursor. The cursor must have been previously opened or else an error occurs. If not closed explicitly, a cursor is closed at the end of the compound statement in which it was declared. See [Cursor Overview](../cursor-overview/index) for an example. See Also -------- * [Cursor Overview](../cursor-overview/index) * [DECLARE CURSOR](../declare-cursor/index) * [OPEN cursor\_name](../open/index) * [FETCH cursor\_name](../fetch/index) * [Cursors in Oracle mode](../sql_modeoracle-from-mariadb-103/index#cursors) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Information Functions ColumnStore Information Functions ================================= Functions --------- MariaDB ColumnStore Information Functions are selectable pseudo functions that return MariaDB ColumnStore specific “meta” information to ensure queries can be locally directed to a specific node. These functions can be specified in the projection (SELECT), WHERE, GROUP BY, HAVING and ORDER BY portions of the SQL statement and will be processed in a distributed manner. | Function | Description | | --- | --- | | idbBlockId(column) | The Logical Block Identifier (LBID) for the block containing the physical row | | idbDBRoot(column) | The DBRoot where the physical row resides | | idbExtentId(column) | The Logical Block Identifier (LBID) for the first block in the extent containing the physical row | | idbExtentMax(column) | The max value from the extent map entry for the extent containing the physical row | | idbExtentMin(column) | The min value from the extent map entry for the extent containing the physical row | | idbExtentRelativeRid(column) | The row id (1 to 8,388,608) within the column's extent | | idbLocalPm() | The PM from which the query was launched. This function will return NULL if the query is launched from a standalone UM | | idbPartition(column) | The three part partition id (Directory.Segment.DBRoot) | | idbPm(column) | The PM where the physical row resides | | idbSegmentDir(column) | The lowest level directory id for the column file containing the physical row | | idbSegment(column) | The number of the segment file containing the physical row | Example ------- SELECT involving a join between a fact table on the PM node and dimension table across all the nodes to import back on local PM: With the [infinidb\_local\_query](../mariadb/configuring-columnstore-local-pm-query-mode/index) variable set to 0 (default with [local PM Query](../mariadb/configuring-columnstore-local-pm-query-mode/index) ): Create a script (i.e., extract\_query\_script.sql in our example) similar to the following: ``` set infinidb_local_query=0; select fact.column1, dim.column2 from fact join dim using (key) where idbPm(fact.key) = idbLocalPm(); ``` The [infinidb\_local\_query](../mariadb/configuring-columnstore-local-pm-query-mode/index) is set to 0 to allow query across all PMs. The query is structured so that the UM process on the PM node gets the fact table data locally from the PM node (as indicated by the use of the idbLocalPm() function), while the dimension table data is extracted from all the PM nodes. Then you can execute the script to pipe it directly into cpimport: ``` mcsmysql source_schema -N < extract_query_script.sql | /usr/local/mariadb/columnstore/bin/cpimport target_schema target_table -s '\t' –n1 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb RENAME USER RENAME USER =========== Syntax ------ ``` RENAME USER old_user TO new_user [, old_user TO new_user] ... ``` Description ----------- The RENAME USER statement renames existing MariaDB accounts. To use it, you must have the global [CREATE USER](../grant/index#global-privileges) privilege or the `[UPDATE](../grant/index#table-privileges)` privilege for the `mysql` database. Each account is named using the same format as for the [CREATE USER](../create-user/index) statement; for example, `'jeffrey'@'localhost'`. If you specify only the user name part of the account name, a host name part of `'%'` is used. If any of the old user accounts do not exist or any of the new user accounts already exist, `ERROR 1396 (HY000)` results. If an error occurs, `RENAME USER` will still rename the accounts that do not result in an error. Examples -------- ``` CREATE USER 'donald', 'mickey'; RENAME USER 'donald' TO 'duck'@'localhost', 'mickey' TO 'mouse'@'localhost'; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Drop Procedure ColumnStore Drop Procedure ========================== The DROP PROCEDURE statement deletes a stored procedure from ColumnStore. images here The following statement drops the *sp\_complex\_variable* procedure: ``` DROP PROCEDURE sp_complex_variable; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb System Variables Added in MariaDB 10.4 System Variables Added in MariaDB 10.4 ====================================== This is a list of [system variables](../server-system-variables/index) that have been added in the [MariaDB 10.4](../what-is-mariadb-104/index) series. The list does not include variables that are not part of the default release. | Variable | Added | | --- | --- | | [analyze\_sample\_percentage](../server-system-variables/index#analyze_sample_percentage) | [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) | | [default\_password\_lifetime](../server-system-variables/index#default_password_lifetime) | [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) | | [disconnect\_on\_expired\_password](../server-system-variables/index#disconnect_on_expired_password) | [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) | | [gtid\_cleanup\_batch\_size](../gtid/index#gtid_cleanup_batch_size) | [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/) | | [innodb\_encrypt\_temporary\_ables](../xtradbinnodb-server-system-variables/index#innodb_encrypt_temporary_tables) | [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/) | | [innodb\_instant\_alter\_column\_allowed](../innodb-system-variables/index#innodb_instant_alter_column_allowed) | [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/) | | [max\_password\_errors](../server-system-variables/index#max_password_errors) | [MariaDB 10.4.2](https://mariadb.com/kb/en/mariadb-1042-release-notes/) | | [optimizer\_trace](../server-system-variables/index#optimizer_trace) | [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) | | [optimizer\_trace\_max\_mem\_size](../server-system-variables/index#optimizer_trace_max_mem_size) | [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) | | [tcp\_nodelay](../server-system-variables/index#tcp_nodelay) | [MariaDB 10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/) | | [tls\_version](../ssltls-system-variables/index#tls_version) | [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/) | | [wsrep\_certification\_rules](../galera-cluster-system-variables/index#wsrep_certification_rules) | [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) | | [wsrep\_trx\_fragment\_size](../galera-cluster-system-variables/index#wsrep_trx_fragment_size) | [MariaDB 10.4.2](https://mariadb.com/kb/en/mariadb-1042-release-notes/) | | [wsrep\_trx\_fragment\_unit](../galera-cluster-system-variables/index#wsrep_trx_fragment_unit) | [MariaDB 10.4.2](https://mariadb.com/kb/en/mariadb-1042-release-notes/) | See Also -------- * [Status Variables Added in MariaDB 10.4](../status-variables-added-in-mariadb-104/index) * [System Variables Added in MariaDB 10.5](../system-variables-added-in-mariadb-105/index) * [System Variables Added in MariaDB 10.3](../system-variables-added-in-mariadb-103/index) * [System Variables Added in MariaDB 10.2](../system-variables-added-in-mariadb-102/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Setting Innodb Buffer Pool Size Dynamically Setting Innodb Buffer Pool Size Dynamically =========================================== **MariaDB starting with [10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)**From [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/), the [InnoDB Buffer Pool](../innodb-buffer-pool/index) size can be set dynamically. Resizing the buffer pool is performed in chunks determined by the size of the [innodb\_buffer\_pool\_chunk\_size](../innodb-system-variables/index#innodb_buffer_pool_chunk_size) variable. The resize operation waits until all active transactions and operations are completed, and new transactions and operations that need to access the buffer pool must wait until the resize is complete (although when decreasing the size, access is permitted when defragmenting and withdrawing pages). Nested transactions may fail if started after the buffer pool resize has begun. The new buffer pool size must be a multiple of [innodb\_buffer\_pool\_chunk\_size](../innodb-system-variables/index#innodb_buffer_pool_chunk_size) \* [innodb\_buffer\_pool\_instances](../innodb-system-variables/index#innodb_buffer_pool_instances) (note that `innodb_buffer_pool_instances` is ignored from [MariaDB 10.5](../what-is-mariadb-105/index), and removed in [MariaDB 10.6](../what-is-mariadb-106/index), as the buffer pool is no longer split into multiple instances). If you attempt to set a different figure, the value is automatically adjusted to a multiple of at least the attempted size. Note that adjusting the [innodb\_buffer\_pool\_chunk\_size](../innodb-system-variables/index#innodb_buffer_pool_chunk_size) setting can result in a change in the buffer pool size. The number of chunks as calculated by [innodb\_buffer\_pool\_size](../innodb-system-variables/index#innodb_buffer_pool_size) / [innodb\_buffer\_pool\_chunk\_size](../innodb-system-variables/index#innodb_buffer_pool_chunk_size) should not exceed 1000 in order to avoid performance issues. A background thread performs the resizing operation. The [Innodb\_buffer\_pool\_resize\_status](../innodb-status-variables/index#innodb_buffer_pool_resize_status) status variable shows the progress of the resizing operation, for example: ``` SHOW STATUS LIKE 'Innodb_buffer_pool_resize_status'; +----------------------------------+----------------------------------+ | Variable_name | Value | +----------------------------------+----------------------------------+ | Innodb_buffer_pool_resize_status | Resizing also other hash tables. | +----------------------------------+----------------------------------+ ``` or ``` SHOW STATUS LIKE 'Innodb_buffer_pool_resize_status'; +----------------------------------+----------------------------------------------------+ | Variable_name | Value | +----------------------------------+----------------------------------------------------+ | Innodb_buffer_pool_resize_status | Completed resizing buffer pool at 161103 16:26:54. | +----------------------------------+----------------------------------------------------+ ``` Progress is also logged in the [error log](../error-log/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Generic Build Instructions Generic Build Instructions ========================== The instructions on this page will help you compile [MariaDB](../mariadb/index) from source. Links to more complete instructions for specific platforms can be found on the [source](../source/index) page. First, [get a copy of the MariaDB source](../getting-the-mariadb-source-code/index). Next, [prepare your system to be able to compile the source](../build-environment-setup-for-linux/index). If you don't want to run MariaDB as yourself, then you should create a `mysql` user. The example below uses this user. Using cmake ----------- [MariaDB 5.5](../what-is-mariadb-55/index) and above is compiled using *cmake*. It is recommended to create a build directory **beside** your source directory ``` mkdir build-mariadb cd build-mariadb ``` **NOTE** If you have built MariaDB in the past and have recently updated the repository, you should perform a complete cleanup of old artifacts (such as cmake configured files). In the base repository run: ``` git clean -xffd && git submodule foreach --recursive git clean -xffd ``` You can configure your build simply by running *cmake* without any special options, like ``` cmake ../server ``` where `server` is where you installed MariaDB. If you are building in the source directory, just omit `../server`. If you want it to be configured exactly as a normal MariaDB server release is built, use ``` cmake ../server -DBUILD_CONFIG=mysql_release ``` This will configure the build to generate binary tarballs similar to release tarballs from downloads.mariadb.org. Unfortunately this doesn't work on old platforms, like OpenSuse Leap 15.0, because MariaDB binary tarballs are built to minimize external dependencies, and that needs static libraries that might not be provided by the platform by default, and would need to be installed manually. To do a build suitable for debugging use: ``` cmake ../server -DCMAKE_BUILD_TYPE=Debug ``` By default, MariaDB is compiled with the `-Werror` flag, which causes compiling to abort if there is a compiler warning. You can disable that by configuring with `-DMYSQL_MAINTAINER_MODE=OFF`. ``` cmake ../server -DCMAKE_BUILD_TYPE=Debug -DMYSQL_MAINTAINER_MODE=OFF. ``` All *cmake* configuration options for MariaDB can be displayed with: ``` cmake ../server -LH ``` To build and install MariaDB after running *cmake* use ``` cmake --build . sudo cmake --install . ``` If the commands above fail, you can enable more compilation information by doing: ``` cmake --build . --verbose ``` If you want to generate a binary tarball, run ``` cpack ``` Using BUILD Scripts ------------------- There are also `BUILD` scripts for the most common systems for those that doesn't want to dig into cmake options. These are optimized for in source builds. The scripts are of type 'compile-#cpu#-how\_to\_build'. Some common scripts-are | Script | Description | | --- | --- | | compile-pentium64 | Compile an optimized binary optimized for 64 bit pentium (works also for amd64) | | compile-pentium-debug | Compile a debug binary optimized for 64 bit pentium | | compile-pentium-valgrind-max | Compile a debug binary that can be used with [valgrind](http://www.valgrind.org/) to find wrong memory accesses and memory leaks. Should be used if one want's to run the `mysql-test-run` test suite with the `--valgrind` option | Some common suffixes used for the scripts: | Suffix | Description | | --- | --- | | `32` | Compile for 32 bit cpu's | | `64` | Compile for 64 bit cpu's | | `-max` | Enable (almost) all features and plugins that MariaDB supports | | `-gprof` | binary is compiled with profiling (gcc --pg) | | `-gcov` | binary is compiled with code coverage (gcc -fprofile-arcs -ftest-coverage) | | `-valgrind` | The binary is compiled for debugging and optimized to be used with [valgrind](http://www.valgrind.org/). | | `-debug` | The binary is compiled with all symbols (gcc -g) and the `[DBUG](../creating-a-trace-file/index)` log system is enabled. | All `BUILD` scripts support the following options: | Suffix | Description | | --- | --- | | -h, --help | Show this help message. | | -n, --just-print | Don't actually run any commands; just print them. | | -c, --just-configure | Stop after running configure. Combined with --just-print shows configure options. | | --extra-configs=xxx | Add this to configure options | | --extra-flags=xxx | Add this C and CXX flags | | --extra-cflags=xxx | Add this to C flags | | --extra-cxxflags=xxx | Add this to CXX flags | | --verbose | Print out full compile lines | | --with-debug=full | Build with full debug(no optimizations, keep call stack). | A typical compilation used by a developer would be: ``` shell> ./BUILD/compile-pentium64-debug ``` This configures the source for debugging and runs make. The server binary will be `sql/mariadbd` or `sql/mysqld`. Starting MariaDB for the First Time ----------------------------------- After installing MariaDB (using `sudo make install`), but prior to starting MariaDB for the first time, one should: 1. ensure the directory where you installed MariaDB is owned by the mysql user (if the user doesn't exist, you'll need to create it) 2. run the `mysql_install_db` script to generate the needed system tables Here is an example: ``` # The following assumes that the 'mysql' user exists and that we installed MariaDB # in /usr/local/mysql chown -R mysql /usr/local/mysql/ cd /usr/local/mysql/ scripts/mysql_install_db --user=mysql /usr/local/mysql/bin/mysqld_safe --user=mysql & ``` Testing MariaDB --------------- If you want to test your compiled MariaDB, you can do either of: Run unit tests: ``` cmake --build . --target test ``` Or run mtr tests: ``` mysql-test/mysql-test-run --force ``` Each of the above are run from the build directory. There is no need to '`make install`/`cmake --install .`' MariaDB prior to running them. **NOTE:** If you are doing more extensive testing or debugging of MariaDB (like with real application data and workloads) you may want to start and run MariaDB directly from the source directory instead of installing it with '`sudo make install`'. If so, see [Running MariaDB from the Source Directory](../running-mariadb-from-the-source-directory/index). Increasing Version Number or Tagging a Version ---------------------------------------------- If you have made code changes and want to increase the version number or tag our version with a specific tag you can do this by editing the `VERSION` file. Tags are shown when running the '`mysqld --version`' command. Non-ascii Symbols ----------------- MariaDB builds with `readline`; using an alternative such as `Editline` may result in problems with non-ascii symbols. Post-install Tasks ------------------ * [Installing system tables (mysql\_install\_db)](../installing-system-tables-mysql_install_db/index) * [Starting and Stopping MariaDB Automatically](../starting-and-stopping-mariadb-automatically/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb REGEXP REGEXP ====== Syntax ------ ``` expr REGEXP pat, expr RLIKE pat ``` Description ----------- Performs a pattern match of a string expression `expr` against a pattern `pat`. The pattern can be an extended regular expression. See [Regular Expressions Overview](../regular-expressions-overview/index) for details on the syntax for regular expressions (see also [PCRE Regular Expressions](../pcre-regular-expressions/index)). Returns `1` if `expr` matches `pat` or `0` if it doesn't match. If either `expr` or `pat` are NULL, the result is NULL. The negative form [NOT REGEXP](../not-regexp/index) also exists, as an alias for `NOT (string REGEXP pattern)`. RLIKE and NOT RLIKE are synonyms for REGEXP and NOT REGEXP, originally provided for mSQL compatibility. The pattern need not be a literal string. For example, it can be specified as a string expression or table column. **Note:** Because MariaDB uses the C escape syntax in strings (for example, "\n" to represent the newline character), you must double any "\" that you use in your REGEXP strings. REGEXP is not case sensitive, except when used with binary strings. [MariaDB 10.0.5](https://mariadb.com/kb/en/mariadb-1005-release-notes/) moved to the PCRE regex library - see [PCRE Regular Expressions](../pcre-regular-expressions/index) for enhancements to REGEXP introduced in [MariaDB 10.0.5](https://mariadb.com/kb/en/mariadb-1005-release-notes/). The [default\_regex\_flags](../server-system-variables/index#default_regex_flags) variable addresses the remaining compatibilities between PCRE and the old regex library. Examples -------- ``` SELECT 'Monty!' REGEXP 'm%y%%'; +-------------------------+ | 'Monty!' REGEXP 'm%y%%' | +-------------------------+ | 0 | +-------------------------+ SELECT 'Monty!' REGEXP '.*'; +----------------------+ | 'Monty!' REGEXP '.*' | +----------------------+ | 1 | +----------------------+ SELECT 'new*\n*line' REGEXP 'new\\*.\\*line'; +---------------------------------------+ | 'new*\n*line' REGEXP 'new\\*.\\*line' | +---------------------------------------+ | 1 | +---------------------------------------+ SELECT 'a' REGEXP 'A', 'a' REGEXP BINARY 'A'; +----------------+-----------------------+ | 'a' REGEXP 'A' | 'a' REGEXP BINARY 'A' | +----------------+-----------------------+ | 1 | 0 | +----------------+-----------------------+ SELECT 'a' REGEXP '^[a-d]'; +---------------------+ | 'a' REGEXP '^[a-d]' | +---------------------+ | 1 | +---------------------+ ``` ### default\_regex\_flags examples [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) introduced the [default\_regex\_flags](../server-system-variables/index#default_regex_flags) variable to address the remaining compatibilities between PCRE and the old regex library. The default behaviour (multiline match is off) ``` SELECT 'a\nb\nc' RLIKE '^b$'; +---------------------------+ | '(?m)a\nb\nc' RLIKE '^b$' | +---------------------------+ | 0 | +---------------------------+ ``` Enabling the multiline option using the PCRE option syntax: ``` SELECT 'a\nb\nc' RLIKE '(?m)^b$'; +---------------------------+ | 'a\nb\nc' RLIKE '(?m)^b$' | +---------------------------+ | 1 | +---------------------------+ ``` Enabling the multiline option using default\_regex\_flags ``` SET default_regex_flags='MULTILINE'; SELECT 'a\nb\nc' RLIKE '^b$'; +-----------------------+ | 'a\nb\nc' RLIKE '^b$' | +-----------------------+ | 1 | +-----------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Performance Schema System Variables Performance Schema System Variables =================================== The following variables are used with MariaDB's [Performance Schema](../performance-schema/index). See [Performance Schema Options](../mysqld-options/index#performance-schema-options) for Performance Schema options that are not system variables. See [Server System Variables](../server-system-variables/index) for a complete list of system variables and instructions on setting them. See also the [Full list of MariaDB options, system and status variables](../full-list-of-mariadb-options-system-and-status-variables/index). #### `performance_schema` * **Description:** If set to `1` (`0` is default), enables the Performance Schema * **Commandline:** `--performance-schema=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `performance_schema_accounts_size` * **Description:** Maximum number of rows in the [performance\_schema.accounts](../performance-schema-accounts-table/index) table. If set to 0, the [Performance Schema](../performance-schema/index) will not store statistics in the accounts table. Use `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-accounts-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_digests_size` * **Description:** Maximum number of rows that can be stored in the [events\_statements\_summary\_by\_digest](../performance-schema-events_statements_summary_by_digest-table/index) table. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-digests-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `200` --- #### `performance_schema_events_stages_history_long_size` * **Description:** Number of rows in the [events\_stages\_history\_long](../performance-schema-events_stages_history_long-table/index) table. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-events-stages-history-long-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_events_stages_history_size` * **Description:** Number of rows per thread in the [events\_stages\_history](../performance-schema-events_stages_history-table/index) table. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-events-stages-history-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1024` --- #### `performance_schema_events_statements_history_long_size` * **Description:** Number of rows in the [events\_statements\_history\_long](../performance-schema-events_statements_history_long-table/index) table. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-events-statements-history-long-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_events_statements_history_size` * **Description:** Number of rows per thread in the [events\_statements\_history](../performance-schema-events_statements_history-table/index) table. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-events-statements-history-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1024` --- #### `performance_schema_events_transactions_history_long_size` * **Description:** Number of rows in [events\_transactions\_history\_long](../performance-schema-events_transactions_history_long-table/index) table. Use `0` to disable, `-1` for automated sizing. * **Commandline:** `--performance-schema-events-transactions-history-long-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_events_transactions_history_size` * **Description:**Number of rows per thread in [events\_transactions\_history](../performance-schema-events_transactions_history-table/index). Use 0 to disable, -1 for automated sizing. * **Commandline:** `--performance-schema-events-transactions-history-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1024` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_events_waits_history_long_size` * **Description:** Number of rows contained in the [events\_waits\_history\_long](../performance-schema-events_waits_history_long-table/index) table. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-events-waits-history-long-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_events_waits_history_size` * **Description:** Number of rows per thread contained in the [events\_waits\_history](../performance-schema-events_waits_history-table/index) table. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-events-waits-history-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1024` --- #### `performance_schema_hosts_size` * **Description:** Number of rows stored in the [hosts](../performance-schema-hosts-table/index) table. If set to zero, no connection statistics are kept for the hosts table. `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-hosts-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_max_cond_classes` * **Description:** Specifies the maximum number of condition instruments. * **Commandline:** `--performance-schema-max-cond-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `90` (>= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)), `80` (<= [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)) * **Range:** `0` to `256` --- #### `performance_schema_max_cond_instances` * **Description:** Specifies the maximum number of instrumented condition objects. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-max-cond-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_max_digest_length` * **Description:** Maximum length considered for digest text, when stored in performance\_schema tables. * **Commandline:** `--performance-schema-max-digest-length=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1024` * **Range:** `0` to `1048576` --- #### `performance_schema_max_file_classes` * **Description:** Specifies the maximum number of file instruments. * **Commandline:** `--performance-schema-max-file-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:**`80` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)), `50` (<= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)) * **Range:** `0` to `256` --- #### `performance_schema_max_file_handles` * **Description:** Specifies the maximum number of opened file objects. Should always be higher than [open\_files\_limit](../server-system-variables/index#open_files_limit). * **Commandline:** `--performance-schema-max-file-handles=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `32768` * **Range:** `-1` to `32768` --- #### `performance_schema_max_file_instances` * **Description:** Specifies the maximum number of instrumented file objects. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-max-file-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_max_index_stat` * **Description:** Maximum number of index statistics for instrumented tables. Use 0 to disable, -1 for automated scaling. * **Commandline:** `--performance-schema-max-index-stat=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_memory_classes` * **Description:** Maximum number of memory pool instruments. * **Commandline:** `--performance-schema-max-memory-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `320` * **Range:** `0` to `1024` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_metadata_locks` * **Description:** Maximum number of [Performance Schema metadata locks](../performance-schema-metadata_locks-table/index). Use 0 to disable, -1 for automated scaling. * **Commandline:** `--performance-schema-max-metadata-locks=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `104857600` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_mutex_classes` * **Description:** Specifies the maximum number of mutex instruments. * **Commandline:** `--performance-schema-max-mutex-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `210` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)), `200` (<= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)) * **Range:** `0` to `256` --- #### `performance_schema_max_mutex_instances` * **Description:** Specifies the maximum number of instrumented mutex instances. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-max-mutex-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:**`-1` * **Range:** `-1` to `104857600` --- #### `performance_schema_max_prepared_statement_instances` * **Description:** Maximum number of instrumented prepared statements. Use 0 to disable, -1 for automated scaling. * **Commandline:** `--performance-schema-max-prepared-statement-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_program_instances` * **Description:** Maximum number of instrumented programs. Use 0 to disable, -1 for automated scaling. * **Commandline:** `--performance-schema-max-program-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_rwlock_classes` * **Description:** Specifies the maximum number of rwlock instruments. * **Commandline:** `--performance-schema-max-rwlock-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `50` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)), `40` (<= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)) * **Range:** `0` to `256` --- #### `performance_schema_max_rwlock_instances` * **Description:** Specifies the maximum number of instrumented rwlock objects. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-max-rwlock-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:**`-1` * **Range:** `-1` to `104857600` --- #### `performance_schema_max_socket_classes` * **Description:** Specifies the maximum number of socket instruments. * **Commandline:** `--performance-schema-max-socket-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `10` * **Range:** `0` to `256` --- #### `performance_schema_max_socket_instances` * **Description:** Specifies the maximum number of instrumented socket objects. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-max-socket-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:**`-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_max_sql_text_length` * **Description:** Maximum length of displayed sql text. * **Commandline:** `--performance-schema-max-sql-text-length=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1024` * **Range:** `0` to `1048576` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_stage_classes` * **Description:** Specifies the maximum number of stage instruments. * **Commandline:** `--performance-schema-max-stage-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `160` (>= [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)), `150` (<= [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/)) * **Range:** `0` to `256` --- #### `performance_schema_max_statement_classes` * **Description:** Specifies the maximum number of statement instruments. Automatically calculated at server build based on the number of available statements. Should be left as either autosized or disabled, as changing to any positive value has no benefit and will most likely allocate unnecessary memory. Setting to zero disables all statement instrumentation, and no memory will be allocated for this purpose. * **Commandline:** `--performance-schema-max-statement-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** Autosized (see description) * **Range:** `0` to `256` --- #### `performance_schema_max_statement_stack` * **Description:** Number of rows per thread in EVENTS\_STATEMENTS\_CURRENT. * **Commandline:** `--performance-schema-max-statement-stack=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `10` * **Range:** `1` to `256` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_table_handles` * **Description:** Specifies the maximum number of opened table objects. `0` for disabling, `-1` (the default) for automated sizing. See also the [Performance Schema table\_handles table](../performance-schema-table_handles-table/index). * **Commandline:** `--performance-schema-max-table-handles=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_max_table_instances` * **Description:** Specifies the maximum number of instrumented table objects. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-max-table-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:**`-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_max_table_lock_stat` * **Description:** Maximum number of lock statistics for instrumented tables. Use 0 to disable, -1 for automated scaling. * **Commandline:** `--performance-schema-max-table-lock-stat=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` * **Introduced:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) --- #### `performance_schema_max_thread_classes` * **Description:** Specifies the maximum number of thread instruments. * **Commandline:** `--performance-schema-max-thread-classes=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `50` * **Range:** `0` to `256` --- #### `performance_schema_max_thread_instances` * **Description:** Specifies how many of the running server threads (see [max\_connections](../server-system-variables/index#max_connections) and [max\_delayed\_threads](../server-system-variables/index#max_delayed_threads)) can be instrumented. Should be greater than the sum of max\_connections and max\_delayed\_threads. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-max-thread-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:**`-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_session_connect_attrs_size` * **Description:** Per thread preallocated memory for holding connection attribute strings. Incremented if the strings are larger than the reserved space. `0` for disabling, `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-session-connect-attrs-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- #### `performance_schema_setup_actors_size` * **Description:** The maximum number of rows to store in the performance schema [setup\_actors](../performance-schema-setup_actors-table/index) table. `-1` (from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)) denotes automated sizing. * **Commandline:** `--performance-schema-setup-actors-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)), `100` (<= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)) * **Range:** `-1` to `1024` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)), `0` to `1024` (<= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)) --- #### `performance_schema_setup_objects_size` * **Description:** The maximum number of rows that can be stored in the performance schema [setup\_objects](../performance-schema-setup_objects-table/index) table. `-1` (from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)) denotes automated sizing. * **Commandline:** `--performance-schema-setup-objects-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)), `100` (<= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)) * **Range:** `-1` to `1048576` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)), `0` to `1048576` (<= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)) --- #### `performance_schema_users_size` * **Description:** Number of rows in the [performance\_schema.users](../performance-schema-users-table/index) table. If set to 0, the [Performance Schema](../performance-schema/index) will not store connection statistics in the users table. `-1` (the default) for automated sizing. * **Commandline:** `--performance-schema-users-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `-1` * **Range:** `-1` to `1048576` --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SUBSTR SUBSTR ====== Description ----------- `SUBSTR()` is a synonym for `[SUBSTRING](../substring/index)()`. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema file_summary_by_instance Table Performance Schema file\_summary\_by\_instance Table ==================================================== The [Performance Schema](../performance-schema/index) `file_summary_by_instance` table contains file events summarized by instance. It contains the following columns: | Column | Description | | --- | --- | | `FILE_NAME` | File name. | | `EVENT_NAME` | Event name. | | `OBJECT_INSTANCE_BEGIN` | Address in memory. Together with `FILE_NAME` and `EVENT_NAME` uniquely identifies a row. | | `COUNT_STAR` | Number of summarized events | | `SUM_TIMER_WAIT` | Total wait time of the summarized events that are timed. | | `MIN_TIMER_WAIT` | Minimum wait time of the summarized events that are timed. | | `AVG_TIMER_WAIT` | Average wait time of the summarized events that are timed. | | `MAX_TIMER_WAIT` | Maximum wait time of the summarized events that are timed. | | `COUNT_READ` | Number of all read operations, including `FGETS`, `FGETC`, `FREAD`, and `READ`. | | `SUM_TIMER_READ` | Total wait time of all read operations that are timed. | | `MIN_TIMER_READ` | Minimum wait time of all read operations that are timed. | | `AVG_TIMER_READ` | Average wait time of all read operations that are timed. | | `MAX_TIMER_READ` | Maximum wait time of all read operations that are timed. | | `SUM_NUMBER_OF_BYTES_READ` | Bytes read by read operations. | | `COUNT_WRITE` | Number of all write operations, including `FPUTS`, `FPUTC`, `FPRINTF`, `VFPRINTF`, `FWRITE`, and `PWRITE`. | | `SUM_TIMER_WRITE` | Total wait time of all write operations that are timed. | | `MIN_TIMER_WRITE` | Minimum wait time of all write operations that are timed. | | `AVG_TIMER_WRITE` | Average wait time of all write operations that are timed. | | `MAX_TIMER_WRITE` | Maximum wait time of all write operations that are timed. | | `SUM_NUMBER_OF_BYTES_WRITE` | Bytes written by write operations. | | `COUNT_MISC` | Number of all miscellaneous operations not counted above, including `CREATE`, `DELETE`, `OPEN`, `CLOSE`, `STREAM_OPEN`, `STREAM_CLOSE`, `SEEK`, `TELL`, `FLUSH`, `STAT`, `FSTAT`, `CHSIZE`, `RENAME`, and `SYNC`. | | `SUM_TIMER_MISC` | Total wait time of all miscellaneous operations that are timed. | | `MIN_TIMER_MISC` | Minimum wait time of all miscellaneous operations that are timed. | | `AVG_TIMER_MISC` | Average wait time of all miscellaneous operations that are timed. | | `MAX_TIMER_MISC` | Maximum wait time of all miscellaneous operations that are timed. | I/O operations can be avoided by caching, in which case they will not be recorded in this table. You can [TRUNCATE](../truncate-table/index) the table, which will reset all counters to zero. Example ------- ``` SELECT * FROM file_summary_by_instance\G ... *************************** 204. row *************************** FILE_NAME: /var/lib/mysql/test/db.opt EVENT_NAME: wait/io/file/sql/dbopt OBJECT_INSTANCE_BEGIN: 140578961971264 COUNT_STAR: 6 SUM_TIMER_WAIT: 39902495024 MIN_TIMER_WAIT: 177888 AVG_TIMER_WAIT: 6650415692 MAX_TIMER_WAIT: 21026400404 COUNT_READ: 1 SUM_TIMER_READ: 21026400404 MIN_TIMER_READ: 21026400404 AVG_TIMER_READ: 21026400404 MAX_TIMER_READ: 21026400404 SUM_NUMBER_OF_BYTES_READ: 65 COUNT_WRITE: 0 SUM_TIMER_WRITE: 0 MIN_TIMER_WRITE: 0 AVG_TIMER_WRITE: 0 MAX_TIMER_WRITE: 0 SUM_NUMBER_OF_BYTES_WRITE: 0 COUNT_MISC: 5 SUM_TIMER_MISC: 18876094620 MIN_TIMER_MISC: 177888 AVG_TIMER_MISC: 3775218924 MAX_TIMER_MISC: 18864558060 *************************** 205. row *************************** FILE_NAME: /var/log/mysql/mariadb-bin.000157 EVENT_NAME: wait/io/file/sql/binlog OBJECT_INSTANCE_BEGIN: 140578961971968 COUNT_STAR: 6 SUM_TIMER_WAIT: 73985877680 MIN_TIMER_WAIT: 251136 AVG_TIMER_WAIT: 12330979468 MAX_TIMER_WAIT: 73846656340 COUNT_READ: 0 SUM_TIMER_READ: 0 MIN_TIMER_READ: 0 AVG_TIMER_READ: 0 MAX_TIMER_READ: 0 SUM_NUMBER_OF_BYTES_READ: 0 COUNT_WRITE: 2 SUM_TIMER_WRITE: 62583004 MIN_TIMER_WRITE: 27630192 AVG_TIMER_WRITE: 31291284 MAX_TIMER_WRITE: 34952812 SUM_NUMBER_OF_BYTES_WRITE: 369 COUNT_MISC: 4 SUM_TIMER_MISC: 73923294676 MIN_TIMER_MISC: 251136 AVG_TIMER_MISC: 18480823560 MAX_TIMER_MISC: 73846656340 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Activating the Binary Log Activating the Binary Log ========================= To enable binary logging, start the server with the `[--log-bin[=name](../replication-and-binary-log-server-system-variables/index#log_bin)]` option. If you specify a filename with an extension (for example `.log`), the extension will be silently ignored. If you don't provide a name (which can, optionally, include an absolute path), the default will be `datadir/log-basename-bin`, `datadir/mysql-bin` or `datadir/mariadb-bin` (the latter two if [--log-basename](../mysqld-options-full-list/index#-log-basename) is not specified, and dependent on server version). Datadir is determined by the value of the [datadir](../server-system-variables/index#datadir) system variable. We strongly recommend you use either [--log-basename](../mysqld-options-full-list/index#-log-basename) or specify a filename to ensure that [replication](../replication/index) doesn't stop if the hostname of the computer changes. The directory storing the binary logs will contain a binary log index, as well as the individual binary log files. The binary log files will have a series of numbers as filename extensions. Each additional binary log will increment the extension number, so the oldest binary logs will have lower numbers, the most recent, higher numbers. A new binary log, with a new extension, is created every time the server starts, the logs are flushed, or the maximum size is reached (determined by [max\_binlog\_size](../replication-and-binary-log-system-variables/index#max_binlog_size)). The binary log index file contains a master list of all the binary logs, in order. A sample listing from a directory containing the binary logs: ``` shell> ls -l total 100 ... -rw-rw---- 1 mysql adm 2098 Apr 19 00:46 mariadb-bin.000079 -rw-rw---- 1 mysql adm 332 Apr 19 00:56 mariadb-bin.000080 -rw-rw---- 1 mysql adm 347 Apr 19 07:36 mariadb-bin.000081 -rw-rw---- 1 mysql adm 306 Apr 20 07:15 mariadb-bin.000082 -rw-rw---- 1 mysql adm 332 Apr 20 07:41 mariadb-bin.000083 -rw-rw---- 1 mysql adm 373 Apr 21 07:56 mariadb-bin.000084 -rw-rw---- 1 mysql adm 347 Apr 21 09:09 mariadb-bin.000085 -rw-rw---- 1 mysql adm 398 Apr 21 21:24 mariadb-bin.000086 -rw-rw---- 1 mysql adm 816 Apr 21 17:05 mariadb-bin.index ``` The binary log index file will by default have the same name as the individual binary logs, with the extension .index. You can specify an alternative name with the `--log-bin-index[=filename]` [option](../replication-and-binary-log-system-variables/index#log_bin_index). Clients with the SUPER privilege can disable and re-enable the binary log for the current session by setting the [sql\_log\_bin](../replication-and-binary-log-server-system-variables/index#sql_log_bin) variable. ``` SET sql_log_bin = 0; SET sql_log_bin = 1; ``` Binary Log Format ----------------- There are three formats for the binary log. The default is [mixed logging](../binary-log-formats/index#mixed-logging), which is a mix of [statement-based](../binary-log-formats/index#statement-based-logging) and [row-based logging](../binary-log-formats/index#row-based-logging). See [Binary Log Formats](../binary-log-formats/index) for a full discussion. See Also -------- * [Setting sql\_log\_bin](../set-sql_log_bin/index) * [PURGE LOGS](../sql-commands-purge-logs/index) - Delete logs * [FLUSH LOGS](../flush/index) - Close and rotate logs Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb INSERT INSERT ====== Syntax ------ ``` INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [PARTITION (partition_list)] [(col,...)] {VALUES | VALUE} ({expr | DEFAULT},...),(...),... [ ON DUPLICATE KEY UPDATE col=expr [, col=expr] ... ] [RETURNING select_expr [, select_expr ...]] ``` Or: ``` INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [PARTITION (partition_list)] SET col={expr | DEFAULT}, ... [ ON DUPLICATE KEY UPDATE col=expr [, col=expr] ... ] [RETURNING select_expr [, select_expr ...]] ``` Or: ``` INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [PARTITION (partition_list)] [(col,...)] SELECT ... [ ON DUPLICATE KEY UPDATE col=expr [, col=expr] ... ] [RETURNING select_expr [, select_expr ...]] ``` The `INSERT` statement is used to insert new rows into an existing table. The `INSERT ... VALUES` and `INSERT ... SET` forms of the statement insert rows based on explicitly specified values. The `INSERT ... SELECT` form inserts rows selected from another table or tables. `INSERT ... SELECT` is discussed further in the `[INSERT ... SELECT](../insert-select/index)` article. The table name can be specified in the form `db_name`.`tbl_name` or, if a default database is selected, in the form `tbl_name` (see [Identifier Qualifiers](../identifier-qualifiers/index)). This allows to use [INSERT ... SELECT](../insert-select/index) to copy rows between different databases. The PARTITION clause can be used in both the INSERT and the SELECT part. See [Partition Pruning and Selection](../partition-pruning-and-selection/index) for details. **MariaDB starting with [10.5](../what-is-mariadb-105/index)**The RETURNING clause was introduced in [MariaDB 10.5](../what-is-mariadb-105/index). The columns list is optional. It specifies which values are explicitly inserted, and in which order. If this clause is not specified, all values must be explicitly specified, in the same order they are listed in the table definition. The list of value follow the `VALUES` or `VALUE` keyword (which are interchangeable, regardless how much values you want to insert), and is wrapped by parenthesis. The values must be listed in the same order as the columns list. It is possible to specify more than one list to insert more than one rows with a single statement. If many rows are inserted, this is a speed optimization. For one-row statements, the `SET` clause may be more simple, because you don't need to remember the columns order. All values are specified in the form `col` = `expr`. Values can also be specified in the form of a SQL expression or subquery. However, the subquery cannot access the same table that is named in the `INTO` clause. If you use the `LOW_PRIORITY` keyword, execution of the `INSERT` is delayed until no other clients are reading from the table. If you use the `HIGH_PRIORITY` keyword, the statement has the same priority as `SELECT`s. This affects only storage engines that use only table-level locking (MyISAM, MEMORY, MERGE). However, if one of these keywords is specified, [concurrent inserts](../concurrent-inserts/index) cannot be used. See [HIGH\_PRIORITY and LOW\_PRIORITY clauses](../high_priority-and-low_priority-clauses/index) for details. INSERT DELAYED -------------- For more details on the `DELAYED` option, see [INSERT DELAYED](../insert-delayed/index). HIGH PRIORITY and LOW PRIORITY ------------------------------ See [HIGH\_PRIORITY and LOW\_PRIORITY](../high_priority-and-low_priority/index). Defaults and Duplicate Values ----------------------------- See [INSERT - Default & Duplicate Values](../insert-default-duplicate-values/index) for details.. INSERT IGNORE ------------- See [INSERT IGNORE](../insert-ignore/index). INSERT ON DUPLICATE KEY UPDATE ------------------------------ See [INSERT ON DUPLICATE KEY UPDATE](../insert-on-duplicate-key-update/index). Examples -------- Specifying the column names: ``` INSERT INTO person (first_name, last_name) VALUES ('John', 'Doe'); ``` Inserting more than 1 row at a time: ``` INSERT INTO tbl_name VALUES (1, "row 1"), (2, "row 2"); ``` Using the `SET` clause: ``` INSERT INTO person SET first_name = 'John', last_name = 'Doe'; ``` SELECTing from another table: ``` INSERT INTO contractor SELECT * FROM person WHERE status = 'c'; ``` See [INSERT ON DUPLICATE KEY UPDATE](../insert-on-duplicate-key-update/index) and [INSERT IGNORE](../insert-ignore/index) for further examples. INSERT ... RETURNING -------------------- `INSERT ... RETURNING` returns a resultset of the inserted rows. This returns the listed columns for all the rows that are inserted, or alternatively, the specified SELECT expression. Any SQL expressions which can be calculated can be used in the select expression for the RETURNING clause, including virtual columns and aliases, expressions which use various operators such as bitwise, logical and arithmetic operators, string functions, date-time functions, numeric functions, control flow functions, secondary functions and stored functions. Along with this, statements which have subqueries and prepared statements can also be used. ### Examples Simple INSERT statement ``` INSERT INTO t2 VALUES (1,'Dog'),(2,'Lion'),(3,'Tiger'),(4,'Leopard') RETURNING id2,id2+id2,id2&id2,id2||id2; +-----+---------+---------+----------+ | id2 | id2+id2 | id2&id2 | id2||id2 | +-----+---------+---------+----------+ | 1 | 2 | 1 | 1 | | 2 | 4 | 2 | 1 | | 3 | 6 | 3 | 1 | | 4 | 8 | 4 | 1 | +-----+---------+---------+----------+ ``` Using stored functions in RETURNING ``` DELIMITER | CREATE FUNCTION f(arg INT) RETURNS INT BEGIN RETURN (SELECT arg+arg); END| DELIMITER ; PREPARE stmt FROM "INSERT INTO t1 SET id1=1, animal1='Bear' RETURNING f(id1), UPPER(animal1)"; EXECUTE stmt; +---------+----------------+ | f(id1) | UPPER(animal1) | +---------+----------------+ | 2 | BEAR | +---------+----------------+ ``` Subqueries in the RETURNING clause that return more than one row or column cannot be used. Aggregate functions cannot be used in the RETURNING clause. Since aggregate functions work on a set of values, and if the purpose is to get the row count, ROW\_COUNT() with SELECT can be used or it can be used in INSERT...SELECT...RETURNING if the table in the RETURNING clause is not the same as the INSERT table. See Also -------- * [INSERT DELAYED](../insert-delayed/index) * [INSERT SELECT](../insert-select/index) * [REPLACE](../replace/index) Equivalent to DELETE + INSERT of conflicting row. * [HIGH\_PRIORITY and LOW\_PRIORITY](../high_priority-and-low_priority/index) * [Concurrent Inserts](../concurrent-inserts/index) * [INSERT - Default & Duplicate Values](../insert-default-duplicate-values/index) * [INSERT IGNORE](../insert-ignore/index) * [INSERT ON DUPLICATE KEY UPDATE](../insert-on-duplicate-key-update/index) * [How to quickly insert data into MariaDB](../how-to-quickly-insert-data-into-mariadb/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb AVG AVG === Syntax ------ ``` AVG([DISTINCT] expr) ``` Description ----------- Returns the average value of expr. The DISTINCT option can be used to return the average of the distinct values of expr. NULL values are ignored. It is an [aggregate function](../aggregate-functions/index), and so can be used with the [GROUP BY](../group-by/index) clause. AVG() returns NULL if there were no matching rows. From [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/), AVG() can be used as a [window function](../window-functions/index). Examples -------- ``` CREATE TABLE sales (sales_value INT); INSERT INTO sales VALUES(10),(20),(20),(40); SELECT AVG(sales_value) FROM sales; +------------------+ | AVG(sales_value) | +------------------+ | 22.5000 | +------------------+ SELECT AVG(DISTINCT(sales_value)) FROM sales; +----------------------------+ | AVG(DISTINCT(sales_value)) | +----------------------------+ | 23.3333 | +----------------------------+ ``` Commonly, AVG() is used with a [GROUP BY](../select/index#group-by) clause: ``` CREATE TABLE student (name CHAR(10), test CHAR(10), score TINYINT); INSERT INTO student VALUES ('Chun', 'SQL', 75), ('Chun', 'Tuning', 73), ('Esben', 'SQL', 43), ('Esben', 'Tuning', 31), ('Kaolin', 'SQL', 56), ('Kaolin', 'Tuning', 88), ('Tatiana', 'SQL', 87), ('Tatiana', 'Tuning', 83); SELECT name, AVG(score) FROM student GROUP BY name; +---------+------------+ | name | AVG(score) | +---------+------------+ | Chun | 74.0000 | | Esben | 37.0000 | | Kaolin | 72.0000 | | Tatiana | 85.0000 | +---------+------------+ ``` Be careful to avoid this common mistake, not grouping correctly and returning mismatched data: ``` SELECT name,test,AVG(score) FROM student; +------+------+------------+ | name | test | MIN(score) | +------+------+------------+ | Chun | SQL | 31 | +------+------+------------+ ``` As a [window function](../window-functions/index): ``` CREATE TABLE student_test (name CHAR(10), test CHAR(10), score TINYINT); INSERT INTO student_test VALUES ('Chun', 'SQL', 75), ('Chun', 'Tuning', 73), ('Esben', 'SQL', 43), ('Esben', 'Tuning', 31), ('Kaolin', 'SQL', 56), ('Kaolin', 'Tuning', 88), ('Tatiana', 'SQL', 87), ('Tatiana', 'Tuning', 83); SELECT name, test, score, AVG(score) OVER (PARTITION BY test) AS average_by_test FROM student_test; +---------+--------+-------+-----------------+ | name | test | score | average_by_test | +---------+--------+-------+-----------------+ | Chun | SQL | 75 | 65.2500 | | Chun | Tuning | 73 | 68.7500 | | Esben | SQL | 43 | 65.2500 | | Esben | Tuning | 31 | 68.7500 | | Kaolin | SQL | 56 | 65.2500 | | Kaolin | Tuning | 88 | 68.7500 | | Tatiana | SQL | 87 | 65.2500 | | Tatiana | Tuning | 83 | 68.7500 | +---------+--------+-------+-----------------+ ``` See Also -------- * [MAX](../max/index) (maximum) * [MIN](../min/index) (minimum) * [SUM](../sum/index) (sum total) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Deploying to Remote Servers with Ansible Deploying to Remote Servers with Ansible ======================================== If we manage several remote servers, running commands on them manually can be frustrating and time consuming. Ansible allows one to run commands on a whole group of servers. This page shows some examples of ansible-playbook invocations. We'll see how to deploy roles or parts of them to remote servers. Then we'll see how to run commands on remote hosts, and possibly to get information from them. Make sure to read [Ansible Overview](../ansible-overview/index) first, to understand Ansible general concepts. Pinging Remote Servers ---------------------- Let's start with the simplest example: we just want our local Ansible to ping remote servers to see if they are reachable. Here's how to do it: ``` ansible -i production-mariadb all -m ping ``` Before proceeding with more useful examples, let's discuss this syntax. * **ansible** is the executable we can call to run a command from remote servers. * **-i production-mariadb** means that the servers must be read from an inventory called production-mariadb. * **all** means that the command must be executed against all servers from the above inventory. * **-m ping** specifies that we want to run the ping module. This is not the ping Linux command. It tells us if Ansible is able to connect a remote server and run a simple commands on them. To run ping on a specific group or host, we can just replace "all" with a group name or host name from the inventory: ``` ansible -i production-mariadb main_cluster -m ping ``` Running Commands on Remote Servers ---------------------------------- The previous examples show how to run an Ansible module on remote servers. But it's also possible to run custom commands over SSH. Here's how: ``` ansible -i production-mariadb all -a 'echo $PATH' ``` This command shows the value of `$PATH` on all servers in the inventory "production-mariadb". We can also run commands as root by adding the `-b` (or `--become`) option: ``` # print a MariaDB variable ansible -i production-mariadb all -b -a 'mysql -e "SHOW GLOBAL VARIABLES LIKE \'innodb_buffer_pool_size\';"' # reboot servers ansible -i production-mariadb all -b -a 'reboot' ``` Applying Roles to Remote Servers -------------------------------- We saw how to run commands on remote hosts. Applying roles to remote hosts is not much harder, we just need to add some information. An example: ``` ansible-playbook -i production-mariadb production-mariadb.yml ``` Let's see what changed: * **ansible-playbook** is the executable file that we need to call to apply playbooks and roles. * **production-mariadb.yml** is the play that associates the servers listed in the inventory to their roles. If we call ansible-playbook with no additional arguments, we will apply all applicable roles to all the servers mentioned in the play. To only apply roles to certain servers, we can use the `-l` parameter to specify a group, an individual host, or a pattern: ``` # Apply to the mariadb-main role role ansible-playbook -i production-mariadb -l mariadb-main production-mariadb.yml # Apply to the mariadb-main-01 host ansible-playbook -i production-mariadb -l mariadb-main-01 production-mariadb.yml # Apply to multiple hosts whose name starts with "mariadb-main-" ansible-playbook -i production-mariadb -l mariadb-main-* production-mariadb.yml ``` We can also apply tasks from roles selectively. Tasks may optionally have tags, and each tag corresponds to an operation that we may want to run on our remote hosts. For example, a "mariadb" role could have the "timezone-update" tag, to update the contents of the [timezone tables](../time-zones/index#mysql-time-zone-tables). To only apply the tasks with the "timezone-update" tag, we can use this command: ``` ansible-playbook -i production-mariadb --tag timezone-update production-mariadb.yml ``` Using tags is especially useful for database servers. While most of the technologies typically managed by Ansible are stateless (web servers, load balancers, etc.) database servers are not. We must pay special attention not to run tasks that could cause a database server outage, for example destroying its data directory or restarting the service when it is not necessary. ### Check mode We should always test our playbooks and roles on test servers before applying them to production. However, if test servers and production servers are not exactly in the same state (which means, some facts may differ) it is still possible that applying roles will fail. If it fails in the initial stage, Ansible will not touch the remote hosts at all. But there are cases where Ansible could successfully apply some tasks, and fail to apply another task. After the first failure, ansible-playbook will show errors and exit. But this could leave a host in an inconsistent state. Ansible has a *check mode* that is meant to greatly reduce the chances of a failure. When run in check mode, ansible-playbook will read the inventory, the play and roles; it will figure out which tasks need to be applied; then it will connect to target hosts, read facts, and value all the relevant variables. If all these steps succeed, it is unlikely that running ansible-playbook without check mode will fail. To run ansible-playbook in check mode, just add the `--check` (or `-C`) parameter. References ---------- Further documentation can be found in the Ansible website: * [ansible](https://docs.ansible.com/ansible/latest/cli/ansible.html) tool. * [ansible-playbook](https://docs.ansible.com/ansible/latest/cli/ansible-playbook.html) tool. * [Validating tasks: check mode and diff mode](https://docs.ansible.com/ansible/latest/user_guide/playbooks_checkmode.html). --- Content initially contributed by [Vettabase Ltd](https://vettabase.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb ColumnStore Configuration File Update and Distribution ColumnStore Configuration File Update and Distribution ====================================================== In the case where an entry in the MariaDB ColumnStore's configuration needs to be updated and distributed, this can be done from the command line from Performance Module #1. All changes made to MariaDB ColumnStore's configuration file need to be applied on PM1. NOTE: 'mcsadmin distributeconfigfile' only needs to be run if the system is Active. If the system is down, then just make the change and when the system is started, the update will get distributed. Here is an example ``` /usr/local/mariadb/columnstore/bin/configxml.sh setconfig SystemConfig SystemName mcs-1 mcsadmin distributeconfigfile ``` In the cases where the MariaDB ColumnStore's configuration files gets out of sync with the PM1 copy, run the following to get MariaDB ColumnStore's configuration file redistribute to the other nodes. To do this run the following on PM1: ``` mscadmin distributeconfigfile ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MAKEDATE MAKEDATE ======== Syntax ------ ``` MAKEDATE(year,dayofyear) ``` Description ----------- Returns a date, given `year` and `day-of-year values`. `dayofyear` must be greater than 0 or the result is NULL. Examples -------- ``` SELECT MAKEDATE(2011,31), MAKEDATE(2011,32); +-------------------+-------------------+ | MAKEDATE(2011,31) | MAKEDATE(2011,32) | +-------------------+-------------------+ | 2011-01-31 | 2011-02-01 | +-------------------+-------------------+ SELECT MAKEDATE(2011,365), MAKEDATE(2014,365); +--------------------+--------------------+ | MAKEDATE(2011,365) | MAKEDATE(2014,365) | +--------------------+--------------------+ | 2011-12-31 | 2014-12-31 | +--------------------+--------------------+ SELECT MAKEDATE(2011,0); +------------------+ | MAKEDATE(2011,0) | +------------------+ | NULL | +------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema TRIGGERS Table Information Schema TRIGGERS Table ================================= The [Information Schema](../information_schema/index) `TRIGGERS` table contains information about [triggers](../triggers/index). It has the following columns: | Column | Description | | --- | --- | | `TRIGGER_CATALOG` | Always `def`. | | `TRIGGER_SCHEMA` | Database name in which the trigger occurs. | | `TRIGGER_NAME` | Name of the trigger. | | `EVENT_MANIPULATION` | The event that activates the trigger. One of `INSERT`, `UPDATE` or `'DELETE`. | | `EVENT_OBJECT_CATALOG` | Always `def`. | | `EVENT_OBJECT_SCHEMA` | Database name on which the trigger acts. | | `EVENT_OBJECT_TABLE` | Table name on which the trigger acts. | | `ACTION_ORDER` | Indicates the order that the action will be performed in (of the list of a table's triggers with identical `EVENT_MANIPULATION` and `ACTION_TIMING` values). Before [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) introduced the [FOLLOWS and PRECEDES clauses](../create-trigger/index#followsprecedes-other_trigger_name), always `0` | | `ACTION_CONDITION` | `NULL` | | `ACTION_STATEMENT` | Trigger body, UTF-8 encoded. | | `ACTION_ORIENTATION` | Always `ROW`. | | `ACTION_TIMING` | Whether the trigger acts `BEFORE` or `AFTER` the event that triggers it. | | `ACTION_REFERENCE_OLD_TABLE` | Always `NULL`. | | `ACTION_REFERENCE_NEW_TABLE` | Always `NULL`. | | `ACTION_REFERENCE_OLD_ROW` | Always `OLD`. | | `ACTION_REFERENCE_NEW_ROW` | Always `NEW`. | | `CREATED` | Always `NULL`. | | `SQL_MODE` | The `[SQL\_MODE](../sql-mode/index)` when the trigger was created, and which it uses for execution. | | `DEFINER` | The account that created the trigger, in the form `user_name@host_name` | | `CHARACTER_SET_CLIENT` | The client [character set](../data-types-character-sets-and-collations/index) when the trigger was created, from the session value of the `[character\_set\_client](../server-system-variables/index#character_set_client)` system variable. | | `COLLATION_CONNECTION` | The client [collation](../data-types-character-sets-and-collations/index) when the trigger was created, from the session value of the [collation\_connection](../server-system-variables/index#collation_connection) system variable. | | `DATABASE_COLLATION` | [Collation](../data-types-character-sets-and-collations/index) of the associated database. | Queries to the `TRIGGERS` table will return information only for databases and tables for which you have the `TRIGGER` [privilege](../grant/index#table-privileges). Similar information is returned by the `[SHOW TRIGGERS](../show-triggers/index)` statement. See also -------- * [Trigger Overview](../trigger-overview/index) * `[CREATE TRIGGER](../create-trigger/index)` * `[DROP TRIGGER](../drop-trigger/index)` * `[SHOW TRIGGERS](../show-triggers/index)` * `[SHOW CREATE TRIGGER](../show-create-trigger/index)` * [Trigger Limitations](../trigger-limitations/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Virtual Machine to Test the Cassandra Storage Engine Virtual Machine to Test the Cassandra Storage Engine ==================================================== CassandraSE is no longer actively being developed and has been removed in [MariaDB 10.6](../what-is-mariadb-106/index). See [MDEV-23024](https://jira.mariadb.org/browse/MDEV-23024). Julien Duponchelle has made a virtual machine available for testing the Cassandra storage engine. Find out more at [Cassandra MariaDB VirtualBox](http://julien.duponchelle.info/Cassandra-MariaDB-Virtual-Box.html). The virtual machine is based on: * Ubuntu 12.04 * DataStax Cassandra * [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/) + Cassandra [Vagrant](http://www.vagrantup.com/) is used for setup. Full [instructions](http://julien.duponchelle.info/Cassandra-MariaDB-Virtual-Box.html) are at Julien's website. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Configuring MariaDB for Remote Client Access Configuring MariaDB for Remote Client Access ============================================ Some MariaDB packages bind MariaDB to 127.0.0.1 (the loopback IP address) by default as a security measure using the [bind-address](../server-system-variables/index#bind_address) configuration directive. Old MySQL packages sometimes disabled TCP/IP networking altogether using the [skip-networking](../server-system-variables/index#skip_networking) directive. Before going in to how to configure these, let's explain what each of them actually does: * [skip-networking](../server-system-variables/index#skip_networking) is fairly simple. It just tells MariaDB to run without any of the TCP/IP networking options. * [bind-address](../server-system-variables/index#bind_address) requires a little bit of background information. A given server usually has at least two networking interfaces (although this is not required) and can easily have more. The two most common are a *Loopback* network device and a physical *Network Interface Card* (NIC) which allows you to communicate with the network. MariaDB is bound to the loopback interface by default because it makes it impossible to connect to the TCP port on the server from a remote host (the bind-address must refer to a local IP address, or you will receive a fatal error and MariaDB will not start). This of course is not desirable if you want to use the TCP port from a remote host, so you must remove this bind-address directive (MariaDB only supports one bind-address, but binds to 0.0.0.0, or :: (every IP) if the bind-address directive is left out). If [bind-address](../server-system-variables/index#bind_address) is bound to 127.0.0.1 (localhost), one can't connect to the MariaDB server from other hosts or from the same host over TCP/IP on a different interface than the loopback (127.0.0.1). This for example will not work (connecting with a hostname that points to a local IP of the host): ``` (/my/maria-10.4) ./client/mysql --host=myhost --protocol=tcp --port=3306 test ERROR 2002 (HY000): Can't connect to MySQL server on 'myhost' (115) (/my/maria-10.4) telnet myhost 3306 Trying 192.168.0.11... telnet: connect to address 192.168.0.11: Connection refused ``` Using 'localhost' works when binding with `bind_address`: ``` (my/maria-10.4) ./client/mysql --host=localhost --protocol=tcp --port=3306 test Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Welcome to the MariaDB monitor. Commands end with ; or \g. ... ``` Finding the Defaults File ------------------------- To enable MariaDB to listen to remote connections, you need to edit your defaults file. See [Configuring MariaDB with my.cnf](../configuring-mariadb-with-mycnf/index) for more detail. Common locations for defaults files: ``` * /etc/my.cnf (*nix/BSD) * $MYSQL_HOME/my.cnf (*nix/BSD) *Most Notably /etc/mysql/my.cnf * SYSCONFDIR/my.cnf (*nix/BSD) * DATADIR\my.ini (Windows) ``` You can see which defaults files are read and in which order by executing: ``` shell> mysqld --help --verbose ./sql/mysqld Ver 10.4.2-MariaDB-valgrind-max-debug for Linux on x86_64 (Source distribution) Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Starts the MariaDB database server. Usage: ./sql/mysqld [OPTIONS] Default options are read from the following files in the given order: /etc/my.cnf /etc/mysql/my.cnf ~/.my.cnf ``` The last line shows which defaults files are read. Editing the Defaults File ------------------------- Once you have located the defaults file, use a text editor to open the file and try to find lines like this under the [mysqld] section: ``` [mysqld] ... skip-networking ... bind-address = <some ip-address> ... ``` (The lines may not be in this order, and the order doesn't matter.) If you are able to locate these lines, make sure they are both commented out (prefaced with hash (#) characters), so that they look like this: ``` [mysqld] ... #skip-networking ... #bind-address = <some ip-address> ... ``` (Again, the order of these lines don't matter) Alternatively, just add the following lines **at the end** of your .my.cnf (notice that the file name starts with a dot) file in your home directory or alternative **last** in your /etc/my.cnf file. ``` [mysqld] skip-networking=0 skip-bind-address ``` This works as one can have any number of <mysqld> sections. Save the file and restart the mysqld daemon or service (see [Starting and Stopping MariaDB](../starting-and-stopping-mariadb/index)). You can check the options mysqld is using by executing: ``` shell> ./sql/mysqld --print-defaults ./sql/mysqld would have been started with the following arguments: --bind-address=127.0.0.1 --innodb_file_per_table=ON --server-id=1 --skip-bind-address ... ``` It doesn't matter if you have the original --bind-address left as the later --skip-bind-address will overwrite it. Granting User Connections From Remote Hosts ------------------------------------------- Now that your MariaDB server installation is setup to accept connections from remote hosts, we have to add a user that is allowed to connect from something other than 'localhost' (Users in MariaDB are defined as 'user'@'host', so 'chadmaynard'@'localhost' and 'chadmaynard'@'1.1.1.1' (or 'chadmaynard'@'server.domain.local') are different users that can have completely different permissions and/or passwords. To create a new user: * log into the [mysql command line client](../mysql-command-line-client/index) (or your favorite graphical client if you wish) ``` Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 36 Server version: 5.5.28-MariaDB-mariadb1~lucid mariadb.org binary distribution Copyright (c) 2000, 2012, Oracle, Monty Program Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MariaDB [(none)]> ``` * if you are interested in viewing any existing remote users, issue the following SQL statement on the [mysql.user](../mysqluser-table/index) table: ``` SELECT User, Host FROM mysql.user WHERE Host <> 'localhost'; +--------+-----------+ | User | Host | +--------+-----------+ | daniel | % | | root | 127.0.0.1 | | root | ::1 | | root | gandalf | +--------+-----------+ 4 rows in set (0.00 sec) ``` (If you have a fresh install, it is normal for no rows to be returned) Now you have some decisions to make. At the heart of every grant statement you have these things: * list of allowed privileges * what database/tables these privileges apply to * username * host this user can connect from * and optionally a password It is common for people to want to create a "root" user that can connect from anywhere, so as an example, we'll do just that, but to improve on it we'll create a root user that can connect from anywhere on my local area network (LAN), which has addresses in the subnet 192.168.100.0/24. This is an improvement because opening a MariaDB server up to the Internet and granting access to all hosts is bad practice. ``` GRANT ALL PRIVILEGES ON *.* TO 'root'@'192.168.100.%' IDENTIFIED BY 'my-new-password' WITH GRANT OPTION; ``` (% is a wildcard) For more information about how to use GRANT, please see the [GRANT](../grant/index) page. At this point we have accomplished our goal and we have a user 'root' that can connect from anywhere on the 192.168.100.0/24 LAN. Port 3306 is Configured in Firewall ----------------------------------- One more point to consider whether the firwall is configured to allow incoming request from remote clients: On RHEL and CentOS 7, it may be necessary to configure the firewall to allow TCP access to MySQL from remote hosts. To do so, execute both of these commands: ``` firewall-cmd --add-port=3306/tcp firewall-cmd --permanent --add-port=3306/tcp ``` Caveats ------- * If your system is running a software firewall (or behind a hardware firewall or NAT) you must allow connections destined to TCP port that MariaDB runs on (by default and almost always 3306). * To undo this change and not allow remote access anymore, simply remove the `skip-bind-address` line or uncomment the [bind-address](../server-system-variables/index#bind_address) line in your defaults file. The end result should be that you should have in the output from `./sql/mysqld --print-defaults` the option `--bind-address=127.0.0.1` and no `--skip-bind-address`. *The initial version of this article was copied, with permission, from <http://hashmysql.org/wiki/Remote_Clients_Cannot_Connect> on 2012-10-30.* Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb System Variables Added in MariaDB 10.3 System Variables Added in MariaDB 10.3 ====================================== This is a list of [system variables](../server-system-variables/index) that have been added in the [MariaDB 10.3](../what-is-mariadb-103/index) series. The list does not include variables that are not part of the default release. | Variable | Added | | --- | --- | | [alter\_algorithm](../server-system-variables/index#alter_algorithm) | [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/) | | [bind\_address](../server-system-variables/index#bind_address) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [binlog\_file\_cache\_size](../replication-and-binary-log-server-system-variables/index#binlog_file_cache_size) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [gtid\_pos\_auto\_engines](../gtid/index#gtid_pos_auto_engines) | [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) | | [column\_compression\_threshold](../storage-engine-independent-column-compression/index#column_compression_threshold) | [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) | | [column\_compression\_zlib\_level](../storage-engine-independent-column-compression/index#column_compression_zlib_level) | [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) | | [column\_compression\_zlib\_strategy](../storage-engine-independent-column-compression/index#column_compression_zlib_strategy) | [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) | | [column\_compression\_zlib\_wrap](../storage-engine-independent-column-compression/index#column_compression_zlib_wrap) | [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) | | [idle\_readonly\_transaction\_timeout](../server-system-variables/index#idle_readonly_transaction_timeout) | [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) | | [idle\_transaction\_timeout](../server-system-variables/index#idle_transaction_timeout) | [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) | | [idle\_write\_transaction\_timeout](../server-system-variables/index#idle_write_transaction_timeout) | [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) | | [in\_predicate\_conversion\_threshold](../server-system-variables/index#in_predicate_conversion_threshold) | [MariaDB 10.3.18](https://mariadb.com/kb/en/mariadb-10318-release-notes/) | | [innodb\_encrypt\_temporary\_ables](../xtradbinnodb-server-system-variables/index#innodb_encrypt_temporary_tables) | [MariaDB 10.3.17](https://mariadb.com/kb/en/mariadb-10317-release-notes/) | | [innodb\_instant\_alter\_column\_allowed](../innodb-system-variables/index#innodb_instant_alter_column_allowed) | [MariaDB 10.3.23](https://mariadb.com/kb/en/mariadb-10323-release-notes/) | | [log\_disabled\_statements](../server-system-variables/index#log_disabled_statements) | [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) | | [log\_slow\_disabled\_statements](../server-system-variables/index#log_slow_disabled_statements) | [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) | | [rpl\_semi\_sync\_\*](../semisynchronous-replication/index#system-variables) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [secure\_timestamp](../server-system-variables/index#secure_timestamp) | [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/) | | [slave\_transaction\_retry\_errors](../replication-and-binary-log-server-system-variables/index#slave_transaction_retry_errors) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [slave\_transaction\_retry\_interval](../replication-and-binary-log-server-system-variables/index#slave_transaction_retry_interval) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [system\_versioning\_alter\_history](../system-versioned-tables/index#system_versioning_alter_history) | [MariaDB 10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/) | | [system\_versioning\_asof](../system-versioned-tables/index#system_versioning_asof) | [MariaDB 10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/) | | [system\_versioning\_innodb\_algorithm\_simple](../system-versioned-tables/index#system_versioning_innodb_algorithm_simple) | [MariaDB 10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/) | | [tcp\_keepalive\_interval](../server-system-variables/index#tcp_keepalive_interval) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [tcp\_keepalive\_probes](../server-system-variables/index#tcp_keepalive_probes) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [tcp\_keepalive\_time](../server-system-variables/index#tcp_keepalive_time) | [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | [version\_source\_revision](../server-system-variables/index#version_source_revision) | [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) | | [wsrep\_certification\_rules](../galera-cluster-system-variables/index#wsrep_certification_rules) | [MariaDB 10.3.13](https://mariadb.com/kb/en/mariadb-10313-release-notes/) | | [wsrep\_reject\_queries](../galera-cluster-system-variables/index#wsrep_reject_queries) | [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/) | See Also -------- * [Status Variables Added in MariaDB 10.3](../status-variables-added-in-mariadb-103/index) * [System Variables Added in MariaDB 10.4](../system-variables-added-in-mariadb-104/index) * [System Variables Added in MariaDB 10.2](../system-variables-added-in-mariadb-102/index) * [System Variables Added in MariaDB 10.1](../system-variables-added-in-mariadb-101/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Syntax Differences between MariaDB and SQL Server Syntax Differences between MariaDB and SQL Server ================================================= This article contains a non-exhaustive list of syntax differences between MariaDB and SQL Server, and is written for SQL Server users that are unfamiliar with MariaDB. Compatibility Features ---------------------- Some features are meant to improve syntax and semantics compatibility between MariaDB versions, between MariaDB and MySQL, and between MariaDB and other DBMSs. This section focuses on compatibility between MariaDB and SQL Server. ### sql\_mode and old\_mode SQL semantics and syntax, in MariaDB, are affected by the [sql\_mode](../sql_mode/index) variable. Its value is a comma-separated list of flags, and each of them, if specified, affects a different aspect of SQL syntax and semantics. A particularly important flag for users familiar with SQL Server is [MSSQL](../sql_modemssql/index). sql\_mode can be changed locally, in which case it only affects the current session; or globally, in which case it will affect all new connections (but not the connections already established). sql\_mode must be assigned a comma-separated list of flags. A usage example: ``` # check the current global and local sql_mode values SELECT @@global.sql_mode; SELECT @@session.sql_mode; # empty sql_mode for all usaers SET GLOBAL sql_mode = ''; # add MSSQL flag to the sql_mode for the current session SET SESSION sql_mode = CONCAT(sql_mode, ',MSSQL'); ``` [old\_mode](../old-mode/index) is very similar to sql\_mode, but its purpose is to provide compatibility with older MariaDB versions. Its flags shouldn't affect compatibility with SQL Server (though it is theoretically possible that some of them do, as a side effect). ### Executable Comments MariaDB supports [executable comments](../comment-syntax/index#executable-comment-syntax). These are designed to write generic queries that are only executed by MariaDB, and optionally only certain versions. The following examples show how to insert SQL code that will be ignored by SQL Server but executed by MariaDB, or some of its versions. * Executed by MariaDB and MySQL (see below): ``` SELECT * FROM tab /*! FORCE INDEX (idx_a) */ WHERE a = 1 OR b = 2; ``` * Executed by MariaDB only: ``` SELECT * /*M! , @in_transaction */ FROM tab; ``` * Executed by MariaDB starting from version 10.0.5: ``` DELETE FROM user WHERE id = 100 /*!M100005 RETURNING email */; ``` As explained in the [Understanding MariaDB Architecture](../understanding-mariadb-architecture/index) page, MariaDB was initially forked from MySQL. At that time, executable comments were already supported by MySQL. This is why the `/*! ... */` syntax is supported by both MariaDB and MySQL. But because MariaDB also supports specific syntax not supported by MySQL, it added the `/*M! ... */` syntax. Generic Syntax -------------- Here we discuss some differences between MariaDB and SQL Server syntax that may affect any user, as well as some hints to make queries compatible with a reasonable amount of work. ### Delimiters SQL Server uses two different terminators: * The *batch terminator* is the `go` command. It tells Microsoft clients to send the text we typed to SQL Server. * The *query terminator* is a semicolon (`;`) and it tells SQL Server where a query ends. It is rarely necessary to use `;` in SQL Server. It is required for certain common table expressions, for example. But the same doesn't apply to MariaDB. **Normally, with MariaDB you only use `;`.** However, MariaDB also has some situations where you want to use a `;` but you don't want the [mysql](../mysql-command-line-client/index) command-line client to send the query yet. This can be done in any situation, but it is particularly useful when creating [stored routines](../stored-routines/index) or using [BEGIN NOT ATOMIC](../begin-end/index). The reason is better explained with an example: ``` CREATE PROCEDURE p() BEGIN SELECT * FROM t1; SELECT * FROM t2; END; ``` If we enter this procedure in this way in the `mysql` client, as soon as we type the first `;` (after the first `SELECT`) and press enter, the statement will be sent. MariaDB will try to parse it, and will return an error. To avoid this, `mysql` implements the [DELIMITER](../delimiters/index) statement. This client statement is never sent to MariaDB. Instead, the client uses it to find out when the typed query should be sent. Let's correct the above example: ``` DELIMITER || CREATE PROCEDURE p() BEGIN SELECT * FROM t1; SELECT * FROM t2; END; DELIMITER ; ``` ### Names In MariaDB, most [names](../identifier-names/index) have a maximum length of 64 characters. When migrating an SQL Server database to MariaDB, check if some names exceed this limit (SQL Server maximum length is 128). By default, MariaDB names are case-sensitive if the operating system has case-sensitive file names (Linux), and case-insensitive if the operating system is case-insensitive (Windows). SQL Server is case-insensitive by default on all operating systems. When migrating a SQL Server database to MariaDB on Linux, to avoid problems you may want to set the [lower\_case\_table\_names](../server-system-variables/index#lower_case_table_names) system variable to 1, making table names, database names and aliases case-insensitive. Names can be quoted inside backtick characters (```). This character can be used in names, in which case it should be doubled. By default this is the only way to quote names. To also enable the use of double quotes (`"`), modify sql\_mode adding the `ANSI_QUOTES` flag. This is the equivalent of setting [QUOTED\_IDENTIFIER](https://docs.microsoft.com/en-us/sql/t-sql/statements/set-quoted-identifier-transact-sql?view=sql-server-ver15) ON in SQL Server. To also enable the use of SQL Server style quotes (`[` and `]`), modify sql\_mode adding the `MSSQL` flag. The case-sensitivity of stored procedures and functions is never a problem, as they are case-insensitive in SQL Server. ### Quoting Strings In SQL Server, by default strings can only be quoted with single-quotes (`'`), and to use a double quote in a string it should be doubled (`''`). This also works by default in MariaDB. SQL Server also allows to use double quotes (`"`) to quote strings. This works by default in MariaDB, but as mentioned before it won't work if sql\_mode contains the `ANSI_QUOTES` flag. ### NULL The default semantics of [NULL](../null-values/index) in SQL Server and MariaDB is the same, by default. However, SQL Server allows one to change it globally with [SET ANSI\_NULLS OFF](https://docs.microsoft.com/en-us/sql/t-sql/statements/set-ansi-nulls-transact-sql), or at database level with [ALTER DATABASE](https://docs.microsoft.com/en-us/sql/t-sql/statements/alter-database-transact-sql). There is no way to achieve exactly the same result in MariaDB. To perform NULL-safe comparisons in MariaDB, one should replace the [=](../equal/index) operator with the [<=>](../null-safe-equal/index) operator. Also, note that MariaDB doesn't support the `UNKNOWN` pseudo-value. An expression like `NULL OR 0` returns `NULL` in MariaDB. ### LIKE In MariaDB, [LIKE](../like/index) expressions only have two characters with special meanings: `%` and `_`. These two characters have the same meanings they have in SQL Server. The additional characters recognized by SQL Server (`[`, `]` and `^`) are part of regular expressions. MariaDB supports the [REGEXP](../regexp/index) operator, that supports the full regular expressions syntax. Data Definition Language ------------------------ Here we discuss some DDL differences that database administrators will want to be aware of. While this section is meant to highlight the most noticeable DDL differences between MariaDB and SQL Server, there are many others, both in the syntax and in the semantics. See the [ALTER](../alter/index) statement documentation. ### Altering Tables Online Altering tables online can be a problem, especially when the tables are big and we don't want to cause a disruption. MariaDB offers the following solutions to help: * The [ALTER TABLE ... ALGORITHM](../alter-table/index#algorithm) clause allows one to specify which algorithm should be used to run a certain operation. For example `INPLACE` tells MariaDB not to create a table copy (perhaps because we don't have enough disk space), and `INSTANT` tells MariaDB to execute the operation instantaneously. Not all algorithms are supported for certain operations. If the algorithm we've chosen cannot be used, the [ALTER TABLE](../alter-table/index) statement will fail with an error. * The [ALTER TABLE ... LOCK](../alter-table/index#alock) clause allows one to specify which lock type should be used. For example `NONE` tells MariaDB to avoid any lock on the table, and `SHARED` only allows one to acquire a share lock. If the operation requires a lock that is more strict than the one we are requesting, the [ALTER TABLE](../alter-table/index) statement will fail with an error. Sometimes this happens because the `LOCK` level we want is not available for the specified `ALGORITHM`. To find out which operations require a table copy and which lock levels are necessary, see [InnoDB Online DDL Overview](../innodb-online-ddl-overview/index). An `ALTER TABLE` can be queued because a long-running statement (even a `SELECT`) required a [metadata lock](../metadata-locking/index). Since this may cause troubles, sometimes we want the operation to simply fail if the wait is too long. This can be achieved with the [WAIT and NOWAIT](../wait-and-nowait/index) clauses, whose syntax is a bit different from SQL Server. SQL Server `WITH ONLINE = ON` is equivalent to MariaDB `LOCK = NONE`. However, note that [most ALTER TABLE statements](../innodb-online-ddl-operations-with-the-instant-alter-algorithm/index) support `ALGORITHM = INSTANT`, which is non-blocking and much faster (almost instantaneous, as the syntax suggests). ### IF EXISTS, IF NOT EXISTS, OR REPLACE Most DDL statements, including [ALTER TABLE](../alter-table/index), support the following syntax: * `DROP IF EXISTS`: A warning (not an error) is produced if the object does not exist. * `OR REPLACE`: If the object exists, it is dropped and recreated; otherwise it is created. This operation is atomic, so at no point in time does the object not exist. * `CREATE IF NOT EXISTS`: If the object already exists, a warning (not an error) is produced. The object will not be replaced. These statements are functionally similar (but less verbose) than SQL Server snippets similar to the following: ``` IF NOT EXISTS ( SELECT name FROM sysobjects WHERE name = 'my_table' AND xtype = 'U' ) CREATE TABLE my_table ( ... ) go ``` ### Altering Columns With SQL Server, the only syntax to alter a table column is `ALTER TABLE ... ALTER COLUMN`. MariaDB provides more [ALTER TABLE](../alter-table/index) commands to obtain the same result: * [CHANGE COLUMN](../alter-table/index#change-column) allows one to perform any change by specifying a new column definition, including the name. * [MODIFY COLUMN](../alter-table/index#modify-column) allows any change, except renaming the column. This is a slightly simpler syntax that we can use when we don't want to change a column name. * [ALTER COLUMN](../alter-table/index#alter-column) allows one to change or drop the `DEFAULT` value. * [RENAME COLUMN](../alter-table/index#rename-column) allows one to only change the column name. Using a more specific syntax is less error-prone. For example, by using `ALTER TABLE ... ALTER COLUMN` we will not accidentally change the data type. The word `COLUMN` is usually optional, except in the case of `RENAME COLUMN`. ### SHOW Statements MariaDB supports [SHOW](../show/index) statements to quickly list all objects of a certain type (tables, views, triggers...). Most `SHOW` statements support a `LIKE` clause to filter data. For example, to list the tables in the current database whose name begins with 'wp\_': ``` SHOW TABLES LIKE 'wp\_%'; ``` This is the equivalent of this query, which would work on both MariaDB and SQL Server: ``` SELECT TABLE_SCHEMA, TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME LIKE 'wp\_'; ``` ### SHOW CREATE Statements In general, for each `CREATE` statement MariaDB also supports a `SHOW CREATE` statement. For example there is a [SHOW CREATE TABLE](../show-create-table/index) that returns the [CREATE TABLE](../create-table/index) statement that can be used to recreate a table. Though SQL Server has no way to show the DDL statement to recreate an object, `SHOW CREATE` statements are functionally similar to `sp_helptext()`. ### Database Comments MariaDB does not support extended properties. Instead, it supports a `COMMENT` clause for most [CREATE](../create/index) and [ALTER](../alter/index) statements. For example, to create and then change a table comment: ``` CREATE TABLE counter ( c INT UNSIGNED AUTO_INCREMENT PRIMARY KEY ) COMMENT 'Monotonic counter' ; ALTER TABLE counter COMMENT 'Counter. It can contain many values, we only care about the max'; ``` Comments can be seen with `SHOW CREATE` statements, or by querying `information_schema` tables. For example: ``` SELECT TABLE_COMMENT FROM information_schema.TABLES WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 'counter'; +-----------------------------------------------------------------+ | TABLE_COMMENT | +-----------------------------------------------------------------+ | Counter. It can contain many values, we only care about the max | +-----------------------------------------------------------------+ ``` ### Error Handling MariaDB [SHOW ERRORS](../show-errors/index) and [SHOW WARNINGS](../show-warnings/index) statements can be used to show errors, or warning and errors. This is convenient for clients, but stored procedures cannot work with the output of these commands. Instead, inside stored procedures you can: * Use the [GET DIAGNOSTICS](../get-diagnostics/index) command to assign error properties to variables. This is the equivalent of using SQL Server functions like `ERROR_NUMBER()` or `ERROR_STATE()`. * Add a [DECLARE HANDLER](../declare-handler/index) block to handle all errors, a class of errors, or a specific error. This is the equivalent of SQL Server `TRY ... CATCH`. * An error or warning can be generated on purpose using [SIGNAL](../signal/index). Inside a `DECLARE HANDLER` block, [RESIGNAL](../resignal/index) can be used to issue the error again, and interrupt the execution of the block. These are the equivalents of SQL Server `RAISERROR()`. Administration -------------- Administration and maintenance commands in MariaDB use different syntax to SQL Server. * [OPTIMIZE TABLE](../optimize-table/index) rebuilds table data and indexes. It can be considered as the MariaDB equivalent of SQL Server's `ALTER INDEX REBUILD`. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index) for more information. This statement is always locking. It supports [WAIT and NOWAIT](../wait-and-nowait/index) syntax, * MariaDB has an [ANALYZE TABLE](../analyze-table/index) command, which is an equivalent of `UPDATE STATISTICS`. BULK INSERT ----------- MariaDB has no `BULK INSERT` statement. Instead, it supports: * [LOAD DATA INFILE](../load-data-infile/index) to load data from files in CSV or similar formats; * [LOAD XML INFILE](../load-xml/index) to load data from XML files. See also [How to Quickly Insert Data Into MariaDB](../how-to-quickly-insert-data-into-mariadb/index). See Also -------- * [SQL Server and MariaDB Types Comparison](../sql-server-and-mariadb-types-comparison/index) * [MariaDB Transactions and Isolation Levels for SQL Server Users](../mariadb-transactions-and-isolation-levels-for-sql-server-users/index) * [SQL\_MODE=MSSQL](../sql_modemssql/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Athens - MariaDB 5.3: Technical Status - notes Athens - MariaDB 5.3: Technical Status - notes ============================================== **Note:** This page is obsolete. The information is old, outdated, or otherwise currently incorrect. We are keeping the page for historical reasons only. **Do not** rely on the information in this article. Pictures from this session: * <https://plus.google.com/b/102059736934609902389/102059736934609902389/posts/HCxA2J4gw5k> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Installing MariaDB .deb Files Installing MariaDB .deb Files ============================= Installing MariaDB with APT --------------------------- On Debian, Ubuntu, and other similar Linux distributions, it is highly recommended to install the relevant `.deb` packages from MariaDB's repository using `[apt](http://manpages.ubuntu.com/manpages/bionic/man8/apt.8.html)`, `[aptitude](http://manpages.ubuntu.com/manpages/bionic/man8/aptitude-curses.8.html)`, [Ubuntu Software Center](https://help.ubuntu.com/community/UbuntuSoftwareCenter), [Synaptic Package Manager](https://help.ubuntu.com/community/SynapticHowto), or another package manager. This page walks you through the simple installation steps using `apt`. ### Adding the MariaDB APT repository We currently have APT repositories for the following Linux distributions: * Debian 9 (Jessie) * Debian 10 (Buster) * Debian 11 (Bullseye) * Debian Unstable (Sid) * Ubuntu 18.04 LTS (Bionic) * Ubuntu 20.04 LTS (Focal) * Ubuntu 20.10 (Groovy) * Ubuntu 21.04 (Hirsute) * Ubuntu 21.10 (Impish) #### Using the MariaDB Package Repository Setup Script If you want to install MariaDB with `apt`, then you can configure `apt` to install from MariaDB Corporation's MariaDB Package Repository by using the [MariaDB Package Repository setup script](../mariadb-package-repository-setup-and-usage/index). MariaDB Corporation provides a MariaDB Package Repository for several Linux distributions that use `apt` to manage packages. This repository contains software packages related to MariaDB Server, including the server itself, [clients and utilities](../clients-utilities/index), [client libraries](../client-libraries/index), [plugins](../plugins/index), and [Mariabackup](../mariabackup/index). The MariaDB Package Repository setup script automatically configures your system to install packages from the MariaDB Package Repository. To use the script, execute the following command: ``` curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup | sudo bash ``` Note that this script also configures a repository for [MariaDB MaxScale](../maxscale/index) and a repository for MariaDB Tools, which currently only contains [Percona XtraBackup](../percona-xtrabackup/index) and its dependencies. See [MariaDB Package Repository Setup and Usage](../mariadb-package-repository-setup-and-usage/index) for more information. #### Using the MariaDB Repository Configuration Tool If you want to install MariaDB with `apt`, then you can configure `apt` to install from MariaDB Foundation's MariaDB Repository by using the [MariaDB Repository Configuration Tool](https://downloads.mariadb.org/mariadb/repositories/). The MariaDB Foundation provides a MariaDB repository for several Linux distributions that use `apt-get` to manage packages. This repository contains software packages related to MariaDB Server, including the server itself, [clients and utilities](../clients-utilities/index), [client libraries](../client-libraries/index), [plugins](../plugins/index), and [Mariabackup](../mariabackup/index). The MariaDB Repository Configuration Tool can easily generate the appropriate commands to add the repository for your distribution. There are several ways to add the repository. ##### Executing add-apt-repository One way to add an `apt` repository is by using the `[add-apt-repository](http://manpages.ubuntu.com/manpages/bionic/man1/add-apt-repository.1.html)` command. This command will add the repository configuration to `/etc/apt/sources.list`. For example, if you wanted to use the repository to install [MariaDB 10.3](../what-is-mariadb-103/index) on Ubuntu 18.04 LTS (Bionic), then you could use the following commands to add the MariaDB `apt` repository: ``` sudo apt-get install software-properties-common sudo add-apt-repository 'deb [arch=amd64,arm64,ppc64el] http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.3/ubuntu bionic main' ``` And then you would have to update the package cache by executing the following command: ``` sudo apt update ``` ##### Creating a Source List File Another way to add an `apt` repository is by creating a [source list](http://manpages.ubuntu.com/manpages/bionic/man5/sources.list.5.html) file in `/etc/apt/sources.list.d/`. For example, if you wanted to use the repository to install [MariaDB 10.3](../what-is-mariadb-103/index) on Ubuntu 18.04 LTS (Bionic), then you could create the `MariaDB.list` file in `/etc/apt/sources.list.d/` with the following contents to add the MariaDB `apt` repository: ``` # MariaDB 10.3 repository list - created 2019-01-27 09:50 UTC # http://downloads.mariadb.org/mariadb/repositories/ deb [arch=amd64,arm64,ppc64el] http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.3/ubuntu bionic main deb-src http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.3/ubuntu bionic main ``` And then you would have to update the package cache by executing the following command: ``` sudo apt update ``` ##### Using Ubuntu Software Center Another way to add an `apt` repository is by using [Ubuntu Software Center](https://help.ubuntu.com/community/UbuntuSoftwareCenter). You can do this by going to the **Software Sources** window. This window can be opened either by navigating to **Edit** > **Software Sources** or by navigating to **System** > **Administration** > **Software Sources**. Once the **Software Sources** window is open, go to the **Other Software** tab, and click the **Add** button. At that point, you can input the repository information provided by the [MariaDB Repository Configuration Tool](https://downloads.mariadb.org/mariadb/repositories/). See [here](https://help.ubuntu.com/community/UbuntuSoftwareCenter#Managing_software_sources) for more information. ##### Using Synaptic Package Manager Another way to add an `apt` repository is by using [Synaptic Package Manager](https://help.ubuntu.com/community/SynapticHowto). You can do this by going to the **Software Sources** window. This window can be opened either by navigating to **System** > **Administrator** > **Software Sources** or by navigating to **Settings** > **Repositories**. Once the **Software Sources** window is open, go to the **Other Software** tab, and click the **Add** button. At that point, you can input the repository information provided by the [MariaDB Repository Configuration Tool](https://downloads.mariadb.org/mariadb/repositories/). See [here](https://help.ubuntu.com/community/SynapticHowto#Managing_Repositories) for more information. #### Pinning the MariaDB Repository to a Specific Minor Release If you wish to pin the `apt` repository to a specific minor release, or if you would like to downgrade to a specific minor release, then you can create a `apt` repository with the URL hard-coded to that specific minor release. The MariaDB Foundation archives repositories of old minor releases at the following URL: * <http://archive.mariadb.org/> Archives are only of the distros and architectures supported at the time of release. For example [MariaDB 10.0.38](https://mariadb.com/kb/en/mariadb-10038-release-notes/) is exists for Ubuntu `precise`, `trusty`, `xenial`, `wily`, and `yakkety` obtained looking in <https://archive.mariadb.org/mariadb-10.0.38/repo/ubuntu/dists>. For example, if you wanted to pin your repository to [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/) on Ubuntu 20.04 LTS (Focal), then you would have to first remove any existing MariaDB repository source list file from `/etc/apt/sources.list.d/`. And then you could use the following commands to add the MariaDB `apt-get` repository: ``` sudo add-apt-repository 'deb [arch=amd64,arm64,ppc64el,s390x] http://archive.mariadb.org/mariadb-10.5.9/repo/ubuntu/ focal main main/debug' ``` Ensure you have the [signing key installed](#Importing_the_MariaDB_GPG_Public_Key). Ubuntu Xenial and older will need: ``` sudo apt-get install -y apt-transport-https ``` And then you would have to update the package cache by executing the following command: ``` sudo apt update ``` ### Updating the MariaDB APT repository to a New Major Release MariaDB's `apt` repository can be updated to a new major release. How this is done depends on how you originally configured the repository. #### Updating the Major Release with the MariaDB Package Repository Setup Script If you configured `apt` to install from MariaDB Corporation's MariaDB Package Repository by using the [MariaDB Package Repository setup script](../mariadb-package-repository-setup-and-usage/index), then you can update the major release that the repository uses by running the script again. #### Updating the Major Release with the MariaDB Repository Configuration Tool If you configured `apt` to install from MariaDB Foundation's MariaDB Repository by using the [MariaDB Repository Configuration Tool](https://downloads.mariadb.org/mariadb/repositories/), then you can update the major release in various ways, depending on how you originally added the repository. ##### Updating a Repository with add-apt-repository If you added the `apt` repository by using the `[add-apt-repository](http://manpages.ubuntu.com/manpages/bionic/man1/add-apt-repository.1.html)` command, then you can update the major release that the repository uses by using the the `[add-apt-repository](http://manpages.ubuntu.com/manpages/bionic/man1/add-apt-repository.1.html)` command again. First, look for the repository string for the old version in `/etc/apt/sources.list`. And then, you can remove the repository for the old version by executing the `[add-apt-repository](http://manpages.ubuntu.com/manpages/bionic/man1/add-apt-repository.1.html)` command and providing the `--remove` option. For example, if you wanted to remove a [MariaDB 10.2](../what-is-mariadb-102/index) repository, then you could do so by executing something like the following: ``` sudo add-apt-repository --remove 'deb [arch=amd64,arm64,ppc64el] http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.2/ubuntu bionic main' ``` After that, you can add the repository for the new version with the `[add-apt-repository](http://manpages.ubuntu.com/manpages/bionic/man1/add-apt-repository.1.html)` command. For example, if you wanted to use the repository to install [MariaDB 10.3](../what-is-mariadb-103/index) on Ubuntu 18.04 LTS (Bionic), then you could use the following commands to add the MariaDB `apt` repository: ``` sudo apt-get install software-properties-common sudo add-apt-repository 'deb [arch=amd64,arm64,ppc64el] http://sfo1.mirrors.digitalocean.com/mariadb/repo/10.3/ubuntu bionic main' ``` And then you would have to update the package cache by executing the following command: ``` sudo apt update ``` After that, the repository should refer to [MariaDB 10.3](../what-is-mariadb-103/index). ##### Updating a Source List File If you added the `apt` repository by creating a [source list](http://manpages.ubuntu.com/manpages/bionic/man5/sources.list.5.html) file in `/etc/apt/sources.list.d/`, then you can update the major release that the repository uses by updating the source list file in-place. For example, if you wanted to change the repository from [MariaDB 10.2](../what-is-mariadb-102/index) to [MariaDB 10.3](../what-is-mariadb-103/index), and if the source list file was at `/etc/apt/sources.list.d/MariaDB.list`, then you could execute the following: ``` sudo sed -i 's/10.2/10.3/' /etc/apt/sources.list.d/MariaDB.list ``` And then you would have to update the package cache by executing the following command: ``` sudo apt update ``` After that, the repository should refer to [MariaDB 10.3](../what-is-mariadb-103/index). ### Importing the MariaDB GPG Public Key Before MariaDB can be installed, you also have to import the GPG public key that is used to verify the digital signatures of the packages in our repositories. This allows the `apt` utility to verify the integrity of the packages that it installs. * Prior to Debian 9 (Stretch), and Debian Unstable (Sid), and Ubuntu 16.04 LTS (Xenial), the id of our GPG public key is `0xcbcb082a1bb943db`. The full key fingerprint is: ``` 1993 69E5 404B D5FC 7D2F E43B CBCB 082A 1BB9 43DB ``` The `[apt-key](http://manpages.ubuntu.com/manpages/bionic/man8/apt-key.8.html)` utility can be used to import this key. For example: ``` sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xcbcb082a1bb943db ``` * Starting with Debian 9 (Stretch) and Ubuntu 16.04 LTS (Xenial), the id of our GPG public key is `0xF1656F24C74CD1D8`. The full key fingerprint is: ``` 177F 4010 FE56 CA33 3630 0305 F165 6F24 C74C D1D8 ``` The `[apt-key](http://manpages.ubuntu.com/manpages/bionic/man8/apt-key.8.html)` utility can be used to import this key. For example: ``` sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8 ``` Starting with Debian 9 (Stretch), the `[dirmngr](https://manpages.debian.org/stretch/dirmngr/dirmngr.8.en.html)` package needs to be installed before the GPG public key can be imported. To install it, execute: `sudo apt install dirmngr` If you are unsure which GPG public key you need, then it is perfectly safe to import both keys. The command used to import the GPG public key is the same on both Debian and Ubuntu. For example: ``` $ sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xcbcb082a1bb943db Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /tmp/tmp.ASyOPV87XC --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xcbcb082a1bb943db gpg: requesting key 1BB943DB from hkp server keyserver.ubuntu.com gpg: key 1BB943DB: "MariaDB Package Signing Key <[email protected]>" imported gpg: no ultimately trusted keys found gpg: Total number processed: 1 gpg: imported: 1 ``` Once the GPG public key is imported, you are ready to install packages from the repository. ### Installing MariaDB Packages with APT After the `apt` repository is configured, you can install MariaDB by executing the `[apt-get](http://manpages.ubuntu.com/manpages/bionic/man8/apt-get.8.html)` command. The specific command that you would use would depend on which specific packages that you want to install. #### Installing the Most Common Packages with APT To Install the most common packages, first you would have to update the package cache by executing the following command: ``` sudo apt update ``` **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, to Install the most common packages, execute the following command: ``` sudo apt-get install mariadb-server galera-4 mariadb-client libmariadb3 mariadb-backup mariadb-common ``` **MariaDB [10.2](../what-is-mariadb-102/index) - [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.2](../what-is-mariadb-102/index) and [MariaDB 10.3](../what-is-mariadb-103/index), to Install the most common packages, execute the following command: ``` sudo apt-get install mariadb-server galera mariadb-client libmariadb3 mariadb-backup mariadb-common ``` **MariaDB until [10.1](../what-is-mariadb-101/index)**In [MariaDB 10.1](../what-is-mariadb-101/index) and before, to Install the most common packages, execute the following command: ``` sudo apt-get install mariadb-server galera mariadb-client libmysqlclient18 mariadb-backup mariadb-common ``` #### Installing MariaDB Server with APT To Install MariaDB Server, first you would have to update the package cache by executing the following command: ``` sudo apt update ``` Then, execute the following command: ``` sudo apt-get install mariadb-server ``` #### Installing MariaDB Galera Cluster with APT The process to install MariaDB Galera Cluster with the MariaDB `apt-get` repository is practically the same as installing standard MariaDB Server. In [MariaDB 10.1](../what-is-mariadb-101/index) and later, Galera Cluster support has been included in the standard MariaDB Server packages, so you will need to install the `mariadb-server` package, as you normally would. In [MariaDB 10.4](../what-is-mariadb-104/index) and later, you also need to install the `galera-4` package to obtain the [Galera](../galera/index) 4 wsrep provider library. In [MariaDB 10.3](../what-is-mariadb-103/index) and before, you also need to install the `galera-3` package to obtain the [Galera](../galera/index) 3 wsrep provider library. To install MariaDB Galera Cluster, first you would have to update the package cache by executing the following command: ``` sudo apt update ``` **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, to install MariaDB Galera Cluster, you could execute the following command: ``` sudo apt-get install mariadb-server mariadb-client galera-4 ``` **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, to install MariaDB Galera Cluster, you could execute the following command: ``` sudo apt-get install mariadb-server mariadb-client galera-3 ``` MariaDB Galera Cluster also has a separate package that can be installed on arbitrator nodes. In [MariaDB 10.4](../what-is-mariadb-104/index) and later, the package is called `galera-arbitrator-4` In [MariaDB 10.3](../what-is-mariadb-103/index) and before, the package is called `galera-arbitrator-3`. This package should be installed on whatever node you want to serve as the arbitrator. It can either run on a separate server that is not acting as a cluster node, which is the recommended configuration, or it can run on a server that is also acting as an existing cluster node. **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, to install the arbitrator package, you could execute the following command: ``` sudo apt-get install galera-arbitrator-4 ``` **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, to install the arbitrator package, you could execute the following command: ``` sudo apt-get install galera-arbitrator-3 ``` See [MariaDB Galera Cluster](../galera/index) for more information on MariaDB Galera Cluster. #### Installing MariaDB Clients and Client Libraries with APT In [MariaDB 10.2](../what-is-mariadb-102/index) and later, [MariaDB Connector/C](../about-mariadb-connector-c/index) has been included as the client library. To Install the clients and client libraries, first you would have to update the package cache by executing the following command: ``` sudo apt update ``` Then, in [MariaDB 10.2](../what-is-mariadb-102/index) and later, execute the following command: ``` sudo apt-get install mariadb-client libmariadb3 ``` Or in [MariaDB 10.1](../what-is-mariadb-101/index) and before, execute the following command: ``` sudo apt-get install mariadb-client libmysqlclient18 ``` #### Installing Mariabackup with APT To install [Mariabackup](../mariabackup/index), first you would have to update the package cache by executing the following command: ``` sudo apt update ``` Then, execute the following command: ``` sudo apt-get install mariadb-backup ``` #### Installing Plugins with APT Some [plugins](../plugins/index) may also need to be installed. For example, to install the `[cracklib\_password\_check](../cracklib-password-check-plugin/index)` password validation plugin, first you would have to update the package cache by executing the following command: ``` sudo apt update ``` Then, execute the following command: ``` sudo apt-get install mariadb-cracklib-password-check ``` #### Installing Older Versions from the Repository The MariaDB `apt` repository contains the last few versions of MariaDB. To show what versions are available, use the `[apt-cache](http://manpages.ubuntu.com/manpages/bionic/man8/apt-cache.8.html)` command: ``` sudo apt-cache showpkg mariadb-server ``` In the output you will see the available versions. To install an older version of a package instead of the latest version we just need to specify the package name, an equal sign, and then the version number. However, when installing an older version of a package, if `apt-get` has to install dependencies, then it will automatically choose to install the latest versions of those packages. To ensure that all MariaDB packages are on the same version in this scenario, it is necessary to specify them all. Therefore, to install [MariaDB 10.3.14](https://mariadb.com/kb/en/mariadb-10314-release-notes/) from this `apt` repository, we would do the following: ``` sudo apt-get install mariadb-server=10.3.14-1 mariadb-client=10.3.14-1 libmariadb3=10.3.14-1 mariadb-backup=10.3.14-1 mariadb-common=10.3.14-1 ``` The rest of the install and setup process is as normal. Installing MariaDB with dpkg ---------------------------- While it is not recommended, it is possible to download and install the `.deb` packages manually. However, it is generally recommended to use a package manager like `apt-get`. A tarball that contains the `.deb` packages can be downloaded from the following URL: * <https://downloads.mariadb.com> For example, to install the [MariaDB 10.4.8](https://mariadb.com/kb/en/mariadb-1048-release-notes/) `.deb` packages on Ubuntu 18.04 LTS (Bionic), you could execute the following: ``` sudo apt-get update sudo apt-get install libdbi-perl libdbd-mysql-perl psmisc libaio1 socat wget https://downloads.mariadb.com/MariaDB/mariadb-10.4.8/repo/ubuntu/mariadb-10.4.8-ubuntu-bionic-amd64-debs.tar tar -xvf mariadb-10.4.8-ubuntu-bionic-amd64-debs.tar cd mariadb-10.4.8-ubuntu-bionic-amd64-debs/ sudo dpkg --install ./mariadb-common*.deb \ ./mysql-common*.deb \ ./mariadb-client*.deb \ ./libmariadb3*.deb \ ./libmysqlclient18*.deb sudo dpkg --install ./mariadb-server*.deb \ ./mariadb-backup*.deb \ ./galera-4*.deb ``` After Installation ------------------ After the installation is complete, you can [start MariaDB](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index). If you are using [MariaDB Galera Cluster](../galera/index), then keep in mind that the first node will have to be [bootstrapped](../getting-started-with-mariadb-galera-cluster/index#bootstrapping-a-new-cluster). Installation Issues ------------------- **MariaDB starting with [5.5](../what-is-mariadb-55/index)**### Upgrading `mariadb-server` and `mariadb-client` packages As noted in [MDEV-4266](https://jira.mariadb.org/browse/MDEV-4266), the `mariadb-server` and `mariadb-client` packages have a minor upgrade issue if you use '`apt-get install mariadb-server`' or '`apt-get install mariadb-client`' to upgrade them instead of the more common '`apt-get upgrade`'. This is because those two packages depend on `mariadb-server-5.5` and `mariadb-client-5.5` with no specific version of those packages. For example, if you have the `mariadb-server` package installed, version 5.5.29 and you install version 5.5.30 of that package it will not automatically upgrade the `mariadb-server-5.5` package to version 5.5.30 like you would expect because the 5.5.29 version of that package satisfies the dependency. The `mariadb-server` and `mariadb-client` packages are virtual packages, they only exist to require the installation of the `mariadb-server-5.5` and `mariadb-client-5.5` packages, respectively. MariaDB will function normally with a, for example, version 5.5.30 version of the `mariadb-server` package and a version 5.5.29 version of the `mariadb-server-5.5` package. No data is at risk. However, expected behavior is for '`apt-get install mariadb-server`' to upgrade everything to the latest version (if a new version is available), so this is definitely a bug. A fix is planned for this bug in a future version of MariaDB. In the mean time, when upgrading MariaDB, use '`apt-get upgrade`' or '`apt-get install mariadb-server-5.5`'. Available DEB Packages ---------------------- The available DEB packages depend on the specific MariaDB release series. ### Available DEB Packages in [MariaDB 10.4](../what-is-mariadb-104/index) **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index), the following DEBs are available: | Package Name | Description | | --- | --- | | `galera-4` | The WSREP provider for [Galera](../galera/index) 4. | | `libmariadb3` | Dynamic client libraries. | | `libmariadb-dev` | Development headers and static libraries. | | `libmariadbclient18` | Virtual package to satisfy external depends | | `libmysqlclient18` | Virtual package to satisfy external depends | | `mariadb-backup` | [Mariabackup](../mariabackup/index) | | `mariadb-client` | Client tools like `mysql` CLI, `mysqldump`, and others. | | `mariadb-client-core` | Core client tools | | `mariadb-common` | Character set files and `/etc/my.cnf` | | `mariadb-plugin-connect` | The `[CONNECT](../connect/index)` storage engine. | | `mariadb-plugin-cracklib-password-check` | The `[cracklib\_password\_check](../cracklib-password-check-plugin/index)` password validation plugin. | | `mariadb-plugin-gssapi-client` | The client-side component of the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin. | | `mariadb-plugin-gssapi-server` | The server-side component of the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin. | | `mariadb-plugin-rocksdb` | The [MyRocks](../myrocks/index) storage engine. | | `mariadb-plugin-spider` | The `[SPIDER](../spider/index)` storage engine. | | `mariadb-plugin-tokudb` | The [TokuDB](../tokudb/index) storage engine. | | `mariadb-server` | The server and server tools, like [myisamchk](../myisamchk/index) and [mysqlhotcopy](../mysqlhotcopy/index) are here. | | `mariadb-server-core` | The core server. | | `mariadb-test` | `mysql-client-test` executable, and **mysql-test** framework with the tests. | | `mariadb-test-data` | MariaDB database regression test suite - data files | ### Available DEB Packages in [MariaDB 10.2](../what-is-mariadb-102/index) and [MariaDB 10.3](../what-is-mariadb-103/index) **MariaDB starting with [10.2](../what-is-mariadb-102/index)**In [MariaDB 10.2](../what-is-mariadb-102/index) and [MariaDB 10.3](../what-is-mariadb-103/index), the following DEBs are available: | Package Name | Description | | --- | --- | | `galera` | The WSREP provider for [Galera](../galera/index) 3. | | `libmariadb3` | Dynamic client libraries. | | `libmariadb-dev` | Development headers and static libraries. | | `libmariadbclient18` | Virtual package to satisfy external depends | | `libmysqlclient18` | Virtual package to satisfy external depends | | `mariadb-backup` | [Mariabackup](../mariabackup/index) | | `mariadb-client` | Client tools like `mysql` CLI, `mysqldump`, and others. | | `mariadb-client-core` | Core client tools | | `mariadb-common` | Character set files and `/etc/my.cnf` | | `mariadb-plugin-connect` | The `[CONNECT](../connect/index)` storage engine. | | `mariadb-plugin-cracklib-password-check` | The `[cracklib\_password\_check](../cracklib-password-check-plugin/index)` password validation plugin. | | `mariadb-plugin-gssapi-client` | The client-side component of the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin. | | `mariadb-plugin-gssapi-server` | The server-side component of the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin. | | `mariadb-plugin-rocksdb` | The [MyRocks](../myrocks/index) storage engine. | | `mariadb-plugin-spider` | The `[SPIDER](../spider/index)` storage engine. | | `mariadb-plugin-tokudb` | The [TokuDB](../tokudb/index) storage engine. | | `mariadb-server` | The server and server tools, like [myisamchk](../myisamchk/index) and [mysqlhotcopy](../mysqlhotcopy/index) are here. | | `mariadb-server-core` | The core server. | | `mariadb-test` | `mysql-client-test` executable, and **mysql-test** framework with the tests. | | `mariadb-test-data` | MariaDB database regression test suite - data files | ### Available DEB Packages in [MariaDB 10.1](../what-is-mariadb-101/index) **MariaDB starting with [10.1](../what-is-mariadb-101/index)**In [MariaDB 10.1](../what-is-mariadb-101/index), the following DEBs are available: | Package Name | Description | | --- | --- | | `galera` | The WSREP provider for [Galera](../galera/index) 3. | | `libmysqlclient18` | Dynamic client libraries. | | `mariadb-backup` | [Mariabackup](../mariabackup/index) | | `mariadb-client` | Client tools like `mysql` CLI, `mysqldump`, and others. | | `mariadb-client-core` | Core client tools | | `mariadb-common` | Character set files and `/etc/my.cnf` | | `mariadb-plugin-connect` | The `[CONNECT](../connect/index)` storage engine. | | `mariadb-plugin-cracklib-password-check` | The `[cracklib\_password\_check](../cracklib-password-check-plugin/index)` password validation plugin. | | `mariadb-plugin-gssapi-client` | The client-side component of the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin. | | `mariadb-plugin-gssapi-server` | The server-side component of the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin. | | `mariadb-plugin-spider` | The `[SPIDER](../spider/index)` storage engine. | | `mariadb-plugin-tokudb` | The [TokuDB](../tokudb/index) storage engine. | | `mariadb-server` | The server and server tools, like [myisamchk](../myisamchk/index) and [mysqlhotcopy](../mysqlhotcopy/index) are here. | | `mariadb-server-core` | The core server. | | `mariadb-test` | `mysql-client-test` executable, and **mysql-test** framework with the tests. | | `mariadb-test-data` | MariaDB database regression test suite - data files | Actions Performed by DEB Packages --------------------------------- ### Users and Groups Created When the `mariadb-server` DEB package is installed, it will create a user and group named `mysql`, if they do not already exist. See Also -------- * [Differences in MariaDB in Debian](../differences-in-mariadb-in-debian/index) * [Installing MariaDB .deb Files with Ansible](../installing-mariadb-deb-files-with-ansible/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb resolveip resolveip ========= resolveip is a utility for resolving IP addresses to host names and vice versa. Usage ----- ``` resolveip [OPTIONS] hostname or IP-address ``` Options ------- | Option | Description | | --- | --- | | `-?`, `--help` | Display help and exit. | | `-I`, `--info` | Synonym for `--help`. | | `-s`, `--silent#` | Be more silent. | | `-V`, `--version` | Display version information and exit. | Examples -------- ``` shell> resolveip mariadb.org IP address of mariadb.org is 166.78.144.191 ``` ``` resolveip 166.78.144.191 Host name of 166.78.144.191 is mariadb.org ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Buildbot Setup for Virtual Machines - CentOS 6.2 Buildbot Setup for Virtual Machines - CentOS 6.2 ================================================ Base install ------------ ``` qemu-img create -f qcow2 /kvm/vms/vm-centos6-amd64-serial.qcow2 8G qemu-img create -f qcow2 /kvm/vms/vm-centos6-i386-serial.qcow2 8G ``` Start each VM booting from the server install iso one at a time and perform the following install steps: ``` kvm -m 1024 -hda /kvm/vms/vm-centos6-amd64-serial.qcow2 -cdrom /kvm/iso/centos/CentOS-6.2-x86_64-bin-DVD1.iso -redir tcp:22255::22 -boot d -smp 2 -cpu qemu64 -net nic,model=virtio -net user kvm -m 1024 -hda /kvm/vms/vm-centos6-i386-serial.qcow2 -cdrom /kvm/iso/centos/CentOS-6.2-i386-bin-DVD1.iso -redir tcp:22256::22 -boot d -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user ``` Once running you can connect to the VNC server from your local host with: ``` vncviewer -via ${remote-host} localhost ``` Replace ${remote-host} with the host the vm is running on. **Note:** When you activate the install, vncviewer may disconnect with a complaint about the rect being too large. This is fine. The CentOS installer has just resized the vnc screen. Simply reconnect. Install, picking default options mostly, with the following notes: * The Installer will throw up a "Storage Device Warning", choose "Yes, discard any data" * Set the hostname to centos6-amd64 (or centos6-i386) * Click the "Configure Network" button on the Hostname screen. + Edit System eth0 to "connect automatically" + Apply and then close the "Network Connections" window * Set Timezone to Europe/Helsinki (keep "System clock uses UTC" checked) * When partitioning disks, choose "Use All Space" + **do not** check the "Encrypt system" checkbox + **do** check the "Review and modify partitioning layout" checkbox + Delete the LVM stuff and leaving the sda1 partition alone, repartition the physical volume as follows | Device | Size(MB) | Mount Point | Type | Format | | --- | --- | --- | --- | --- | | sda2 | 5672 | / | ext4 | yes | | sda3 | (max allowable) | (n/a) | swap | yes | * Minimal install * Customize Later When the install is finished, you will be prompted to reboot. Go ahead and do so, but it will fail. Kill the VM (after the reboot fails) and start it up again: ``` kvm -m 1024 -hda /kvm/vms/vm-centos6-amd64-serial.qcow2 -redir tcp:22255::22 -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user kvm -m 1024 -hda /kvm/vms/vm-centos6-i386-serial.qcow2 -redir tcp:22256::22 -boot c -smp 2 -cpu qemu32,-nx -net nic,model=virtio -net user ``` You may connect via VNC as before, but ssh is probably preferred. Login as root. Now that the VM is installed, it's time to configure it. ``` ssh -p 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa root@localhost ssh -p 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa root@localhost ``` After logging in as root, create a local user ``` adduser ${username} usermod -a -G wheel ${username} passwd ${username} ``` Enable password-less sudo and serial console: ``` visudo # Uncomment the line "%wheel ALL=(ALL) NOPASSWD: ALL" # Comment out this line: # Defaults requiretty ``` Still logged in as root, add to /boot/grub/menu.lst: ``` serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1 terminal --timeout=3 serial console ``` also add in menu.lst to kernel line (after removing 'quiet'): ``` console=tty0 console=ttyS0,115200n8 ``` Add login prompt on serial console: ``` cat >>/etc/inittab <<END # Serial console. S0:2345:respawn:/sbin/agetty -h -L ttyS0 19200 vt100 END ``` Logout as root, and then, from the VM host server: Install proper ssh: ``` ssh -t -p 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa localhost "sudo yum install openssh-server openssh-clients" ssh -t -p 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa localhost "sudo yum install openssh-server openssh-clients" ``` Create a .ssh folder: ``` ssh -t -p 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa localhost "mkdir -v .ssh" ssh -t -p 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa localhost "mkdir -v .ssh" ``` Copy over the authorized keys file: ``` scp -P 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/authorized_keys localhost:.ssh/ scp -P 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/authorized_keys localhost:.ssh/ ``` Set permissions on the .ssh folder correctly: ``` ssh -t -p 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa localhost "chmod -R go-rwx .ssh" ssh -t -p 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i ~/.ssh/buildbot.id_dsa localhost "chmod -R go-rwx .ssh" ``` Create the buildbot user: ``` ssh -p 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no localhost 'chmod -R go-rwx .ssh; sudo adduser buildbot; sudo usermod -a -G wheel buildbot; sudo mkdir ~buildbot/.ssh; sudo cp -vi .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -vR buildbot:buildbot ~buildbot/.ssh; sudo chmod -vR go-rwx ~buildbot/.ssh' ssh -p 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no localhost 'chmod -R go-rwx .ssh; sudo adduser buildbot; sudo usermod -a -G wheel buildbot; sudo mkdir ~buildbot/.ssh; sudo cp -vi .ssh/authorized_keys ~buildbot/.ssh/; sudo chown -vR buildbot:buildbot ~buildbot/.ssh; sudo chmod -vR go-rwx ~buildbot/.ssh' ``` Upload the ttyS0.conf file and put it where it goes: ``` scp -P 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/ttyS0.conf buildbot@localhost: scp -P 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/ttyS0.conf buildbot@localhost: ssh -p 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no buildbot@localhost 'sudo cp -vi ttyS0.conf /etc/init/; rm -v ttyS0.conf;' ssh -p 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no buildbot@localhost 'sudo cp -vi ttyS0.conf /etc/init/; rm -v ttyS0.conf;' ``` Update the VM: ``` ssh -p 22255 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no buildbot@localhost ssh -p 22256 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no buildbot@localhost ``` Once logged in: ``` sudo yum update ``` After updating, shut down the VM: ``` sudo shutdown -h now ``` VMs for building .rpms ---------------------- ``` for i in '/kvm/vms/vm-centos6-amd64-serial.qcow2 22255 qemu64' '/kvm/vms/vm-centos6-i386-serial.qcow2 22256 qemu64' ; do \ set $i; \ runvm --user=buildbot --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/build/')" \ "sudo yum -y groupinstall 'Development Tools'" \ "sudo yum -y install wget tree gperf readline-devel ncurses-devel zlib-devel pam-devel libaio-devel openssl-devel libxml2 libxml2-devel unixODBC-devel bzr perl perl\(DBI\)" \ "sudo yum -y remove systemtap-sdt-dev" \ "bzr co --lightweight lp:mariadb-native-client" \ "sudo mkdir -vp /usr/src/redhat/SOURCES /usr/src/redhat/SPECS /usr/src/redhat/RPMS /usr/src/redhat/SRPMS" \ "wget http://www.cmake.org/files/v2.8/cmake-2.8.8.tar.gz;tar -zxvf cmake-2.8.8.tar.gz;cd cmake-2.8.8;./configure;make;sudo make install"; \ done ``` Also: * [Installing the Boost library needed for the OQGraph storage engine](../installing-the-boost-library-needed-for-the-oqgraph-storage-engine/index) VMs for install testing. ------------------------ `MariaDB.local.repo` points at a local directory on the VM. `MariaDB.repo` points at the real MariaDB YUM repository. ``` for i in '/kvm/vms/vm-centos6-amd64-serial.qcow2 22255 qemu64' '/kvm/vms/vm-centos6-i386-serial.qcow2 22256 qemu64' ; do \ set $i; \ runvm --user=buildbot --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/install/')" \ "sudo yum -y update" \ "sudo yum -y install patch libaio perl perl-Time-HiRes perl-DBI libtool-ltdl unixODBC" \ "= scp -P $2 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/MariaDB.local.repo buildbot@localhost:/tmp/" \ "sudo mv -vi /tmp/MariaDB.local.repo /etc/yum.repos.d/"; \ done ``` VMs for MySQL upgrade testing ----------------------------- ``` for i in '/kvm/vms/vm-centos6-amd64-serial.qcow2 22255 qemu64' '/kvm/vms/vm-centos6-i386-serial.qcow2 22256 qemu64' ; do \ set $i; \ runvm --user=buildbot --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/upgrade/')" \ "sudo yum -y update" \ 'sudo yum -y install mysql-server libtool-ltdl unixODBC' \ 'sudo /etc/init.d/mysqld start' \ 'mysql -uroot -e "create database mytest; use mytest; create table t(a int primary key); insert into t values (1); select * from t"' \ "= scp -P $2 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/MariaDB.local.repo buildbot@localhost:/tmp/" \ "sudo mv -vi /tmp/MariaDB.local.repo /etc/yum.repos.d/"; \ done ``` The MariaDB upgrade testing VMs were not built. There is currently an error with installing MariaDB from the YUM repo. VMs for MariaDB upgrade testing ------------------------------- ``` for i in '/kvm/vms/vm-centos6-amd64-serial.qcow2 22255 qemu64' '/kvm/vms/vm-centos6-i386-serial.qcow2 22256 qemu64' ; do \ set $i; \ runvm --user=buildbot --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/upgrade2/')" \ 'sudo yum -y update' \ "= scp -P $2 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/MariaDB.repo buildbot@localhost:/tmp/" \ 'sudo rpm --verbose --import http://downloads.mariadb.org/repo/RPM-GPG-KEY-MariaDB' \ 'sudo mv -vi /tmp/MariaDB.repo /etc/yum.repos.d/' \ 'sudo yum -y remove mysql-libs' \ 'sudo yum -y install MariaDB-server MariaDB-client MariaDB-test' \ 'sudo yum -y install cronie cronie-anacron crontabs.noarch postfix' \ 'sudo /etc/init.d/mysqld start' \ 'mysql -uroot -prootpass -e "create database mytest; use mytest; create table t(a int primary key); insert into t values (1); select * from t"' \ 'sudo rm -v /etc/yum.repos.d/MariaDB.repo' \ "= scp -P $2 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no /kvm/vms/MariaDB.local.repo buildbot@localhost:/tmp/" \ 'sudo mv -vi /tmp/MariaDB.local.repo /etc/yum.repos.d/'; \ done ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb WITH WITH ==== **MariaDB starting with [10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)**Common Table Expressions were introduced in [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). ### Syntax ``` WITH [RECURSIVE] table_reference [(columns_list)] AS ( SELECT ... ) [CYCLE cycle_column_list RESTRICT] SELECT ... ``` ### Description The `WITH` keyword signifies a [Common Table Expression](../common-table-expressions/index) (CTE). It allows you to refer to a subquery expression many times in a query, as if having a temporary table that only exists for the duration of a query. There are two kinds of CTEs: * [Non-Recursive](../non-recursive-common-table-expressions-overview/index) * [Recursive](../recursive-common-table-expressions-overview/index) (signified by the `RECURSIVE` keyword, supported since [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) You can use `table_reference` as any normal table in the external `SELECT` part. You can also use `WITH` in subqueries, as well as with [EXPLAIN](../explain/index) and [SELECT](../select/index). Poorly-formed recursive CTEs can in theory cause infinite loops. The [max\_recursive\_iterations](../server-system-variables/index#max_recursive_iterations) system variable limits the number of recursions. #### CYCLE ... RESTRICT **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**The CYCLE clause enables CTE cycle detection, avoiding excessive or infinite loops, MariaDB supports a relaxed, non-standard grammar. The SQL Standard permits a CYCLE clause, as follows: ``` WITH RECURSIVE ... ( ... ) CYCLE <cycle column list> SET <cycle mark column> TO <cycle mark value> DEFAULT <non-cycle mark value> USING <path column> ``` where all clauses are mandatory. MariaDB does not support this, but from 10.5.2 permits a non-standard relaxed grammar, as follows: ``` WITH RECURSIVE ... ( ... ) CYCLE <cycle column list> RESTRICT ``` With the use of `CYCLE ... RESTRICT` it makes no difference whether the CTE uses `UNION ALL` or `UNION DISTINCT` anymore. `UNION ALL` means "all rows, but without cycles", which is exactly what the `CYCLE` clause enables. And `UNION DISTINCT` means all rows should be different, which, again, is what will happen — as uniqueness is enforced over a subset of columns, complete rows will automatically all be different. ### Examples Below is an example with the `WITH` at the top level: ``` WITH t AS (SELECT a FROM t1 WHERE b >= 'c') SELECT * FROM t2, t WHERE t2.c = t.a; ``` The example below uses `WITH` in a subquery: ``` SELECT t1.a, t1.b FROM t1, t2 WHERE t1.a > t2.c AND t2.c IN(WITH t AS (SELECT * FROM t1 WHERE t1.a < 5) SELECT t2.c FROM t2, t WHERE t2.c = t.a); ``` Below is an example of a Recursive CTE: ``` WITH RECURSIVE ancestors AS ( SELECT * FROM folks WHERE name="Alex" UNION SELECT f.* FROM folks AS f, ancestors AS a WHERE f.id = a.father OR f.id = a.mother ) SELECT * FROM ancestors; ``` Take the following structure, and data, ``` CREATE TABLE t1 (from_ int, to_ int); INSERT INTO t1 VALUES (1,2), (1,100), (2,3), (3,4), (4,1); SELECT * FROM t1; +-------+------+ | from_ | to_ | +-------+------+ | 1 | 2 | | 1 | 100 | | 2 | 3 | | 3 | 4 | | 4 | 1 | +-------+------+ ``` Given the above, the following query would theoretically result in an infinite loop due to the last record in t1 (note that [max\_recursive\_iterations](../server-system-variables/index#max_recursive_iterations) is set to 10 for the purposes of this example, to avoid the excessive number of cycles): ``` SET max_recursive_iterations=10; WITH RECURSIVE cte (depth, from_, to_) AS ( SELECT 0,1,1 UNION DISTINCT SELECT depth+1, t1.from_, t1.to_ FROM t1, cte WHERE t1.from_ = cte.to_ ) SELECT * FROM cte; +-------+-------+------+ | depth | from_ | to_ | +-------+-------+------+ | 0 | 1 | 1 | | 1 | 1 | 2 | | 1 | 1 | 100 | | 2 | 2 | 3 | | 3 | 3 | 4 | | 4 | 4 | 1 | | 5 | 1 | 2 | | 5 | 1 | 100 | | 6 | 2 | 3 | | 7 | 3 | 4 | | 8 | 4 | 1 | | 9 | 1 | 2 | | 9 | 1 | 100 | | 10 | 2 | 3 | +-------+-------+------+ ``` However, the CYCLE ... RESTRICT clause (from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)) can overcome this: ``` WITH RECURSIVE cte (depth, from_, to_) AS ( SELECT 0,1,1 UNION SELECT depth+1, t1.from_, t1.to_ FROM t1, cte WHERE t1.from_ = cte.to_ ) CYCLE from_, to_ RESTRICT SELECT * FROM cte; +-------+-------+------+ | depth | from_ | to_ | +-------+-------+------+ | 0 | 1 | 1 | | 1 | 1 | 2 | | 1 | 1 | 100 | | 2 | 2 | 3 | | 3 | 3 | 4 | | 4 | 4 | 1 | +-------+-------+------+ ``` ### See Also * [Non-Recursive Common Table Expressions Overview](../non-recursive-common-table-expressions-overview/index) * [Recursive Common Table Expressions Overview](../recursive-common-table-expressions-overview/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb List of Performance Schema Tables List of Performance Schema Tables ================================= Below is a list of all [Performance Schema](../performance-schema/index) tables as well as a brief description of each of them. | Table | Description | | --- | --- | | `[accounts](../performance-schema-accounts-table/index)` | Client account connection statistics. | | `[cond\_instances](../performance-schema-cond_instances-table/index)` | Synchronization object instances. | | `[events\_stages\_current](../performance-schema-events_stages_current-table/index)` | Current stage events. | | `[events\_stages\_history](../performance-schema-events_stages_history-table/index)` | Ten most recent stage events per thread. | | `[events\_stages\_history\_long](../performance-schema-events_stages_history_long-table/index)` | Ten thousand most recent stage events. | | `[events\_stages\_summary\_by\_account\_by\_event\_name](../performance-schema-events_stages_summary_by_account_by_event_name-table/index)` | Summarized stage events per account and event name. | | `[events\_stages\_summary\_by\_host\_by\_event\_name](../performance-schema-events_stages_summary_by_host_by_event_name-table/index)` | Summarized stage events per host and event name. | | `[events\_stages\_summary\_by\_thread\_by\_event\_name](../performance-schema-events_stages_summary_by_thread_by_event_name-table/index)` | Summarized stage events per thread and event name. | | `[events\_stages\_summary\_by\_user\_by\_event\_name](../performance-schema-events_stages_summary_by_user_by_event_name-table/index)` | Summarized stage events per user name and event name. | | `[events\_stages\_summary\_global\_by\_event\_name](../performance-schema-events_stages_summary_global_by_event_name-table/index)` | Summarized stage events per event name. | | `[events\_statements\_current](../performance-schema-events_statements_current-table/index)` | Current statement events. | | `[events\_statements\_history](../performance-schema-events_statements_history-table/index)` | Ten most recent events per thread. | | `[events\_statements\_history\_long](../performance-schema-events_statements_history_long-table/index)` | Ten thousand most recent stage events. | | `[events\_statements\_summary\_by\_account\_by\_event\_name](../performance-schema-events_statements_summary_by_account_by_event_name-table/index)` | Summarized statement events per account and event name. | | `[events\_statements\_summary\_by\_digest](../performance-schema-events_statements_summary_by_digest-table/index)` | Summarized statement events by scheme and digest. | | `[events\_statements\_summary\_by\_host\_by\_event\_name](../performance-schema-events_statements_summary_by_host_by_event_name-table/index)` | Summarized statement events by host and event name. | | `[events\_statements\_summary\_by\_program](../performance-schema-events_statements_summary_by_program-table/index)` | Events for a particular stored program. | | `[events\_statements\_summary\_by\_thread\_by\_event\_name](../performance-schema-events_statements_summary_by_thread_by_event_name-table/index)` | Summarized statement events by thread and event name. | | `[events\_statements\_summary\_by\_user\_by\_event\_name](../performance-schema-events_statements_summary_by_user_by_event_name-table/index)` | Summarized statement events by user and event name. | | `[events\_statements\_summary\_global\_by\_event\_name](../performance-schema-events_statements_summary_global_by_event_name-table/index)` | Summarized statement events by event name. | | `[events\_transactions\_current](../performance-schema-events_transactions_current-table/index)` | Current transaction events for each thread. | | `[events\_transactions\_history](../performance-schema-events_transactions_history-table/index)` | Most recent completed transaction events for each thread. | | `[events\_transactions\_history\_long](../performance-schema-events_transactions_history_long-table/index)` | Most recent completed transaction events that have ended globally. | | `[events\_transactions\_summary\_by\_account\_by\_event\_name](../performance-schema-tables-performance-schema-events_transactions_summary_by/index)` | Transaction events aggregated by account and event. | | `[events\_transactions\_summary\_by\_host\_by\_event\_name](../performance-schema-events_transactions_summary_by_host_by_event_name-table/index)` | Transaction events aggregated by host and event.. | | `[events\_transactions\_summary\_by\_thread\_by\_event\_name](../performance-schema-events_transactions_summary_by_thread_by_event_name-tabl/index)` | Transaction events aggregated by thread and event.. | | `[events\_transactions\_summary\_by\_user\_by\_event\_name](../performance-schema-events_transactions_summary_by_user_by_event_name-table/index)` | Transaction events aggregated by user and event.. | | `[events\_transactions\_summary\_global\_by\_event\_name](../performance-schema-events_transactions_summary_global_by_event_name-table/index)` | Transaction events aggregated by event name. | | `[events\_waits\_current](../performance-schema-events_waits_current-table/index)` | Current wait events. | | `[events\_waits\_history](../performance-schema-events_waits_history-table/index)` | Ten most recent wait events per thread. | | `[events\_waits\_history\_long](../performance-schema-events_waits_history_long-table/index)` | Ten thousand most recent wait events per thread. | | `[events\_waits\_summary\_by\_account\_by\_event\_name](../performance-schema-events_waits_summary_by_account_by_event_name-table/index)` | Summarized wait events by account and event name. | | `[events\_waits\_summary\_by\_host\_by\_event\_name](../performance-schema-events_waits_summary_by_host_by_event_name-table/index)` | Summarized wait events by host and event name. | | `[events\_waits\_summary\_by\_instance](../performance-schema-events_waits_summary_by_instance-table/index)` | Summarized wait events by instance. | | `[events\_waits\_summary\_by\_thread\_by\_event\_name](../performance-schema-events_waits_summary_by_thread_by_event_name-table/index)` | Summarized wait events by thread and event name. | | `[events\_waits\_summary\_by\_user\_by\_event\_name](../performance-schema-events_waits_summary_by_user_by_event_name-table/index)` | Summarized wait events by user and event name. | | `[events\_waits\_summary\_global\_by\_event\_name](../performance-schema-events_waits_summary_global_by_event_name-table/index)` | Summarized wait events by event name. | | `[file\_instances](../performance-schema-file_instances-table/index)` | Seen files. | | `[file\_summary\_by\_event\_name](../performance-schema-file_summary_by_event_name-table/index)` | File events summarized by event name. | | `[file\_summary\_by\_instance](../performance-schema-file_summary_by_instance-table/index)` | File events summarized by instance. | | `[global\_status](../performance-schema-global_status-table/index)` | Global status variables and values. | | `[host\_cache](../performance-schema-host_cache-table/index)` | Host and IP information. | | `[hosts](../performance-schema-hosts-table/index)` | Connections by host. | | `[memory\_summary\_by\_account\_by\_event\_name](../performance-schema-memory_summary_by_account_by_event_name-table/index)` | Memory usage statistics aggregated by account and event. | | `[memory\_summary\_by\_host\_by\_event\_name](../performance-schema-memory_summary_by_host_by_event_name-table/index)` | Memory usage statistics aggregated by host. and event. | | `[memory\_summary\_by\_thread\_by\_event\_name](../performance-schema-memory_summary_by_thread_by_event_name-table/index)` | Memory usage statistics aggregated by thread and event.. | | `[memory\_summary\_by\_user\_by\_event\_name](../performance-schema-memory_summary_by_user_by_event_name-table/index)` | Memory usage statistics aggregated by user and event.. | | `[memory\_summary\_global\_by\_event\_name](../performance-schema-memory_global_by_event_name-table/index)` | Memory usage statistics aggregated by event. | | `[metadata\_locks](../performance-schema-metadata_locks-table/index)` | [Metadata locks](../metadata-locking/index). | | `[mutex\_instances](../performance-schema-mutex_instances-table/index)` | Seen mutexes. | | `[objects\_summary\_global\_by\_type](../performance-schema-objects_summary_global_by_type-table/index)` | Object wait events. | | `[performance\_timers](../performance-schema-performance_timers-table/index)` | Available event timers. | | `[prepared\_statements\_instances](../performance-schema-prepared_statements_instances-table/index)` | Aggregate statistics of prepared statements. | | `[replication\_applier\_configuration](../performance-schema-replication_applier_configuration-table/index)` | Configuration settings affecting replica transactions. | | `[replication\_applier\_status](../performance-schema-replication_applier_status-table/index)` | General transaction execution status on the replica. | | `[replication\_applier\_status\_by\_coordinator](../performance-schema-replication_applier_status_by_coordinator-table/index)` | Coordinator thread specific information. | | `[replication\_applier\_status\_by\_worker](../performance-schema-replication_applier_status_by_worker-table/index)` | Replica worker thread specific information. | | `[replication\_connection\_configuration](../performance-schema-replication_connection_configuration-table/index)` | Rreplica's configuration settings used for connecting to the primary. | | `[rwlock\_instances](../performance-schema-rwlock_instances-table/index)` | Seen read-write locks. | | `[session\_account\_connect\_attrs](../performance-schema-session_account_connect_attrs-table/index)` | Current session connection attributes. | | `[session\_connect\_attrs](../performance-schema-session_connect_attrs-table/index)` | All session connection attributes. | | `[session\_status](../performance-schema-session_status-table/index)` | Session status variables and values. | | `[setup\_actors](../performance-schema-setup_actors-table/index)` | Details on foreground thread monitoring. | | `[setup\_consumers](../performance-schema-setup_consumers-table/index)` | Consumers for which event information is stored. | | `[setup\_instruments](../performance-schema-setup_instruments-table/index)` | Instrumented objects for which events are collected. | | `[setup\_objects](../performance-schema-setup_objects-table/index)` | Objects to be monitored. | | `[setup\_timers](../performance-schema-setup_timers-table/index)` | Currently selected event timers. | | `[socket\_instances](../performance-schema-socket_instances-table/index)` | Active connections. | | `[socket\_summary\_by\_event\_name](../performance-schema-socket_summary_by_event_name-table/index)` | Timer and byte count statistics by socket instrument. | | `[socket\_summary\_by\_instance](../performance-schema-socket_summary_by_instance-table/index)` | Timer and byte count statistics by socket instance. | | `[status\_by\_account](../performance-schema-status_by_account-table/index)` | Status variable info by host/user account. | | `[status\_by\_host](../performance-schema-status_by_host-table/index)` | Status variable info by host. | | `[status\_by\_thread](../performance-schema-status_by_thread-table/index)` | Status variable info about active foreground threads. | | `[status\_by\_user](../performance-schema-status_by_user-table/index)` | Status variable info by user. | | `[table\_handles](../performance-schema-table_handles-table/index)` | Table lock information. | | `[table\_io\_waits\_summary\_by\_index\_usage](../performance-schema-table_io_waits_summary_by_index_usage-table/index)` | Aggregate table I/O wait events by index. | | `[table\_io\_waits\_summary\_by\_table](../performance-schema-table_io_waits_summary_by_table-table/index)` | Aggregate table I/O wait events by table. | | `[table\_lock\_waits\_summary\_by\_table](../performance-schema-table_lock_waits_summary_by_table-table/index)` | Aggregate table lock wait events by table. | | `[threads](../performance-schema-threads-table/index)` | Server thread information. | | `[user\_variables\_by\_thread](../performance-schema-user_variables_by_thread-table/index)` | [User-defined variables](../user-defined-variables/index) by thread. | | `[users](../performance-schema-users-table/index)` | Connection statistics by user. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SELECT INTO SELECT INTO =========== Syntax ------ ``` SELECT col_name [, col_name] ... INTO var_name [, var_name] ... table_expr ``` Description ----------- SELECT ... INTO enables selected columns to be stored directly into variables. No resultset is produced. The query should return a single row. If the query returns no rows, a warning with error code 1329 occurs (No data), and the variable values remain unchanged. If the query returns multiple rows, error 1172 occurs (Result consisted of more than one row). If it is possible that the statement may retrieve multiple rows, you can use `LIMIT 1` to limit the result set to a single row. The INTO clause can also be specified at the end of the statement. In the context of such statements that occur as part of events executed by the Event Scheduler, diagnostics messages (not only errors, but also warnings) are written to the error log, and, on Windows, to the application event log. This statement can be used with both [local variables](../declare-variable/index) and [user-defined variables](../user-defined-variables/index). For the complete syntax, see [SELECT](../select/index). Another way to set a variable's value is the [SET](../set-variable/index) statement. `SELECT ... INTO` results are not stored in the [query cache](../query-cache/index) even if `SQL_CACHE` is specified. Examples -------- ``` SELECT id, data INTO @x,@y FROM test.t1 LIMIT 1; ``` See Also -------- * [SELECT](../select/index) - full SELECT syntax. * [SELECT INTO OUTFILE](../select-into-outfile/index) - formatting and writing the result to an external file. * [SELECT INTO DUMPFILE](../select-into-dumpfile/index) - binary-safe writing of the unformatted results to an external file. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Database Design Example Phase 3: Implementation Database Design Example Phase 3: Implementation =============================================== This article follows on from [Database Design Example Phase 2: Design](../database-design-example-phase-2-design/index). With the design complete, it's time to [install MariaDB](../getting-installing-and-upgrading-mariadb/index) and run the [CREATE](../create/index) statements, as follows: ``` CREATE DATABASE poets_circle; CREATE TABLE poet ( poet_code INT NOT NULL, first_name VARCHAR(30), surname VARCHAR(40), address VARCHAR(100), postcode VARCHAR(20), email VARCHAR(254), PRIMARY KEY(poet_code) ); CREATE TABLE poem( poem_code INT NOT NULL, title VARCHAR(50), contents TEXT, poet_code INT NOT NULL, PRIMARY KEY(poem_code), INDEX(poet_code), FOREIGN KEY(poet_code) REFERENCES poet(poet_code) ); CREATE TABLE publication( publication_code INT NOT NULL, title VARCHAR(100), price MEDIUMINT UNSIGNED, PRIMARY KEY(publication_code) ); CREATE TABLE poem_publication( poem_code INT NOT NULL, publication_code INT NOT NULL, PRIMARY KEY(poem_code, publication_code), INDEX(publication_code), FOREIGN KEY(poem_code) REFERENCES poem(poem_code), FOREIGN KEY(publication_code) REFERENCES publication(publication_code) ); CREATE TABLE sales_publication( sales_code INT NOT NULL, publication_code INT NOT NULL, PRIMARY KEY(sales_code, publication_code) ); CREATE TABLE customer( customer_code INT NOT NULL, first_name VARCHAR(30), surname VARCHAR(40), address VARCHAR(100), postcode VARCHAR(20), email VARCHAR(254), PRIMARY KEY(customer_code) ); CREATE TABLE sale( sale_code INT NOT NULL, sale_date DATE, amount INT UNSIGNED, customer_code INT NOT NULL, PRIMARY KEY(sale_code), INDEX(customer_code), FOREIGN KEY(customer_code) REFERENCES customer(customer_code) ); ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SPIDER_DIRECT_SQL SPIDER\_DIRECT\_SQL =================== Syntax ------ ``` SPIDER_DIRECT_SQL('sql', 'tmp_table_list', 'parameters') ``` Description ----------- A [UDF](../user-defined-functions/index) installed with the [Spider Storage Engine](../spider/index), this function is used to execute the SQL string `sql` on the remote server, as defined in `parameters`. If any resultsets are returned, they are stored in the `tmp_table_list`. The function returns `1` if the SQL executes successfully, or `0` if it fails. Examples -------- ``` SELECT SPIDER_DIRECT_SQL('SELECT * FROM s', '', 'srv "node1", port "8607"'); +----------------------------------------------------------------------+ | SPIDER_DIRECT_SQL('SELECT * FROM s', '', 'srv "node1", port "8607"') | +----------------------------------------------------------------------+ | 1 | +----------------------------------------------------------------------+ ``` See also -------- * [SPIDER\_BG\_DIRECT\_SQL](../spider_bg_direct_sql/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DES_DECRYPT DES\_DECRYPT ============ DES\_DECRYPT has been deprecated from [MariaDB 10.10.0](https://mariadb.com/kb/en/mariadb-10100-release-notes/), and will be removed in a future release. Syntax ------ ``` DES_DECRYPT(crypt_str[,key_str]) ``` Description ----------- Decrypts a string encrypted with `[DES\_ENCRYPT()](../des_encrypt/index)`. If an error occurs, this function returns `NULL`. This function works only if MariaDB has been configured with [TLS support](../secure-connections-overview/index). If no `key_str` argument is given, `DES_DECRYPT()` examines the first byte of the encrypted string to determine the DES key number that was used to encrypt the original string, and then reads the key from the DES key file to decrypt the message. For this to work, the user must have the SUPER privilege. The key file can be specified with the `--des-key-file` server option. If you pass this function a `key_str` argument, that string is used as the key for decrypting the message. If the `crypt_str` argument does not appear to be an encrypted string, MariaDB returns the given crypt\_str. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ! ! = Syntax ------ ``` NOT, ! ``` Description ----------- Logical NOT. Evaluates to 1 if the operand is 0, to 0 if the operand is non-zero, and NOT NULL returns NULL. By default, the `!` operator has a [higher precedence](../operator-precedence/index). If the `HIGH_NOT_PRECEDENCE` [SQL\_MODE](../sql-mode/index) flag is set, `NOT` and `!` have the same precedence. Examples -------- ``` SELECT NOT 10; +--------+ | NOT 10 | +--------+ | 0 | +--------+ SELECT NOT 0; +-------+ | NOT 0 | +-------+ | 1 | +-------+ SELECT NOT NULL; +----------+ | NOT NULL | +----------+ | NULL | +----------+ SELECT ! (1+1); +---------+ | ! (1+1) | +---------+ | 0 | +---------+ SELECT ! 1+1; +-------+ | ! 1+1 | +-------+ | 1 | +-------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb statement_performance_analyzer statement\_performance\_analyzer ================================ Syntax ------ ``` statement_performance_analyzer(in_action,in_table, in_views) # in_action ENUM('snapshot', 'overall', 'delta', 'create_tmp', 'create_table', 'save', 'cleanup') # in_table VARCHAR(129) # in_views SET ('with_runtimes_in_95th_percentile', 'analysis', 'with_errors_or_warnings', 'with_full_table_scans', 'with_sorting', 'with_temp_tables', 'custom') ``` Description ----------- `statement_performance_analyzer` is a [stored procedure](../stored-procedures/index) available with the [Sys Schema](../sys-schema/index) which returns a report on running statements. The following options from the [sys\_config](../sys-schema-sys_config-table/index) table impact the output: * statement\_performance\_analyzer.limit - maximum number of rows (default 100) returned for views that have no built-in limit. * statement\_performance\_analyzer.view - custom query/view to be used (default NULL). If the statement\_performance\_analyzer.limit configuration option is greater than 0, there can't be a LIMIT clause in the query/view definition If the debug option is set (default OFF), the procedure will also produce debugging output. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Identifier to File Name Mapping Identifier to File Name Mapping =============================== Some identifiers map to a file name on the filesystem. Databases each have their own directory, while, depending on the [storage engine](storage-engine), table names and index names may map to a file name. Not all characters that are allowed in table names can be used in file names. Every filesystem has its own rules of what characters can be used in file names. To let the user create tables using all characters allowed in the SQL Standard and to not depend on whatever particular filesystem a particular database resides, MariaDB encodes "potentially unsafe" characters in the table name to derive the corresponding file name. This is implemented using a special character set. MariaDB converts a table name to the "filename" character set to get the file name for this table. And it converts the file name from the "filename" character set to, for example, utf8 to get the table name for this file name. The conversion rules are as follows: if the identifier is made up only of basic Latin numbers, letters and/or the underscore character, the encoding matches the name (see however [Identifier Case Sensitivity](../identifier-case-sensitivity/index)). Otherwise they are encoded according to the following table: | Code Range | Pattern | Number | Used | Unused | Blocks | | --- | --- | --- | --- | --- | --- | | 00C0..017F | [@][0..4][g..z] | 5\*20= 100 | 97 | 3 | Latin-1 Supplement + Latin Extended-A | | 0370..03FF | [@][5..9][g..z] | 5\*20= 100 | 88 | 12 | Greek and Coptic | | 0400..052F | [@][g..z][0..6] | 20\*7= 140 | 137 | 3 | Cyrillic + Cyrillic Supplement | | 0530..058F | [@][g..z][7..8] | 20\*2= 40 | 38 | 2 | Armenian | | 2160..217F | [@][g..z][9] | 20\*1= 20 | 16 | 4 | Number Forms | | 0180..02AF | [@][g..z][a..k] | 20\*11=220 | 203 | 17 | Latin Extended-B + IPA Extensions | | 1E00..1EFF | [@][g..z][l..r] | 20\*7= 140 | 136 | 4 | Latin Extended Additional | | 1F00..1FFF | [@][g..z][s..z] | 20\*8= 160 | 144 | 16 | Greek Extended | | .... .... | [@][a..f][g..z] | 6\*20= 120 | 0 | 120 | RESERVED | | 24B6..24E9 | [@][@][a..z] | 26 | 26 | 0 | Enclosed Alphanumerics | | FF21..FF5A | [@][a..z][@] | 26 | 26 | 0 | Halfwidth and Fullwidth forms | Code Range values are UCS-2. All of this encoding happens transparently at the filesystem level with one exception. Until MySQL 5.1.6, an old encoding was used. Identifiers created in a version before MySQL 5.1.6, and which haven't been updated to the new encoding, the server prefixes `mysql50` to their name. ### Examples Find the file name for a table with a non-Latin1 name: ``` select cast(convert("this_is_таблица" USING filename) as binary); +------------------------------------------------------------------+ | cast(convert("this_is_таблица" USING filename) as binary) | +------------------------------------------------------------------+ | this_is_@y0@g0@h0@r0@o0@i1@g0 | +------------------------------------------------------------------+ ``` Find the table name for a file name: ``` select convert(_filename "this_is_@y0@g0@h0@r0@o0@i1@g0" USING utf8); +---------------------------------------------------------------+ | convert(_filename "this_is_@y0@g0@h0@r0@o0@i1@g0" USING utf8) | +---------------------------------------------------------------+ | this_is_таблица | +---------------------------------------------------------------+ ``` An old table created before MySQL 5.1.6, with the old encoding: ``` SHOW TABLES; +--------------------+ | Tables_in_test | +--------------------+ | #mysql50#table@1 | +--------------------+ ``` The prefix needs to be supplied to reference this table: ``` SHOW COLUMNS FROM `table@1`; ERROR 1146 (42S02): Table 'test.table@1' doesn't exist SHOW COLUMNS FROM `#mysql50#table@1`; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | i | int(11) | YES | | NULL | | +-------+---------+------+-----+---------+-------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb OQGRAPH Examples OQGRAPH Examples ================ Creating a Table with origid, destid Only ----------------------------------------- ``` CREATE TABLE oq_backing ( origid INT UNSIGNED NOT NULL, destid INT UNSIGNED NOT NULL, PRIMARY KEY (origid, destid), KEY (destid) ); ``` Some data can be inserted into the backing table to test with later: ``` INSERT INTO oq_backing(origid, destid) VALUES (1,2), (2,3), (3,4), (4,5), (2,6), (5,6); ``` Now the read-only [OQGRAPH](../oqgraph/index) table is created. From [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) onwards you can use the following syntax: ``` CREATE TABLE oq_graph ENGINE=OQGRAPH data_table='oq_backing' origid='origid' destid='destid'; ``` Prior to [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/), the [CREATE](../create-table/index) statement must match the format below - any difference will result in an error. ``` CREATE TABLE oq_graph ( latch VARCHAR(32) NULL, origid BIGINT UNSIGNED NULL, destid BIGINT UNSIGNED NULL, weight DOUBLE NULL, seq BIGINT UNSIGNED NULL, linkid BIGINT UNSIGNED NULL, KEY (latch, origid, destid) USING HASH, KEY (latch, destid, origid) USING HASH ) ENGINE=OQGRAPH data_table='oq_backing' origid='origid' destid='destid'; ``` Creating a Table with Weight ---------------------------- For the examples on this page, we'll create a second OQGRAPH table and backing table, this time with `weight` as well. ``` CREATE TABLE oq2_backing ( origid INT UNSIGNED NOT NULL, destid INT UNSIGNED NOT NULL, weight DOUBLE NOT NULL, PRIMARY KEY (origid, destid), KEY (destid) ); ``` ``` INSERT INTO oq2_backing(origid, destid, weight) VALUES (1,2,1), (2,3,1), (3,4,3), (4,5,1), (2,6,10), (5,6,2); ``` ``` CREATE TABLE oq2_graph ( latch VARCHAR(32) NULL, origid BIGINT UNSIGNED NULL, destid BIGINT UNSIGNED NULL, weight DOUBLE NULL, seq BIGINT UNSIGNED NULL, linkid BIGINT UNSIGNED NULL, KEY (latch, origid, destid) USING HASH, KEY (latch, destid, origid) USING HASH ) ENGINE=OQGRAPH data_table='oq2_backing' origid='origid' destid='destid' weight='weight'; ``` Shortest Path ------------- A `latch` value of `'dijkstras'` and an `origid` and `destid` is used for finding the shortest path between two nodes, for example: ``` SELECT * FROM oq_graph WHERE latch='breadth_first' AND origid=1 AND destid=6; +----------+--------+--------+--------+------+--------+ | latch | origid | destid | weight | seq | linkid | +----------+--------+--------+--------+------+--------+ | dijkstras| 1 | 6 | NULL | 0 | 1 | | dijkstras| 1 | 6 | 1 | 1 | 2 | | dijkstras| 1 | 6 | 1 | 2 | 6 | +----------+--------+--------+--------+------+--------+ ``` Note that nodes are uni-directional, so there is no path from node 6 to node 1: ``` SELECT * FROM oq_graph WHERE latch='dijkstras' AND origid=6 AND destid=1; Empty set (0.00 sec) ``` Using the [GROUP\_CONCAT](../group_concat/index) function can produce more readable results, for example: ``` SELECT GROUP_CONCAT(linkid ORDER BY seq) AS path FROM oq_graph WHERE latch='dijkstras' AND origid=1 AND destid=6; +-------+ | path | +-------+ | 1,2,6 | +-------+ ``` Using the table `oq2_graph`, the shortest path is different: ``` SELECT GROUP_CONCAT(linkid ORDER BY seq) AS path FROM oq2_graph WHERE latch='dijkstras' AND origid=1 AND destid=6; +-------------+ | path | +-------------+ | 1,2,3,4,5,6 | +-------------+ ``` The reason is the weight between nodes 2 and 6 is `10` in `oq_graph2`, so the shortest path taking into account `weight` is now across more nodes. Possible Destinations --------------------- ``` SELECT GROUP_CONCAT(linkid) AS dests FROM oq_graph WHERE latch='dijkstras' AND origid=2; +-----------+ | dests | +-----------+ | 5,4,6,3,2 | +-----------+ ``` Note that this returns all possible destinations along the path, not just immediate links. Leaf Nodes ---------- **MariaDB [10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)**Support for the `leaves` latch value was introduced in [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/). A `latch` value of `'leaves'` and either `origid` or `destid` is used for finding leaf nodes at the beginning or end of a graph. ``` INSERT INTO oq_backing(origid, destid) VALUES (1,2), (2,3), (3,5), (4,5), (5,6), (6,7), (6,8), (2,8); ``` For example, to find all reachable nodes from `origid` that only have incoming edges: ``` SELECT * FROM oq_graph WHERE latch='leaves' AND origid=2; +--------+--------+--------+--------+------+--------+ | latch | origid | destid | weight | seq | linkid | +--------+--------+--------+--------+------+--------+ | leaves | 2 | NULL | 4 | 2 | 7 | | leaves | 2 | NULL | 1 | 1 | 8 | +--------+--------+--------+--------+------+--------+ ``` And to find all nodes from which a path can be found to `destid` that only have outgoing edges: ``` SELECT * FROM oq_graph WHERE latch='leaves' AND destid=5; +--------+--------+--------+--------+------+--------+ | latch | origid | destid | weight | seq | linkid | +--------+--------+--------+--------+------+--------+ | leaves | NULL | 5 | 3 | 2 | 1 | | leaves | NULL | 5 | 1 | 1 | 4 | +--------+--------+--------+--------+------+--------+ ``` Summary of Implemented Latch Commands ------------------------------------- | Latch | Alternative | additional where clause fields | Graph operation | | --- | --- | --- | --- | | NULL | (unspecified) | (none) | List original data | | (empty string) | 0 | (none extra) | List all vertices in linkid column | | (empty string) | 0 | origid | List all first hop vertices from origid in linkid column | | dijkstras | 1 | origid, destid | Find shortest path using Dijkstras algorithm between origid and destid, with traversed vertex ids in linkid column | | dijkstras | 1 | origid | Find all vertices reachable from origid, listed in linkid column, and report sum of weights of vertices on path to given vertex in weight | | dijkstras | 1 | destid | Find all vertices from which a path can be found to destid, listed in linkid column, and report sum of weights of vertices on path to given vertex in weight | | breadth\_first | 2 | origid | List vertices reachable from origid in linkid column | | breadth\_first | 2 | destid | List vertices from which a path can be found to destid in linkid column | | breadth\_first | 2 | origid, destid | Find shortest path between origid and destid, report in linkid column | | leaves | 4 | origid | List vertices reachable from origid, that only have incoming edges (from [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)) | | leaves | 4 | destid | List vertices from which a path can be found to destid, that only have outgoing edges (from [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)) | | leaves | 4 | origid, destid | Not supported, will return an empty result | --- Note: the use of integer latch commands is deprecated and may be phased out in a future release. Currently, numeric values in the strings are interpreted as aliases, and use of an integer column can be optionally allowed, for the latch commands column. The use of integer latches is controlled using the [oqgraph\_allow\_create\_integer\_latch](../oqgraph-system-and-status-variables/index#oqgraph_allow_create_integer_latch) system variable. See Also -------- * [OQGRAPH Overview](../oqgraph-overview/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Can't create a table starting with a capital letter. All tables are lower case- Can't create a table starting with a capital letter. All tables are lower case- =============================================================================== Hi, I was playing around with my MariaDB ColumnStore and I noticed the I am not able to create tables/databases with capital letters, it seems that only lowercase can be used: CREATE TABLE TEST ( Codice\_Regione INT (11), Codice\_Citta\_Metropolitana VARCHAR (50), Codice\_Provincia INT (11), Progressivo\_del\_Comune INT (11), Codice\_Comune\_formato\_alfanumerico VARCHAR (25), Denominazione\_corrente VARCHAR (100), Denominazione\_altra\_lingua VARCHAR (300), Codice\_Ripartizione\_Geografica INT (11), Ripartizione\_geografica VARCHAR (25), Denominazione\_regione VARCHAR (125), Denominazione\_Citta\_metropolitana VARCHAR (25), Denominazione\_provincia VARCHAR (125), Flag\_Comune\_capoluogo\_di\_provincia VARCHAR (25), Sigla\_automobilistica VARCHAR (2), Codice\_Comune\_formato\_numerico INT (11), Codice\_Comune\_numerico\_con\_110\_province\_dal\_2010al\_2016 INT (11), Codice\_Comune\_numerico\_con\_107\_province\_dal\_2006al\_2009 INT (11), Codice\_Comune\_numerico\_con\_103\_province\_dal\_1995al\_2005 INT (11), Codice\_Catastale\_del\_comune VARCHAR (25), Popolazione\_legale\_2011\_09102011 BIGINT, Codice\_NUTS12010 VARCHAR (25), Codice\_NUTS22010 VARCHAR (25), Codice\_NUTS32010 VARCHAR (25), Codice\_NUTS12006 VARCHAR (25), Codice\_NUTS22006 VARCHAR (25), Codice\_NUTS32006 VARCHAR (25) ) My CS Version is 1.1.2 install/10.2.10-MariaDB-log and my standard mariadb is 10.2.12-MariaDB Is this by design? Thanks for the info. Luca Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema memory_summary_by_host_by_event_name Table Performance Schema memory\_summary\_by\_host\_by\_event\_name Table =================================================================== **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**The memory\_summary\_by\_host\_by\_event\_name table was introduced in [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). There are five memory summary tables in the Performance Schema that share a number of fields in common. These include: * [memory\_summary\_by\_account\_by\_event\_name](../performance-schema-memory_summary_by_account_by_event_name-table/index) * memory\_summary\_by\_host\_by\_event\_name * [memory\_summary\_by\_thread\_by\_event\_name](../performance-schema-memory_summary_by_thread_by_event_name-table/index) * [memory\_summary\_by\_user\_by\_event\_name](../performance-schema-memory_summary_by_user_by_event_name-table/index) * [memory\_global\_by\_event\_name](../performance-schema-memory_global_by_event_name-table/index) The `memory_summary_by_host_by_event_name` table contains memory usage statistics aggregated by host and event. The table contains the following columns: | Field | Type | Null | Default | Description | | --- | --- | --- | --- | --- | | HOST | char(60) | YES | NULL | Host portion of the account. | | EVENT\_NAME | varchar(128) | NO | NULL | Event name. | | COUNT\_ALLOC | bigint(20) unsigned | NO | NULL | Total number of allocations to memory. | | COUNT\_FREE | bigint(20) unsigned | NO | NULL | Total number of attempts to free the allocated memory. | | SUM\_NUMBER\_OF\_BYTES\_ALLOC | bigint(20) unsigned | NO | NULL | Total number of bytes allocated. | | SUM\_NUMBER\_OF\_BYTES\_FREE | bigint(20) unsigned | NO | NULL | Total number of bytes freed | | LOW\_COUNT\_USED | bigint(20) | NO | NULL | Lowest number of allocated blocks (lowest value of CURRENT\_COUNT\_USED). | | CURRENT\_COUNT\_USED | bigint(20) | NO | NULL | Currently allocated blocks that have not been freed (COUNT\_ALLOC minus COUNT\_FREE). | | HIGH\_COUNT\_USED | bigint(20) | NO | NULL | Highest number of allocated blocks (highest value of CURRENT\_COUNT\_USED). | | LOW\_NUMBER\_OF\_BYTES\_USED | bigint(20) | NO | NULL | Lowest number of bytes used. | | CURRENT\_NUMBER\_OF\_BYTES\_USED | bigint(20) | NO | NULL | Current number of bytes used (total allocated minus total freed). | | HIGH\_NUMBER\_OF\_BYTES\_USED | bigint(20) | NO | NULL | Highest number of bytes used. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema SPIDER_ALLOC_MEM Table Information Schema SPIDER\_ALLOC\_MEM Table =========================================== The [Information Schema](../information_schema/index) `SPIDER_ALLOC_MEM` table is installed along with the [Spider](../spider/index) storage engine. It shows information about Spider's memory usage. It contains the following columns: | Column | Description | | --- | --- | | `ID` | | | `FUNC_NAME` | | | `FILE_NAME` | | | `LINE_NO` | | | `TOTAL_ALLOC_MEM` | | | `CURRENT_ALLOC_MEM` | | | `ALLOC_MEM_COUNT` | | | `FREE_MEM_COUNT` | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Stored Procedure Overview Stored Procedure Overview ========================= A Stored Procedure is a routine invoked with a [CALL](../call/index) statement. It may have input parameters, output parameters and parameters that are both input parameters and output parameters. Creating a Stored Procedure --------------------------- Here's a skeleton example to see a stored procedure in action: ``` DELIMITER // CREATE PROCEDURE Reset_animal_count() MODIFIES SQL DATA UPDATE animal_count SET animals = 0; // DELIMITER ; ``` First, the delimiter is changed, since the function definition will contain the regular semicolon delimiter. The procedure is named `Reset_animal_count`. `MODIFIES SQL DATA` indicates that the procedure will perform a write action of sorts, and modify data. It's for advisory purposes only. Finally, there's the actual SQL statement - an UPDATE. ``` SELECT * FROM animal_count; +---------+ | animals | +---------+ | 101 | +---------+ CALL Reset_animal_count(); SELECT * FROM animal_count; +---------+ | animals | +---------+ | 0 | +---------+ ``` A more complex example, with input parameters, from an actual procedure used by banks: ``` CREATE PROCEDURE Withdraw /* Routine name */ (parameter_amount DECIMAL(6,2), /* Parameter list */ parameter_teller_id INTEGER, parameter_customer_id INTEGER) MODIFIES SQL DATA /* Data access clause */ BEGIN /* Routine body */ UPDATE Customers SET balance = balance - parameter_amount WHERE customer_id = parameter_customer_id; UPDATE Tellers SET cash_on_hand = cash_on_hand + parameter_amount WHERE teller_id = parameter_teller_id; INSERT INTO Transactions VALUES ( parameter_customer_id, parameter_teller_id, parameter_amount); END; ``` See [CREATE PROCEDURE](../create-procedure/index) for full syntax details. Why use Stored Procedures? -------------------------- Security is a key reason. Banks commonly use stored procedures so that applications and users don't have direct access to the tables. Stored procedures are also useful in an environment where multiple languages and clients are all used to perform the same operations. Stored Procedure listings and definitions ----------------------------------------- To find which stored functions are running on the server, use [SHOW PROCEDURE STATUS](../show-procedure-status/index). ``` SHOW PROCEDURE STATUS\G *************************** 1. row *************************** Db: test Name: Reset_animal_count Type: PROCEDURE Definer: root@localhost Modified: 2013-06-03 08:55:03 Created: 2013-06-03 08:55:03 Security_type: DEFINER Comment: character_set_client: utf8 collation_connection: utf8_general_ci Database Collation: latin1_swedish_ci ``` or query the [routines table](../information-schema-routines-table/index) in the INFORMATION\_SCHEMA database directly: ``` SELECT ROUTINE_NAME FROM INFORMATION_SCHEMA.ROUTINES WHERE ROUTINE_TYPE='PROCEDURE'; +--------------------+ | ROUTINE_NAME | +--------------------+ | Reset_animal_count | +--------------------+ ``` To find out what the stored procedure does, use [SHOW CREATE PROCEDURE](../show-create-procedure/index). ``` SHOW CREATE PROCEDURE Reset_animal_count\G *************************** 1. row *************************** Procedure: Reset_animal_count sql_mode: Create Procedure: CREATE DEFINER=`root`@`localhost` PROCEDURE `Reset_animal_count`() MODIFIES SQL DATA UPDATE animal_count SET animals = 0 character_set_client: utf8 collation_connection: utf8_general_ci Database Collation: latin1_swedish_ci ``` Dropping and Updating a Stored Procedure ---------------------------------------- To drop a stored procedure, use the [DROP PROCEDURE](../drop-procedure/index) statement. ``` DROP PROCEDURE Reset_animal_count(); ``` To change the characteristics of a stored procedure, use [ALTER PROCEDURE](../alter-procedure/index). However, you cannot change the parameters or body of a stored procedure using this statement; to make such changes, you must drop and re-create the procedure using [CREATE OR REPLACE PROCEDURE](../create-procedure/index#or-replace) (which retains existing privileges), or DROP PROCEDURE followed CREATE PROCEDURE . Permissions in Stored Procedures -------------------------------- See the article [Stored Routine Privileges](../stored-routine-privileges/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DROP TABLE DROP TABLE ========== Syntax ------ ``` DROP [TEMPORARY] TABLE [IF EXISTS] [/*COMMENT TO SAVE*/] tbl_name [, tbl_name] ... [WAIT n|NOWAIT] [RESTRICT | CASCADE] ``` Description ----------- `DROP TABLE` removes one or more tables. You must have the `DROP` privilege for each table. All table data and the table definition are removed, as well as [triggers](../triggers/index) associated to the table, so be careful with this statement! If any of the tables named in the argument list do not exist, MariaDB returns an error indicating by name which non-existing tables it was unable to drop, but it also drops all of the tables in the list that do exist. **Important**: When a table is dropped, user privileges on the table are not automatically dropped. See [GRANT](../grant/index). If another thread is using the table in an explicit transaction or an autocommit transaction, then the thread acquires a [metadata lock (MDL)](../metadata-locking/index) on the table. The `DROP TABLE` statement will wait in the "Waiting for table metadata lock" [thread state](../thread-states/index) until the MDL is released. MDLs are released in the following cases: * If an MDL is acquired in an explicit transaction, then the MDL will be released when the transaction ends. * If an MDL is acquired in an autocommit transaction, then the MDL will be released when the statement ends. * Transactional and non-transactional tables are handled the same. Note that for a partitioned table, `DROP TABLE` permanently removes the table definition, all of its partitions, and all of the data which was stored in those partitions. It also removes the partitioning definition (.par) file associated with the dropped table. For each referenced table, `DROP TABLE` drops a temporary table with that name, if it exists. If it does not exist, and the `TEMPORARY` keyword is not used, it drops a non-temporary table with the same name, if it exists. The `TEMPORARY` keyword ensures that a non-temporary table will not accidentally be dropped. Use `IF EXISTS` to prevent an error from occurring for tables that do not exist. A `NOTE` is generated for each non-existent table when using `IF EXISTS`. See [SHOW WARNINGS](../show-warnings/index). If a [foreign key](../foreign-keys/index) references this table, the table cannot be dropped. In this case, it is necessary to drop the foreign key first. `RESTRICT` and `CASCADE` are allowed to make porting from other database systems easier. In MariaDB, they do nothing. The comment before the table names (`/*COMMENT TO SAVE*/`) is stored in the [binary log](../binary-log/index). That feature can be used by replication tools to send their internal messages. It is possible to specify table names as `db_name`.`tab_name`. This is useful to delete tables from multiple databases with one statement. See [Identifier Qualifiers](../identifier-qualifiers/index) for details. The [DROP privilege](../grant/index#table-privileges) is required to use `DROP TABLE` on non-temporary tables. For temporary tables, no privilege is required, because such tables are only visible for the current session. **Note:** `DROP TABLE` automatically commits the current active transaction, unless you use the `TEMPORARY` keyword. **MariaDB starting with [10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/)**From [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/), `DROP TABLE` reliably deletes table remnants inside a storage engine even if the `.frm` file is missing. Before then, a missing `.frm` file would result in the statement failing. **MariaDB starting with [10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/)**### WAIT/NOWAIT Set the lock wait timeout. See [WAIT and NOWAIT](../wait-and-nowait/index). DROP TABLE in replication ------------------------- `DROP TABLE` has the following characteristics in [replication](../replication/index): * `DROP TABLE IF EXISTS` are always logged. * `DROP TABLE` without `IF EXISTS` for tables that don't exist are not written to the [binary log](../binary-log/index). * Dropping of `TEMPORARY` tables are prefixed in the log with `TEMPORARY`. These drops are only logged when running [statement](../binary-log-formats/index#statement-based) or [mixed mode](../binary-log-formats/index#mixed) replication. * One `DROP TABLE` statement can be logged with up to 3 different `DROP` statements: + `DROP TEMPORARY TABLE list_of_non_transactional_temporary_tables` + `DROP TEMPORARY TABLE list_of_transactional_temporary_tables` + `DROP TABLE list_of_normal_tables` `DROP TABLE` on the primary is treated on the replica as `DROP TABLE IF EXISTS`. You can change that by setting [slave-ddl-exec-mode](../replication-and-binary-log-server-system-variables/index#slave_ddl_exec_mode) to `STRICT`. Dropping an Internal #sql-... Table ----------------------------------- From [MariaDB 10.6](../what-is-mariadb-106/index), [DROP TABLE is atomic](#atomic-drop-table) and the following does not apply. Until [MariaDB 10.5](../what-is-mariadb-105/index), if the [mariadbd/mysqld process](../mysqld-options/index) is killed during an [ALTER TABLE](../alter-table/index) you may find a table named #sql-... in your data directory. In [MariaDB 10.3](../what-is-mariadb-103/index), InnoDB tables with this prefix will be deleted automatically during startup. From [MariaDB 10.4](../what-is-mariadb-104/index), these temporary tables will always be deleted automatically. If you want to delete one of these tables explicitly you can do so by using the following syntax: ``` DROP TABLE `#mysql50##sql-...`; ``` When running an `ALTER TABLE…ALGORITHM=INPLACE` that rebuilds the table, InnoDB will create an internal `#sql-ib` table. Until [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/), for these tables, the `.frm` file will be called something else. In order to drop such a table after a server crash, you must rename the `#sql*.frm` file to match the `#sql-ib*.ibd` file. From [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/), the same name as the .frm file is used for the intermediate copy of the table. The #sql-ib names are used by TRUNCATE and delayed DROP. From [MariaDB 10.2.19](https://mariadb.com/kb/en/mariadb-10219-release-notes/) and [MariaDB 10.3.10](https://mariadb.com/kb/en/mariadb-10310-release-notes/), the #sql-ib tables will be deleted automatically. Dropping All Tables in a Database --------------------------------- The best way to drop all tables in a database is by executing [DROP DATABASE](../drop-database/index), which will drop the database itself, and all tables in it. However, if you want to drop all tables in the database, but you also want to keep the database itself and any other non-table objects in it, then you would need to execute `DROP TABLE` to drop each individual table. You can construct these `DROP TABLE` commands by querying the [TABLES](../information-schema-tables-table/index) table in the [information\_schema](../information-schema-tables/index) database. For example: ``` SELECT CONCAT('DROP TABLE IF EXISTS `', TABLE_SCHEMA, '`.`', TABLE_NAME, '`;') FROM information_schema.TABLES WHERE TABLE_SCHEMA = 'mydb'; ``` Atomic DROP TABLE ----------------- **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**From [MariaDB 10.6](../what-is-mariadb-106/index), `DROP TABLE` for a single table is atomic ([MDEV-25180](https://jira.mariadb.org/browse/MDEV-25180)) for most engines, including InnoDB, MyRocks, MyISAM and Aria. This means that if there is a crash (server down or power outage) during `DROP TABLE`, all tables that have been processed so far will be completely dropped, including related trigger files and status entries, and the [binary log](../binary-log/index) will include a `DROP TABLE` statement for the dropped tables. Tables for which the drop had not started will be left intact. In older MariaDB versions, there was a small chance that, during a server crash happening in the middle of `DROP TABLE`, some storage engines that were using multiple storage files, like [MyISAM](../myisam-storage-engine/index), could have only a part of its internal files dropped. In [MariaDB 10.5](../what-is-mariadb-105/index), `DROP TABLE` was extended to be able to delete a table that was only partly dropped ([MDEV-11412](https://jira.mariadb.org/browse/MDEV-11412)) as explained above. Atomic `DROP TABLE` is the final piece to make `DROP TABLE` fully reliable. Dropping multiple tables is crash-safe. See [Atomic DDL](../atomic-ddl/index) for more information. Examples -------- ``` DROP TABLE Employees, Customers; ``` Notes ----- Beware that `DROP TABLE` can drop both tables and [sequences](../create-sequence/index). This is mainly done to allow old tools like [mysqldump](../mysqldump/index) to work with sequences. See Also -------- * [CREATE TABLE](../create-table/index) * [ALTER TABLE](../alter-table/index) * [SHOW CREATE TABLE](../show-create-table/index) * [DROP SEQUENCE](../drop-sequence/index) * Variable [slave-ddl-exec-mode](../replication-and-binary-log-server-system-variables/index#slave_ddl_exec_mode). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Thread Pool in MariaDB 5.1 - 5.3 Thread Pool in MariaDB 5.1 - 5.3 ================================ This article describes the old thread pool in [MariaDB 5.1](../what-is-mariadb-51/index) - 5.3. [MariaDB 5.5](../what-is-mariadb-55/index) and later use an improved thread pool - see [Thread pool in MariaDB](../thread-pool-in-mariadb/index). About pool of threads --------------------- This is an extended version of the pool-of-threads code from MySQL 6.0. This allows you to use a limited set of threads to handle all queries, instead of the old 'one-thread-per-connection' style. In recent times, its also been referred to as "thread pool" or "thread pooling" as this feature (in a different implementation) is available in Enterprise editions of MySQL (not in the Community edition). This can be a very big win if most of your queries are short running queries and there are few table/row locks in your system. Instructions ------------ To enable pool-of-threads you must first run configure with the `--with-libevent` option. (This is automatically done if you use any 'max' scripts in the BUILD directory): ``` ./configure --with-libevent ``` When starting mysqld with the pool of threads code you should use ``` mysqld --thread-handling=pool-of-threads --thread-pool-size=20 ``` Default values are: ``` thread-handling= one-thread-per-connection thread-pool-size= 20 ``` One issue with pool-of-threads is that if all worker threads are doing work (like running long queries) or are locked by a row/table lock no new connections can be established and you can't login and find out what's wrong or login and kill queries. To help this, we have introduced two new options for mysqld; [extra\_port](../thread-pool-system-and-status-variables/index#extra_port) and [extra\_max\_connections](../thread-pool-system-and-status-variables/index#extra_max_connections): ``` --extra-port=# (Default 0) --extra-max-connections=# (Default 1) ``` If [extra-port](../thread-pool-system-and-status-variables/index#extra_port) is <> 0 then you can connect max\_connections number of normal threads + 1 extra SUPER user through the 'extra-port' TCP/IP port. These connections use the old one-thread-per-connection method. To connect with through the extra port, use: ``` mysql --port='number-of-extra-port' --protocol=tcp ``` This allows you to freely use, on connection bases, the optimal connection/thread model. See also -------- * [Thread-handling and thread-pool-size variables](../thread-pool-system-and-status-variables/index) * [How MySQL Uses Threads for Client Connections](http://dev.mysql.com/doc/refman/5.6/en/connection-threads.html) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Query Response Time Plugin Query Response Time Plugin ========================== The `query_response_time` plugin creates the [QUERY\_RESPONSE\_TIME](../information-schema-query_response_time-table/index) table in the [INFORMATION\_SCHEMA](../information-schema/index) database. The plugin also adds the [SHOW QUERY\_RESPONSE\_TIME](../show-query_response_time/index) and [FLUSH QUERY\_RESPONSE\_TIME](../flush/index) statements. The [slow query log](../slow-query-log/index) provides exact information about queries that take a long time to execute. However, sometimes there are a large number of queries that each take a very short amount of time to execute. This feature provides a tool for analyzing that information by counting and displaying the number of queries according to the the length of time they took to execute. This feature is based on Percona's [Response Time Distribution](http://www.percona.com/doc/percona-server/5.5/diagnostics/response_time_distribution.html). Installing the Plugin --------------------- This shared library actually consists of two different plugins: * `QUERY_RESPONSE_TIME` - An INFORMATION\_SCHEMA plugin that exposes statistics. * `QUERY_RESPONSE_TIME_AUDIT` - audit plugin, collects statistics. Both plugins need to be installed to get meaningful statistics. Although the plugin's shared library is distributed with MariaDB by default, the plugin is not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB. The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing [INSTALL SONAME](../install-soname/index) or [INSTALL PLUGIN](../install-plugin/index). For example: ``` INSTALL SONAME 'query_response_time'; ``` The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the [--plugin-load](../mysqld-options/index#-plugin-load) or the [--plugin-load-add](../mysqld-options/index#-plugin-load-add) options. This can be specified as a command-line argument to [mysqld](../mysqld-options/index) or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... plugin_load_add = query_response_time ``` Uninstalling the Plugin ----------------------- You can uninstall the plugin dynamically by executing [UNINSTALL SONAME](../uninstall-soname/index) or [UNINSTALL PLUGIN](../uninstall-plugin/index). For example: ``` UNINSTALL SONAME 'query_response_time'; ``` If you installed the plugin by providing the [--plugin-load](../mysqld-options/index#-plugin-load) or the [--plugin-load-add](../mysqld-options/index#-plugin-load-add) options in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), then those options should be removed to prevent the plugin from being loaded the next time the server is restarted. Response Time Distribution -------------------------- The user can define time intervals that divide the range 0 to positive infinity into smaller intervals and then collect the number of commands whose execution times fall into each of those intervals. Each interval is described as: ``` (range_base ^ n; range_base ^ (n+1)] ``` The range\_base is some positive number (see Limitations). The interval is defined as the difference between two nearby powers of the range base. For example, if the range base=10, we have the following intervals: ``` (0; 10 ^ -6], (10 ^ -6; 10 ^ -5], (10 ^ -5; 10 ^ -4], ..., (10 ^ -1; 10 ^1], (10^1; 10^2]...(10^7; positive infinity] ``` or ``` (0; 0.000001], (0.000001; 0.000010], (0.000010; 0.000100], ..., (0.100000; 1.0]; (1.0; 10.0]...(1000000; positive infinity] ``` For each interval, a count is made of the queries with execution times that fell into that interval. You can select the range of the intervals by changing the range base. For example, for base range=2 we have the following intervals: ``` (0; 2 ^ -19], (2 ^ -19; 2 ^ -18], (2 ^ -18; 2 ^ -17], ..., (2 ^ -1; 2 ^1], (2 ^ 1; 2 ^ 2]...(2 ^ 25; positive infinity] ``` or ``` (0; 0.000001], (0.000001, 0.000003], ..., (0.25; 0.5], (0.5; 2], (2; 4]...(8388608; positive infinity] ``` Small numbers look strange (i.e., don’t look like powers of 2), because we lose precision on division when the ranges are calculated at runtime. In the resulting table, you look at the high boundary of the range. For example, you may see: ``` SELECT * FROM INFORMATION_SCHEMA.QUERY_RESPONSE_TIME; +----------------+-------+----------------+ | TIME | COUNT | TOTAL | +----------------+-------+----------------+ | 0.000001 | 0 | 0.000000 | | 0.000010 | 17 | 0.000094 | | 0.000100 | 4301 0.236555 | | 0.001000 | 1499 | 0.824450 | | 0.010000 | 14851 | 81.680502 | | 0.100000 | 8066 | 443.635693 | | 1.000000 | 0 | 0.000000 | | 10.000000 | 0 | 0.000000 | | 100.000000 | 1 | 55.937094 | | 1000.000000 | 0 | 0.000000 | | 10000.000000 | 0 | 0.000000 | | 100000.000000 | 0 | 0.000000 | | 1000000.000000 | 0 | 0.000000 | | TOO LONG | 0 | TOO LONG | +----------------+-------+----------------+ ``` This means there were: ``` * 17 queries with 0.000001 < query execution time < = 0.000010 seconds; total execution time of the 17 queries = 0.000094 seconds * 4301 queries with 0.000010 < query execution time < = 0.000100 seconds; total execution time of the 4301 queries = 0.236555 seconds * 1499 queries with 0.000100 < query execution time < = 0.001000 seconds; total execution time of the 1499 queries = 0.824450 seconds * 14851 queries with 0.001000 < query execution time < = 0.010000 seconds; total execution time of the 14851 queries = 81.680502 seconds * 8066 queries with 0.010000 < query execution time < = 0.100000 seconds; total execution time of the 8066 queries = 443.635693 seconds * 1 query with 10.000000 < query execution time < = 100.0000 seconds; total execution time of the 1 query = 55.937094 seconds ``` Using the Plugin ---------------- ### Using the Information Schema Table You can get the distribution by querying the the [QUERY\_RESPONSE\_TIME](../information-schema-query_response_time-table/index) table in the [INFORMATION\_SCHEMA](../information-schema/index) database. For example: ``` SELECT * FROM INFORMATION_SCHEMA.QUERY_RESPONSE_TIME; ``` You can also write more complex queries. For example: ``` SELECT c.count, c.time, (SELECT SUM(a.count) FROM INFORMATION_SCHEMA.QUERY_RESPONSE_TIME as a WHERE a.count != 0) as query_count, (SELECT COUNT(*) FROM INFORMATION_SCHEMA.QUERY_RESPONSE_TIME as b WHERE b.count != 0) as not_zero_region_count, (SELECT COUNT(*) FROM INFORMATION_SCHEMA.QUERY_RESPONSE_TIME) as region_count FROM INFORMATION_SCHEMA.QUERY_RESPONSE_TIME as c WHERE c.count > 0; ``` Note: If [query\_response\_time\_stats](#query_response_time_stats) is set to `ON`, then the execution times for these two SELECT queries will also be collected. ### Using the SHOW Statement As an alternative to the [QUERY\_RESPONSE\_TIME](../information-schema-query_response_time-table/index) table in the [INFORMATION\_SCHEMA](../information-schema/index) database, you can also use the [SHOW QUERY\_RESPONSE\_TIME](../show-query_response_time/index) statement. For example: ``` SHOW QUERY_RESPONSE_TIME; ``` ### Flushing Plugin Data Flushing the plugin data does two things: * Clears the collected times from the [QUERY\_RESPONSE\_TIME](../information-schema-query_response_time-table/index) table in the [INFORMATION\_SCHEMA](../information-schema/index) database. * Reads the value of [query\_response\_time\_range\_base](#query_response_time_range_base) and uses it to set the range base for the table. Plugin data can be flushed with the [FLUSH QUERY\_RESPONSE\_TIME](../flush/index) statement. For example: ``` FLUSH QUERY_RESPONSE_TIME; ``` Setting the [query\_response\_time\_flush](#query_response_time_flush) system variable has the same effect. For example: ``` SET GLOBAL query_response_time_flush=1; ``` Versions -------- | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Stable | [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/) | | 1.0 | Gamma | [MariaDB 10.0.10](https://mariadb.com/kb/en/mariadb-10010-release-notes/) | | 1.0 | Alpha | [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) | System Variables ---------------- ### `query_response_time_flush` * **Description:** Updating this variable flushes the statistics and re-reads [query\_response\_time\_range\_base](#query_response_time_range_base). * **Commandline:** None * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- ### `query_response_time_range_base` * **Description:** Select base of log for `QUERY_RESPONSE_TIME` ranges. WARNING: variable change takes affect only after flush. * **Commandline:** `--query-response-time-range-base=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `10` * **Range:** `2` to `1000` --- ### `query_response_time_exec_time_debug` * **Description:** Pretend queries take this many microseconds. When 0 (the default) use the actual execution time. + This system variable is only available when the plugin is a [debug build](../compiling-mariadb-for-debugging/index). * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `31536000` --- ### `query_response_time_stats` * **Description:** Enable or disable query response time statistics collecting * **Commandline:** `query-response-time-stats[={0|1}]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- Options ------- ### `query_response_time` * **Description:** Controls how the server should treat the plugin when the server starts up. + Valid values are: - `OFF` - Disables the plugin without removing it from the [mysql.plugins](../mysqlplugin-table/index) table. - `ON` - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled. - `FORCE` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. - `FORCE_PLUS_PERMANENT` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with [UNINSTALL SONAME](../uninstall-soname/index) or [UNINSTALL PLUGIN](../uninstall-plugin/index) while the server is running. + See [Plugin Overview: Configuring Plugin Activation at Server Startup](../plugin-overview/index#configuring-plugin-activation-at-server-startup) for more information. * **Commandline:** `--query-response-time=value` * **Data Type:** `enumerated` * **Default Value:** `ON` * **Valid Values:** `OFF`, `ON`, `FORCE`, `FORCE_PLUS_PERMANENT` --- ### `query_response_time_audit` * **Description:** Controls how the server should treat the plugin when the server starts up. + Valid values are: - `OFF` - Disables the plugin without removing it from the [mysql.plugins](../mysqlplugin-table/index) table. - `ON` - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled. - `FORCE` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. - `FORCE_PLUS_PERMANENT` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with [UNINSTALL SONAME](../uninstall-soname/index) or [UNINSTALL PLUGIN](../uninstall-plugin/index) while the server is running. + See [Plugin Overview: Configuring Plugin Activation at Server Startup](../plugin-overview/index#configuring-plugin-activation-at-server-startup) for more information. * **Commandline:** `--query-response-time-audit=value` * **Data Type:** `enumerated` * **Default Value:** `ON` * **Valid Values:** `OFF`, `ON`, `FORCE`, `FORCE_PLUS_PERMANENT` --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Restoring Data from Dump Files Restoring Data from Dump Files ============================== If you lose your data in MariaDB, but have been using [mysqldump](../mysqldump/index) to make regular backups of your data in MariaDB, you can use the dump files to restore your data. This is the point of the back-ups, after all. To restore a dump file, it's just a matter of having the mysql client execute all of the SQL statements that the file contains. There are some things to consider before restoring from a dump file, so read this section all of the way through before restoring. One simple and perhaps clumsy method to restore from a dump file is to enter something like the following: ``` mysql --user admin_restore --password < /data/backup/db1.sql ``` Again, this is not using [mysqldump](../mysqldump/index). The [mysqldump](../mysqldump/index) utility is only for making back-up copies, not restoring databases. Instead, you would use the mysql client, which will read the dump file's content in order to batch execute the SQL statements that it contains. Notice that the redirect for `STDOUT` is not used here, but the redirect for the standard input (`STDIN`); the less-than sign is used since the dump file is an input source. Also, notice that in this example a database isn't specified. That's given within the dump file. You may want to stop MariaDB before doing a restore, and then start it again when done. #### Restoring One Table The problem with restoring from a dump file is that you may overwrite tables or databases that you wish you hadn't. For instance, your dump file might be a few days old and only one table may have been lost. If you restore all of the databases or all of the tables in a database, you would be restoring the data back to it's state at the time of the backup, a few days before. This could be quite a disaster. This is why dumping by database and table can be handy. However, that could be cumbersome. A simple and easy method of limiting a restoration would be to create temporarily a user who only has privileges for the table you want to restore. You would enter a [GRANT](../grant/index) statement like this: ``` GRANT SELECT ON db1.* TO 'admin_restore_temp'@'localhost' IDENTIFIED BY 'its_pwd'; GRANT ALL ON db1.table1 TO 'admin_restore_temp'@'localhost'; ``` These two SQL statements allow the temporary user to have the needed [SELECT](../select/index) privileges on all of the tables of `db1` and `ALL` privileges for the `table1` table. Now when you restore the dump file containing the whole `db1` database, only `table1` will be replaced with the back-up copy. Of course, MariaDB will generate errors. To overlook the errors and to proceed with the restoration of data where no errors are generated (i.e., `table1`), use the `--force` option. Here's what you would enter at the command-line for this situation: ``` mysql --user admin_restore_temp --password --force < /data/backup/db1.sql ``` Other References ---------------- * [How to Restore a Database with Command Line or Restore Tools](https://blog.devart.com/how-to-restore-mysql-database-from-backup.html) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ORDER BY ORDER BY ======== Description ----------- Use the `ORDER BY` clause to order a resultset, such as that are returned from a [SELECT](../select/index) statement. You can specify just a column or use any expression with functions. If you are using the `GROUP BY` clause, you can use grouping functions in `ORDER BY`. Ordering is done after grouping. You can use multiple ordering expressions, separated by commas. Rows will be sorted by the first expression, then by the second expression if they have the same value for the first, and so on. You can use the keywords `ASC` and `DESC` after each ordering expression to force that ordering to be ascending or descending, respectively. Ordering is ascending by default. You can also use a single integer as the ordering expression. If you use an integer *n*, the results will be ordered by the *n*th column in the select expression. When string values are compared, they are compared as if by the [STRCMP](../strcmp/index) function. `STRCMP` ignores trailing whitespace and may normalize characters and ignore case, depending on the [collation](../data-types-character-sets-and-collations/index) in use. Duplicated entries in the `ORDER BY` clause are removed. `ORDER BY` can also be used to order the activities of a [DELETE](../delete/index) or [UPDATE](../update/index) statement (usually with the [LIMIT](../limit/index) clause). **MariaDB starting with [10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/)**Until [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), it was not possible to use `ORDER BY` (or [LIMIT](../limit/index)) in a multi-table [UPDATE](../update/index) statement. This restriction was lifted in [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/). **MariaDB starting with [10.5](../what-is-mariadb-105/index)**From [MariaDB 10.5](../what-is-mariadb-105/index), MariaDB allows packed sort keys and values of non-sorted fields in the sort buffer. This can make filesort temporary files much smaller when VARCHAR, CHAR or BLOBs are used, notably speeding up some ORDER BY sorts. Examples -------- ``` CREATE TABLE seq (i INT, x VARCHAR(1)); INSERT INTO seq VALUES (1,'a'), (2,'b'), (3,'b'), (4,'f'), (5,'e'); SELECT * FROM seq ORDER BY i; +------+------+ | i | x | +------+------+ | 1 | a | | 2 | b | | 3 | b | | 4 | f | | 5 | e | +------+------+ SELECT * FROM seq ORDER BY i DESC; +------+------+ | i | x | +------+------+ | 5 | e | | 4 | f | | 3 | b | | 2 | b | | 1 | a | +------+------+ SELECT * FROM seq ORDER BY x,i; +------+------+ | i | x | +------+------+ | 1 | a | | 2 | b | | 3 | b | | 5 | e | | 4 | f | +------+------+ ``` ORDER BY in an [UPDATE](../update/index) statement, in conjunction with [LIMIT](../limit/index): ``` UPDATE seq SET x='z' WHERE x='b' ORDER BY i DESC LIMIT 1; SELECT * FROM seq; +------+------+ | i | x | +------+------+ | 1 | a | | 2 | b | | 3 | z | | 4 | f | | 5 | e | +------+------+ ``` From [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/), `ORDER BY` can be used in a multi-table update: ``` CREATE TABLE warehouse (product_id INT, qty INT); INSERT INTO warehouse VALUES (1,100),(2,100),(3,100),(4,100); CREATE TABLE store (product_id INT, qty INT); INSERT INTO store VALUES (1,5),(2,5),(3,5),(4,5); UPDATE warehouse,store SET warehouse.qty = warehouse.qty-2, store.qty = store.qty+2 WHERE (warehouse.product_id = store.product_id AND store.product_id >= 1) ORDER BY store.product_id DESC LIMIT 2; SELECT * FROM warehouse; +------------+------+ | product_id | qty | +------------+------+ | 1 | 100 | | 2 | 100 | | 3 | 98 | | 4 | 98 | +------------+------+ SELECT * FROM store; +------------+------+ | product_id | qty | +------------+------+ | 1 | 5 | | 2 | 5 | | 3 | 7 | | 4 | 7 | +------------+------+ ``` See Also -------- * [Why is ORDER BY in a FROM subquery ignored?](../why-is-order-by-in-a-from-subquery-ignored/index) * [SELECT](../select/index) * [UPDATE](../update/index) * [DELETE](../delete/index) * [Improvements to ORDER BY Optimization](../improvements-to-order-by/index) * [Joins and Subqueries](../joins-subqueries/index) * [LIMIT](../limit/index) * [GROUP BY](../group-by/index) * [Common Table Expressions](../common-table-expressions/index) * [SELECT WITH ROLLUP](../select-with-rollup/index) * [SELECT INTO OUTFILE](../select-into-outfile/index) * [SELECT INTO DUMPFILE](../select-into-dumpfile/index) * [FOR UPDATE](../for-update/index) * [LOCK IN SHARE MODE](../lock-in-share-mode/index) * [Optimizer Hints](../optimizer-hints/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb FROM_UNIXTIME FROM\_UNIXTIME ============== Syntax ------ ``` FROM_UNIXTIME(unix_timestamp), FROM_UNIXTIME(unix_timestamp,format) ``` Description ----------- Returns a representation of the unix\_timestamp argument as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS.uuuuuu format, depending on whether the function is used in a string or numeric context. The value is expressed in the current [time zone](../time-zones/index). unix\_timestamp is an internal timestamp value such as is produced by the [UNIX\_TIMESTAMP()](../unix_timestamp/index) function. If format is given, the result is formatted according to the format string, which is used the same way as listed in the entry for the [DATE\_FORMAT()](../date_format/index) function. Timestamps in MariaDB have a maximum value of 2147483647, equivalent to 2038-01-19 05:14:07. This is due to the underlying 32-bit limitation. Using the function on a timestamp beyond this will result in NULL being returned. Use [DATETIME](../datetime/index) as a storage type if you require dates beyond this. The options that can be used by FROM\_UNIXTIME(), as well as [DATE\_FORMAT()](../date_format/index) and [STR\_TO\_DATE()](../str_to_date/index), are: | Option | Description | | --- | --- | | `%a` | Short weekday name in current locale (Variable [lc\_time\_names](../server-system-variables/index#lc_time_names)). | | `%b` | Short form month name in current locale. For locale en\_US this is one of: Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov or Dec. | | `%c` | Month with 1 or 2 digits. | | `%D` | Day with English suffix 'th', 'nd', 'st' or 'rd''. (1st, 2nd, 3rd...). | | `%d` | Day with 2 digits. | | `%e` | Day with 1 or 2 digits. | | `%f` | [Microseconds](../microseconds-in-mariadb/index) 6 digits. | | `%H` | Hour with 2 digits between 00-23. | | `%h` | Hour with 2 digits between 01-12. | | `%I` | Hour with 2 digits between 01-12. | | `%i` | Minute with 2 digits. | | `%j` | Day of the year (001-366) | | `%k` | Hour with 1 digits between 0-23. | | `%l` | Hour with 1 digits between 1-12. | | `%M` | Full month name in current locale (Variable [lc\_time\_names](../server-system-variables/index#lc_time_names)). | | `%m` | Month with 2 digits. | | `%p` | AM/PM according to current locale (Variable [lc\_time\_names](../server-system-variables/index#lc_time_names)). | | `%r` | Time in 12 hour format, followed by AM/PM. Short for '%I:%i:%S %p'. | | `%S` | Seconds with 2 digits. | | `%s` | Seconds with 2 digits. | | `%T` | Time in 24 hour format. Short for '%H:%i:%S'. | | `%U` | Week number (00-53), when first day of the week is Sunday. | | `%u` | Week number (00-53), when first day of the week is Monday. | | `%V` | Week number (01-53), when first day of the week is Sunday. Used with %X. | | `%v` | Week number (01-53), when first day of the week is Monday. Used with %x. | | `%W` | Full weekday name in current locale (Variable [lc\_time\_names](../server-system-variables/index#lc_time_names)). | | `%w` | Day of the week. 0 = Sunday, 6 = Saturday. | | `%X` | Year with 4 digits when first day of the week is Sunday. Used with %V. | | `%x` | Year with 4 digits when first day of the week is Sunday. Used with %v. | | `%Y` | Year with 4 digits. | | `%y` | Year with 2 digits. | | `%#` | For [str\_to\_date](../str_to_date/index)(), skip all numbers. | | `%.` | For [str\_to\_date](../str_to_date/index)(), skip all punctation characters. | | `%@` | For [str\_to\_date](../str_to_date/index)(), skip all alpha characters. | | `%%` | A literal `%` character. | Performance Considerations -------------------------- If your [session time zone](../server-system-variables/index#time_zone) is set to `SYSTEM` (the default), `FROM_UNIXTIME()` will call the OS function to convert the data using the system time zone. At least on Linux, the corresponding function (`localtime_r`) uses a global mutex inside glibc that can cause contention under high concurrent load. Set your time zone to a named time zone to avoid this issue. See [mysql time zone tables](../time-zones/index#mysql-time-zone-tables) for details on how to do this. Examples -------- ``` SELECT FROM_UNIXTIME(1196440219); +---------------------------+ | FROM_UNIXTIME(1196440219) | +---------------------------+ | 2007-11-30 11:30:19 | +---------------------------+ SELECT FROM_UNIXTIME(1196440219) + 0; +-------------------------------+ | FROM_UNIXTIME(1196440219) + 0 | +-------------------------------+ | 20071130113019.000000 | +-------------------------------+ SELECT FROM_UNIXTIME(UNIX_TIMESTAMP(), '%Y %D %M %h:%i:%s %x'); +---------------------------------------------------------+ | FROM_UNIXTIME(UNIX_TIMESTAMP(), '%Y %D %M %h:%i:%s %x') | +---------------------------------------------------------+ | 2010 27th March 01:03:47 2010 | +---------------------------------------------------------+ ``` See Also -------- * [UNIX\_TIMESTAMP()](../unix_timestamp/index) * [DATE\_FORMAT()](../date_format/index) * [STR\_TO\_DATE()](../str_to_date/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Get, Build and Test Latest MariaDB the Lazy Way Get, Build and Test Latest MariaDB the Lazy Way =============================================== The intention of this documentation is show all the steps of getting, building and testing the latest MariaDB server (10.5 at time of writing) from GitHub. Each stage links to the full documentation for that step if you need to find out more. [Install all tools needed to build MariaDB](../build_environment_setup_for_linux/index) --------------------------------------------------------------------------------------- ### OpenSuse ``` sudo zypper install git gcc gcc-c++ make bison ncurses ncurses-devel zlib-devel libevent-devel cmake openssl ``` ### Debian ``` apt install -y build-essential bison apt build-dep mariadb-server ``` [Set Up git](../using-git/index) -------------------------------- Fetch and checkout the MariaDB source to a subdirectory of the current directory ``` git clone https://github.com/MariaDB/server.git mariadb cd mariadb git checkout 10.5 ``` [Build It](../generic-build-instructions/index) ----------------------------------------------- The following command builds a server the same way that is used for building releases. Use `cmake . -DCMAKE_BUILD_TYPE=Debug` to build for debugging. ``` cmake . -DBUILD_CONFIG=mysql_release && make -j8 ``` [Check the Server (If You Want To)](%5bmysql-test) -------------------------------------------------- ``` cd mysql-test mtr --parallel=8 --force ``` [Install the Default Databases](../mariadb-install-db/index) ------------------------------------------------------------ ``` ./scripts/mariadb-install-db --srcdir=. ``` (Older MariaDB version use [mysql\_install\_db](../mysql_install_db/index)) Install the Server (If needed) ------------------------------ You can also [run and test mariadb directly from the build directory](../running-mariadb-from-the-build-directory/index), in which case you can skip the rest of the steps below. ``` make install ``` ### [Start the Server](../starting-and-stopping-mariadb-automatically/index) Start the server in it's own terminal window for testing. Note that the directory depends on your system! ``` /usr/sbin/mysqld ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Using InnoDB Instead of XtraDB Using InnoDB Instead of XtraDB ============================== By default [MariaDB 10.1](../what-is-mariadb-101/index) and earlier releases come compiled with [XtraDB](../about-xtradb/index) as the default InnoDB replacement. From [MariaDB 10.2](../what-is-mariadb-102/index), InnoDB is the default. **MariaDB starting with [5.5](../what-is-mariadb-55/index)**Starting from [MariaDB 5.5](../what-is-mariadb-55/index), all standard MariaDB distributions also includes InnoDB as a plugin. To use the InnoDB plugin instead of XtraDB you can add to your [my.cnf](../mysqld-startup-options/index) file: ``` [mysqld] ignore_builtin_innodb plugin_load=ha_innodb.so # The following should not be needed if you are using a mariadb package: plugin_dir=/usr/local/mysql/lib/mysql/plugin ``` **MariaDB until [5.3](../what-is-mariadb-53/index)**For [MariaDB 5.3](../what-is-mariadb-53/index) and below, the name of the library is `ha_innodb_plugin.so` The reasons you may want to use InnoDB instead of XtraDB are: * You want to benchmark the difference between InnoDB/XtraDB * You hit a bug in XtraDB * You got a table space crash in XtraDB and recovery doesn't work. In some cases InnoDB may do a better job to recover data. See Also -------- * [Compiling with the InnoDB plugin from Oracle](../compiling-with-the-innodb-plugin-from-oracle/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Container Cheat Sheet MariaDB Container Cheat Sheet ============================= * Get the images Images can be found on [MariaDB Docker Hub](https://hub.docker.com/_/mariadb). To get the list of images run ``` $ docker images ls ``` * Create the network ``` $ docker network create mynetwork ``` It is good practice to create the Docker network and attach the container to the network. * Start the container with server options To start the container in the background with the MariaDB server image run: ``` $ docker run --rm --detach \ --env MARIADB_ROOT_PASSWORD=sosecret \ --network mynetwork \ --name mariadb-server \ mariadb:latest ``` Additionally [environment variables](https://hub.docker.com/_/mariadb) are also provided. * Get the list of running containers (specify the flag **-a** in case you want to see all containers) ``` $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES ad374ec8a272 mariadb:latest "docker-entrypoint.s…" 3 seconds ago Up 1 second 3306/tcp mariadb-server ``` * Start the client from the container To start the *mariadb* client inside the created container and run specific commands, run the following: ``` $ docker exec -it mariadb-server mariadb -psosecret -e "SHOW PLUGINS" ``` * Inspect logs from the container ``` $ docker logs mariadb-server ``` In the logs you can find status information about the server, plugins, generated passwords, errors and so on. * Restart the container ``` $ docker restart mariadb-server ``` * Run commands within the container ``` $ docker exec -it mariadb-server bash ``` * Use a volume to specify configuration options ``` $ docker run --detach --env MARIADB_USER=anel \ --env MARIADB_PASSWORD=anel \ --env MARIADB_DATABASE=my_db \ --env MARIADB_RANDOM_ROOT_PASSWORD=1 \ --volume $PWD/my_container_config:/etc/mysql/conf.d:z \ --network mynetwork \ --name mariadb-server1 \ mariadb:latest ``` One can specify custom [configuration files](../configuring-mariadb-with-option-files/index) through the **/etc/mysql/conf.d** volume during container startup. * Use a volume to specify grants during container start ``` $ docker run --detach --env MARIADB_USER=anel\ --env MARIADB_PASSWORD=anel \ --env MARIADB_DATABASE=my_db \ --env MARIADB_RANDOM_ROOT_PASSWORD=1 \ --volume $PWD/my_init_db:/docker-entrypoint-initdb.d \ --network mynetwork \ --name mariadb-server1 \ mariadb:latest ``` User created with the environment variables has full grants only to the *MARIADB\_DATABASE*. In order to override those grants, one can specify grants to a user, or execute any SQL statements from host file to **docker-entrypoint-initdb.d**. In the *local\_init\_dir* directory we can find the file, created like this: ``` $ echo "GRANT ALL PRIVILEGES ON *.* TO anel;" > my_init_db/my_grants.sql ``` See Also -------- * [Installing and using MariaDB via Docker](../installing-and-using-mariadb-via-docker/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.global_priv Table mysql.global\_priv Table ======================== **MariaDB starting with [10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/)**The `mysql.global_priv` table was introduced in [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/) to replace the [mysql.user](../mysqluser-table/index) table. The `mysql.global_priv` table contains information about users that have permission to access the MariaDB server, and their global privileges. Note that the MariaDB privileges occur at many levels. A user may not be granted `create` privilege at the user level, but may still have `create` permission on certain tables or databases, for example. See [privileges](../grant/index) for a more complete view of the MariaDB privilege system. The `mysql.global_priv` table contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | `Host` | `char(60)` | NO | PRI | | Host (together with `User` makes up the unique identifier for this account). | | `User` | `char(80)` | NO | PRI | | User (together with `Host` makes up the unique identifier for this account). | | `Priv` | `longtext` | NO | | | Global privileges, granted to the account and other account properties | From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), in order to help the server understand which version a privilege record was written by, the `priv` field contains a new JSON field, `version_id` ([MDEV-21704](https://jira.mariadb.org/browse/MDEV-21704)). Examples -------- ``` select * from mysql.global_priv; +-----------+-------------+---------------------------------------------------------------------------------------------------------------------------------------+ | Host | User | Priv | +-----------+-------------+---------------------------------------------------------------------------------------------------------------------------------------+ | localhost | root | {"access": 18446744073709551615,"plugin":"mysql_native_password","authentication_string":"*6C387FC3893DBA1E3BA155E74754DA6682D04747"} | | 127.% | msandbox | {"access":1073740799,"plugin":"mysql_native_password","authentication_string":"*6C387FC3893DBA1E3BA155E74754DA6682D04747"} | | localhost | msandbox | {"access":1073740799,"plugin":"mysql_native_password","authentication_string":"*6C387FC3893DBA1E3BA155E74754DA6682D04747"} | | localhost | msandbox_rw | {"access":487487,"plugin":"mysql_native_password","authentication_string":"*6C387FC3893DBA1E3BA155E74754DA6682D04747"} | | 127.% | msandbox_rw | {"access":487487,"plugin":"mysql_native_password","authentication_string":"*6C387FC3893DBA1E3BA155E74754DA6682D04747"} | | 127.% | msandbox_ro | {"access":262145,"plugin":"mysql_native_password","authentication_string":"*6C387FC3893DBA1E3BA155E74754DA6682D04747"} | | localhost | msandbox_ro | {"access":262145,"plugin":"mysql_native_password","authentication_string":"*6C387FC3893DBA1E3BA155E74754DA6682D04747"} | | 127.% | rsandbox | {"access":524288,"plugin":"mysql_native_password","authentication_string":"*B07EB15A2E7BD9620DAE47B194D5B9DBA14377AD"} | +-----------+-------------+---------------------------------------------------------------------------------------------------------------------------------------+ ``` Readable format: ``` SELECT CONCAT(user, '@', host, ' => ', JSON_DETAILED(priv)) FROM mysql.global_priv; +--------------------------------------------------------------------------------------+ | CONCAT(user, '@', host, ' => ', JSON_DETAILED(priv)) | +--------------------------------------------------------------------------------------+ | root@localhost => { "access": 18446744073709551615, "plugin": "mysql_native_password", "authentication_string": "*6C387FC3893DBA1E3BA155E74754DA6682D04747" } | | msandbox@127.% => { "access": 1073740799, "plugin": "mysql_native_password", "authentication_string": "*6C387FC3893DBA1E3BA155E74754DA6682D04747" } | +--------------------------------------------------------------------------------------+ ``` A particular user: ``` SELECT CONCAT(user, '@', host, ' => ', JSON_DETAILED(priv)) FROM mysql.global_priv WHERE user='marijn'; +--------------------------------------------------------------------------------------+ | CONCAT(user, '@', host, ' => ', JSON_DETAILED(priv)) | +--------------------------------------------------------------------------------------+ | marijn@localhost => { "access": 0, "plugin": "mysql_native_password", "authentication_string": "", "account_locked": true, "password_last_changed": 1558017158 } | +--------------------------------------------------------------------------------------+ ``` From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/): ``` GRANT FILE ON *.* TO user1@localhost; SELECT Host, User, JSON_DETAILED(Priv) FROM mysql.global_priv WHERE user='user1'\G *************************** 1. row *************************** Host: localhost User: user1 JSON_DETAILED(Priv): { "access": 512, "plugin": "mysql_native_password", "authentication_string": "", "password_last_changed": 1581070979, "version_id": 100502 } ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Replication When the Primary and Replica Have Different Table Definitions Replication When the Primary and Replica Have Different Table Definitions ========================================================================= The terms *master* and *slave* have historically been used in replication, but the terms terms *primary* and *replica* are now preferred. The old terms are used still used in parts of the documentation, and in MariaDB commands, although [MariaDB 10.5](../what-is-mariadb-105/index) has begun the process of renaming. The documentation process is ongoing. See [MDEV-18777](https://jira.mariadb.org/browse/MDEV-18777) to follow progress on this effort. While replication is usually meant to take place between primaries and replicas with the same table definitions and this is recommended, in certain cases replication can still take place even if the definitions are identical. Tables on the replica and the primary do not need to have the same definition in order for [replication](../replication/index) to take place. There can be differing numbers of columns, or differing data definitions and, in certain cases, replication can still proceed. Different Column Definitions - Attribute Promotion and Demotion --------------------------------------------------------------- It is possible in some cases to replicate to a replica that has a column of a different type on the replica and the primary. This process is called attribute promotion (to a larger type) or attribute demotion (to a smaller type). The conditions differ depending on whether [statement-based](../binary-log-formats/index#statement-based) or [row-based replication](../binary-log-formats/index#row-based) is used. ### Statement-Based Replication When using [statement-based replication](../binary-log-formats/index#statement-based), generally, if a statement can run successfully on the replica, it will be replicated. If a column definition is the same or a larger type on the replica than on the primary, it can replicate successfully. For example a column defined as `[VARCHAR(10)](../varchar/index)` will successfully be replicated on a replica with a definition of `VARCHAR(12)`. Replicating to a replica where the column is defined as smaller than on the primary can also work. For example, given the following table definitions: Master: ``` DESC r; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | id | tinyint(4) | YES | | NULL | | | v | varchar(10) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+ ``` Slave ``` DESC r; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | id | tinyint(4) | YES | | NULL | | | v | varchar(8) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+ ``` the statement ``` INSERT INTO r VALUES (6,'hi'); ``` would successfully replicate because the value inserted into the `v` field can successfully be inserted on both the primary and the smaller replica equivalent. However, the following statement would fail: ``` INSERT INTO r VALUES (7,'abcdefghi') ``` In this case, the value fits in the primary definition, but is too long for the replica field, and so replication will fail. ``` SHOW SLAVE STATUS\G *************************** 1. row *************************** ... Slave_IO_Running: Yes Slave_SQL_Running: No ... Last_Errno: 1406 Last_Error: Error 'Data too long for column 'v' at row 1' on query. Default database: 'test'. Query: 'INSERT INTO r VALUES (7,'abcdefghi')' ... ``` ### Row-Based Replication When using [row-based replication](../binary-log-formats/index#row-based), the value of the [slave\_type\_conversions](../replication-and-binary-log-server-system-variables/index#slave_type_conversions) variable is important. The default value of this variable is empty, in which case MariaDB will not perform attribute promotion or demotion. If the column definitions do not match, replication will stop. If set to `ALL_NON_LOSSY`, safe replication is permitted. If set to `ALL_LOSSY` as well, replication will be permitted even if data loss takes place. For example: Master: ``` DESC r; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | id | smallint(6) | YES | | NULL | | | v | varchar(10) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+ ``` Slave: ``` SHOW VARIABLES LIKE 'slave_ty%'; +------------------------+-------+ | Variable_name | Value | +------------------------+-------+ | slave_type_conversions | | +------------------------+-------+ DESC r; +-------+------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+------------+------+-----+---------+-------+ | id | tinyint(4) | YES | | NULL | | | v | varchar(1) | YES | | NULL | | +-------+------------+------+-----+---------+-------+ ``` The following query will fail: ``` INSERT INTO r VALUES (3,'c'); ``` ``` SHOW SLAVE STATUS\G; ... Slave_IO_Running: Yes Slave_SQL_Running: No ... Last_Errno: 1677 Last_Error: Column 0 of table 'test.r' cannot be converted from type 'smallint' to type 'tinyint(4)' ... ``` By changing the value of the [slave\_type\_conversions](../replication-and-binary-log-server-system-variables/index#slave_type_conversions), replication can proceed: ``` SET GLOBAL slave_type_conversions='ALL_NON_LOSSY,ALL_LOSSY'; START SLAVE; ``` ``` SHOW SLAVE STATUS\G; *************************** 1. row *************************** ... Slave_IO_Running: Yes Slave_SQL_Running: Yes ... ``` #### Supported Conversions * Between [TINYINT](../tinyint/index), [SMALLINT](../smallint/index), [MEDIUMINT](../mediumint/index), [INT](../int/index) and [BIGINT](../bigint/index). If lossy conversion is supported, the value from the primary will be converted to the maximum or minimum permitted on the replica, which non-lossy conversions require the replica column to be large enough. For example, SMALLINT UNSIGNED can be converted to MEDIUMINT, but not SMALLINT SIGNED. Different Number or Order of Columns ------------------------------------ Replication can also take place when the primary and replica have a different number of columns if the following criteria are met: * columns must be in the same order on the primary and replica * common columns must be defined with the same data type * extra columns must be defined after the common columns ### Row-Based The following example replicates incorrectly (replication proceeds, but the data is corrupted), as the columns are not in the same order. Master: ``` CREATE OR REPLACE TABLE r (i1 INT, i2 INT); ``` Slave: ``` ALTER TABLE r ADD i3 INT AFTER i1; ``` Master: ``` INSERT INTO r (i1,i2) VALUES (1,1); SELECT * FROM r; +------+------+ | i1 | i2 | +------+------+ | 1 | 1 | +------+------+ ``` Slave: ``` SELECT * FROM r; +------+------+------+ | i1 | i3 | i2 | +------+------+------+ | 1 | 1 | NULL | +------+------+------+ ``` ### Statement-Based Using statement-based replication, the same example may work, even though the columns are not in the same order. Master: ``` CREATE OR REPLACE TABLE r (i1 INT, i2 INT); ``` Slave: ``` ALTER TABLE r ADD i3 INT AFTER i1; ``` Master: ``` INSERT INTO r (i1,i2) VALUES (1,1); SELECT * FROM r; +------+------+ | i1 | i2 | +------+------+ | 1 | 1 | +------+------+ ``` Slave: ``` SELECT * FROM r; +------+------+------+ | i1 | i3 | i2 | +------+------+------+ | 1 | NULL | 1 | +------+------+------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb HELP Command HELP Command ============ Syntax ------ ``` HELP search_string ``` Description ----------- The `HELP` command can be used in any MariaDB client, such as the [mysql](../mysql-command-line-client/index) command-line client, to get basic syntax help and a short description for most commands and functions. If you provide an argument to the `HELP` command, the [mysql](../mysql-command-line-client/index) client uses it as a search string to access server-side help. The proper operation of this command requires that the help tables in the `mysql` database be initialized with help topic information. If there is no match for the search string, the search fails. Use `HELP contents` to see a list of the help categories: ``` HELP contents You asked for help about help category: "Contents" For more information, type 'help <item>', where <item> is one of the following categories: Account Management Administration Compound Statements Data Definition Data Manipulation Data Types Functions Functions and Modifiers for Use with GROUP BY Geographic Features Help Metadata Language Structure Plugins Procedures Sequences Table Maintenance Transactions User-Defined Functions Utility ``` If a search string matches multiple items, MariaDB shows a list of matching topics: ``` HELP drop Many help items for your request exist. To make a more specific request, please type 'help <item>', where <item> is one of the following topics: ALTER TABLE DROP DATABASE DROP EVENT DROP FUNCTION DROP FUNCTION UDF DROP INDEX DROP PACKAGE DROP PACKAGE BODY DROP PROCEDURE DROP ROLE DROP SEQUENCE DROP SERVER DROP TABLE DROP TRIGGER DROP USER DROP VIEW ``` Then you can enter a topic as the search string to see the help entry for that topic. The help is provided with the MariaDB server and makes use of four help tables found in the `mysql` database: [help\_relation](../mysqlhelp_relation-table/index), [help\_topic](../mysqlhelp_topic-table/index), [help\_category](../mysqlhelp_category-table/index) and [help\_keyword](../mysqlhelp_keyword-table/index). These tables are populated by the `mysql_install_db` or `fill_help_table.sql` scripts which, until [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/), contain data generated from an old version of MySQL. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Programmatic & Compound Statements Programmatic & Compound Statements =================================== Compound statements in MariaDB can be used both inside and outside of [stored programs](../stored-programs-and-views/index). | Title | Description | | --- | --- | | [Using Compound Statements Outside of Stored Programs](../using-compound-statements-outside-of-stored-programs/index) | Compound statements are not just for stored programs. | | [BEGIN END](../begin-end/index) | How to write compound statements. | | [CASE Statement](../case-statement/index) | Conditional construct with multiple choices. | | [DECLARE CONDITION](../declare-condition/index) | For declaring a named error condition (SQLSTATE or error code). | | [DECLARE HANDLER](../declare-handler/index) | Construct to declare how errors are handled. | | [DECLARE Variable](../declare-variable/index) | Declare local variables within stored programs. | | [FOR](../for/index) | FOR loops allow code to be executed a fixed number of times. | | [GOTO](../goto/index) | Jump to the given label. | | [IF](../if/index) | A basic conditional construct statement. | | [ITERATE](../iterate/index) | Used to repeat the execution of the current loop. | | [Labels](../labels/index) | Identifiers used to identify a BEGIN ... END construct. | | [LEAVE](../leave/index) | Used to exit a code block. | | [LOOP](../loop/index) | Used to loop within a code block without a condition. | | [REPEAT LOOP](../repeat-loop/index) | Used to repeat statements until a search condition is true. | | [RESIGNAL](../resignal/index) | Used to send a SIGNAL again for the previous error. | | [RETURN](../return/index) | Statement to terminate execution of a stored function and return a value. | | [SELECT INTO](../selectinto/index) | SQL statement for inserting values into variables. | | [SET Variable](../set-variable/index) | Used to insert a value into a variable with a code block. | | [SIGNAL](../signal/index) | May be used to produce a custom error message. | | [WHILE](../while/index) | Used to repeat a block of SQL statements while a search condition is true. | | [Cursors](../programmatic-compound-statements-cursors/index) | Structure for traversing and processing results, sequentially. | | [Diagnostics](../programmatic-compound-statements-diagnostics/index) | Error conditions and statement information. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHOW COLUMNS SHOW COLUMNS ============ Syntax ------ ``` SHOW [FULL] {COLUMNS | FIELDS} FROM tbl_name [FROM db_name] [LIKE 'pattern' | WHERE expr] ``` Description ----------- `SHOW COLUMNS` displays information about the columns in a given table. It also works for views. The `LIKE` clause, if present on its own, indicates which column names to match. The `WHERE` and `LIKE` clauses can be given to select rows using more general conditions, as discussed in [Extended SHOW](../extended-show/index). If the data types differ from what you expect them to be based on a `CREATE TABLE` statement, note that MariaDB sometimes changes data types when you create or alter a table. The conditions under which this occurs are described in the [Silent Column Changes](../silent-column-changes/index) article. The `FULL` keyword causes the output to include the column collation and comments, as well as the privileges you have for each column. You can use `db_name.tbl_name` as an alternative to the `tbl_name FROM db_name` syntax. In other words, these two statements are equivalent: ``` SHOW COLUMNS FROM mytable FROM mydb; SHOW COLUMNS FROM mydb.mytable; ``` `SHOW COLUMNS` displays the following values for each table column: **Field** indicates the column name. **Type** indicates the column data type. **Collation** indicates the collation for non-binary string columns, or NULL for other columns. This value is displayed only if you use the FULL keyword. The **Null** field contains YES if NULL values can be stored in the column, NO if not. The **Key** field indicates whether the column is indexed: * If **Key** is empty, the column either is not indexed or is indexed only as a secondary column in a multiple-column, non-unique index. * If **Key** is ***PRI***, the column is a `PRIMARY KEY` or is one of the columns in a multiple-column `PRIMARY KEY`. * If **Key** is ***UNI***, the column is the first column of a unique-valued index that cannot contain `NULL` values. * If **Key** is ***MUL***, multiple occurrences of a given value are allowed within the column. The column is the first column of a non-unique index or a unique-valued index that can contain `NULL` values. If more than one of the **Key** values applies to a given column of a table, **Key** displays the one with the highest priority, in the order PRI, UNI, MUL. A `UNIQUE` index may be displayed as `PRI` if it cannot contain `NULL` values and there is no `PRIMARY KEY` in the table. A `UNIQUE` index may display as `MUL` if several columns form a composite `UNIQUE` index; although the combination of the columns is unique, each column can still hold multiple occurrences of a given value. The **Default** field indicates the default value that is assigned to the column. The **Extra** field contains any additional information that is available about a given column. | Value | Description | | --- | --- | | `AUTO_INCREMENT` | The column was created with the `AUTO_INCREMENT` keyword. | | `PERSISTENT` | The column was created with the `PERSISTENT` keyword. (New in 5.3) | | `VIRTUAL` | The column was created with the `VIRTUAL` keyword. (New in 5.3) | | on update `CURRENT_TIMESTAMP` | The column is a `TIMESTAMP` column that is automatically updated on `INSERT` and `UPDATE`. | **Privileges** indicates the privileges you have for the column. This value is displayed only if you use the `FULL` keyword. **Comment** indicates any comment the column has. This value is displayed only if you use the `FULL` keyword. `SHOW FIELDS` is a synonym for `SHOW COLUMNS`. Also [DESCRIBE](../describe/index) and [EXPLAIN](../explain/index) can be used as shortcuts. You can also list a table's columns with: ``` mysqlshow db_name tbl_name ``` See the [mysqlshow](../mysqlshow/index) command for more details. The [DESCRIBE](../describe/index) statement provides information similar to `SHOW COLUMNS`. The [information\_schema.COLUMNS](../information-schema-columns-table/index) table provides similar, but more complete, information. The [SHOW CREATE TABLE](../show-create-table/index), [SHOW TABLE STATUS](../show-table-status/index), and [SHOW INDEX](../show-index/index) statements also provide information about tables. Examples -------- ``` SHOW COLUMNS FROM city; +------------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+----------+------+-----+---------+----------------+ | Id | int(11) | NO | PRI | NULL | auto_increment | | Name | char(35) | NO | | | | | Country | char(3) | NO | UNI | | | | District | char(20) | YES | MUL | | | | Population | int(11) | NO | | 0 | | +------------+----------+------+-----+---------+----------------+ ``` ``` SHOW COLUMNS FROM employees WHERE Type LIKE 'Varchar%'; +---------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------------+-------------+------+-----+---------+-------+ | first_name | varchar(30) | NO | MUL | NULL | | | last_name | varchar(40) | NO | | NULL | | | position | varchar(25) | NO | | NULL | | | home_address | varchar(50) | NO | | NULL | | | home_phone | varchar(12) | NO | | NULL | | | employee_code | varchar(25) | NO | UNI | NULL | | +---------------+-------------+------+-----+---------+-------+ ``` See Also -------- * [DESCRIBE](../describe/index) * [mysqlshow](../mysqlshow/index) * [SHOW CREATE TABLE](../show-create-table/index) * [SHOW TABLE STATUS](../show-table-status/index) * [SHOW INDEX](../show-index/index) * [Extended SHOW](../extended-show/index) * [Silent Column Changes](../silent-column-changes/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb last_insert_grn_id last\_insert\_grn\_id ===================== Syntax ------ ``` last_insert_grn_id() ``` Description ----------- `last_insert_grn_id` is a [user-defined function](../user-defined-functions/index) (UDF) included with the [Mroonga storage engine](../mroonga/index). It returns the unique Groonga id of the last-inserted record. See [Creating Mroonga User-Defined Functions](../creating-mroonga-user-defined-functions/index) for details on creating this UDF if required. Examples -------- ``` SELECT last_insert_grn_id(); +----------------------+ | last_insert_grn_id() | +----------------------+ | 3 | +----------------------+ ``` See Also -------- * [Creating Mroonga User-Defined Functions](../creating-mroonga-user-defined-functions/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb 10.2.12 Release Upgrade Tests 10.2.12 Release Upgrade Tests ============================= ### Tested revision d361401bc26f49480daec8b0307afff6edae2ecc ### Test date 2018-01-07 07:34:24 ### Summary Some tests failed due to [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103), [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094) as usual. Crash recovery with encryption also fails due to [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103). ### Details | type | pagesize | OLD version | file format | encrypted | compressed | | NEW version | file format | encrypted | compressed | readonly | result | notes | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | recovery | 16 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 16 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | recovery | 4 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 4 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | recovery | 32 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | recovery | 32 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 64 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 64 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | recovery | 8 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 8 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | recovery | 16 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 16 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 4 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 4 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 32 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 32 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 64 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 64 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 8 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 8 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 16 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 4 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 32 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 64 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 8 | 10.2.12 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 16 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 4 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 32 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 64 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 8 | 10.2.12 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 16 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | TEST\_FAILURE | | undo-recovery | 4 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | TEST\_FAILURE | | undo-recovery | 32 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | TEST\_FAILURE | | undo-recovery | 64 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | TEST\_FAILURE | | undo-recovery | 8 | 10.2.12 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | TEST\_FAILURE | | undo-recovery | 16 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 4 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 32 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 64 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 8 | 10.2.12 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 16 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 16 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 16 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | crash | 16 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 16 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 4 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 4 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 32 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 32 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 8 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 8 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 16 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 16 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 4 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 4 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 8 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 8 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 16 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 4 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 32 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 64 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 8 | 10.2.11 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 16 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 4 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 32 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 64 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 8 | 10.2.11 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 16 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 4 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 32 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 64 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 8 | 10.2.11 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 16 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 4 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 32 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 64 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 8 | 10.2.11 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 16 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 16 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 16 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 4 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 32 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 64 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | normal | 8 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13094](https://jira.mariadb.org/browse/MDEV-13094)(1) | | crash | 16 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 16 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 4 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 4 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 32 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 32 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 8 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 8 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13103](https://jira.mariadb.org/browse/MDEV-13103)(1) | | crash | 16 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 16 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 4 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 4 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 8 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 8 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 16 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 4 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 32 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 64 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 8 | 10.2.6 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 16 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 4 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 32 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 64 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 8 | 10.2.6 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 16 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 4 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 32 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 64 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 8 | 10.2.6 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 16 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 4 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 32 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 64 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 8 | 10.2.6 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 16 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 4 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 4 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 8 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 8 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 16 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 16 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 4 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 4 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 8 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 8 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 16 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 4 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 32 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 64 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 8 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 16 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 4 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 32 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 64 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 8 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 16 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 4 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 32 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 64 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 8 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 16 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 4 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 32 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 64 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 8 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 16 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 4 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 4 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 8 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 8 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 16 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 16 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 4 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 4 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 8 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 8 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.2.12 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.2.12 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.2.12 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.2.12 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 4 | 10.0.14 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 8 | 10.0.14 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 16 | 10.0.14 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 16 | 10.0.14 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 4 | 10.0.14 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 8 | 10.0.14 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 10.0.18 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 4 | 10.0.18 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 8 | 10.0.18 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 10.0.18 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 4 | 10.0.18 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 8 | 10.0.18 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 64 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 8 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 16 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 32 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 4 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 4 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 8 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 16 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 64 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 32 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | crash | 64 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | crash | 8 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | crash | 16 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | crash | 32 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | crash | 4 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | crash | 4 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | crash | 8 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | crash | 16 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | crash | 64 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | crash | 32 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 4 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 32 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 64 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 8 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 4 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 32 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 64 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 8 | 5.7.20 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | normal | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | normal | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | on | - | - | OK | | | undo | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | | undo | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.2.12 (inbuilt) | | - | - | - | OK | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. 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programming_docs
mariadb InnoDB System Variables InnoDB System Variables ======================= This page documents system variables related to the [InnoDB storage engine](../innodb/index). For options that are not system variables, see [InnoDB Options](../mysqld-options/index#innodb-options). See [Server System Variables](../server-system-variables/index) for a complete list of system variables and instructions on setting them. Also see the [Full list of MariaDB options, system and status variables](../full-list-of-mariadb-options-system-and-status-variables/index). #### `have_innodb` * **Description:** If the server supports [InnoDB tables](../innodb/index), will be set to `YES`, otherwise will be set to `NO`. Removed in [MariaDB 10.0](../what-is-mariadb-100/index), use the [Information Schema PLUGINS](../information-schema-plugins-table/index) table or [SHOW ENGINES](../show-engines/index) instead. * **Scope:** Global * **Dynamic:** No * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `ignore_builtin_innodb` * **Description:** Setting this to `1` results in the built-in InnoDB storage engine being ignored. In some versions of MariaDB, XtraDB is the default and is always present, so this variable is ignored and setting it results in a warning. From [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) to [MariaDB 10.0.8](https://mariadb.com/kb/en/mariadb-1008-release-notes/), when InnoDB was the default instead of XtraDB, this variable needed to be set. Usually used in conjunction with the [plugin-load=innodb=ha\_innodb](../mysqld-options/index#-plugin-load) option to use the InnoDB plugin. * **Commandline:** `--ignore-builtin-innodb` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_adaptive_checkpoint` * **Description:** Replaced with [innodb\_adaptive\_flushing\_method](#innodb_adaptive_flushing_method). Controls adaptive checkpointing. InnoDB's fuzzy checkpointing can cause stalls, as many dirty blocks are flushed at once as the checkpoint age nears the maximum. Adaptive checkpointing aims for more consistent flushing, approximately `modified age / maximum checkpoint age`. Can result in larger transaction log files + `reflex` Similar to [innodb\_max\_dirty\_pages\_pct](#innodb_max_dirty_pages_pct) flushing but flushes blocks constantly and contiguously based on the oldest modified age. If the age exceeds 1/2 of the maximum age capacity, flushing will be weak contiguous. If the age exceeds 3/4, flushing will be strong. Strength can be adjusted by the variable [innodb\_io\_capacity](#innodb_io_capacity). + `estimate` The default, and independent of [innodb\_io\_capacity](#innodb_io_capacity). If the oldest modified age exceeds 1/2 of the maximum age capacity, blocks will be flushed every second at a rate determined by the number of modified blocks, LSN progress speed and the average age of all modified blocks. + `keep_average` Attempts to keep the I/O rate constant by using a shorter loop cycle of one tenth of a second. Designed for SSD cards. * **Commandline:** `--innodb-adaptive-checkpoint=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `estimate` * **Valid Values:** `none` or `0`, `reflex` or `1`, `estimate` or `2`, `keep_average` or `3` * **Removed:** XtraDB 5.5 - replaced with [innodb\_adaptive\_flushing\_method](#innodb_adaptive_flushing_method) --- #### `innodb_adaptive_flushing` * **Description:** If set to `1`, the default, the server will dynamically adjust the flush rate of dirty pages in the [InnoDB](../innodb/index) buffer pool. This assists to reduce brief bursts of I/O activity. If set to `0`, adaptive flushing will only take place when the limit specified by [innodb\_adaptive\_flushing\_lwm](#innodb_adaptive_flushing_lwm) is reached. * **Commandline:** `--innodb-adaptive-flushing={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_adaptive_flushing_lwm` * **Description:** Adaptive flushing is enabled when this low water mark percentage of the [InnoDB redo log](../innodb-redo-log/index) capacity is reached. Takes effect even if [innodb\_adaptive\_flushing](#innodb_adaptive_flushing) is disabled. * **Commandline:** `--innodb-adaptive-flushing-lwm=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `double` * **Default Value:** `10.000000` * **Range:** `0` to `70` --- #### `innodb_adaptive_flushing_method` * **Description:** Determines the method of flushing dirty blocks from the InnoDB [buffer pool](../innodb-buffer-pool/index). If set to `native` or `0`, the original InnoDB method is used. The maximum checkpoint age is determined by the total length of all transaction log files. When the checkpoint age reaches the maximum checkpoint age, blocks are flushed. This can cause lag if there are many updates per second and many blocks with an almost identical age need to be flushed. If set to `estimate` or `1`, the default, the oldest modified age will be compared with the maximum age capacity. If it's more than 1/4 of this age, blocks are flushed every second. The number of blocks flushed is determined by the number of modified blocks, the LSN progress speed and the average age of all modified blocks. It's therefore independent of the [innodb\_io\_capacity](#innodb_io_capacity) for the 1-second loop, but not entirely so for the 10-second loop. If set to `keep_average` or `2`, designed specifically for SSD cards, a shorter loop cycle is used in an attempt to keep the I/O rate constant. Removed in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 and replaced with InnoDB flushing method from MySQL 5.6. * **Commandline:** `innodb-adaptive-flushing-method=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `estimate` * **Valid Values:** `native` or `0`, `estimate` or `1`, `keep_average` or `2` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) - replaced with InnoDB flushing method from MySQL 5.6 --- #### `innodb_adaptive_hash_index` * **Description:** If set to `1`, the default until [MariaDB 10.5](../what-is-mariadb-105/index), the [InnoDB](../innodb/index) hash index is enabled. Based on performance testing ([MDEV-17492](https://jira.mariadb.org/browse/MDEV-17492)), the InnoDB adaptive hash index helps performance in mostly read-only workloads, and could slow down performance in other environments, especially [DROP TABLE](../drop-table/index), [TRUNCATE TABLE](../truncate-table/index), [ALTER TABLE](../alter-table/index), or [DROP INDEX](../drop-index/index) operations. * **Commandline:** `--innodb-adaptive-hash-index={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` (>= [MariaDB 10.5](../what-is-mariadb-105/index)), `ON` (<= [MariaDB 10.4](../what-is-mariadb-104/index)) --- #### `innodb_adaptive_hash_index_partitions` * **Description:** Specifies the number of partitions for use in adaptive searching. If set to `1`, no extra partitions are created. XtraDB-only. From [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB), this is an alias for [innodb\_adaptive\_hash\_index\_parts](#innodb_adaptive_hash_index_parts) to allow for easier upgrades. * **Commandline:** `innodb-adaptive-hash-index-partitions=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `1` to `64` --- #### `innodb_adaptive_hash_index_parts` * **Description:** Specifies the number of partitions for use in adaptive searching. If set to `1`, no extra partitions are created. * **Commandline:** `innodb-adaptive-hash-index-parts=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `8` * **Range:** `1` to `512` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_adaptive_max_sleep_delay` * **Description:** Maximum time in microseconds to automatically adjust the [innodb\_thread\_sleep\_delay](#innodb_thread_sleep_delay) value to, based on the workload. Useful in extremely busy systems with hundreds of thousands of simultaneous connections. `0` disables any limit. Deprecated and ignored from [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/). * **Commandline:** `--innodb-adaptive-max-sleep-delay=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** + `0` (>= [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/)) + `150000` (<= [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/)) * **Range:** `0` to `1000000` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Deprecated:** [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_additional_mem_pool_size` * **Description:** Size in bytes of the [InnoDB](../innodb/index) memory pool used for storing information about internal data structures. Defaults to 8MB, if your application has many tables and a large structure, and this is exceeded, operating system memory will be allocated and warning messages written to the error log, in which case you should increase this value. Deprecated in [MariaDB 10.0](../what-is-mariadb-100/index) and removed in [MariaDB 10.2](../what-is-mariadb-102/index) along with InnoDB's internal memory allocator. * **Commandline:** `--innodb-additional-mem-pool-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `8388608` * **Range:** `2097152` to `4294967295` * **Deprecated:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_api_bk_commit_interval` * **Description:** Time in seconds between auto-commits for idle connections using the InnoDB memcached interface (not implemented in MariaDB). * **Commandline:** `--innodb-api-bk-commit-interval=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `5` * **Range:** `1` to `1073741824` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) --- #### `innodb_api_disable_rowlock` * **Description:** For use with MySQL's memcached (not implemented in MariaDB) * **Commandline:** `--innodb-api-disable-rowlock={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) --- #### `innodb_api_enable_binlog` * **Description:** For use with MySQL's memcached (not implemented in MariaDB) * **Commandline:** `--innodb-api-enable-binlog={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) --- #### `innodb_api_enable_mdl` * **Description:** For use with MySQL's memcached (not implemented in MariaDB) * **Commandline:** `--innodb-api-enable-mdl={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) --- #### `innodb_api_trx_level` * **Description:** For use with MySQL's memcached (not implemented in MariaDB) * **Commandline:** `--innodb-api-trx-level=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) --- #### `innodb_auto_lru_dump` * **Description:** Renamed [innodb\_buffer\_pool\_restore\_at\_startup](#innodb_buffer_pool_restore_at_startup) since XtraDB 5.5.10-20.1, which was in turn replaced by [innodb\_buffer\_pool\_load\_at\_startup](#innodb_buffer_pool_load_at_startup) in [MariaDB 10.0](../what-is-mariadb-100/index). * **Commandline:** `--innodb-auto-lru-dump=#` * **Removed:** XtraDB 5.5.10-20.1 --- #### `innodb_autoextend_increment` * **Description:** Size in MB to increment an auto-extending shared tablespace file when it becomes full. If [innodb\_file\_per\_table](#innodb_file_per_table) was set to `1`, this setting does not apply to the resulting per-table tablespace files, which are automatically extended in their own way. * **Commandline:** `--innodb-autoextend-increment=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `64` (from [MariaDB 10.0](../what-is-mariadb-100/index)) `8` (before [MariaDB 10.0](../what-is-mariadb-100/index)), * **Range:** `1` to `1000` --- #### `innodb_autoinc_lock_mode` * **Description:** The lock mode that is used when generating `[AUTO\_INCREMENT](../auto_increment/index)` values for InnoDB tables. + Valid values are: - `0` is the traditional lock mode. - `1` is the consecutive lock mode. - `2` is the interleaved lock mode. + In order to use [Galera Cluster](../galera/index), the lock mode needs to be set to `2`. + See [AUTO\_INCREMENT Handling in InnoDB: AUTO\_INCREMENT Lock Modes](../auto_increment-handling-in-xtradbinnodb/index#auto_increment-lock-modes) for more information. * **Commandline:** `--innodb-autoinc-lock-mode=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `0` to `2` --- #### `innodb_background_scrub_data_check_interval` * **Description:** Check if spaces needs scrubbing every [innodb\_background\_scrub\_data\_check\_interval](#innodb_background_scrub_data_check_interval) seconds. See [Data Scrubbing](../innodb-data-scrubbing/index). Deprecated and ignored from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). * **Commandline:** `--innodb-background-scrub-data-check-interval=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `3600` * **Range:** `1` to `4294967295` * **Deprecated:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_background_scrub_data_compressed` * **Description:** Enable scrubbing of compressed data by background threads (same as encryption\_threads). See [Data Scrubbing](../innodb-data-scrubbing/index). Deprecated and ignored from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). * **Commandline:** `--innodb-background-scrub-data-compressed={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `0` * **Deprecated:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_background_scrub_data_interval` * **Description:** Scrub spaces that were last scrubbed longer than this number of seconds ago. See [Data Scrubbing](../innodb-data-scrubbing/index). Deprecated and ignored from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). * **Commandline:** `--innodb-background-scrub-data-interval=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `604800` * **Range:** `1` to `4294967295` * **Deprecated:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_background_scrub_data_uncompressed` * **Description:** Enable scrubbing of uncompressed data by background threads (same as encryption\_threads). See [Data Scrubbing](../innodb-data-scrubbing/index). Deprecated and ignored from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). * **Commandline:** `--innodb-background-scrub-data-uncompressed={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `0` * **Deprecated:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_blocking_buffer_pool_restore` * **Description:** If set to `1` (`0` is default), XtraDB will wait until the least-recently used (LRU) dump is completely restored upon restart before reporting back to the server that it has successfully started up. Available with XtraDB only, not InnoDB. * **Commandline:** `innodb-blocking-buffer-pool-restore={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.0.0](https://mariadb.com/kb/en/mariadb-1000-release-notes/) --- #### `innodb_buf_dump_status_frequency` * **Description:** Determines how often (as a percent) the buffer pool dump status should be printed in the logs. For example, `10` means that the buffer pool dump status is printed when every 10% of the number of buffer pool pages are dumped. The default is `0` (only start and end status is printed). * **Commandline:** `--innodb-buf-dump-status-frequency=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `100` --- #### `innodb_buffer_pool_chunk_size` * **Description:** Chunk size used for dynamically resizing the [buffer pool](../innodb-buffer-pool/index). Note that changing this setting can change the size of the buffer pool. When [large-pages](../server-system-variables/index#large_pages) is used this value is effectively rounded up to the next multiple of [large-page-size](../server-system-variables/index#large_page_size). See [Setting Innodb Buffer Pool Size Dynamically](../setting-innodb-buffer-pool-size-dynamically/index). From [MariaDB 10.8.0](https://mariadb.com/kb/en/mariadb-1080-release-notes/), the variable is autosized based on the [buffer pool size](../innodb-buffer-pool/index). * **Commandline:** `--innodb-buffer-pool-chunk-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** + `autosize (0)`, resulting in [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size)/64, if [large\_pages](../server-system-variables/index#large_pages) round down to multiple of largest page size, with 1MiB minimum (>= [MariaDB 10.8.1](https://mariadb.com/kb/en/mariadb-1081-release-notes/)) + `134217728` (<= [MariaDB 10.8.0](https://mariadb.com/kb/en/mariadb-1080-release-notes/)) * **Range:** + `0`, as autosize, and then `1048576` to `18446744073709551615` (>= [MariaDB 10.8](../what-is-mariadb-108/index)) + `1048576` to [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size)/[innodb\_buffer\_pool\_instances](#innodb_buffer_pool_instances) (<= [MariaDB 10.7](../what-is-mariadb-107/index)) * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_buffer_pool_dump_at_shutdown` * **Description:** Whether to record pages cached in the [buffer pool](../innodb-buffer-pool/index) on server shutdown, which reduces the length of the warmup the next time the server starts. The related [innodb\_buffer\_pool\_load\_at\_startup](#innodb_buffer_pool_load_at_startup) specifies whether the buffer pool is automatically warmed up at startup. * **Commandline:** `--innodb-buffer-pool-dump-at-shutdown={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** + `ON` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `OFF` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_buffer_pool_dump_now` * **Description:** Immediately records pages stored in the [buffer pool](../innodb-buffer-pool/index). The related [innodb\_buffer\_pool\_load\_now](#innodb_buffer_pool_load_now) does the reverse, and will immediately warm up the buffer pool. * **Commandline:** `--innodb-buffer-pool-dump-now={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_buffer_pool_dump_pct` * **Description:** Dump only the hottest N% of each [buffer pool](../innodb-buffer-pool/index), defaults to 100 until [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). Since [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/), defaults to 25% along with the changes to [innodb\_buffer\_pool\_dump\_at\_shutdown](#innodb_buffer_pool_dump_at_shutdown) and [innodb\_buffer\_pool\_load\_at\_startup](#innodb_buffer_pool_load_at_startup). * **Commandline:** `--innodb-buffer-pool-dump-pct={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** + `25` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `100` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Range:** `1` to `100` --- #### `innodb_buffer_pool_evict` * **Description:** Evict pages from the buffer pool. If set to "uncompressed" then all uncompressed pages are evicted from the buffer pool. Variable to be used only for testing. Only exists in DEBUG builds. * **Commandline:** `--innodb-buffer-pool-evict=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `""` * **Valid Values:** "" or "uncompressed" --- #### `innodb_buffer_pool_filename` * **Description:** The file that holds the [buffer pool](../innodb-buffer-pool/index) list of page numbers set by [innodb\_buffer\_pool\_dump\_at\_shutdown](#innodb_buffer_pool_dump_at_shutdown) and [innodb\_buffer\_pool\_dump\_now](#innodb_buffer_pool_dump_now). * **Commandline:** `--innodb-buffer-pool-filename=file` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `ib_buffer_pool` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_buffer_pool_instances` * **Description:** If [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size) is set to more than 1GB, innodb\_buffer\_pool\_instances divides the [InnoDB](../innodb/index) buffer pool into this many instances. The default was 1 in [MariaDB 5.5](../what-is-mariadb-55/index), but for large systems with buffer pools of many gigabytes, many instances can help reduce contention concurrency. The default is 8 in MariaDB 10 (except on Windows 32-bit, where it varies according to [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size), or from [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/), where it is set to 1 if [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size) < 1GB). Each instance manages its own data structures and takes an equal portion of the total buffer pool size, so for example if innodb\_buffer\_pool\_size is 4GB and innodb\_buffer\_pool\_instances is set to 4, each instance will be 1GB. Each instance should ideally be at least 1GB in size. Deprecated and ignored from [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/), as the original reasons for for splitting the buffer pool have mostly gone away. * **Commandline:** `--innodb-buffer-pool-instances=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** >= [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/): `8`, `1` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) if [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size) < 1GB), or dependent on [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size) (Windows 32-bit) * **Deprecated:** [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_buffer_pool_load_abort` * **Description:** Aborts the process of restoring [buffer pool](../innodb-buffer-pool/index) contents started by [innodb\_buffer\_pool\_load\_at\_startup](#innodb_buffer_pool_load_at_startup) or [innodb\_buffer\_pool\_load\_now](#innodb_buffer_pool_load_now). * **Commandline:** `--innodb-buffer-pool-load-abort={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_buffer_pool_load_at_startup` * **Description:** Specifies whether the [buffer pool](../innodb-buffer-pool/index) is automatically warmed up when the server starts by loading the pages held earlier. The related [innodb\_buffer\_pool\_dump\_at\_shutdown](#innodb_buffer_pool_dump_at_shutdown) specifies whether pages are saved at shutdown. If the buffer pool is large and taking a long time to load, increasing [innodb\_io\_capacity](#innodb_io_capacity) at startup may help. * **Commandline:** `--innodb-buffer-pool-load-at-startup={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** + `ON` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `OFF` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) --- #### `innodb_buffer_pool_load_now` * **Description:** Immediately warms up the [buffer pool](../innodb-buffer-pool/index) by loading the stored data pages. The related [innodb\_buffer\_pool\_dump\_now](#innodb_buffer_pool_dump_now) does the reverse, and immediately records pages stored in the buffer pool. * **Commandline:** `--innodb-buffer-pool-load-now={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_buffer_pool_load_pages_abort` * **Description:** Number of pages during a buffer pool load to process before signaling [innodb\_buffer\_pool\_load\_abort=1](#innodb_buffer_pool_load_abort). Debug builds only. * **Commandline:** `--innodb-buffer-pool-load-pages-abort=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `9223372036854775807` * **Range:** `1` to `9223372036854775807` * **Introduced:** [MariaDB 10.3](../what-is-mariadb-103/index) --- #### `innodb_buffer_pool_populate` * **Description:** When set to `1` (`0` is default), XtraDB will preallocate pages in the buffer pool on starting up so that NUMA allocation decisions are made while the buffer cache is still clean. XtraDB only. This option was made ineffective in [MariaDB 10.0.23](https://mariadb.com/kb/en/mariadb-10023-release-notes/). Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-buffer-pool-populate={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.0.23](https://mariadb.com/kb/en/mariadb-10023-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_buffer_pool_restore_at_startup` * **Description:** Time in seconds between automatic buffer pool dumps. If set to a non-zero value, XtraDB will also perform an automatic restore of the [buffer pool](../innodb-buffer-pool/index) at startup. If set to `0`, automatic dumps are not performed, nor automatic restores on startup. Replaced by [innodb\_buffer\_pool\_load\_at\_startup](#innodb_buffer_pool_load_at_startup) in [MariaDB 10.0](../what-is-mariadb-100/index). * **Commandline:** `innodb-buffer-pool-restore-at-startup` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range - 32 bit:** `0` to `4294967295` * **Range - 64 bit:** `0` to `18446744073709547520` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) - replaced by [innodb\_buffer\_pool\_load\_at\_startup](#innodb_buffer_pool_load_at_startup) --- #### `innodb_buffer_pool_shm_checksum` * **Description:** Used with Percona's SHM buffer pool patch in XtraDB 5.5. Was shortly deprecated and removed in XtraDB 5.6. XtraDB only. * **Commandline:** `innodb-buffer-pool-shm-checksum={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_buffer_pool_shm_key` * **Description:** Used with Percona's SHM buffer pool patch in XtraDB 5.5. Later deprecated in XtraDB 5.5, and removed in XtraDB 5.6. * **Commandline:** `innodb-buffer-pool-shm-key={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `0` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_buffer_pool_size` * **Description:** InnoDB buffer pool size in bytes. The primary value to adjust on a database server with entirely/primarily [InnoDB](../innodb/index) tables, can be set up to 80% of the total memory in these environments. See the [InnoDB Buffer Pool](../innodb-buffer-pool/index) for more on setting this variable, and also [Setting InnoDB Buffer Pool Size Dynamically](../setting-innodb-buffer-pool-size-dynamically/index) if doing so dynamically. * **Commandline:** `--innodb-buffer-pool-size=#` * **Scope:** Global * **Dynamic:** Yes (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), No (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Data Type:** `numeric` * **Default Value:** `134217728` (128iMB) * **Range:** + Minimum: `5242880` (5MiB ) for [InnoDB Page Size](innodb-page-size) <= 16k otherwise `25165824` (24MiB) for [InnoDB Page Size](innodb-page-size) > 16k (for versions less than next line) + Minimium: `2MiB` [InnoDB Page Size](innodb-page-size) = 4k, `3MiB` [InnoDB Page Size](innodb-page-size) = 8k, `5MiB` [InnoDB Page Size](innodb-page-size) = 16k, `10MiB` [InnoDB Page Size](innodb-page-size) = 32k, `20MiB` [InnoDB Page Size](innodb-page-size) = 64k, (>= [MariaDB 10.2.42](https://mariadb.com/kb/en/mariadb-10242-release-notes/), >= [MariaDB 10.3.33](https://mariadb.com/kb/en/mariadb-10333-release-notes/), >= [MariaDB 10.4.23](https://mariadb.com/kb/en/mariadb-10423-release-notes/), >= [MariaDB 10.5.14](https://mariadb.com/kb/en/mariadb-10514-release-notes/), >= [MariaDB 10.6.6](https://mariadb.com/kb/en/mariadb-1066-release-notes/), >= [MariaDB 10.7.2](https://mariadb.com/kb/en/mariadb-1072-release-notes/)) + Minimum: 1GiB for [innodb\_buffer\_pool\_instances](#innodb_buffer_pool_instances) > 1 (<= [MariaDB 10.7](../what-is-mariadb-107/index)) + Maximium: `9223372036854775807` (8192PB) (all versions) --- #### `innodb_change_buffer_dump` * **Description:** If set, causes the contents of the InnoDB change buffer to be dumped to the server error log at startup. Only available in debug builds. * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.2.28](https://mariadb.com/kb/en/mariadb-10228-release-notes/), [MariaDB 10.3.19](https://mariadb.com/kb/en/mariadb-10319-release-notes/), [MariaDB 10.4.9](https://mariadb.com/kb/en/mariadb-1049-release-notes/) --- #### `innodb_change_buffer_max_size` * **Description:** Maximum size of the [InnoDB Change Buffer](../innodb-change-buffering/index) as a percentage of the total buffer pool. The default is 25%, and this can be increased up to 50% for servers with high write activity, and lowered down to 0 for servers used exclusively for reporting. * **Commandline:** `--innodb-change-buffer-max-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `25` * **Range:** `0` to `50` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_change_buffering` * **Description:** Sets how [InnoDB](../innodb/index) change buffering is performed. See [InnoDB Change Buffering](../innodb-change-buffering/index) for details on the settings. Deprecated and ignored from [MariaDB 10.9.0](https://mariadb.com/kb/en/mariadb-1090-release-notes/). * **Commandline:** `--innodb-change-buffering=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` (>= [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/)), `string` (<= [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/)) * **Default Value:** + >= [MariaDB 10.5.15](https://mariadb.com/kb/en/mariadb-10515-release-notes/), [MariaDB 10.6.7](https://mariadb.com/kb/en/mariadb-1067-release-notes/), [MariaDB 10.7.3](https://mariadb.com/kb/en/mariadb-1073-release-notes/), [MariaDB 10.8.2](https://mariadb.com/kb/en/mariadb-1082-release-notes/): `none` + <= [MariaDB 10.5.14](https://mariadb.com/kb/en/mariadb-10514-release-notes/), [MariaDB 10.6.6](https://mariadb.com/kb/en/mariadb-1066-release-notes/), [MariaDB 10.7.2](https://mariadb.com/kb/en/mariadb-1072-release-notes/), [MariaDB 10.8.1](https://mariadb.com/kb/en/mariadb-1081-release-notes/):`all` * **Valid Values:** `inserts`, `none`, `deletes`, `purges`, `changes`, `all` * **Deprecated:** [MariaDB 10.9.0](https://mariadb.com/kb/en/mariadb-1090-release-notes/) --- #### `innodb_change_buffering_debug` * **Description:** If set to `1`, an [InnoDB Change Buffering](../innodb-change-buffering/index) debug flag is set. `1` forces all changes to the change buffer, while `2` causes a crash at merge. `0`, the default, indicates no flag is set. Only available in debug builds. * **Commandline:** `--innodb-change-buffering-debug=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `2` --- #### `innodb_checkpoint_age_target` * **Description:** The maximum value of the checkpoint age. If set to `0`, has no effect. Removed in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 and replaced with InnoDB flushing method from MySQL 5.6. * **Commandline:** `innodb-checkpoint-age-target=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` upwards * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) - replaced with InnoDB flushing method from MySQL 5.6. --- #### `innodb_checksum_algorithm` * **Description:** Specifies how the InnoDB tablespace checksum is generated and verified. + `innodb`: Backwards compatible with earlier versions (<= [MariaDB 5.5](../what-is-mariadb-55/index)). Deprecated in [MariaDB 10.3.29](https://mariadb.com/kb/en/mariadb-10329-release-notes/), [MariaDB 10.4.19](https://mariadb.com/kb/en/mariadb-10419-release-notes/), [MariaDB 10.5.10](https://mariadb.com/kb/en/mariadb-10510-release-notes/) and removed in [MariaDB 10.6](../what-is-mariadb-106/index). If really needed, data files can still be converted with [innochecksum](../innochecksum/index). + `crc32`: A newer, faster algorithm, but incompatible with earlier versions. Tablespace blocks will be converted to the new format over time, meaning that a mix of checksums may be present. + `full_crc32` and `strict_full_crc32`: From [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/). Permits encryption to be supported over a [SPATIAL INDEX](../spatial-index/index), which `crc32` does not support. Newly-created data files will carry a flag that indicates that all pages of the file will use a full CRC-32C checksum over the entire page contents (excluding the bytes where the checksum is stored, at the very end of the page). Such files will always use that checksum, no matter what parameter `innodb_checksum_algorithm` is assigned to. Even if `innodb_checksum_algorithm` is modified later, the same checksum will continue to be used. A special flag will be set in the FSP\_SPACE\_FLAGS in the first data page to indicate the new format of checksum and encryption/page\_compressed. ROW\_FORMAT=COMPRESSED tables will only use the old format. These tables do not support new features, such as larger innodb\_page\_size or instant ADD/DROP COLUMN. Also cleans up the MariaDB tablespace flags - flags are reserved to store the page\_compressed compression algorithm, and to store the compressed payload length, so that checksum can be computed over the compressed (and possibly encrypted) stream and can be validated without decrypting or decompressing the page. In the full\_crc32 format, there no longer are separate before-encryption and after-encryption checksums for pages. The single checksum is computed on the page contents that is written to the file.See [MDEV-12026](https://jira.mariadb.org/browse/MDEV-12026) for details. + `none`: Writes a constant rather than calculate a checksum. Deprecated in [MariaDB 10.3.29](https://mariadb.com/kb/en/mariadb-10329-release-notes/), [MariaDB 10.4.19](https://mariadb.com/kb/en/mariadb-10419-release-notes/), [MariaDB 10.5.10](https://mariadb.com/kb/en/mariadb-10510-release-notes/) and removed in [MariaDB 10.6](../what-is-mariadb-106/index) as was mostly used to disable the original, slow, page checksum for benchmarketing purposes. + `strict_crc32`, `strict_innodb` and `strict_none`: The options are the same as the regular options, but InnoDB will halt if it comes across a mix of checksum values. These are faster, as both new and old checksum values are not required, but can only be used when setting up tablespaces for the first time. * **Commandline:** `--innodb-checksum-algorithm=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** + `full_crc32` (>= [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)) + `crc32` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `innodb` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Valid Values:** + >= [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/): `crc32`, `full_crc32`, `strict_crc32`, `strict_full_crc32` + [MariaDB 10.5](../what-is-mariadb-105/index), >= [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/): `innodb`, `crc32`, `full_crc32`, `none`, `strict_innodb`, `strict_crc32`, `strict_none`, `strict_full_crc32` + <= [MariaDB 10.4.2](https://mariadb.com/kb/en/mariadb-1042-release-notes/): `innodb`, `crc32`, `none`, `strict_innodb`, `strict_crc32`, `strict_none` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_checksums` * **Description:** By default, [InnoDB](../innodb/index) performs checksum validation on all pages read from disk, which provides extra fault tolerance. You would usually want this set to `1` in production environments, although setting it to `0` can provide marginal performance improvements. Deprecated and functionality replaced by [innodb\_checksum\_algorithm](#innodb_checksum_algorithm) in [MariaDB 10.0](../what-is-mariadb-100/index), and should be removed to avoid conflicts. `ON` is equivalent to `--innodb_checksum_algorithm=innodb` and `OFF` to `--innodb_checksum_algorithm=none`. * **Commandline:** `--innodb-checksums`, `--skip-innodb-checksums` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` * **Deprecated:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) --- #### `innodb_cleaner_lsn_age_factor` * **Description:** XtraDB has enhanced page cleaner heuristics, and with these in place, the default InnoDB adaptive flushing may be too aggressive. As a result, a new LSN age factor formula has been introduced, controlled by this variable. The default setting, `high_checkpoint`, uses the new formula, while the alternative, `legacy`, uses the original algorithm. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `--innodb-cleaner-lsn-age-factor=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** + `deprecated` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `high_checkpoint` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) * **Valid Values:** + `high_checkpoint`, `legacy` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) + `deprecated`, `high_checkpoint`, `legacy` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_cmp_per_index_enabled` * **Description:** If set to `ON` (`OFF` is default), per-index compression statistics are stored in the [INFORMATION\_SCHEMA.INNODB\_CMP\_PER\_INDEX](../information-schema-innodb-tables-information-schema-innodb_cmp_per_index-an/index) table. These are expensive to record, so this setting should only be changed with care, such as for performance tuning on development or replica servers. * **Commandline:** `--innodb-cmp-per-index-enabled={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_commit_concurrency` * **Description:** Limit to the number of transaction threads that can can commit simultaneously. 0, the default, imposes no limit. While you can change from one positive limit to another at runtime, you cannot set this variable to 0, or change it from 0, while the server is running. Deprecated and ignored from [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/). * **Commandline:** `--innodb-commit-concurrency=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `1000` * **Deprecated:** [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_compression_algorithm` * **Description:** Compression algorithm used for [InnoDB page compression](../innodb-page-compression/index). The supported values are: + `none`: Pages are not compressed. + `zlib`: Pages are compressed using the bundled `[zlib](https://www.zlib.net/)` compression algorithm. + `lz4`: Pages are compressed using the `[lz4](https://code.google.com/p/lz4/)` compression algorithm. + `lzo`: Pages are compressed using the `[lzo](http://www.oberhumer.com/opensource/lzo/)` compression algorithm. + `lzma`: Pages are compressed using the `[lzma](http://tukaani.org/xz/)` compression algorithm. + `bzip2`: Pages are compressed using the `[bzip2](http://www.bzip.org/)` compression algorithm. + `snappy`: Pages are compressed using the `[snappy](http://google.github.io/snappy/)` algorithm. + On many distributions, MariaDB may not support all page compression algorithms by default. From [MariaDB 10.7](../what-is-mariadb-107/index), libraries can be installed as a plugin. See [Compression Plugins](../compression-plugins/index). + See [InnoDB Page Compression: Configuring the InnoDB Page Compression Algorithm](../innodb-page-compression/index#configuring-the-innodb-page-compression-algorithm) for more information. * **Commandline:** `--innodb-compression-algorithm=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** `zlib` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/), [MariaDB 10.1.22](https://mariadb.com/kb/en/mariadb-10122-release-notes/)), `none` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/), [MariaDB 10.1.21](https://mariadb.com/kb/en/mariadb-10121-release-notes/)) * **Valid Values:**`none`, `zlib`, `lz4`, `lzo`, `lzma`, `bzip2` or `snappy` ([MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/)) --- #### `innodb_compression_default` * **Description:** Whether or not [InnoDB page compression](../innodb-page-compression/index) is enabled by default for new tables. + The default value is `OFF`, which means new tables are not compressed. + See [InnoDB Page Compression: Enabling InnoDB Page Compression by Default](../innodb-page-compression/index#enabling-innodb-page-compression-by-default) for more information. * **Commandline:** `--innodb-compression-default={0|1}` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) --- #### `innodb_compression_failure_threshold_pct` * **Description:** Specifies the percentage cutoff for expensive compression failures during updates to a table that uses [InnoDB page compression](../innodb-page-compression/index), after which free space is added to each new compressed page, dynamically adjusted up to the level set by [innodb\_compression\_pad\_pct\_max](#innodb_compression_pad_pct_max). Zero disables checking of compression efficiency and adjusting padding. + See [InnoDB Page Compression: Configuring the Failure Threshold and Padding](../innodb-page-compression/index#configuring-the-failure-threshold-and-padding) for more information. * **Commandline:** `--innodb-compression-failure-threshold-pct=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `5` * **Range:** `0` to `100` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_compression_level` * **Description:** Specifies the default level of compression for tables that use [InnoDB page compression](../innodb-page-compression/index). + Only a subset of InnoDB page compression algorithms support compression levels. If an InnoDB page compression algorithm does not support compression levels, then the compression level value is ignored. + The compression level can be set to any value between `1` and `9`. The default compression level is `6`. The range goes from the fastest to the most compact, which means that `1` is the fastest and `9` is the most compact. + See [InnoDB Page Compression: Configuring the Default Compression Level](../innodb-page-compression/index#configuring-the-default-compression-level) for more information. * **Commandline:** `--innodb-compression-level=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `6` * **Range:** `1` to `9` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_compression_pad_pct_max` * **Description:** The maximum percentage of reserved free space within each compressed page for tables that use [InnoDB page compression](../innodb-page-compression/index). Reserved free space is used when the page's data is reorganized and might be recompressed. Only used when [innodb\_compression\_failure\_threshold\_pct](#innodb_compression_failure_threshold_pct) is not zero, and the rate of compression failures exceeds its setting. + See [InnoDB Page Compression: Configuring the Failure Threshold and Padding](../innodb-page-compression/index#configuring-the-failure-threshold-and-padding) for more information. * **Commandline:** `--innodb-compression-pad-pct-max=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `50` * **Range:** `0` to `75` * **Introduced:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_concurrency_tickets` * **Description:** Number of times a newly-entered thread can enter and leave [InnoDB](../innodb/index) until it is again subject to the limitations of [innodb\_thread\_concurrency](#innodb_thread_concurrency) and may possibly be queued. Deprecated and ignored from [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/). * **Commandline:** `--innodb-concurrency-tickets=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** + `0` (>= [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/)) + `5000` (<= [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/)) * **Range:** `1` to `18446744073709551615` * **Deprecated:** [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_corrupt_table_action` * **Description:** What action to perform when a corrupt table is found. XtraDB only. + When set to `assert`, the default, XtraDB will intentionally crash the server when it detects corrupted data in a single-table tablespace, with an assertion failure. + When set to `warn`, it will pass corruption as corrupt table instead of crashing, and disable all further I/O (except for deletion) on the table file. + If set to `salvage`, read access is permitted, but corrupted pages are ignored. [innodb\_file\_per\_table](#innodb_file_per_table) must be enabled for this option. Previously named `innodb_pass_corrupt_table`. + Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-corrupt-table-action=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** + `assert` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) + `deprecated` (<= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) * **Valid Values:** + `deprecated`, `assert`, `warn`, `salvage` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `assert`, `warn`, `salvage` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_data_file_path` * **Description:** Individual [InnoDB](../innodb/index) data files, paths and sizes. The value of [innodb\_data\_home\_dir](#innodb_data_home_dir) is joined to each path specified by innodb\_data\_file\_path to get the full directory path. If innodb\_data\_home\_dir is an empty string, absolute paths can be specified here. A file size is specified with K for kilobytes, M for megabytes and G for gigabytes, and whether or not to autoextend the data file is also specified. * **Commandline:** `--innodb-data-file-path=name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `ibdata1:12M:autoextend` (from [MariaDB 10.0](../what-is-mariadb-100/index)), `ibdata1:10M:autoextend` (before [MariaDB 10.0](../what-is-mariadb-100/index)) --- #### `innodb_data_home_dir` * **Description:** Directory path for all [InnoDB](../innodb/index) data files in the shared tablespace (assuming [innodb\_file\_per\_table](#innodb_file_per_table) is not enabled). File-specific information can be added in [innodb\_data\_file\_path](#innodb_data_file_path), as well as absolute paths if innodb\_data\_home\_dir is set to an empty string. * **Commandline:** `--innodb-data-home-dir=path` * **Scope:** Global * **Dynamic:** No * **Data Type:** `directory name` * **Default Value:** `The MariaDB data directory` --- #### `innodb_deadlock_detect` * **Description:** By default, the InnoDB deadlock detector is enabled. If set to off, deadlock detection is disabled and MariaDB will rely on [innodb\_lock\_wait\_timeout](#innodb_lock_wait_timeout) instead. This may be more efficient in systems with high concurrency as deadlock detection can cause a bottleneck when a number of threads have to wait for the same lock. * **Commandline:** `--innodb-deadlock-detect` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `1` * **Introduced:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) --- #### `innodb_deadlock_report` * **Description:** How to report deadlocks (if [innodb\_deadlock\_detect=ON](#innodb_deadlock_detect)). + `off`: Do not report any details of deadlocks. + `basic`: Report transactions and waiting locks. + `full`: Default. Report transactions, waiting locks and blocking locks. * **Commandline:** `--innodb-deadlock-report=val` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** `full` * **Valid Values:** `off`, `basic`, `full` * **Introduced:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_default_page_encryption_key` * **Description:** Encryption key used for page encryption. + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB Encryption Keys](../innodb-encryption-keys/index) for more information. * **Commandline:** `--innodb-default-page-encryption-key=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `1` to `255` * **Introduced:** [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) * **Removed:** [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) --- #### `innodb_default_encryption_key_id` * **Description:** ID of encryption key used by default to encrypt InnoDB tablespaces. + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB Encryption Keys](../innodb-encryption-keys/index) for more information. * **Commandline:** `--innodb-default-encryption-key-id=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `1` to `4294967295` --- #### `innodb_default_row_format` * **Description:** Specifies the default [row format](../innodb-row-formats-overview/index) to be used for InnoDB tables. The compressed row format cannot be set as the default. + See [InnoDB Row Formats Overview: Default Row Format](../innodb-row-formats-overview/index#default-row-format) for more information. * **Commandline:** `--innodb-default-row-format=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** `dynamic` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), `compact` (>= [MariaDB 10.1.32](https://mariadb.com/kb/en/mariadb-10132-release-notes/)) * **Valid Values:** `redundant`, `compact` or `dynamic` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/), [MariadB 10.1.32](https://mariadb.com/kb/en/mariadb-10132-release-notes/) --- #### `innodb_defragment` * **Description:** When set to `1` (the default is `0`), InnoDB defragmentation is enabled. When set to FALSE, all existing defragmentation will be paused and new defragmentation commands will fail. Paused defragmentation commands will resume when this variable is set to true again. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index). * **Commandline:** `--innodb-defragment={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_defragment_fill_factor` * **Description:**. Indicates how full defragmentation should fill a page. Together with [innodb\_defragment\_fill\_factor\_n\_recs](#innodb_defragment_fill_factor_n_recs) ensures defragmentation won’t pack the page too full and cause page split on the next insert on every page. The variable indicating more defragmentation gain is the one effective. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index). * **Commandline:** `--innodb-defragment-fill-factor=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `double` * **Default Value:** `0.9` * **Range:** `0.7` to `1` --- #### `innodb_defragment_fill_factor_n_recs` * **Description:** Number of records of space that defragmentation should leave on the page. This variable, together with [innodb\_defragment\_fill\_factor](#innodb_defragment_fill_factor), is introduced so defragmentation won't pack the page too full and cause page split on the next insert on every page. The variable indicating more defragmentation gain is the one effective. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index). * **Commandline:** `--innodb-defragment-fill-factor-n-recs=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `20` * **Range:** `1` to `100` --- #### `innodb_defragment_frequency` * **Description:** Maximum times per second for defragmenting a single index. This controls the number of times the defragmentation thread can request X\_LOCK on an index. The defragmentation thread will check whether 1/defragment\_frequency (s) has passed since it last worked on this index, and put the index back in the queue if not enough time has passed. The actual frequency can only be lower than this given number. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index). * **Commandline:** `--innodb-defragment-frequency=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `integer` * **Default Value:** `40` * **Range:** `1` to `1000` --- #### `innodb_defragment_n_pages` * **Description:** Number of pages considered at once when merging multiple pages to defragment. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index). * **Commandline:** `--innodb-defragment-n-pages=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `7` * **Range:** `2` to `32` --- #### `innodb_defragment_stats_accuracy` * **Description:** Number of defragment stats changes there are before the stats are written to persistent storage. Defaults to zero, meaning disable defragment stats tracking. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index). * **Commandline:** `--innodb-defragment-stats-accuracy=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `4294967295` --- #### `innodb_dict_size_limit` * **Description:** Size in bytes of a soft limit the memory used by tables in the data dictionary. Once this limit is reached, XtraDB will attempt to remove unused entries. If set to `0`, the default and standard InnoDB behavior, there is no limit to memory usage. Removed in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 and replaced by MySQL 5.6's new [table\_definition\_cache](../server-system-variables/index#table_definition_cache) implementation. * **Commandline:** `innodb-dict-size-limit=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Default Value - 32 bit:** `2147483648` * **Default Value - 64 bit:** `9223372036854775807` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) - replaced by MySQL 5.6's [table\_definition\_cache](../server-system-variables/index#table_definition_cache) implementation. --- #### `innodb_disable_sort_file_cache` * **Description:** If set to `1` (`0` is default), the operating system file system cache for merge-sort temporary files is disabled. * **Commandline:** `--innodb-disable-sort-file-cache={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_disallow_writes` * **Description:** Tell InnoDB to stop any writes to disk. * **Commandline:** None * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.3.35](https://mariadb.com/kb/en/mariadb-10335-release-notes/), [MariaDB 10.4.25](https://mariadb.com/kb/en/mariadb-10425-release-notes/), [MariaDB 10.5.16](https://mariadb.com/kb/en/mariadb-10516-release-notes/), [MariaDB 10.6.8](https://mariadb.com/kb/en/mariadb-1068-release-notes/), [MariaDB 10.7.4](https://mariadb.com/kb/en/mariadb-1074-release-notes/) --- #### `innodb_doublewrite` * **Description:** If set to `1`, the default, to improve fault tolerance [InnoDB](../innodb/index) first stores data to a [doublewrite buffer](../innodb-doublewrite-buffer/index) before writing it to data file. Disabling will provide a marginal peformance improvement. * **Commandline:** `--innodb-doublewrite`, `--skip-innodb-doublewrite` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_doublewrite_file` * **Description:** The absolute or relative path and filename to a dedicated tablespace for the [doublewrite buffer](../xtradbinnodb-doublewrite-buffer/index). In heavy workloads, the doublewrite buffer can impact heavily on the server, and moving it to a different drive will reduce contention on random reads. Since the doublewrite buffer is mostly sequential writes, a traditional HDD is a better choice than SSD. This Percona XtraDB variable has not been ported to XtraDB 5.6. * **Commandline:** `innodb-doublewrite-file=filename` * **Scope:** Global * **Dynamic:** No * **Data Type:** `filename` * **Default Value:** `NULL` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_empty_free_list_algorithm` * **Description:** XtraDB 5.6.13-61 introduced an algorithm to assist with reducing mutex contention when the buffer pool free list is empty, controlled by this variable. If set to `backoff`, the default until [MariaDB 10.1.24](https://mariadb.com/kb/en/mariadb-10124-release-notes/), the new algorithm will be used. If set to `legacy`, the original InnoDB algorithm will be used. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. See [#1651657](https://bugs.launchpad.net/percona-server/+bug/1651657) for the reasons this was changed back to `legacy` in XtraDB 5.6.36-82.0. When upgrading from 10.0 to 10.1 (>= 10.1.24), for large buffer pools the default will remain `backoff`, while for small ones it will be changed to `legacy`. * **Commandline:** `innodb-empty-free-list-algorithm=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** + `deprecated` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `legacy` (>= [MariaDB 10.1.24](https://mariadb.com/kb/en/mariadb-10124-release-notes/)) + `backoff` (<= [MariaDB 10.1.23](https://mariadb.com/kb/en/mariadb-10123-release-notes/)) * **Valid Values:** + `deprecated`, `backoff`, `legacy` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `backoff`, `legacy` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) * **Introduced:** [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/) * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_enable_unsafe_group_commit` * **Description:** Unneeded after XtraDB 1.0.5. If set to `0`, the default, InnoDB will keep transactions between the transaction log and [binary log](../binary-log/index)s in the same order. Safer, but slower. If set to `1`, transactions can be group-committed, but there is no guarantee of the order being kept, and a small risk of the two logs getting out of sync. In write-intensive environments, can lead to a significant improvement in performance. * **Commandline:** `--innodb-enable-unsafe-group-commit` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `1` * **Removed:** Not needed after XtraDB 1.0.5 --- #### `innodb_encrypt_log` * **Description:** Enables encryption of the [InnoDB redo log](../innodb-redo-log/index). This also enables encryption of some temporary files created internally by InnoDB, such as those used for merge sorts and row logs. + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB / XtraDB Enabling Encryption: Enabling Encryption for Redo Log](../innodb-enabling-encryption/index#enabling-encryption-for-the-redo-log) for more information. * **Commandline:** `--innodb-encrypt-log` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_encrypt_tables` * **Description:** Enables automatic encryption of all InnoDB tablespaces. + `OFF` - Disables table encryption for all new and existing tables that have the `[ENCRYPTED](../create-table/index#encrypted)` table option set to `DEFAULT`. + `ON` - Enables table encryption for all new and existing tables that have the `[ENCRYPTED](../create-table/index#encrypted)` table option set to `DEFAULT`, but allows unencrypted tables to be created. + `FORCE` - Enables table encryption for all new and existing tables that have the `[ENCRYPTED](../create-table/index#encrypted)` table option set to `DEFAULT`, and doesn't allow unencrypted tables to be created (CREATE TABLE ... ENCRYPTED=NO will fail). + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB / XtraDB Enabling Encryption: Enabling Encryption for Automatically Encrypted Tablespaces](../innodb-enabling-encryption/index#enabling-encryption-for-automatically-encrypted-tablespaces) for more information. * **Commandline:** `--innodb-encrypt-tables={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Valid Values:** `ON`, `OFF`, `FORCE` --- #### `innodb_encrypt_temporary_tables` * **Description:** Enables automatic encryption of the InnoDB [temporary tablespace](../innodb-temporary-tablespaces/index). + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB / XtraDB Enabling Encryption: Enabling Encryption for Temporary Tablespaces](../innodb-enabling-encryption/index#enabling-encryption-for-temporary-tablespaces) for more information. * **Commandline:** `--innodb-encrypt-temporary-tables={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Valid Values:** `ON`, `OFF` * **Introduced:** [MariaDB 10.2.26](https://mariadb.com/kb/en/mariadb-10226-release-notes/), [MariaDB 10.3.17](https://mariadb.com/kb/en/mariadb-10317-release-notes/), [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/) --- #### `innodb_encryption_rotate_key_age` * **Description:** Re-encrypt in background any page having a key older than this number of key versions. When setting up encryption, this variable must be set to a non-zero value. Otherwise, when you enable encryption through `[innodb\_encrypt\_tables](#innodb_encrypt_tables)` MariaDB won't be able to automatically encrypt any unencrypted tables. + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB / XtraDB Encryption Keys: Key Rotation](../innodb-xtradb-encryption-keys/index#key-rotation) for more information. * **Commandline:** `--innodb-encryption-rotate-key-age=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `0` to `4294967295` --- #### `innodb_encryption_rotation_iops` * **Description:** Use this many iops for background key rotation operations performed by the background encryption threads. + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB / XtraDB Encryption Keys: Key Rotation](../innodb-xtradb-encryption-keys/index#key-rotation) for more information. * **Commandline:** `--innodb-encryption-rotation_iops=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `100` * **Range:** `0` to `4294967295` --- #### `innodb_encryption_threads` * **Description:** Number of background encryption threads threads performing background key rotation and [scrubbing](../innodb-data-scrubbing/index). When setting up encryption, this variable must be set to a non-zero value. Otherwise, when you enable encryption through [innodb\_encrypt\_tables](#innodb_encrypt_tables) MariaDB won't be able to automatically encrypt any unencrypted tables. Recommended never be set higher than 255. + See [Data-at-Rest Encryption](../data-at-rest-encryption/index) and [InnoDB Background Encryption Threads](../innodb-background-encryption-threads/index) for more information. * **Commandline:** `--innodb-encryption-threads=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** + `0` to `4294967295` (<= [MariaDB 10.1.45](https://mariadb.com/kb/en/mariadb-10145-release-notes/), [MariaDB 10.2.32](https://mariadb.com/kb/en/mariadb-10232-release-notes/), [MariaDB 10.3.23](https://mariadb.com/kb/en/mariadb-10323-release-notes/), [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/), [MariaDB 10.5.3](https://mariadb.com/kb/en/mariadb-1053-release-notes/)) + `0` to `255` (>= [MariaDB 10.1.46](https://mariadb.com/kb/en/mariadb-10146-release-notes/), [MariaDB 10.2.33](https://mariadb.com/kb/en/mariadb-10233-release-notes/), [MariaDB 10.3.24](https://mariadb.com/kb/en/mariadb-10324-release-notes/), [MariaDB 10.4.14](https://mariadb.com/kb/en/mariadb-10414-release-notes/), [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/)) --- #### `innodb_extra_rsegments` * **Description:** Removed in XtraDB 5.5 and replaced by [innodb\_rollback\_segments](#innodb_rollback_segments). Usually there is one rollback segment protected by single mutex, a source of contention in high write environments. This option specifies a number of extra user rollback segments. Changing the default will make the data readable by XtraDB only, and is incompatible with InnoDB. After modifying, the server must be slow-shutdown. If there is existing data, it must be dumped before changing, and re-imported after the change has taken effect. * **Commandline:** `--innodb-extra-rsegments=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `126` * **Removed:** XtraDB 5.5 - replaced by [innodb\_rollback\_segments](#innodb_rollback_segments) --- #### `innodb_extra_undoslots` * **Description:** Usually, InnoDB has 1024 undo slots in its rollback segment, so 1024 transactions can run in parallel. New transactions will fail if all slots are used. Setting this variable to `1` expands the available undo slots to 4072. Not recommended unless you get the `Warning: cannot find a free slot for an undo log` error in the error log, as it makes data files unusable for ibbackup, or MariaDB servers not run with this option. See also [undo log](../undo-log/index). * **Commandline:** `--innodb-extra-undoslots={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** XtraDB 5.5 --- #### `innodb_fake_changes` * **Description:** From [MariaDB 5.5](../what-is-mariadb-55/index) until [MariaDB 10.1](../what-is-mariadb-101/index), XtraDB-only option that enables the fake changes feature. In [replication](../replication/index), setting up or restarting a replica can cause a replication reads to perform more slowly, as MariaDB is single-threaded and needs to read the data before it can execute the queries. This can be speeded up by prefetching threads to warm the server, replaying the statements and then rolling back at commit. This however has an overhead from locking rows only then to undo changes at rollback. Fake changes attempts to reduce this overhead by reading the rows for INSERT, UPDATE and DELETE statements but not updating them. The rollback is then very fast with little or nothing to do. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. Not present in [MariaDB 10.3](../what-is-mariadb-103/index) and beyond. * **Commandline:** `--innodb-fake-changes={0|1}` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_fast_checksum` * **Description:** Implements a more CPU efficient XtraDB checksum algorithm, useful for write-heavy loads with high I/O. If set to `1` on a server with tables that have been created with it set to `0`, reads will be slower, so tables should be recreated (dumped and reloaded). XtraDB will fail to start if set to `0` and there are tables created while set to `1`. Replaced with [innodb\_checksum\_algorithm](#innodb_checksum_algorithm) in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6. * **Commandline:** `--innodb-fast-checksum={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 - replaced with [innodb\_checksum\_algorithm](#innodb_checksum_algorithm) --- #### `innodb_fast_shutdown` * **Description:** The shutdown mode. + `0` - InnoDB performs a slow shutdown, including full purge (before [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/), not always, due to [MDEV-13603](https://jira.mariadb.org/browse/MDEV-13603)) and change buffer merge. Can be very slow, even taking hours in extreme cases. + `1` - the default, [InnoDB](../innodb/index) performs a fast shutdown, not performing a full purge or an insert buffer merge. + `2`, the [InnoDB redo log](../xtradbinnodb-redo-log/index) is flushed and a cold shutdown takes place, similar to a crash. The resulting startup then performs crash recovery. Extremely fast, in cases of emergency, but risks corruption. Not suitable for upgrades between major versions! + `3` (from [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/)) - active transactions will not be rolled back, but all changed pages will be written to data files. The active transactions will be rolled back by a background thread on a subsequent startup. The fastest option that will not involve [InnoDB redo log](../xtradbinnodb-redo-log/index) apply on subsequent startup. See [MDEV-15832](https://jira.mariadb.org/browse/MDEV-15832). * **Commandline:** `--innodb-fast-shutdown[=#]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `0` to `3` (>= [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/)), `0` to `2` (<= [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/)) --- #### `innodb_fatal_semaphore_wait_threshold` * **Description:** In MariaDB, the fatal semaphore timeout is configurable. This variable sets the maximum number of seconds for semaphores to time out in InnoDB. * **Commandline:** `--innodb-fatal-semaphore-wait-threshold=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `600` * **Range:** `1` to `4294967295` --- #### `innodb_file_format` * **Description:** File format for new [InnoDB](../innodb/index) tables. Can either be `Antelope`, the default and the original format, or `Barracuda`, which supports [compression](../compression/index). Note that this value is also used when a table is re-created with an [ALTER TABLE](../alter-table/index) which requires a table copy. See [XtraDB/InnoDB File Format](../xtradbinnodb-file-format/index) for more on the file formats. Removed in 10.3.1 and restored as a deprecated and unused variable in 10.4.3 for compatibility purposes. * **Commandline:** `--innodb-file-format=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** + `Barracuda` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `Antelope` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Valid Values:** `Antelope`, `Barracuda` * **Deprecated:** [MariaDB 10.2](../what-is-mariadb-102/index) * **Removed:** [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) * **Re-introduced:** [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) (for compatibility purposes) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_file_format_check` * **Description:** If set to `1`, the default, [InnoDB](../innodb/index) checks the shared tablespace file format tag. If this is higher than the current version supported by XtraDB/InnoDB (for example Barracuda when only Antelope is supported), XtraDB/InnoDB will will not start. If it the value is not higher, XtraDB/InnoDB starts correctly and the [innodb\_file\_format\_max](#innodb_file_format_max) value is set to this value. If innodb\_file\_format\_check is set to `0`, no checking is performed. See [XtraDB/InnoDB File Format](../xtradbinnodb-file-format/index) for more on the file formats. * **Commandline:** `--innodb-file-format-check={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` * **Deprecated:** [MariaDB 10.2](../what-is-mariadb-102/index) * **Removed:** [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) --- #### `innodb_file_format_max` * **Description:** The highest [XtraDB/InnoDB](../innodb/index) file format. This is set to the value of the file format tag in the shared tablespace on startup (see [innodb\_file\_format\_check](#innodb_file_format_check)). If the server later creates a higher table format, innodb\_file\_format\_max is set to that value. See [XtraDB/InnoDB File Format](../xtradbinnodb-file-format/index) for more on the file formats. * **Commandline:** `--innodb-file-format-max=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `Antelope` * **Valid Values:** `Antelope`, `Barracuda` * **Deprecated:** [MariaDB 10.2](../what-is-mariadb-102/index) * **Removed:** [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) --- #### `innodb_file_per_table` * **Description:** If set to `ON`, then new [InnoDB](../innodb/index) tables are created with their own [InnoDB file-per-table tablespaces](../innodb-file-per-table-tablespaces/index). If set to `OFF`, then new tables are created in the [InnoDB system tablespace](../innodb-system-tablespaces/index) instead. [Page compression](../compression/index) is only available with file-per-table tablespaces. Note that this value is also used when a table is re-created with an [ALTER TABLE](../alter-table/index) which requires a table copy. * **Commandline:** `--innodb-file-per-table` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_fill_factor` * **Description:** Percentage of B-tree page filled during bulk insert (sorted index build). Used as a hint rather than an absolute value. Setting to `70`, for example, reserves 30% of the space on each B-tree page for the index to grow in future. * **Commandline:** `--innodb-fill-factor=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value**: `100` * **Range:** `10` to `100` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_flush_log_at_timeout` * **Description:** Interval in seconds to write and flush the [InnoDB redo log](../xtradbinnodb-redo-log/index). Before MariaDB 10, this was fixed at one second, which is still the default, but this can now be changed. It's usually increased to reduce flushing and avoid impacting performance of binary log group commit. * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `0` to `2700` --- #### `innodb_flush_log_at_trx_commit` * **Description:** Set to `1`, along with [sync\_binlog=1](../replication-and-binary-log-server-system-variables/index#sync_binlog) for the greatest level of fault tolerance. The value of [innodb\_use\_global\_flush\_log\_at\_trx\_commit](#innodb_use_global_flush_log_at_trx_commit) determines whether this variable can be reset with a SET statement or not. + `1` The default, the log buffer is written to the [InnoDB redo log](../innodb-redo-log/index) file and a flush to disk performed after each transaction. This is required for full ACID compliance. + `0` Nothing is done on commit; rather the log buffer is written and flushed to the [InnoDB redo log](../innodb-redo-log/index) once a second. This gives better performance, but a server crash can erase the last second of transactions. + `2` The log buffer is written to the [InnoDB redo log](../innodb-redo-log/index) after each commit, but flushing takes place once a second. Performance is slightly better, but a OS or power outage can cause the last second's transactions to be lost. + `3` Emulates [MariaDB 5.5](../what-is-mariadb-55/index) [group commit](../group-commit-for-the-binary-log/index) (3 syncs per group commit). See [Binlog group commit and innodb\_flush\_log\_at\_trx\_commit](../binlog-group-commit-and-innodb_flush_log_at_trx_commit/index). This option has not been working correctly since 10.2 and may be removed in future, see <https://github.com/MariaDB/server/pull/1873> * **Commandline:** `--innodb-flush-log-at-trx-commit[=#]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `1` * **Valid Values:** `0`, `1`, `2` or `3` --- #### `innodb_flush_method` * **Description:** [InnoDB](../innodb/index) flushing method. Windows always uses async\_unbuffered and this variable then has no effect. On Unix, before [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/), by default fsync() is used to flush data and logs. Adjusting this variable can give performance improvements, but behavior differs widely on different filesystems, and changing from the default has caused problems in some situations, so test and benchmark carefully before adjusting. In MariaDB, Windows recognises and correctly handles the Unix methods, but if none are specified it uses own default - unbuffered write (analog of O\_DIRECT) + syncs (e.g FileFlushBuffers()) for all files. + `O_DSYNC` - O\_DSYNC is used to open and flush logs, and fsync() to flush the data files. + `O_DIRECT` - O\_DIRECT or directio(), is used to open data files, and fsync() to flush data and logs. Default on Unix from [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/). + `fsync` - Default on Unix until [MariaDB 10.5](../what-is-mariadb-105/index). Can be specified directly, but if the variable is unset on Unix, fsync() will be used by default. + `O_DIRECT_NO_FSYNC` - introduced in [MariaDB 10.0](../what-is-mariadb-100/index). Uses O\_DIRECT during flushing I/O, but skips fsync() afterwards. Not suitable for XFS filesystems. Generally not recommended over O\_DIRECT, as does not get the benefit of [innodb\_use\_native\_aio=ON](#innodb_use_native_aio). + `ALL_O_DIRECT` - introduced in [MariaDB 5.5](../what-is-mariadb-55/index) and available with XtraDB only. Uses O\_DIRECT for opening both data and logs and fsync() to flush data but not logs. Use with large InnoDB files only, otherwise may cause a performance degradation. Set [innodb\_log\_block\_size](#innodb_log_block_size) to 4096 on ext4 filesystems. This is the default log block size on ext4 and will avoid unaligned AIO/DIO warnings. + `unbuffered` - Windows-only default + `async_unbuffered` - Windows-only, alias for `unbuffered` + `normal` - Windows-only, alias for `fsync` * **Commandline:** `--innodb-flush-method=name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `enumeration` (>= [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/)), `string` (<= [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/)) * **Default Value:** + `O_DIRECT` (Unix, >= [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/)) + `fsync` (Unix, >= [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/), <= [MariaDB 10.5](../what-is-mariadb-105/index)) + Not set (<= [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/)) * **Valid Values:** + Unix: `fsync`, `O_DSYNC`, `O_DIRECT`, `O_DIRECT_NO_FSYNC`, `ALL_O_DIRECT` (>= [MariaDB 5.5](../what-is-mariadb-55/index) to <= [MariaDB 10.1](../what-is-mariadb-101/index), XtraDB only) + Windows: `unbuffered`, `async_unbuffered`, `normal` --- #### `innodb_flush_neighbor_pages` * **Description:** Determines whether, when dirty pages are flushed to the data file, neighboring pages in the data file are flushed at the same time. If set to `none`, the feature is disabled. If set to `area`, the default, the standard InnoDB behavior is used. For each page to be flushed, dirty neighboring pages are flushed too. If there's little head seek delay, such as SSD or large enough write buffer, one of the other two options may be more efficient. If set to `cont`, for each page to be flushed, neighboring contiguous blocks are flushed at the same time. Being contiguous, a sequential I/O is used, unlike the random I/O used in `area`. Replaced by [innodb\_flush\_neighbors](#innodb_flush_neighbors) in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6. * **Commandline:** `innodb-flush-neighbor-pages=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `area` * **Valid Values:** `none` or `0`, `area` or `1`, `cont` or `2` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 - replaced by [innodb\_flush\_neighbors](#innodb_flush_neighbors) --- #### `innodb_flush_neighbors` * **Description:** Determines whether flushing a page from the [buffer pool](../innodb-buffer-pool/index) will flush other dirty pages in the same group of pages (extent). In high write environments, if flushing is not aggressive enough, it can fall behind resulting in higher memory usage, or if flushing is too aggressive, cause excess I/O activity. SSD devices, with low seek times, would be less likely to require dirty neighbor flushing to be set. Since [MariaDB 10.4.4](https://mariadb.com/kb/en/mariadb-1044-release-notes/) an attempt is made under Windows and Linux to determine SSD status which was exposed in [information\_schema.innodb\_tablespaces\_scrubbing\_table](../information-schema-innodb_tablespaces_scrubbing-table/index). This variable is ignored for table spaces that are detected as stored on SSD (and the `0` behavior applies). + `1`: The default, flushes contiguous dirty pages in the same extent from the buffer pool. + `0`: No other dirty pages are flushed. + `2`: Flushes dirty pages in the same extent from the buffer pool. * **Commandline:** `--innodb-flush-neighbors=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `1` * **Valid Values:** `0`, `1`, `2` --- #### `innodb_flush_sync` * **Description:** If set to `ON`, the default, the [innodb\_io\_capacity](#innodb_io_capacity) setting is ignored for I/O bursts occuring at checkpoints. * **Commandline:** `--innodb-flush-sync={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value**: `ON` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_flushing_avg_loops` * **Description:** Determines how quickly adaptive flushing will respond to changing workloads. The value is the number of iterations that a previously calculated flushing state snapshot is kept. Increasing the value smooths and slows the rate that the flushing operations change, while decreasing it causes flushing activity to spike quickly in response to workload changes. * **Commandline:** `--innodb-flushing-avg-loops=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `30` * **Range:** `1` to `1000` --- #### `innodb_force_load_corrupted` * **Description:** Set to `0` by default, if set to `1`, [InnoDB](../innodb/index) will be permitted to load tables marked as corrupt. Only use this to recover data you can't recover any other way, or in troubleshooting. Always restore to `0` when the returning to regular use. Given that [MDEV-11412](https://jira.mariadb.org/browse/MDEV-11412) in [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/) aims to allow any metadata for a missing or corrupted table to be dropped, and given that [MDEV-17567](https://jira.mariadb.org/browse/MDEV-17567) and [MDEV-25506](https://jira.mariadb.org/browse/MDEV-25506) and related tasks made DDL operations crash-safe, the parameter no longer serves any purpose and was removed in [MariaDB 10.6.6](https://mariadb.com/kb/en/mariadb-1066-release-notes/). * **Commandline:** `--innodb-force-load-corrupted` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.6.6](https://mariadb.com/kb/en/mariadb-1066-release-notes/) --- #### `innodb_force_primary_key` * **Description:** If set to `1` (`0` is default) CREATE TABLEs without a primary or unique key where all keyparts are NOT NULL will not be accepted, and will return an error. * **Commandline:** `--innodb-force-primary-key` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_force_recovery` * **Description:** [InnoDB](../innodb/index) crash recovery mode. `0` is the default. The other modes are for recovery purposes only, and no data can be changed while another mode is active. Some queries relying on indexes are also blocked. See [InnoDB Recovery Modes](../innodb-recovery-modes/index) for more on mode specifics. * **Commandline:** `--innodb-force-recovery=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `enumeration` * **Default Value:** `0` * **Range:** `0` to `6` --- #### `innodb_foreground_preflush` * **Description:** Before XtraDB 5.6.13-61.0, if the checkpoint age is in the sync preflush zone while a thread is writing to the [XtraDB redo log](../innodb-redo-log/index), it will try to advance the checkpoint by issuing a flush list flush batch if this is not already being done. XtraDB has enhanced page cleaner tuning, and may already be performing furious flushing, resulting in the flush simply adding unneeded mutex pressure. Instead, the thread now waits for the flushes to finish, and then has two options, controlled by this variable. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. + `exponential_backoff` - thread sleeps while it waits for the flush list flush to occur. The sleep time randomly progressively increases, periodically reset to avoid runaway sleeps. + `sync_preflush` - thread issues a flush list batch, and waits for it to complete. This is the same as is used when the page cleaner thread is not running. * **Commandline:** `innodb-foreground-preflush=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** + `deprecated` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `exponential_backoff` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) * **Valid Values:** + `deprecated`, `exponential_backoff`, `sync_preflush` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `exponential_backoff`, `sync_preflush` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_ft_aux_table` * **Description:** Diagnostic variable intended only to be set at runtime. It specifies the qualified name (for example `test/ft_innodb`) of an InnoDB table that has a [FULLTEXT index](../full-text-indexes/index), and after being set the INFORMATION\_SCHEMA tables [INNODB\_FT\_INDEX\_TABLE](../information-schema-innodb_ft_index_table-table/index), [INNODB\_FT\_INDEX\_CACHE](../information-schema-innodb_ft_index_cache-table/index), INNODB\_FT\_CONFIG, [INNODB\_FT\_DELETED](../information-schema-innodb_ft_deleted-table/index), and [INNODB\_FT\_BEING\_DELETED](../information-schema-innodb_ft_being_deleted-table/index) will contain search index information for the specified table. * **Commandline:** `--innodb-ft-aux-table=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` --- #### `innodb_ft_cache_size` * **Description:** Cache size available for a parsed document while creating an InnoDB [FULLTEXT index](../full-text-indexes/index). * **Commandline:** `--innodb-ft-cache-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `8000000` --- #### `innodb_ft_enable_diag_print` * **Description:** If set to `1`, additional [full-text](../full-text-indexes/index) search diagnostic output is enabled. * **Commandline:** `--innodb-ft-enable-diag-print={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_ft_enable_stopword` * **Description:** If set to `1`, the default, a set of [stopwords](../stopwords/index) is associated with an InnoDB [FULLTEXT index](../full-text-indexes/index) when it is created. The stopword list comes from the table set by the session variable [innodb\_ft\_user\_stopword\_table](#innodb_ft_user_stopword_table), if set, otherwise the global variable [innodb\_ft\_server\_stopword\_table](#innodb_ft_server_stopword_table), if that is set, or the [built-in list](../stopwords/index) if neither variable is set. * **Commandline:** `--innodb-ft-enable-stopword={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_ft_max_token_size` * **Description:** Maximum length of words stored in an InnoDB [FULLTEXT index](../full-text-indexes/index). A larger limit will increase the size of the index, slowing down queries, but permit longer words to be searched for. In most normal situations, longer words are unlikely search terms. * **Commandline:** `--innodb-ft-max-token-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `84` * **Range:** `10` to `84` --- #### `innodb_ft_min_token_size` * **Description:** Minimum length of words stored in an InnoDB [FULLTEXT index](../full-text-indexes/index). A smaller limit will increase the size of the index, slowing down queries, but permit shorter words to be searched for. For data stored in a Chinese, Japanese or Korean [character set](../data-types-character-sets-and-collations/index), a value of 1 should be specified to preserve functionality. * **Commandline:** `--innodb-ft-min-token-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `3` * **Range:** `0` to `16` --- #### `innodb_ft_num_word_optimize` * **Description:** Number of words processed during each [OPTIMIZE TABLE](../optimize-table/index) on an InnoDB [FULLTEXT index](../full-text-indexes/index). To ensure all changes are incorporated, multiple OPTIMIZE TABLE statements could be run in case of a substantial change to the index. * **Commandline:** `--innodb-ft-num-word-optimize=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `2000` --- #### `innodb_ft_result_cache_limit` * **Description:** Limit in bytes of the InnoDB [FULLTEXT index](../full-text-indexes/index) query result cache per fulltext query. The latter stages of the full-text search are handled in memory, and limiting this prevents excess memory usage. If the limit is exceeded, the query returns an error. * **Commandline:** `--innodb-ft-result-cache-limit=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `2000000000` * **Range:** `1000000` to `4294967295` (<= [MariaDB 10.2.18](https://mariadb.com/kb/en/mariadb-10218-release-notes/), [MariaDB 10.1.36](https://mariadb.com/kb/en/mariadb-10136-release-notes/), [MariaDB 10.0.36](https://mariadb.com/kb/en/mariadb-10036-release-notes/)) * **Range:** `1000000` to `18446744073709551615` (64-bit, >= [MariaDB 10.2.19](https://mariadb.com/kb/en/mariadb-10219-release-notes/), [MariaDB 10.1.37](https://mariadb.com/kb/en/mariadb-10137-release-notes/), [MariaDB 10.0.37](https://mariadb.com/kb/en/mariadb-10037-release-notes/)) --- #### `innodb_ft_server_stopword_table` * **Description:** Table name containing a list of stopwords to ignore when creating an InnoDB [FULLTEXT index](../full-text-indexes/index), in the format db\_name/table\_name. The specified table must exist before this option is set, and must be an InnoDB table with a single column, a [VARCHAR](../varchar/index) named VALUE. See also [innodb\_ft\_enable\_stopword](#innodb_ft_enable_stopword). * **Commandline:** `--innodb-ft-server-stopword-table=db_name/table_name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** Empty --- #### `innodb_ft_sort_pll_degree` * **Description:** Number of parallel threads used when building an InnoDB [FULLTEXT index](../full-text-indexes/index). See also [innodb\_sort\_buffer\_size](#innodb_sort_buffer_size). * **Commandline:** `--innodb-ft-sort-pll-degree=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `2` * **Range:** `1` to `32` --- #### `innodb_ft_total_cache_size` * **Description:**Total memory allocated for the cache for all InnoDB [FULLTEXT index](../full-text-indexes/index) tables. A force sync is triggered if this limit is exceeded. * **Commandline:** `--innodb-ft-total-cache-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `640000000` * **Range:** `32000000` to `1600000000` * **Introduced:** [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/) --- #### `innodb_ft_user_stopword_table` * **Description:** Table name containing a list of stopwords to ignore when creating an InnoDB [FULLTEXT index](../full-text-indexes/index), in the format db\_name/table\_name. The specified table must exist before this option is set, and must be an InnoDB table with a single column, a [VARCHAR](../varchar/index) named VALUE. See also [innodb\_ft\_enable\_stopword](#innodb_ft_enable_stopword). * **Commandline:** `--innodb-ft-user-stopword-table=db_name/table_name` * **Scope:** Session * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** Empty --- #### `innodb_ibuf_accel_rate` * **Description:** Allows the insert buffer activity to be adjusted. The following formula is used: [real activity] = [default activity] \* (innodb\_io\_capacity/100) \* (innodb\_ibuf\_accel\_rate/100). As `innodb_ibuf_accel_rate` is increased from its default value of `100`, the lowest setting, insert buffer activity is increased. See also [innodb\_io\_capacity](#innodb_io_capacity). This Percona XtraDB variable has not been ported to XtraDB 5.6. * **Commandline:** `innodb-ibuf-accel-rate=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `100` * **Range:** `100` to `999999999` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_ibuf_active_contract` * **Description:** Specifies whether the insert buffer can be processed before it's full. If set to `0`, the standard InnoDB method is used, and the buffer is not processed until it's full. If set to `1`, the default, the insert buffer can be processed before it is full. This Percona XtraDB variable has not been ported to XtraDB 5.6. * **Commandline:** `innodb-ibuf-active-contract=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `0` to `1` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_ibuf_max_size` * **Description:** Maximum size in bytes of the insert buffer. Defaults to half the size of the [buffer pool](../innodb-buffer-pool/index) so you may want to reduce if you have a very large buffer pool. If set to `0`, the insert buffer is disabled, which will cause all secondary index updates to be performed synchronously, usually at a cost to performance. This Percona XtraDB variable has not been ported to XtraDB 5.6. * **Commandline:** `innodb-ibuf-max-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** 1/2 the size of the InnoDB buffer pool * **Range:** `0` to 1/2 the size of the InnoDB buffer pool * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_idle_flush_pct` * **Description:** Up to what percentage of dirty pages should be flushed when innodb finds it has spare resources to do so. Has had no effect since merging InnoDB 5.7 from mysql-5.7.9 ([MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)). Deprecated in [MariaDB 10.2.37](https://mariadb.com/kb/en/mariadb-10237-release-notes/), [MariaDB 10.3.28](https://mariadb.com/kb/en/mariadb-10328-release-notes/), [MariaDB 10.4.18](https://mariadb.com/kb/en/mariadb-10418-release-notes/) and removed in [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/). * **Commandline:** `--innodb-idle-flush-pct=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `100` * **Range:** `0` to `100` * **Deprecated:** [MariaDB 10.2.37](https://mariadb.com/kb/en/mariadb-10237-release-notes/), [MariaDB 10.3.28](https://mariadb.com/kb/en/mariadb-10328-release-notes/), [MariaDB 10.4.18](https://mariadb.com/kb/en/mariadb-10418-release-notes/) * **Removed:** [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/) --- #### `innodb_immediate_scrub_data_uncompressed` * **Description:** Enable scrubbing of data. See [Data Scrubbing](../innodb-data-scrubbing/index). * **Commandline:** `--innodb-immediate-scrub-data-uncompressed={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_import_table_from_xtrabackup` * **Description:** If set to `1`, permits importing of .ibd files exported with the [XtraBackup](../backup-restore-and-import-xtrabackup/index) --export option. Previously named `innodb_expand_import`. Removed in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 and replaced with MySQL 5.6's transportable tablespaces. * **Commandline:** `innodb-import-table-from-xtrabackup=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `1` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_instant_alter_column_allowed` * **Description:** + If a table is altered using ALGORITHM=INSTANT, it can force the table to use a non-canonical format: A hidden metadata record at the start of the clustered index is used to store each column's DEFAULT value. This makes it possible to add new columns that have default values without rebuilding the table. Starting with [MariaDB 10.4](../what-is-mariadb-104/index), a BLOB in the hidden metadata record is used to store column mappings. This makes it possible to drop or reorder columns without rebuilding the table. This also makes it possible to add columns to any position or drop columns from any position in the table without rebuilding the table. If a column is dropped without rebuilding the table, old records will contain garbage in that column's former position, and new records will be written with NULL values, empty strings, or dummy values. + This is generally not a problem. However, there may be cases where you want to avoid putting a table into this format. For example, to ensure that future UPDATE operations after an ADD COLUMN will be performed in-place, to reduce write amplification. (Instantly added columns are essentially always variable-length.) Also avoid bugs similar to [MDEV-19916](https://jira.mariadb.org/browse/MDEV-19916), or to be able to export tables to older versions of the server. + This variable has been introduced as a result, with the following values: + `never` (0): Do not allow instant add/drop/reorder, to maintain format compatibility with MariaDB 10.x and MySQL 5.x. If the table (or partition) is not in the canonical format, then any ALTER TABLE (even one that does not involve instant column operations) will force a table rebuild. + `add_last` (1, default in 10.3): Store a hidden metadata record that allows columns to be appended to the table instantly ([MDEV-11369](https://jira.mariadb.org/browse/MDEV-11369)). In 10.4 or later, if the table (or partition) is not in this format, then any ALTER TABLE (even one that does not involve column changes) will force a table rebuild. + `add_drop_reorder` (2, default): From [MariaDB 10.4](../what-is-mariadb-104/index) only. Like 'add\_last', but allow the metadata record to store a column map, to support instant add/drop/reorder of columns. * **Commandline:** `--innodb-instant-alter-column-allowed=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Valid Values:** + <= [MariaDB 10.3](../what-is-mariadb-103/index): `never`, `add_last` + >= [MariaDB 10.4](../what-is-mariadb-104/index): `never`, `add_last`, `add_drop_reorder` * **Default Value:** + <= [MariaDB 10.3](../what-is-mariadb-103/index): `add_last` + >= [MariaDB 10.4](../what-is-mariadb-104/index): `add_drop_reorder` * **Introduced:** [MariaDB 10.3.23](https://mariadb.com/kb/en/mariadb-10323-release-notes/), [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/), [MariaDB 10.5.3](https://mariadb.com/kb/en/mariadb-1053-release-notes/) --- #### `innodb_instrument_semaphores` * **Description:** Enable semaphore request instrumentation. This could have some effect on performance but allows better information on long semaphore wait problems. * **Commandline:** `--innodb-instrument-semaphores={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.5](https://mariadb.com/kb/en/mariadb-1025-release-notes/) (treated as if `OFF`) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_io_capacity` * **Description:** Limit on I/O activity for InnoDB background tasks, including merging data from the insert buffer and flushing pages. Should be set to around the number of I/O operations per second that system can handle, based on the type of drive/s being used. You can also set it higher when the server starts to help with the extra workload at that time, and then reduce for normal use. Ideally, opt for a lower setting, as at higher value data is removed from the buffers too quickly, reducing the effectiveness of caching. See also [innodb\_flush\_sync](#innodb_flush_sync). + See [InnoDB Page Flushing: Configuring the InnoDB I/O Capacity](../innodb-page-flushing/index#configuring-the-innodb-io-capacity) for more information. * **Commandline:** `--innodb-io-capacity=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `200` * **Range:** `100` to `18446744073709551615` (264-1) --- #### `innodb_io_capacity_max` * **Description:** Upper limit to which InnoDB can extend [innodb\_io\_capacity](#innodb_io_capacity) in case of emergency. See [InnoDB Page Flushing: Configuring the InnoDB I/O Capacity](../innodb-page-flushing/index#configuring-the-innodb-io-capacity) for more information. * **Commandline:** `--innodb-io-capacity-max=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `2000` or twice [innodb\_io\_capacity](#innodb_io_capacity), whichever is higher. * **Range :** `100` to `18446744073709551615` (264-1) --- #### `innodb_kill_idle_transaction` * **Description:** Time in seconds before killing an idle XtraDB transaction. If set to `0` (the default), the feature is disabled. Used to prevent accidental user locks. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `9223372036854775807` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_large_prefix` * **Description:** If set to `1`, tables that use specific [row formats](../innodb-row-formats-overview/index) are permitted to have index key prefixes up to 3072 bytes (for 16k pages, [smaller otherwise](../innodb-limitations/index#page-sizes)). If not set, the limit is 767 bytes. + This applies to the `[DYNAMIC](../innodb-dynamic-row-format/index)` and `[COMPRESSED](../innodb-compressed-row-format/index)` row formats. + Removed in 10.3.1 and restored as a deprecated and unused variable in 10.4.3 for compatibility purposes. * **Commandline:** `--innodb-large-prefix` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** + `ON` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `OFF` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Deprecated:** [MariaDB 10.2](../what-is-mariadb-102/index) * **Removed:** [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) * **Re-introduced:** [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) (for compatibility purposes) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_lazy_drop_table` * **Description:** Deprecated and removed in XtraDB 5.6. [DROP TABLE](../drop-table/index) processing can take a long time when [innodb\_file\_per\_table](#innodb_file_per_table) is set to 1 and there's a large [buffer pool](../xtradbinnodb-memory-buffer/index). If `innodb_lazy_drop_table` is set to `1` (`0` is default), XtraDB attempts to optimize [DROP TABLE](../drop-table/index) processing by deferring the dropping of related pages from the [buffer pool](../xtradbinnodb-memory-buffer/index) until there is time, only initially marking them. * **Commandline:** `innodb-lazy-drop-table={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `0` * **Deprecated:** XtraDB 5.5.30-30.2 * **Removed:** [MariaDB 10.0.0](https://mariadb.com/kb/en/mariadb-1000-release-notes/) --- #### `innodb_lock_schedule_algorithm` * **Description:** Specifies the algorithm that InnoDB/XtraDB uses to decide which of the waiting transactions should be granted the lock once it has been released. The possible values are: `FCFS` (First-Come-First-Served) where locks are granted in the order they appear in the lock queue and `VATS` (Variance-Aware-Transaction-Scheduling) where locks are granted based on the Eldest-Transaction-First heuristic. Note that `VATS` should not be used with [Galera](../galera/index). From [MariaDB 10.1.30](https://mariadb.com/kb/en/mariadb-10130-release-notes/), InnoDB will refuse to start if `VATS` is used with Galera. From [MariaDB 10.2](../what-is-mariadb-102/index), `VATS` is default, but from [MariaDB 10.2.12](https://mariadb.com/kb/en/mariadb-10212-release-notes/), the value will be changed to `FCFS` and a warning produced when using Galera. * **Commandline:** `--innodb-lock-schedule-algorithm=#` * **Scope:** Global * **Dynamic:** No (>= [MariaDB 10.2.12](https://mariadb.com/kb/en/mariadb-10212-release-notes/), [MariaDB 10.1.30](https://mariadb.com/kb/en/mariadb-10130-release-notes/)), Yes (<= [MariaDB 10.2.11](https://mariadb.com/kb/en/mariadb-10211-release-notes/), [MariaDB 10.1.29](https://mariadb.com/kb/en/mariadb-10129-release-notes/)) * **Data Type:** `enum` * **Valid Values:** `FCFS`, `VATS` * **Default Value:** `FCFS` ([MariaDB 10.3.9](https://mariadb.com/kb/en/mariadb-1039-release-notes/), [MariaDB 10.2.17](https://mariadb.com/kb/en/mariadb-10217-release-notes/)), `VATS` ([MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)), `FCFS` ([MariaDB 10.1](../what-is-mariadb-101/index)) * **Deprecated:** [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/), [MariaDB 10.4.16](https://mariadb.com/kb/en/mariadb-10416-release-notes/), [MariaDB 10.3.26](https://mariadb.com/kb/en/mariadb-10326-release-notes/), [MariaDB 10.2.35](https://mariadb.com/kb/en/mariadb-10235-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_lock_wait_timeout` * **Description:** Time in seconds that an InnoDB transaction waits for an InnoDB record lock (or table lock) before giving up with the error `ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction`. When this occurs, the statement (not transaction) is rolled back. The whole transaction can be rolled back if the [innodb\_rollback\_on\_timeout](#innodb_rollback_on_timeout) option is used. Increase this for data warehousing applications or where other long-running operations are common, or decrease for OLTP and other highly interactive applications. This setting does not apply to deadlocks, which InnoDB detects immediately, rolling back a deadlocked transaction. `0` (from [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/)) means no wait. See [WAIT and NOWAIT](../wait-and-nowait/index). Setting to `100000000` or more (from [MariaDB 10.6.3](https://mariadb.com/kb/en/mariadb-1063-release-notes/), `100000000` is the maximum) means the timeout is infinite. * **Commandline:** `--innodb-lock-wait-timeout=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `INT UNSIGNED` (>= [MariaDB 10.6.3](https://mariadb.com/kb/en/mariadb-1063-release-notes/)), `BIGINT UNSIGNED` (<= [MariaDB 10.6.2](https://mariadb.com/kb/en/mariadb-1062-release-notes/)) * **Default Value:** `50` * **Range:** + `0` to `100000000` (>= [MariaDB 10.6.3](https://mariadb.com/kb/en/mariadb-1063-release-notes/)) + `0` to `1073741824` (>= [MariaDB 10.3](../what-is-mariadb-103/index) to <= [MariaDB 10.6.2](https://mariadb.com/kb/en/mariadb-1062-release-notes/)) + `1` to `1073741824` (<= [MariaDB 10.2](../what-is-mariadb-102/index)) --- #### `innodb_locking_fake_changes` * **Description:** From [MariaDB 5.5](../what-is-mariadb-55/index) to [MariaDB 10.1](../what-is-mariadb-101/index), XtraDB-only option that if set to `OFF`, fake transactions (see [innodb\_fake\_changes](#innodb_fake_changes)) don't take row locks. This is an experimental feature to attempt to deal with drawbacks in fake changes blocking real locks. It is not safe for use in all environments. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `--innodb-locking-fake-changes` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_locks_unsafe_for_binlog` * **Description:** Set to `0` by default, in which case XtraDB/InnoDB uses [gap locking](../xtradbinnodb-lock-modes/index#gap-locks). If set to `1`, gap locking is disabled for searches and index scans. Deprecated in [MariaDB 10.0](../what-is-mariadb-100/index), and removed in [MariaDB 10.5](../what-is-mariadb-105/index), use [READ COMMITTED transaction isolation level](../set-transaction/index#read-committed) instead. * **Commandline:** `--innodb-locks-unsafe-for-binlog` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) --- #### `innodb_log_arch_dir` * **Description:** The directory for [XtraDB redo log](../innodb-redo-log/index) archiving. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `--innodb-log-arch-dir=name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** `./` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_log_arch_expire_sec` * **Description:** Time in seconds since the last change after which the archived [XtraDB redo log](../xtradbinnodb-redo-log/index) should be deleted. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `--innodb-log-arch-expire-sec=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_log_archive` * **Description:** Whether or not [XtraDB redo log](../xtradbinnodb-redo-log/index) archiving is enabled. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `--innodb-log-archive={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_log_block_size` * **Description:** Size in bytes of the [XtraDB redo log](../xtradbinnodb-redo-log/index) records. Generally `512`, the default, or `4096`, are the only two useful values. If the server is restarted and this value is changed, all old log files need to be removed. Should be set to `4096` for SSD cards or if [innodb\_flush\_method](#innodb_flush_method) is set to `ALL_O_DIRECT` on ext4 filesystems. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-log-block-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `512` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_log_buffer_size` * **Description:** Size in bytes of the buffer for writing [InnoDB redo log](../xtradbinnodb-redo-log/index) files to disk. Increasing this means larger transactions can run without needing to perform disk I/O before committing. * **Commandline:** `--innodb-log-buffer-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `16777216` (16MB) * **Range:** `262144` to `4294967295` (256KB to 4096MB) --- #### `innodb_log_checksum_algorithm` * **Description:** Experimental feature (as of [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/)), this variable specifies how to generate and verify [XtraDB redo log](../xtradbinnodb-redo-log/index) checksums. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. + `none` - No checksum. A constant value is instead written to logs, and no checksum validation is performed. + `innodb` - The default, and the original InnoDB algorithm. This is inefficient, but compatible with all MySQL, MariaDB and Percona versions that don't support other checksum algorithms. + `crc32` - CRC32© is used for log block checksums, which also permits recent CPUs to use hardware acceleration (on SSE4.2 x86 machines and Power8 or later) for the checksums. + `strict_*` - Whether or not to accept checksums from other algorithms. If strict mode is used, checksums blocks will be considered corrupt if they don't match the specified algorithm. Normally they are considered corrupt only if no other algorithm matches. * **Commandline:** `innodb-log-checksum-algorithm=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** + `deprecated` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `innodb` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) * **Valid Values:** + `deprecated`, `innodb`, `none`, `crc32`, `strict_none`, `strict_innodb`, `strict_crc32` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `innodb`, `none`, `crc32`, `strict_none`, `strict_innodb`, `strict_crc32` (<= [MariaDB 10.1](../what-is-mariadb-101/index)) * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_log_checksums` * **Description:** If set to `1`, the CRC32C for Innodb or `innodb_log_checksum_algorithm` for XtraDB algorithm is used for [InnoDB redo log](../xtradbinnodb-redo-log/index) pages. If disabled, the checksum field contents are ignored. From [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/), the variable is deprecated, and checksums are always calculated, as previously, the InnoDB redo log used the slow innodb algorithm, but with hardware or SIMD assisted CRC-32C computation being available, there is no reason to allow checksums to be disabled on the redo log. * **Commandline:** `innodb-log-checksums={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) * **Deprecated:** [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_log_compressed_pages` * **Description:** Whether or not images of recompressed pages are stored in the [InnoDB redo log](../innodb-redo-log/index). Deprecated and ignored from [MariaDB 10.5.3](https://mariadb.com/kb/en/mariadb-1053-release-notes/). * **Commandline:** `--innodb-log-compressed-pages={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** + `ON` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/), >= [MariaDB 10.1.26](https://mariadb.com/kb/en/mariadb-10126-release-notes/), <= [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/)) + `OFF` ([MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) - [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/), [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) - [MariaDB 10.1.25](https://mariadb.com/kb/en/mariadb-10125-release-notes/)) * **Deprecated:** [MariaDB 10.5.3](https://mariadb.com/kb/en/mariadb-1053-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_log_file_buffering` * **Description:** Whether the file system cache for ib\_logfile0 is enabled. In [MariaDB 10.8.3](https://mariadb.com/kb/en/mariadb-1083-release-notes/), MariaDB disabled the file system cache on the InnoDB write-ahead log file (ib\_logfile0) by default on Linux. With [innodb\_flush\_trx\_log\_at\_commit=2](#innodb_flush_log_at_trx_commit) in particular, writing to the log via the file system cache typically improves throughput, especially on slow storage or at a small number of concurrent transactions. For other values of innodb\_flush\_log\_at\_trx\_commit, direct writes were observed to be mostly but not always faster. Whether it pays off to disable the file system cache on the log may depend on the type of storage, the workload, and the operating system kernel version. If the server is started up with [innodb\_flush\_log\_at\_trx\_commit=2](#innodb_flush_log_at_trx_commit), the value will be changed to innodb\_log\_file\_buffering=ON. Linux and Windows only. * **Commandline:** `--innodb-log-file-buffering={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.8.4](https://mariadb.com/kb/en/mariadb-1084-release-notes/), [MariaDB 10.9.2](https://mariadb.com/kb/en/mariadb-1092-release-notes/) --- #### `innodb_log_file_size` * **Description:** Size in bytes of each [InnoDB redo log](../innodb-redo-log/index) file in the log group. The combined size can be no more than 512GB. Larger values mean less disk I/O due to less flushing checkpoint activity, but also slower recovery from a crash. In [MariaDB 10.5](../what-is-mariadb-105/index), crash recovery has been improved and shouldn't run out of memory, so the default has been increased. It can safely be set higher to reduce checkpoint flushing, even larger than [innodb\_buffer\_pool\_size](#innodb_buffer_pool_size). From [MariaDB 10.9](../what-is-mariadb-109/index) the variable is dynamic, and the server no longer needs to be restarted for the resizing to take place. Unless the log is located in a persistent memory file system (PMEM), an attempt to [SET GLOBAL](../set/index) innodb\_log\_file\_size to less than [innodb\_log\_buffer\_size](#innodb_log_buffer_size) will be refused. Log resizing can be aborted by killing the connection that is executing the SET GLOBAL statement. * **Commandline:** `--innodb-log-file-size=#` * **Scope:** Global * **Dynamic:** Yes (>= [MariaDB 10.9](../what-is-mariadb-109/index)), No (<= [MariaDB 10.8](../what-is-mariadb-108/index)) * **Data Type:** `numeric` * **Default Value:** `100663296` (96MB) (>= [MariaDB 10.5](../what-is-mariadb-105/index)), `50331648` (48MB) (<= [MariaDB 10.4](../what-is-mariadb-104/index)) * **Range:** + >= [MariaDB 10.8.3](https://mariadb.com/kb/en/mariadb-1083-release-notes/): `4194304` to `512GB` (4MB to 512GB) + <= [MariaDB 10.8.2](https://mariadb.com/kb/en/mariadb-1082-release-notes/): `1048576` to `512GB` (1MB to 512GB) --- #### `innodb_log_files_in_group` * **Description:** Number of physical files in the [InnoDB redo log](../xtradbinnodb-redo-log/index). Deprecated and ignored from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Commandline:** `--innodb-log-files-in-group=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1` (>= [MariaDB 10.5](../what-is-mariadb-105/index)), `2` (<= [MariaDB 10.4](../what-is-mariadb-104/index)) * **Range:** `1` to `100` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)), `2` to `100` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) * **Deprecated:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_log_group_home_dir` * **Description:** Path to the [InnoDB redo log](../xtradbinnodb-redo-log/index) files. If none is specified, [innodb\_log\_files\_in\_group](#innodb_log_files_in_group) files named ib\_logfile0 and so on, with a size of [innodb\_log\_file\_size](#innodb_log_file_size) are created in the data directory. * **Commandline:** `--innodb-log-group-home-dir=path` * **Scope:** Global * **Dynamic:** No * **Data Type:** `directory name` --- #### `innodb_log_optimize_ddl` * **Description:** Whether [InnoDB redo log](../innodb-redo-log/index) activity should be reduced when natively creating indexes or rebuilding tables. Reduced logging requires additional page flushing and interferes with [Mariabackup](../mariabackup/index). Enabling this may slow down backup and cause delay due to page flushing. Deprecated and ignored from [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/). Deprecated (but not ignored) from [MariaDB 10.4.16](https://mariadb.com/kb/en/mariadb-10416-release-notes/), [MariaDB 10.3.26](https://mariadb.com/kb/en/mariadb-10326-release-notes/) and [MariaDB 10.2.35](https://mariadb.com/kb/en/mariadb-10235-release-notes/). * **Commandline:** `--innodb-log-optimize-ddl={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** + `OFF` (>= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/), [MariaDB 10.4.16](https://mariadb.com/kb/en/mariadb-10416-release-notes/), [MariaDB 10.3.26](https://mariadb.com/kb/en/mariadb-10326-release-notes/), [MariaDB 10.2.35](https://mariadb.com/kb/en/mariadb-10235-release-notes/)) + `ON` (<= [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/), [MariaDB 10.4.15](https://mariadb.com/kb/en/mariadb-10415-release-notes/), [MariaDB 10.3.25](https://mariadb.com/kb/en/mariadb-10325-release-notes/), [MariaDB 10.2.34](https://mariadb.com/kb/en/mariadb-10234-release-notes/)) * **Introduced:** [MariaDB 10.2.17](https://mariadb.com/kb/en/mariadb-10217-release-notes/), [MariaDB 10.3.9](https://mariadb.com/kb/en/mariadb-1039-release-notes/) * **Deprecated:** [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/), [MariaDB 10.4.16](https://mariadb.com/kb/en/mariadb-10416-release-notes/), [MariaDB 10.3.26](https://mariadb.com/kb/en/mariadb-10326-release-notes/), [MariaDB 10.2.35](https://mariadb.com/kb/en/mariadb-10235-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_log_write_ahead_size` * **Description:** [InnoDB redo log](../xtradbinnodb-redo-log/index) write ahead unit size to avoid read-on-write. Should match the OS cache block IO size. * **Commandline:** `--innodb-log-write-ahead-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `8192` * **Range:** `512` to [innodb\_page\_size](#innodb_page_size) * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_lru_flush_size` * **Description:** Number of pages to flush on LRU eviction. * **Commandline:** `--innodb-lru-flush-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `32` * **Range:** `1` to `18446744073709551615` * **Introduced:** [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/) --- #### `innodb_lru_scan_depth` * **Description:** Specifies how far down the buffer pool least-recently used (LRU) list the cleaning thread should look for dirty pages to flush. This process is performed once a second. In an I/O intensive-workload, can be increased if there is spare I/O capacity, or decreased if in a write-intensive workload with little spare I/O capacity. + See [InnoDB Page Flushing](../innodb-page-flushing/index) for more information. * **Commandline:** `--innodb-lru-scan-depth=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** + `1536` (>= [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/)) + `1024` (<= [MariaDB 10.5.6](https://mariadb.com/kb/en/mariadb-1056-release-notes/)) * **Range - 32bit:** `100` to `232-1` * **Range - 64bit:** `100` to `264-1` --- #### `innodb_max_bitmap_file_size` * **Description:** Limit in bytes of the changed page bitmap files. For faster incremental backup with [Xtrabackup](../backup-restore-and-import-xtrabackup/index), XtraDB tracks pages with changes written to them according to the [XtraDB redo log](../xtradbinnodb-redo-log/index) and writes the information to special changed page bitmap files. These files are rotated when the server restarts or when this limit is reached. XtraDB only. See also [innodb\_track\_changed\_pages](#innodb_track_changed_pages) and [innodb\_max\_changed\_pages](#innodb_max_changed_pages). + Deprecated and ignored in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-max-bitmap-file-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `4096` (4KB) * **Range:** `4096` (4KB) to `18446744073709551615` (16EB) * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) --- #### `innodb_max_changed_pages` * **Description:** Limit to the number of changed page bitmap files (stored in the [Information Schema INNODB\_CHANGED\_PAGES table](../information-schema-innodb_changed_pages-table/index)). Zero is unlimited. See [innodb\_max\_bitmap\_file\_size](#innodb_max_bitmap_file_size) and [innodb\_track\_changed\_pages](#innodb_track_changed_pages). Previously named `innodb_changed_pages_limit`. XtraDB only. + Deprecated and ignored in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-max-changed-pages=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1000000` * **Range:** `0` to `18446744073709551615` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) --- #### `innodb_max_dirty_pages_pct` * **Description:** Maximum percentage of unwritten (dirty) pages in the buffer pool. + See [InnoDB Page Flushing](../innodb-page-flushing/index) for more information. * **Commandline:** `--innodb-max-dirty-pages-pct=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** + `90.000000` (>= [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/)) + `75.000000` (<= [MariaDB 10.5.6](https://mariadb.com/kb/en/mariadb-1056-release-notes/)) * **Range:** `0` to `99.999` --- #### `innodb_max_dirty_pages_pct_lwm` * **Description:** Low water mark percentage of dirty pages that will enable preflushing to lower the dirty page ratio. The value 0 (default) means 'refer to [innodb\_max\_dirty\_pages\_pct](#innodb_max_dirty_pages_pct)'. + See [InnoDB Page Flushing](../innodb-page-flushing/index) for more information. * **Commandline:** `--innodb-max-dirty-pages-pct-lwm=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), `0.001000` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Range:** `0` to `99.999` --- #### `innodb_max_purge_lag` * **Description:** When purge operations are lagging on a busy server, setting innodb\_max\_purge\_lag can help. By default set to `0`, no lag, the figure is used to calculate a time lag for each INSERT, UPDATE, and DELETE when the system is lagging. XtraDB/InnoDB keeps a list of transactions with delete-marked index records due to UPDATE and DELETE statements. The length of this list is `purge_lag`, and the calculation, performed every ten seconds, is as follows: ((purge\_lag/innodb\_max\_purge\_lag)×10)–5 milliseconds. * **Commandline:** `--innodb-max-purge-lag=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `4294967295` --- #### `innodb_max_purge_lag_delay` * **Description:** Maximum delay in milliseconds imposed by the [innodb\_max\_purge\_lag](#innodb_max_purge_lag) setting. If set to `0`, the default, there is no maximum. * **Commandline:** `--innodb-max-purge-lag-delay=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` --- #### `innodb_max_purge_lag_wait` * **Description:** Wait until History list length is below the specified limit. * **Commandline:** `--innodb-max-purge-wait=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `4294967295` * **Range:** `0` to `4294967295` * **Introduced:** [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/), [MariaDB 10.4.16](https://mariadb.com/kb/en/mariadb-10416-release-notes/), [MariaDB 10.3.26](https://mariadb.com/kb/en/mariadb-10326-release-notes/), [MariaDB 10.2.35](https://mariadb.com/kb/en/mariadb-10235-release-notes/) --- #### `innodb_max_undo_log_size` * **Description:** If an undo tablespace is larger than this, it will be marked for truncation if [innodb\_undo\_log\_truncate](#innodb_undo_log_truncate) is set. * **Commandline:** `--innodb-max-undo-log-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** + `10485760` (>= [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)) + `1073741824` (<= [MariaDB 10.2.5](https://mariadb.com/kb/en/mariadb-1025-release-notes/)) * **Range:** `10485760` to `18446744073709551615` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_merge_sort_block_size` * **Description:** Size in bytes of the block used for merge sorting in fast index creation. Replaced in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 by [innodb\_sort\_buffer\_size](#innodb_sort_buffer_size). * **Commandline:** `innodb-merge-sort-block-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1048576` (1M) * **Range:** `1048576` (1M) to `1073741824` (1G) * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) - replaced by [innodb\_sort\_buffer\_size](#innodb_sort_buffer_size) --- #### `innodb_mirrored_log_groups` * **Description:** Unused. Restored as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Deprecated:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) - [MariaDB 10.2.5](https://mariadb.com/kb/en/mariadb-1025-release-notes/) --- #### `innodb_mtflush_threads` * **Description:** Sets the number of threads to use in Multi-Threaded Flush operations. For more information, see [Fusion-io Multi-threaded Flush](../fusion-io-multi-threaded-flush/index). + InnoDB's multi-thread flush feature was deprecated in [MariaDB 10.2.9](https://mariadb.com/kb/en/mariadb-1029-release-notes/) and removed from [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/). In later versions of MariaDB, use `[innodb\_page\_cleaners](#innodb_page_cleaners)` system variable instead. + See [InnoDB Page Flushing: Page Flushing with Multi-threaded Flush Threads](../innodb-page-flushing/index#page-flushing-with-multi-threaded-flush-threads) for more information. * **Commandline:** `--innodb-mtflush-threads=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `8` * **Range:** `1` to `64` * **Deprecated:** [MariaDB 10.2.9](https://mariadb.com/kb/en/mariadb-1029-release-notes/) * **Removed:** [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) --- #### `innodb_monitor_disable` * **Description:** Disables the specified counters in the [INFORMATION\_SCHEMA.INNODB\_METRICS](../information-schema-innodb_metrics-table/index) table. * **Commandline:** `--innodb-monitor-disable=string` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` --- #### `innodb_monitor_enable` * **Description:** Enables the specified counters in the [INFORMATION\_SCHEMA.INNODB\_METRICS](../information-schema-innodb_metrics-table/index) table. * **Commandline:** `--innodb-monitor-enable=string` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` --- #### `innodb_monitor_reset` * **Description:** Resets the count value of the specified counters in the [INFORMATION\_SCHEMA.INNODB\_METRICS](../information-schema-innodb_metrics-table/index) table to zero. * **Commandline:** `--innodb-monitor-reset=string` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` --- #### `innodb_monitor_reset_all` * **Description:** Resets all values for the specified counters in the [INFORMATION\_SCHEMA.INNODB\_METRICS](../information-schema-innodb_metrics-table/index) table. * **Commandline:** `---innodb-monitor-reset-all=string` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` --- #### `innodb_numa_interleave` * **Description:** Whether or not to use the NUMA interleave memory policy to allocate the [InnoDB buffer pool](../innodb-buffer-pool/index). Before [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/), required that MariaDB be compiled on a NUMA-enabled Linux system. * **Commandline:** `innodb-numa-interleave={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.2.23](https://mariadb.com/kb/en/mariadb-10223-release-notes/), [MariaDB 10.3.14](https://mariadb.com/kb/en/mariadb-10314-release-notes/), [MariaDB 10.4.4](https://mariadb.com/kb/en/mariadb-1044-release-notes/) --- #### `innodb_old_blocks_pct` * **Description:** Percentage of the [buffer pool](../xtradbinnodb-memory-buffer/index) to use for the old block sublist. * **Commandline:** `--innodb-old-blocks-pct=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `37` * **Range:** `5` to `95` --- #### `innodb_old_blocks_time` * **Description:** Time in milliseconds an inserted block must stay in the old sublist after its first access before it can be moved to the new sublist. '0' means "no delay". Setting a non-zero value can help prevent full table scans clogging the [buffer pool](../xtradbinnodb-memory-buffer/index). See also [innodb\_old\_blocks\_pct](#innodb_old_blocks_pct). * **Commandline:** `--innodb-old-blocks-time=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1000` * **Range:** `0` to `232-1` --- #### `innodb_online_alter_log_max_size` * **Description:** The maximum size for temporary log files during online DDL (data and index structure changes). The temporary log file is used for each table being altered, or index being created, to store data changes to the table while the process is underway. The table is extended by [innodb\_sort\_buffer\_size](#innodb_sort_buffer_size) up to the limit set by this variable. If this limit is exceeded, the online DDL operation fails and all uncommitted changes are rolled back. A lower value reduces the time a table could lock at the end of the operation to apply all the log's changes, but also increases the chance of the online DDL changes failing. * **Commandline:** `--innodb-online-alter-log-max-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `134217728` * **Range:** `65536` to `264-1` --- #### `innodb_open_files` * **Description:** Maximum .ibd files MariaDB can have open at the same time. Only applies to systems with multiple XtraDB/InnoDB tablespaces, and is separate to the table cache and [open\_files\_limit](#open_files_limit). The default, if [innodb\_file\_per\_table](#innodb_file_per_table) is disabled, is 300 or the value of [table\_open\_cache](../server-system-variables/index#table_open_cache), whichever is higher. It will also auto-size up to the default value if it is set to a value less than `10`. * **Commandline:** `--innodb-open-files=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `autosized` * **Range:** `10` to `4294967295` --- #### `innodb_optimize_fulltext_only` * **Description:** When set to `1` (`0` is default), [OPTIMIZE TABLE](../optimize-table/index) will only process InnoDB [FULLTEXT index](../full-text-indexes/index) data. Only intended for use during fulltext index maintenance. * **Commandline:** `--innodb-optimize-fulltext-only={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_page_cleaners` * **Description:** Number of page cleaner threads. The default is `4`, but the value will be set to the number of [innodb\_buffer\_pool\_instances](#innodb_buffer_pool_instances) if this is lower. If set to `1`, only a single cleaner thread is used, as was the case until [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). Cleaner threads flush dirty pages from the [buffer pool](../xtradbinnodb-buffer-pool/index), performing flush list and least-recently used (LRU) flushing. Deprecated and ignored from [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/), as the original reasons for for splitting the buffer pool have mostly gone away. + See [InnoDB Page Flushing: Page Flushing with Multiple InnoDB Page Cleaner Threads](../innodb-page-flushing/index#page-flushing-with-multiple-innodb-page-cleaner-threads) for more information. * **Commandline:** `--innodb-page-cleaners=#` * **Scope:** Global * **Dynamic:** Yes (>= [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)), No (<= [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/)) * **Data Type:** `numeric` * **Default Value:** `4` (or set to [innodb\_buffer\_pool\_instances](#innodb_buffer_pool_instances) if lower) * **Range:** `1` to `64` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) * **Deprecated:** [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_page_size` * **Description:** Specifies the page size in bytes for all InnoDB tablespaces. The default, `16k`, is suitable for most uses. + A smaller InnoDB page size might work more effectively in a situation with many small writes (OLTP), or with SSD storage, which usually has smaller block sizes. + A larger InnoDB page size can provide a larger [maximum row size](../innodb-row-formats-overview/index#maximum-row-size). + InnoDB's page size can be as large as `64k` for tables using the following [row formats](../innodb-row-formats-overview/index): [DYNAMIC](../innodb-dynamic-row-format/index), [COMPACT](../innodb-compact-row-format/index), and [REDUNDANT](../innodb-redundant-row-format/index). + InnoDB's page size must still be `16k` or less for tables using the [COMPRESSED](../innodb-compressed-row-format/index) row format. + This system variable's value cannot be changed after the `datadir` has been initialized. InnoDB's page size is set when a MariaDB instance starts, and it remains constant afterwards. * **Commandline:** `--innodb-page-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `enumeration` * **Default Value:** `16384` * **Valid Values:** `4k` or `4096`, `8k` or `8192`, `16k` or `16384`, `32k` and `64k`. --- #### `innodb_pass_corrupt_table` * **Removed:** XtraDB 5.5 - renamed [innodb\_corrupt\_table\_action](#innodb_corrupt_table_action). --- #### `innodb_prefix_index_cluster_optimization` * **Description:** Enable prefix optimization to sometimes avoid cluster index lookups. Deprecated and ignored from [MariaDB 10.10](../what-is-mariadb-1010/index), as the optimization is now always enabled. * **Commandline:** `--innodb-prefix-index-cluster-optimization={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.10.1](https://mariadb.com/kb/en/mariadb-10101-release-notes/) --- #### `innodb_print_all_deadlocks` * **Description:** If set to `1` (`0` is default), all XtraDB/InnoDB transaction deadlock information is written to the [error log](../error-log/index). * **Commandline:** `--innodb-print-all-deadlocks={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_purge_batch_size` * **Description:** Units of [InnoDB redo log](../xtradbinnodb-redo-log/index) records that will trigger a purge operation. Together with [innodb\_purge\_threads](#innodb_purge_threads) has a small effect on tuning. * **Commandline:** `--innodb-purge-batch-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `20` * **Range:** `1` to `5000` --- #### `innodb_purge_rseg_truncate_frequency` * **Description:** Frequency with which undo records are purged. Set by default to every 128 times, reducing this increases the frequency at which rollback segments are freed. See also [innodb\_undo\_log\_truncate](#innodb_undo_log_truncate). * **Commandline:** `-- innodb-purge-rseg-truncate-frequency=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `128` * **Range:** `1` to `128` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_purge_threads` * **Description:** Number of background threads dedicated to InnoDB purge operations. The range is `1` to `32`. At least one background thread is always used from [MariaDB 10.0](../what-is-mariadb-100/index). The default has been increased from `1` to `4` in [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/). Setting to a value greater than 1 creates that many separate purge threads. This can improve efficiency in some cases, such as when performing DML operations on many tables. In [MariaDB 5.5](../what-is-mariadb-55/index), the options are `0` and `1`. If set to `0`, the default, purging is done with the primary thread. If set to `1`, purging is done on a separate thread, which could reduce contention. See also [innodb\_purge\_batch\_size](#innodb_purge_batch_size). * **Commandline:** `--innodb-purge-threads=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** + `4` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `1` (>=[MariaDB 10.0](../what-is-mariadb-100/index) to <= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Range:** `1` to `32` --- #### `innodb_random_read_ahead` * **Description:** Originally, random read-ahead was always set as an optimization technique, but was removed in [MariaDB 5.5](../what-is-mariadb-55/index). `innodb_random_read_ahead` permits it to be re-instated if set to `1` (`0`) is default. * **Commandline:** `--innodb-random-read-ahead={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_read_ahead` * **Description:** If set to `linear`, the default, XtraDB/InnoDB will automatically fetch remaining pages if there are enough within the same extent that can be accessed sequentially. If set to `none`, read-ahead is disabled. `random` has been removed and is now ignored, while `both` sets to both `linear` and `random`. Also see [innodb\_read\_ahead\_threshold](#innodb_read_ahead_threshold) for more control on read-aheads. Removed in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 and replaced by MySQL 5.6's [innodb\_random\_read\_ahead](#innodb_random_read_ahead). * **Commandline:** `innodb-read-ahead=value` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `linear` * **Valid Values:** `none`, `random`, `linear`, `both` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 - replaced by MySQL 5.6's [innodb\_random\_read\_ahead](#innodb_random_read_ahead) --- #### `innodb_read_ahead_threshold` * **Description:** Minimum number of pages XtraDB/InnoDB must read from an extent of 64 before initiating an asynchronous read for the following extent. * **Commandline:** `--innodb-read-ahead-threshold=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `56` * **Range:** `0` to `64` --- #### `innodb_read_io_threads` * **Description:** Number of I/O threads for InnoDB reads. You may on rare occasions need to reduce this default on Linux systems running multiple MariaDB servers to avoid exceeding system limits. * **Commandline:** `--innodb-read-io-threads=#` * **Scope:** Global * **Dynamic:** Yes (>= [MariaDB 10.11](../what-is-mariadb-1011/index)), No (<= [MariaDB 10.10](../what-is-mariadb-1010/index)) * **Data Type:** `numeric` * **Default Value:** `4` * **Range:** `1` to `64` --- #### `innodb_read_only` * **Description:** If set to `1` (`0` is default), the server will be read-only. For use in distributed applications, data warehouses or read-only media. * **Commandline:** `--innodb-read-only={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_read_only_compressed` * **Description:** If set (the default before [MariaDB 10.6.6](https://mariadb.com/kb/en/mariadb-1066-release-notes/)), [ROW\_FORMAT=COMPRESSED](../innodb-compressed-row-format/index) tables will be read-only. This was intended to be the first step towards removing write support and deprecating the feature, but this plan has been abandoned. * **Commandline:** `--innodb-read-only-compressed`, `--skip-innodb-read-only-compressed` * **Scope:** * **Dynamic:** * **Data Type:** `boolean` * **Default Value:** `OFF` (>= [MariaDB 10.6.6](https://mariadb.com/kb/en/mariadb-1066-release-notes/)), `ON` (<= [MariaDB 10.6.5](https://mariadb.com/kb/en/mariadb-1065-release-notes/)) * **Introduced:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_recovery_stats` * **Description:** If set to `1` (`0` is default) and recovery is necessary on startup, the server will write detailed recovery statistics to the error log at the end of the recovery process. This Percona XtraDB variable has not been ported to XtraDB 5.6. * **Commandline:** No * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) --- #### `innodb_recovery_update_relay_log` * **Description:** If set to `1` (`0` is default), the relay log info file will be overwritten on crash recovery if the information differs from the InnoDB record. Should not be used if multiple storage engine types are being replicated. Previously named `innodb_overwrite_relay_log_info`. Removed in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 and replaced by MySQL 5.6's `relay-log-recovery` * **Commandline:** `innodb-recovery-update-relay-log={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) - replaced by MySQL 5.6's `relay-log-recovery` --- #### `innodb_replication_delay` * **Description:** Time in milliseconds for the replica server to delay the replication thread if [innodb\_thread\_concurrency](#innodb_thread_concurrency) is reached. Deprecated and ignored from [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/). * **Commandline:** `--innodb-replication-delay=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `4294967295` * **Deprecated:** [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_rollback_on_timeout` * **Description:** InnoDB usually rolls back the last statement of a transaction that's been timed out (see [innodb\_lock\_wait\_timeout](#innodb_lock_wait_timeout)). If innodb\_rollback\_on\_timeout is set to 1 (0 is default), InnoDB will roll back the entire transaction. Before [MariaDB 5.5](../what-is-mariadb-55/index), rolling back the entire transaction was the default behavior. * **Commandline:** `--innodb-rollback-on-timeout` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `0` --- #### `innodb_rollback_segments` * **Description:** Specifies the number of rollback segments that XtraDB/InnoDB will use within a transaction (see [undo log](../undo-log/index)). Deprecated and replaced by [innodb\_undo\_logs](#innodb_undo_logs) in [MariaDB 10.0](../what-is-mariadb-100/index). * **Commandline:** `--innodb-rollback-segments=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `128` * **Range:** `1` to `128` * **Deprecated:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) --- #### `innodb_safe_truncate` * **Description:** Use a backup-safe [TRUNCATE TABLE](../truncate-table/index) implementation and crash-safe rename operations inside InnoDB. This is not compatible with hot backup tools other than [Mariabackup](../mariabackup-overview/index). Users who need to use such tools may set this to `OFF`. * **Commandline:** `--innodb-safe-truncate={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` * **Introduced:** [MariaDB 10.2.19](https://mariadb.com/kb/en/mariadb-10219-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_scrub_log` * **Description:** Enable [InnoDB redo log](../xtradbinnodb-redo-log/index) scrubbing. See [Data Scrubbing](../xtradbinnodb-data-scrubbing/index). Deprecated and ignored from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), as never really worked ([MDEV-13019](https://jira.mariadb.org/browse/MDEV-13019) and [MDEV-18370](https://jira.mariadb.org/browse/MDEV-18370)). If old log contents should be kept secret, then enabling [innodb\_encrypt\_log](index#innodb_encrypt_log) or setting a smaller [innodb\_log\_file\_size](index#innodb_log_file_size) could help. * **Commandline:** `--innodb-scrub-log` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_scrub_log_interval` * **Description:** Used with [Data Scrubbing](../xtradbinnodb-data-scrubbing/index) in 10.1.3 only - replaced in 10.1.4 by [innodb\_scrub\_log\_speed](#innodb_scrub_log_speed). [InnoDB redo log](../xtradbinnodb-redo-log/index) scrubbing interval in milliseconds. * **Commandline:** `--innodb-scrub-log-interval=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `56` * **Range:** `0` to `50000` * **Introduced:** [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) * **Removed:** [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) --- #### `innodb_scrub_log_speed` * **Description:** [InnoDB redo log](../xtradbinnodb-redo-log/index) scrubbing speed in bytes/sec. See [Data Scrubbing](../xtradbinnodb-data-scrubbing/index). Deprecated and ignored from [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). * **Commandline:** `--innodb-scrub-log-speed=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `256` * **Range:** `1` to `50000` * **Deprecated:** [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_sched_priority_cleaner` * **Description:** Set a thread scheduling priority for cleaner and least-recently used (LRU) manager threads. The range from `0` to `39` corresponds in reverse order to Linux nice values of `-20` to `19`. So `0` is the lowest priority (Linux nice value `19`) and `39` is the highest priority (Linux nice value `-20`). XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-sched-priority-cleaner=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `19` * **Range:** `0` to `39` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_show_locks_held` * **Description:** Specifies the number of locks held for each InnoDB transaction to be displayed in [SHOW ENGINE INNODB STATUS](../show-engine/index) output. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-show-locks-held=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `10` * **Range:** `0` to `1000` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_show_verbose_locks` * **Description:** If set to `1`, and [innodb\_status\_output\_locks](#innodb_status_output_locks) is also ON, the traditional InnoDB behavior is followed and locked records will be shown in [SHOW ENGINE INNODB STATUS](../show-engine-innodb-status/index) output. If set to `0`, the default, only high-level information about the lock is shown. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-show-verbose-locks=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `1` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_simulate_comp_failures` * **Description:** Simulate compression failures. Used for testing robustness against random compression failures. XtraDB only. * **Commandline:** None * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `99` --- #### `innodb_sort_buffer_size` * **Description:** Size of the sort buffers used for sorting data when an InnoDB index is created, as well as the amount by which the temporary log file is extended during online DDL operations to record concurrent writes. The larger the setting, the fewer merge phases are required between buffers while sorting. When a [CREATE TABLE](../create-table/index) or [ALTER TABLE](../alter-table/index) creates a new index, three buffers of this size are allocated, as well as pointers for the rows in the buffer. * **Commandline:** `--innodb-sort-buffer-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1048576` (1M) * **Range:** `65536` to `67108864` --- #### `innodb_spin_wait_delay` * **Description:** Maximum delay (not strictly corresponding to a time unit) between spin lock polls. Default changed from `6` to `4` in [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/), as this was verified to give the best throughput by OLTP update index and read-write benchmarks on Intel Broadwell (2/20/40) and ARM (1/46/46). * **Commandline:** `--innodb-spin-wait-delay=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `4` (>= [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/)), `6` (<= [MariaDB 10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/)) * **Range:** `0` to `4294967295` --- #### `innodb_stats_auto_recalc` * **Description:** If set to `1` (the default), persistent statistics are automatically recalculated when the table changes significantly (more than 10% of the rows). Affects tables created or altered with STATS\_PERSISTENT=1 (see [CREATE TABLE](../create-table/index)), or when [innodb\_stats\_persistent](#innodb_stats_persistent) is enabled. [innodb\_stats\_persistent\_sample\_pages](#innodb_stats_persistent_sample_pages) determines how much data to sample when recalculating. See [InnoDB Persistent Statistics](../innodb-persistent-statistics/index). * **Commandline:** `--innodb-stats-auto-recalc={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_stats_auto_update` * **Description:** If set to `0` (`1` is default), index statistics will not be automatically calculated except when an [ANALYZE TABLE](../analyze-table/index) is run, or the table is first opened. Replaced by [innodb\_stats\_auto\_recalc](#innodb_stats_auto_recalc) in [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6. * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `1` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index) - replaced by [innodb\_stats\_auto\_recalc](#innodb_stats_auto_recalc). --- #### `innodb_stats_include_delete_marked` * **Description:** Include delete marked records when calculating persistent statistics. * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) --- #### `innodb_stats_method` * **Description:** Determines how NULLs are treated for InnoDB index statistics purposes. + `nulls_equal`: The default, all NULL index values are treated as a single group. This is usually fine, but if you have large numbers of NULLs the average group size is slanted higher, and the optimizer may miss using the index for ref accesses when it would be useful. + `nulls_unequal`: The opposite approach to `nulls_equal` is taken, with each NULL forming its own group of one. Conversely, the average group size is slanted lower, and the optimizer may use the index for ref accesses when not suitable. + `nulls_ignored`: Ignore NULLs altogether from index group calculations. + See also [Index Statistics](../index-statistics/index), [aria\_stats\_method](../aria-server-system-variables/index#aria_stats_method) and [myisam\_stats\_method](../myisam-server-system-variables/index#myisam_stats_method). * **Commandline:** `--innodb-stats-method=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `nulls_equal` * **Valid Values:** `nulls_equal`, `nulls_unequal`, `nulls_ignored` --- #### `innodb_stats_modified_counter` * **Description:** The number of rows modified before we calculate new statistics. If set to `0`, the default, current limits are used. * **Commandline:** `--innodb-stats-modified-counter=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `18446744073709551615` --- #### `innodb_stats_on_metadata` * **Description:** If set to `1`, the default, XtraDB/InnoDB updates statistics when accessing the INFORMATION\_SCHEMA.TABLES or INFORMATION\_SCHEMA.STATISTICS tables, and when running metadata statements such as [SHOW INDEX](../show-index/index) or [SHOW TABLE STATUS](../show-table-status/index). If set to `0`, statistics are not updated at those times, which can reduce the access time for large schemas, as well as make execution plans more stable. * **Commandline:** `--innodb-stats-on-metadata` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_stats_persistent` * **Description:** [ANALYZE TABLE](../analyze-table/index) produces index statistics, and this setting determines whether they will be stored on disk, or be required to be recalculated more frequently, such as when the server restarts. This information is stored for each table, and can be set with the STATS\_PERSISTENT clause when creating or altering tables (see [CREATE TABLE](../create-table/index)). See [InnoDB Persistent Statistics](../innodb-persistent-statistics/index). * **Commandline:** `--innodb-stats-persistent={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_stats_persistent_sample_pages` * **Description:** Number of index pages sampled when estimating cardinality and statistics for indexed columns. Increasing this value will increases index statistics accuracy, but use more I/O resources when running [ANALYZE TABLE](../analyze-table/index). See [InnoDB Persistent Statistics](../innodb-persistent-statistics/index). * **Commandline:** `--innodb-stats-persistent-sample-pages=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `20` --- #### `innodb_stats_sample_pages` * **Description:** Gives control over the index distribution statistics by determining the number of index pages to sample. Higher values produce more disk I/O, but, especially for large tables, produce more accurate statistics and therefore make more effective use of the query optimizer. Lower values than the default are not recommended, as the statistics can be quite inaccurate. + If [innodb\_stats\_traditional](#innodb_stats_traditional) is enabled, then the exact number of pages configured by this system variable will be sampled for statistics. + If [innodb\_stats\_traditional](#innodb_stats_traditional) is disabled, then the number of pages to sample for statistics is calculated using a logarithmic algorithm, so the exact number can change depending on the size of the table. This means that more samples may be used for larger tables. + If [persistent statistics](../innodb-persistent-statistics/index) are enabled, then the [innodb\_stats\_persistent\_sample\_pages](#innodb_stats_persistent_sample_pages) system variable applies instead. [persistent statistics](../innodb-persistent-statistics/index) are enabled with the [innodb\_stats\_persistent](#innodb_stats_persistent) system variable. + This system variable has been **deprecated**. The [innodb\_stats\_transient\_sample\_pages](#innodb_stats_transient_sample_pages) system variable should be used instead. * **Commandline:** `--innodb-stats-sample-pages=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `8` * **Range:** `1` to `264-1` * **Deprecated:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed:** [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) --- #### `innodb_stats_traditional` * **Description:** This system variable affects how the number of pages to sample for transient statistics is determined, in particular how [innodb\_stats\_transient\_sample\_pages](##innodb_stats_transient_sample_pages)#is used. + If [innodb\_stats\_traditional](#innodb_stats_traditional) is enabled, then the exact number of pages configured by the system variable will be sampled for statistics. + If [innodb\_stats\_traditional](#innodb_stats_traditional) is disabled, then the number of pages to sample for statistics is calculated using a logarithmic algorithm, so the exact number can change depending on the size of the table. This means that more samples may be used for larger tables. + This system variable does not affect the calculation of [persistent statistics](../innodb-persistent-statistics/index). * **Commandline:** `--innodb-stats-traditional={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_stats_transient_sample_pages` * **Description:** Gives control over the index distribution statistics by determining the number of index pages to sample. Higher values produce more disk I/O, but, especially for large tables, produce more accurate statistics and therefore make more effective use of the query optimizer. Lower values than the default are not recommended, as the statistics can be quite inaccurate. + If `[innodb\_stats\_traditional](#innodb_stats_traditional)` is enabled, then the exact number of pages configured by this system variable will be sampled for statistics. + If `[innodb\_stats\_traditional](#innodb_stats_traditional)` is disabled, then the number of pages to sample for statistics is calculated using a logarithmic algorithm, so the exact number can change depending on the size of the table. This means that more samples may be used for larger tables. + If [persistent statistics](../innodb-persistent-statistics/index) are enabled, then the `[innodb\_stats\_persistent\_sample\_pages](#innodb_stats_persistent_sample_pages)` system variable applies instead. [persistent statistics](../innodb-persistent-statistics/index) are enabled with the `[innodb\_stats\_persistent](#innodb_stats_persistent)` system variable. * **Commandline:** `--innodb-stats-transient-sample-pages=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `8` * **Range:** `1` to `264-1` --- #### `innodb_stats_update_need_lock` * **Description:** Setting to `0` (`1` is default) may help reduce contention of the `&dict_operation_lock`, but also disables the *Data\_free* option in [SHOW TABLE STATUS](../show-table-status/index). This Percona XtraDB variable has not been ported to XtraDB 5.6. * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `1` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 --- #### `innodb_status_output` * **Description:** Enable [InnoDB monitor](../xtradbinnodb-monitors/index) output to the [error log](../error-log/index). * **Commandline:** `--innodb-status-output={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_status_output_locks` * **Description:** Enable [InnoDB lock monitor](../xtradb-innodb-monitors/index) output to the [error log](../error-log/index) and [SHOW ENGINE INNODB STATUS](../show-engine-innodb-status/index). Also requires [innodb\_status\_output=ON](#innodb_status_output) to enable output to the error log. * **Commandline:** `--innodb-status-output-locks={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `innodb_strict_mode` * **Description:** If set to `1` (`0` is the default before [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), XtraDB/InnoDB will return errors instead of warnings in certain cases, similar to strict SQL mode. * **Commandline:** `--innodb-strict-mode={0|1}` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** + `ON` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)) + `OFF` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) --- #### `innodb_support_xa` * **Description:** If set to `1`, the default, [XA transactions](../xa-transactions/index) are supported. XA support ensures data is written to the [binary log](../binary-log/index) in the same order to the actual database, which is critical for [replication](../replication/index) and disaster recovery, but comes at a small performance cost. If your database is set up to only permit one thread to change data (for example, on a replication replica with only the replication thread writing), it is safe to turn this option off. Removed in [MariaDB 10.3](../what-is-mariadb-103/index), XA transactions are always supported. * **Commandline:** `--innodb-support-xa` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` * **Deprecated:** [MariaDB 10.2](../what-is-mariadb-102/index) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_sync_array_size` * **Description:** By default `1`, can be increased to split internal thread co-ordinating, giving higher concurrency when there are many waiting threads. * **Commandline:** `--innodb-sync-array-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `1` to `1024` * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_sync_spin_loops` * **Description:** The number of times a thread waits for an XtraDB/InnoDB mutex to be freed before the thread is suspended. * **Commandline:** `--innodb-sync-spin-loops=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `30` * **Range:** `0` to `4294967295` --- #### `innodb_table_locks` * **Description:** If [autocommit](#autocommit) is set to to `0` (`1` is default), setting innodb\_table\_locks to `1`, the default, will cause XtraDB/InnoDB to lock a table internally upon a [LOCK TABLE](lock_tables). * **Commandline:** `--innodb-table-locks` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_thread_concurrency` * **Description:** Once this number of threads is reached (excluding threads waiting for locks), XtraDB/InnoDB will place new threads in a wait state in a first-in, first-out queue for execution, in order to limit the number of threads running concurrently. A setting of `0`, the default, permits as many threads as necessary. A suggested setting is twice the number of CPU's plus the number of disks. Deprecated and ignored from [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/). * **Commandline:** `--innodb-thread-concurrency=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `1000` * **Deprecated:** [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_thread_concurrency_timer_based` * **Description:** If set to `1`, thread concurrency will be handled in a lock-free timer-based manner rather than the default mutex-based method. Depends on atomic op builtins being available. This Percona XtraDB variable has not been ported to XtraDB 5.6. * **Commandline:** `innodb-thread-concurrency-timer-based={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 --- #### `innodb_thread_sleep_delay` * **Description:** Time in microseconds that InnoDB threads sleep before joining the queue. Setting to `0` disables sleep. Deprecated and ignored from [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) * **Commandline:** `--innodb-thread-sleep-delay=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** + `0` (>= [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/).) + `10000` (<= [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/)) * **Range:** `0` to `1000000` * **Deprecated:** [MariaDB 10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_temp_data_file_path` * **Description:** * **Commandline:** `--innodb-temp-data-file-path=path` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** `ibtmp1:12M:autoextend` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_tmpdir` * **Description:** Allows an alternate location to be set for temporary non-tablespace files. If not set (the default), files will be created in the usual [tmpdir](../server-system-variables/index#tmpdir) location. * **Commandline:** `--innodb-tmpdir=path` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** Empty --- #### `innodb_track_changed_pages` * **Description:** For faster incremental backup with [Xtrabackup](../backup-restore-and-import-xtrabackup/index), XtraDB tracks pages with changes written to them according to the [XtraDB redo log](../xtradbinnodb-redo-log/index) and writes the information to special changed page bitmap files. This read-only variable is used for controlling this feature. See also [innodb\_max\_changed\_pages](#innodb_max_changed_pages) and [innodb\_max\_bitmap\_file\_size](#innodb_max_bitmap_file_size). XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-track-changed-pages={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) --- #### `innodb_track_redo_log_now` * **Description:** Available on debug builds only. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-track-redo-log-now={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) --- #### `innodb_undo_directory` * **Description:** Path to the directory (relative or absolute) that InnoDB uses to create separate tablespaces for the [undo logs](../undo-log/index). `.` (the default value before 10.2.2) leaves the undo logs in the same directory as the other log files. From [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/), the default value is NULL, and if no path is specified, undo tablespaces will be created in the directory defined by [datadir](../server-system-variables/index#datadir). Use together with [innodb\_undo\_logs](#innodb_undo_logs) and [innodb\_undo\_tablespaces](#innodb_undo_tablespaces). Undo logs are most usefully placed on a separate storage device. * **Commandline:** `--innodb-undo-directory=name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** NULL (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), `.` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) --- #### `innodb_undo_log_truncate` * **Description:** When enabled, undo tablespaces that are larger than [innodb\_max\_undo\_log\_size](#innodb_max_undo_log_size) are marked for truncation. See also [innodb\_purge\_rseg\_truncate\_frequency](#innodb_purge_rseg_truncate_frequency). * **Commandline:** `--innodb-undo-log-truncate[={0|1}]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_undo_logs` * **Description:** Specifies the number of rollback segments that XtraDB/InnoDB will use within a transaction (or the number of active [undo logs](../undo-log/index)). By default set to the maximum, `128`, it can be reduced to avoid allocating unneeded rollback segments. See the [Innodb\_available\_undo\_logs](../xtradbinnodb-server-status-variables/index#innodb_available_undo_logs) status variable for the number of undo logs available. See also [innodb\_undo\_directory](#innodb_undo_directory) and [innodb\_undo\_tablespaces](#innodb_undo_tablespaces). Replaced [innodb\_rollback\_segments](#innodb_rollback_segments) in [MariaDB 10.0](../what-is-mariadb-100/index). The [Information Schema XTRADB\_RSEG Table](../information-schema-xtradb_rseg-table/index) contains information about the XtraDB rollback segments. Deprecated and ignored in [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/), as it always makes sense to use the maximum number of rollback segments. * **Commandline:** `--innodb-undo-logs=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `128` * **Range:** `0` to `128` * **Deprecated:** [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) * **Removed:** [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) --- #### `innodb_undo_tablespaces` * **Description:** Number of tablespaces files used for dividing up the [undo logs](../undo-log/index). By default, undo logs are all part of the system tablespace, which contains one undo tablespace more than the `innodb_undo_tablespaces` setting. When the undo logs can grow large, splitting them over multiple tablespaces will reduce the size of any single tablespace. Must be set before InnoDB is initialized, or else MariaDB will fail to start, with an error saying that `InnoDB did not find the expected number of undo tablespaces`. The files are created in the directory specified by [innodb\_undo\_directory](../xtradbinnodb-server-system-variables/index#innodb_undo_directory), and are named `undoN`, N being an integer. The default size of an undo tablespace is 10MB. [innodb\_undo\_logs](../xtradbinnodb-server-system-variables/index#innodb_undo_logs) must have a non-zero setting for `innodb_undo_tablespaces` to take effect. * **Commandline:** `--innodb-undo-tablespaces=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `95` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), `0` to `126` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) --- #### `innodb_use_atomic_writes` * **Description:** Implement atomic writes on supported SSD devices. See [atomic write support](../atomic-write-support/index) for other variables affected when this is set. * **Commandline:** `innodb-use-atomic-writes={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)), `OFF` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) --- #### `innodb_use_fallocate` * **Description:** Preallocate files fast, using operating system functionality. On POSIX systems, posix\_fallocate system call is used. + Automatically set to `1` when [innodb\_use\_atomic\_writes](#innodb_use_atomic_writes) is set - see [FusionIO DirectFS atomic write support](../fusionio-directfs-atomic-write-support/index). + See [InnoDB Page Compression: Saving Storage Space with Sparse Files](../innodb-page-compression/index#saving-storage-space-with-sparse-files) for more information. * **Commandline:** `innodb-use-fallocate={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.5](https://mariadb.com/kb/en/mariadb-1025-release-notes/) (treated as if `ON`) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_use_global_flush_log_at_trx_commit` * **Description:** Determines whether a user can set the variable [innodb\_flush\_log\_at\_trx\_commit](#innodb_flush_log_at_trx_commit). If set to `1`, a user cannot reset the value with a SET command, while if set to `1`, a user can reset the value of `innodb_flush_log_at_trx_commit`. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `innodb-use-global-flush-log-at-trx_commit={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_use_mtflush` * **Description:** Whether to enable Multi-Threaded Flush operations. For more information, see Fusion. + InnoDB's multi-thread flush feature was deprecated in [MariaDB 10.2.9](https://mariadb.com/kb/en/mariadb-1029-release-notes/) and removed from [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/). In later versions of MariaDB, use `[innodb\_page\_cleaners](#innodb_page_cleaners)` system variable instead. + See [InnoDB Page Flushing: Page Flushing with Multi-threaded Flush Threads](../innodb-page-flushing/index#page-flushing-with-multi-threaded-flush-threads) for more information. * **Commandline:** `--innodb-use-mtflush={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.9](https://mariadb.com/kb/en/mariadb-1029-release-notes/) * **Removed:** [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) --- #### `innodb_use_native_aio` * **Description:** For Linux systems only, specified whether to use Linux's asynchronous I/O subsystem. Set to `ON` by default, it may be changed to `0` at startup if InnoDB detects a problem, or from [MariaDB 10.6.5](https://mariadb.com/kb/en/mariadb-1065-release-notes/)/[MariaDB 10.7.1](https://mariadb.com/kb/en/mariadb-1071-release-notes/), if a 5.11 - 5.15 Linux kernel is detected, to avoid an io-uring bug/incompatibility ([MDEV-26674](https://jira.mariadb.org/browse/MDEV-26674)). MariaDB-10.6.6/MariaDB-10.7.2 and later also consider 5.15.3+ as a fixed kernel and default to `ON`. To really benefit from the setting, the files should be opened in O\_DIRECT mode ([innodb\_flush\_method=O\_DIRECT](#innodb_flush_method), default from [MariaDB 10.6](../what-is-mariadb-106/index)), to bypass the file system cache. In this way, the reads and writes can be submitted with DMA, using the InnoDB buffer pool directly, and no processor cycles need to be used for copying data. * **Commandline:** `--innodb-use-native-aio={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `innodb_use_purge_thread` * **Description:** Usually with InnoDB, data changed by a transaction is written to an undo space to permit read consistency, and freed when the transaction is complete. Many, or large, transactions, can cause the main tablespace to grow dramatically, reducing performance. This option, introduced in XtraDB 5.1 and removed for 5.5, allows multiple threads to perform the purging, resulting in slower, but much more stable performance. * **Commandline:** `--innodb-use-purge-thread=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `0` to `32` * **Removed:** XtraDB 5.5 --- #### `innodb_use_stacktrace` * **Description:** If set to `ON` (`OFF` is default), a signal handler for SIGUSR2 is installed when the InnoDB server starts. When a long semaphore wait is detected at sync/sync0array.c, a SIGUSR2 signal is sent to the waiting thread and thread that has acquired the RW-latch. For both threads a full stacktrace is produced as well as if possible. XtraDB only. Added as a deprecated and ignored option in [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) (which uses InnoDB as default instead of XtraDB) to allow for easier upgrades. * **Commandline:** `--innodb-use-stacktrace={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Deprecated:** [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_use_sys_malloc` * **Description:** If set the `1`, the default, XtraDB/InnoDB will use the operating system's memory allocator. If set to `0` it will use its own. Deprecated in [MariaDB 10.0](../what-is-mariadb-100/index) and removed in [MariaDB 10.2](../what-is-mariadb-102/index) along with InnoDB's internal memory allocator. * **Commandline:** `--innodb-use-sys-malloc={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` * **Deprecated:** [MariaDB 10.0](../what-is-mariadb-100/index) * **Removed**: [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) --- #### `innodb_use_sys_stats_table` * **Description:** If set to `1` (`0` is default), XtraDB will use the SYS\_STATS system table for extra table index statistics. When a table is opened for the first time, statistics will then be loaded from SYS\_STATS instead of sampling the index pages. Statistics are designed to be maintained only by running an [ANALYZE TABLE](../analyze-table/index). Replaced by MySQL 5.6's Persistent Optimizer Statistics. * **Commandline:** `innodb-use-sys-stats-table={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `0` * **Removed:** [MariaDB 10.0](../what-is-mariadb-100/index)/XtraDB 5.6 --- #### `innodb_use_trim` * **Description:** Use trim to free up space of compressed blocks. + See [InnoDB Page Compression: Saving Storage Space with Sparse Files](../innodb-page-compression/index#saving-storage-space-with-sparse-files) for more information. * **Commandline:** `--innodb-use-trim={0|1}` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)), `OFF` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) * **Deprecated:** [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) * **Removed:** [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/) --- #### `innodb_version` * **Description:** InnoDB version number. From [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/), as the InnoDB implementation in MariaDB has diverged from MySQL, the MariaDB version is instead reported. For example, the InnoDB version reported in [MariaDB 10.1](../what-is-mariadb-101/index) (which is based on MySQL 5.6) included encryption and variable-size page compression before MySQL 5.7 introduced them. [MariaDB 10.2](../what-is-mariadb-102/index) (based on MySQL 5.7) introduced persistent AUTO\_INCREMENT ([MDEV-6076](https://jira.mariadb.org/browse/MDEV-6076)) in a GA release before MySQL 8.0. [MariaDB 10.3](../what-is-mariadb-103/index) (based on MySQL 5.7) introduced instant ADD COLUMN ([MDEV-11369](https://jira.mariadb.org/browse/MDEV-11369)) before MySQL. * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` --- #### `innodb_write_io_threads` * **Description:** Number of I/O threads for InnoDB writes. You may on rare occasions need to reduce this default on Linux systems running multiple MariaDB servers to avoid exceeding system limits. * **Commandline:** `--innodb-write-io-threads=#` * **Scope:** Global * **Dynamic:** Yes (>= [MariaDB 10.11](../what-is-mariadb-1011/index)), No (<= [MariaDB 10.10](../what-is-mariadb-1010/index)) * **Data Type:** `numeric` * **Default Value:** `4` * **Range:** `1` to `64` --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb ColumnStore Create Procedure ColumnStore Create Procedure ============================ Creates a stored routine in ColumnStore. Syntax ------ ``` CREATE [DEFINER = { user | CURRENT_USER }] PROCEDURE sp_name ([proc_parameter[,...]]) [characteristic ...] routine_body proc_parameter: [ IN | OUT | INOUT ] param_name type type: Any valid MariaDB ColumnStore data type routine_body: Valid SQL procedure statement ``` ColumnStore currently accepts definition of stored procedures with only input arguments and a single SELECT query while in Operating Mode = 1 (VTABLE mode). However, while in the Operating Mode = 0 (TABLE mode), ColumnStore will allow additional complex definition of stored procedures (i.e., OUT parameter, declare, cursors,etc.) See Operating Mode for information on Operating Modes images here The following statements create and call the sp\_complex\_variable stored procedure: ``` CREATE PROCEDURE sp_complex_variable(in arg_key int, in arg_date date) begin Select * from lineitem, orders where o_custkey < arg_key and l_partkey < 10000 and l_shipdate>arg_date and l_orderkey = o_orderkey order by l_orderkey, l_linenumber; end call sp_complex_variable(1000, '1998-10-10'); ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb AREA AREA ==== A synonym for [ST\_AREA](../st_area/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Database Normalization: 5th Normal Form and Beyond Database Normalization: 5th Normal Form and Beyond ================================================== This article follows on from the [4th normal form](../database-normalization-4th-normal-form/index) article. There are normal forms beyond 4th that are mainly of academic interest, as the problems they exist to solve rarely appear in practice. This series won't discuss then in detail, but for those interested, the following example provides a taste. ### The sales rep example | Sales rep | Company | Product | | --- | --- | --- | | Felicia Powers | Exclusive | Books | | Afzal Ignesund | Wordsworth | Magazines | | Felicia Powers | Exclusive | Magazines | Usually you would store this data in one table, as you need all three records to see which combinations are valid. *Afzal Ignesund* sells magazines for *Wordsworth*, but not necessarily books. *Felicia Powers* happens to sell both books and magazines for *Exclusive*. However, let's add another condition. If a sales rep sells a certain product, and they sell it for a particular company, then they must sell that product for that company. Let's look at a larger data set adhering to this condition: ### Looking at a larger set of data | Sales rep | Company | Product | | --- | --- | --- | | Felicia Powers | Exclusive | Books | | Felicia Powers | Exclusive | Magazines | | Afzal Ignesund | Wordsworth | Books | | Felicia Powers | Wordsworth | Books | | Felicia Powers | Wordsworth | Magazines | Now, with this extra dependency, you could normalize the table above into three separate tables without losing any facts, as shown below: ### Creating a table with Sales rep and Product | Sales rep | Product | | --- | --- | | Felicia Powers | Books | | Felicia Powers | Magazines | | Afzal Ignesund | Books | ### Creating a table with Sales rep and Company | Sales rep | Company | | --- | --- | | Felicia Powers | Exclusive | | Felicia Powers | Wordsworth | | Afzal Ignesund | Wordsworth | ### Creating a table with Company and Product | Company | Product | | --- | --- | | Exclusive | Books | | Exclusive | Magazines | | Wordsworth | Books | | Wordsworth | Magazines | Basically, a table is in 5th normal form if it cannot be made into any smaller tables with different keys (most tables can obviously be made into smaller tables with the same key!). Beyond 5th normal form you enter the heady realms of domain key normal form, a kind of theoretical ideal. Its practical use to a database designer os similar to that of infinity to a bookkeeper - i.e. it exists in theory but is not going to be used in practice. Even the most demanding owner is not going to expect that of the bookkeeper! For those interested in pursuing this academic and highly theoretical topic further, I suggest obtaining a copy of *An Introduction to Database Systems* by C.J. Date, at the time of writing in its 8th edition, or *Relational Theory for Computer Professionals* by the same author. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema TABLE_PRIVILEGES Table Information Schema TABLE\_PRIVILEGES Table ========================================== The [Information Schema](../information_schema/index) `TABLE_PRIVILEGES` table contains table privilege information derived from the `[mysql.tables\_priv](../mysqltables_priv-table/index)` grant table. It has the following columns: | Column | Description | | --- | --- | | `GRANTEE` | In the format `user_name@host_name`. | | `TABLE_CATALOG` | Always `def`. | | `TABLE_SCHEMA` | Database name. | | `TABLE_NAME` | Table name. | | `PRIVILEGE_TYPE` | One of `SELECT`, `INSERT`, `UPDATE`, `REFERENCES`, `ALTER`, `INDEX`, `DROP` or `CREATE VIEW`. | | `IS_GRANTABLE` | Whether the user has the `[GRANT OPTION](../grant/index#the-grant-option-privilege)` for this privilege. | Similar information can be accessed with the `[SHOW GRANTS](../show-grants/index)` statement. See the `[GRANT](../grant/index)` article for more about privileges. For a description of the privileges that are shown in this table, see [table privileges](../grant/index#table-privileges). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb NULLIF NULLIF ====== Syntax ------ ``` NULLIF(expr1,expr2) ``` Description ----------- Returns NULL if expr1 = expr2 is true, otherwise returns expr1. This is the same as [CASE](../case-operator/index) WHEN expr1 = expr2 THEN NULL ELSE expr1 END. Examples -------- ``` SELECT NULLIF(1,1); +-------------+ | NULLIF(1,1) | +-------------+ | NULL | +-------------+ SELECT NULLIF(1,2); +-------------+ | NULLIF(1,2) | +-------------+ | 1 | +-------------+ ``` See Also -------- * [NULL values](../null-values/index) * [IS NULL operator](../is-null/index) * [IS NOT NULL operator](../is-not-null/index) * [COALESCE function](../coalesce/index) * [IFNULL function](../ifnull/index) * [CONNECT data types](../connect-data-types/index#null-handling) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema SPIDER_WRAPPER_PROTOCOLS Table Information Schema SPIDER\_WRAPPER\_PROTOCOLS Table =================================================== **MariaDB starting with [10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/)**The [Information Schema](../information_schema/index) `SPIDER_WRAPPER_PROTOCOLS` table is installed along with the [Spider](../spider/index) storage engine from [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/). It contains the following columns: | Column | Type | Description | | --- | --- | --- | | `WRAPPER_NAME` | varchar(64) | | | `WRAPPER_VERSION` | varchar(20) | | | `WRAPPER_DESCRIPTION` | longtext | | | `WRAPPER_MATURITY` | varchar(12) | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHUTDOWN SHUTDOWN ======== Syntax ------ ``` SHUTDOWN [WAIT FOR ALL { SLAVES | REPLICAS } ] ``` Description ----------- The `SHUTDOWN` command shuts the server down. WAIT FOR ALL SLAVES ------------------- **MariaDB starting with [10.4.4](https://mariadb.com/kb/en/mariadb-1044-release-notes/)**The `WAIT FOR ALL SLAVES` option was first added in [MariaDB 10.4.4](https://mariadb.com/kb/en/mariadb-1044-release-notes/). `WAIT FOR ALL REPLICAS` has been a synonym since [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/). When a master server is shutdown and it goes through the normal shutdown process, the master kills client threads in random order. By default, the master also considers its binary log dump threads to be regular client threads. As a consequence, the binary log dump threads can be killed while client threads still exist, and this means that data can be written on the master during a normal shutdown that won't be replicated. This is true even if [semi-synchronous replication](../semisynchronous-replication/index) is being used. In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this problem can be solved by shutting down the server with the [SHUTDOWN](index) command and by providing the `WAIT FOR ALL SLAVES` option to the command. For example: ``` SHUTDOWN WAIT FOR ALL SLAVES; ``` When the `WAIT FOR ALL SLAVES` option is provided, the server only kills its binary log dump threads after all client threads have been killed, and it only completes the shutdown after the last [binary log](../binary-log/index) has been sent to all connected replicas. See [Replication Threads: Binary Log Dump Threads and the Shutdown Process](../replication-threads/index#binary-log-dump-threads-and-the-shutdown-process) for more information. Required Permissions -------------------- One must have a `SHUTDOWN` privilege (see [GRANT](../grant/index)) to use this command. It is the same privilege one needs to use the [mariadb-admin/mysqladmin shutdown](../mysqladmin/index#mysqladmin-commands) command. Shutdown for Upgrades --------------------- If you are doing a shutdown to [migrate to another major version of MariaDB](upgrading-between-major-mariadb-version), please ensure that the [innodb\_fast\_shutdown](../innodb-system-variables/index#innodb_fast_shutdown) variable is not 2 (fast crash shutdown). The default of this variable is 1. Example ------- The following example shows how to create an [event](../stored-programs-and-views-events/index) which turns off the server at a certain time: ``` CREATE EVENT `test`.`shutd` ON SCHEDULE EVERY 1 DAY STARTS '2014-01-01 20:00:00' COMMENT 'Shutdown Maria when the office is closed' DO BEGIN SHUTDOWN; END; ``` Other Ways to Stop mysqld ------------------------- You can use the [mariadb-admin/mysqladmin shutdown](../mysqladmin/index) command to take down mysqld cleanly. You can also use the system kill command on Unix with signal SIGTERM (15) ``` kill -SIGTERM pid-of-mysqld-process ``` You can find the process number of the server process in the file that ends with `.pid` in your data directory. The above is identical to `mysqladmin shutdown`. On windows you should use: ``` NET STOP MySQL ``` See Also -------- * [mariadb-admin/mysqladmin shutdown](../mysqladmin/index). * [InnoDB fast shutdown option](../innodb-system-variables/index#innodb_fast_shutdown) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb RANGE COLUMNS and LIST COLUMNS Partitioning Types RANGE COLUMNS and LIST COLUMNS Partitioning Types ================================================= RANGE COLUMNS and LIST COLUMNS are variants of, respectively, [RANGE](../range-partitioning-type/index) and [LIST](../list-partitioning/index). With these partitioning types there is not a single partitioning expression; instead, a list of one or more columns is accepted. The following rules apply: * The list can contain one or more columns. * Columns can be of any [integer](../int/index), [string](../string-data-types/index), [DATE](../date/index), and [DATETIME](../datetime/index) types. * Only bare columns are permitted; no expressions. All the specified columns are compared to the specified values to determine which partition should contain a specific row. See below for details. Syntax ------ The last part of a [CREATE TABLE](../create-table/index) statement can be definition of the new table's partitions. In the case of RANGE COLUMNS partitioning, the syntax is the following: ``` PARTITION BY RANGE COLUMNS (col1, col2, ...) ( PARTITION partition_name VALUES LESS THAN (value1, value2, ...), [ PARTITION partition_name VALUES LESS THAN (value1, value2, ...), ... ] ) ``` The syntax for LIST COLUMNS is the following: ``` PARTITION BY LIST COLUMNS (partitioning_expression) ( PARTITION partition_name VALUES IN (value1, value2, ...), [ PARTITION partition_name VALUES IN (value1, value2, ...), ... ] [ PARTITION partititon_name DEFAULT ] ) ``` `partition_name` is the name of a partition. Comparisons ----------- To determine which partition should contain a row, all specified columns will be compared to each partition definition. With LIST COLUMNS, a row matches a partition if all row values are identical to the specified values. At most one partition can match the row. With RANGE COLUMNS, a row matches a partition if all row values are less than specified values. The first partition that matches row values will be used. `DEFAULT` partition catch all records which do not fit in other partitions. Only one `DEFAULT` partititon allowed. This option added in [MariaDB 10.2](../what-is-mariadb-102/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CONVEXHULL CONVEXHULL ========== A synonym for [ST\_CONVEXHULL](../st_convexhull/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb HEX HEX === Syntax ------ ``` HEX(N_or_S) ``` Description ----------- If `N_or_S` is a number, returns a string representation of the hexadecimal value of `N`, where `N` is a `longlong` (`[BIGINT](../bigint/index)`) number. This is equivalent to `[CONV](../conv/index)(N,10,16)`. If `N_or_S` is a string, returns a hexadecimal string representation of `N_or_S` where each byte of each character in `N_or_S` is converted to two hexadecimal digits. If `N_or_S` is NULL, returns NULL. The inverse of this operation is performed by the [UNHEX](../unhex/index)() function. **MariaDB starting with [10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)**HEX() with an [INET6](../inet6/index) argument returns a hexadecimal representation of the underlying 16-byte binary string. Examples -------- ``` SELECT HEX(255); +----------+ | HEX(255) | +----------+ | FF | +----------+ SELECT 0x4D617269614442; +------------------+ | 0x4D617269614442 | +------------------+ | MariaDB | +------------------+ SELECT HEX('MariaDB'); +----------------+ | HEX('MariaDB') | +----------------+ | 4D617269614442 | +----------------+ ``` From [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/): ``` SELECT HEX(CAST('2001:db8::ff00:42:8329' AS INET6)); +----------------------------------------------+ | HEX(CAST('2001:db8::ff00:42:8329' AS INET6)) | +----------------------------------------------+ | 20010DB8000000000000FF0000428329 | +----------------------------------------------+ ``` See Also -------- * [Hexadecimal literals](../hexadecimal-literals/index) * [UNHEX()](../unhex/index) * [CONV()](../conv/index) * [BIN()](../bin/index) * [OCT()](../oct/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Authentication Plugin - GSSAPI Authentication Plugin - GSSAPI ============================== The `gssapi` authentication plugin allows the user to authenticate with services that use the [Generic Security Services Application Program Interface (GSSAPI)](https://en.wikipedia.org/wiki/Generic_Security_Services_Application_Program_Interface). Windows has a slightly different but very similar API called [Security Support Provider Interface (SSPI)](https://docs.microsoft.com/en-us/windows/desktop/secauthn/sspi). The GSSAPI is a standardized API described in [RFC2743](https://tools.ietf.org/html/rfc2743.html) and [RFC2744](https://tools.ietf.org/html/rfc2744.html). The client and server negotiate using a standardized protocol described in [RFC7546](https://tools.ietf.org/html/rfc7546.html). On Windows, this authentication plugin supports [Kerberos](https://docs.microsoft.com/en-us/windows/desktop/secauthn/microsoft-kerberos) and [NTLM](https://docs.microsoft.com/en-us/windows/desktop/secauthn/microsoft-ntlm) authentication. Windows authentication is supported regardless of whether a [domain](https://en.wikipedia.org/wiki/Windows_domain) is used in the environment. On Unix systems, the most dominant GSSAPI service is [Kerberos](https://en.wikipedia.org/wiki/Kerberos_(protocol)). However, it is less commonly used on Unix systems than it is on Windows. Regardless, this authentication plugin also supports Kerberos authentication on Unix. The `gssapi` authentication plugin is most often used for authenticating with [Microsoft Active Directory](https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/get-started/virtual-dc/active-directory-domain-services-overview). This article gives instructions on configuring the `gssapi` authentication plugin for MariaDB for passwordless login. Installing the Plugin's Package ------------------------------- The `gssapi` authentication plugin's shared library is included in MariaDB packages as the `auth_gssapi.so` or `auth_gssapi.dll` shared library on systems where it can be built. The plugin was first included in [MariaDB 10.1.11](https://mariadb.com/kb/en/mariadb-10111-release-notes/). ### Installing on Linux The `gssapi` authentication plugin is included in [binary tarballs](../installing-mariadb-binary-tarballs/index) on Linux. #### Installing with a Package Manager The `gssapi` authentication plugin can also be installed via a package manager on Linux. In order to do so, your system needs to be configured to install from one of the MariaDB repositories. You can configure your package manager to install it from MariaDB Corporation's MariaDB Package Repository by using the [MariaDB Package Repository setup script](../mariadb-package-repository-setup-and-usage/index). You can also configure your package manager to install it from MariaDB Foundation's MariaDB Repository by using the [MariaDB Repository Configuration Tool](https://downloads.mariadb.org/mariadb/repositories/). ##### Installing with yum/dnf On RHEL, CentOS, Fedora, and other similar Linux distributions, it is highly recommended to install the relevant [RPM package](../rpm/index) from MariaDB's repository using `[yum](../yum/index)` or `[dnf](https://en.wikipedia.org/wiki/DNF_(software))`. Starting with RHEL 8 and Fedora 22, `yum` has been replaced by `dnf`, which is the next major version of `yum`. However, `yum` commands still work on many systems that use `dnf`. For example: ``` sudo yum install MariaDB-gssapi-server ``` ##### Installing with apt-get On Debian, Ubuntu, and other similar Linux distributions, it is highly recommended to install the relevant [DEB package](../installing-mariadb-deb-files/index) from MariaDB's repository using `[apt-get](https://wiki.debian.org/apt-get)`. For example: ``` sudo apt-get install mariadb-plugin-gssapi-server ``` ##### Installing with zypper On SLES, OpenSUSE, and other similar Linux distributions, it is highly recommended to install the relevant [RPM package](../rpm/index) from MariaDB's repository using `[zypper](../installing-mariadb-with-zypper/index)`. For example: ``` sudo zypper install MariaDB-gssapi-server ``` ### Installing on Windows The `gssapi` authentication plugin is included in [MSI](../installing-mariadb-msi-packages-on-windows/index) and [ZIP](../installing-mariadb-windows-zip-packages/index) packages on Windows. Installing the Plugin --------------------- Although the plugin's shared library is distributed with MariaDB by default, the plugin is not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB. The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing `[INSTALL SONAME](../install-soname/index)` or `[INSTALL PLUGIN](../install-plugin/index)`. For example: ``` INSTALL SONAME 'auth_gssapi'; ``` The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the `[--plugin-load](../mysqld-options/index#-plugin-load)` or the `[--plugin-load-add](../mysqld-options/index#-plugin-load-add)` options. This can be specified as a command-line argument to `[mysqld](../mysqld-options/index)` or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... plugin_load_add = auth_gssapi ``` Uninstalling the Plugin ----------------------- You can uninstall the plugin dynamically by executing `[UNINSTALL SONAME](../uninstall-soname/index)` or `[UNINSTALL PLUGIN](../uninstall-plugin/index)`. For example: ``` UNINSTALL SONAME 'auth_gssapi'; ``` If you installed the plugin by providing the `[--plugin-load](../mysqld-options/index#-plugin-load)` or the `[--plugin-load-add](../mysqld-options/index#-plugin-load-add)` options in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), then those options should be removed to prevent the plugin from being loaded the next time the server is restarted. Configuring the Plugin ---------------------- If the MariaDB server is running on Unix, then some additional configuration steps will need to be implemented in order to use the plugin. If the MariaDB server is running on Windows, then no special configuration steps will need to be implemented in order to use the plugin, as long as the following is true: * The Windows server is joined to a domain. * The MariaDB server process is running as either a [NetworkService Account](https://docs.microsoft.com/en-us/windows/desktop/services/networkservice-account) or a [Domain User Account](https://docs.microsoft.com/en-us/windows/desktop/ad/domain-user-accounts). ### Creating a Keytab File on Unix If the MariaDB server is running on Unix, then the KDC server will need to create a keytab file for the MariaDB server. The keytab file contains the service principal name, which is the identity that the MariaDB server will use to communicate with the KDC server. The keytab will need to be transferred to the MariaDB server, and the `mysqld` server process will need read access to this keytab file. How this keytab file is generated depends on whether the KDC server is **[Microsoft Active Directory KDC](https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/get-started/virtual-dc/active-directory-domain-services-overview)** or **[MIT Kerberos KDC](http://web.mit.edu/Kerberos/krb5-1.12/doc/index.html)**. #### Creating a Keytab File with Microsoft Active Directory If you are using **[Microsoft Active Directory KDC](https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/get-started/virtual-dc/active-directory-domain-services-overview)**, then you may need to create a keytab using the `[ktpass.exe](https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/ktpass)` utility on a Windows host. The service principal will need to be mapped to an existing domain user. To do so, follow the steps listed below. Be sure to replace the following items in the step below: * Replace `${HOST}` with the fully qualified DNS name for the MariaDB server host. * Replace `${DOMAIN}` with the Active Directory domain. * Replace `${AD_USER}` with the existing domain user. * Replace `${PASSWORD}` with the password for the service principal. To create the service principal, execute the following: ``` ktpass.exe /princ mariadb/${HOST}@${DOMAIN} /mapuser ${AD_USER} /pass ${PASSWORD} /out mariadb.keytab /crypto all /ptype KRB5_NT_PRINCIPAL /mapop set ``` #### Creating a Keytab File with MIT Kerberos If you are using **[MIT Kerberos KDC](http://web.mit.edu/Kerberos/krb5-1.12/doc/index.html)**, then you can create a [keytab](http://web.mit.edu/Kerberos/krb5-1.12/doc/admin/install_appl_srv.html#the-keytab-file) file using the `[kadmin](https://web.mit.edu/kerberos/krb5-1.12/doc/admin/admin_commands/kadmin_local.html)` utility. To do so, follow the steps listed below. In the following steps, be sure to replace `${HOST}` with the fully qualified DNS name for the MariaDB server host. First, create the service principal using the `[kadmin](https://web.mit.edu/kerberos/krb5-1.12/doc/admin/admin_commands/kadmin_local.html)` utility. For example: ``` kadmin -q "addprinc -randkey mariadb/${HOST}" ``` Then, export the newly created user to the keytab file using the `[kadmin](https://web.mit.edu/kerberos/krb5-1.12/doc/admin/admin_commands/kadmin_local.html)` utility. For example: ``` kadmin -q "ktadd -k /path/to/mariadb.keytab mariadb/${HOST}" ``` More details can be found at the following links: * [MIT Kerberos Documentation: Database administration](http://web.mit.edu/Kerberos/krb5-1.12/doc/admin/database.html) * [MIT Kerberos Documentation: Application servers](http://web.mit.edu/Kerberos/krb5-1.12/doc/admin/appl_servers.html) ### Configuring the Path to the Keytab File on Unix If the MariaDB server is running on Unix, then the path to the keytab file that was previously created can be set by configuring the `[gssapi\_keytab\_path](#gssapi_keytab_path)` system variable. This can be specified as a command-line argument to `[mysqld](../mysqld-options/index)` or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... gssapi_keytab_path=/path/to/mariadb.keytab ``` ### Configuring the Service Principal Name The service principal name can be set by configuring the `[gssapi\_principal\_name](#gssapi_principal_name)` system variable. This can be specified as a command-line argument to `[mysqld](../mysqld-options/index)` or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... gssapi_principal_name=service_principal_name/host.domain.com@REALM ``` If a service principal name is not provided, then the plugin will try to use `mariadb/host.domain.com@REALM` by default. If the MariaDB server is running on Unix, then the plugin needs a service principal name in order to function. If the MariaDB server is running on Windows, then the plugin does not usually need a service principal in order to function. However, if you want to use one anyway, then one can be created with the `[setspn](https://social.technet.microsoft.com/wiki/contents/articles/717.service-principal-names-spns-setspn-syntax-setspn-exe.aspx)` utility. Different KDC implementations may use different canonical forms to identify principals. See [RFC2744: Section 3.10](https://tools.ietf.org/html/rfc2744.html#section-3.10) to learn what the standard says about principal names. More details can be found at the following links: * [Active Directory Domain Services: Service Principal Names](https://docs.microsoft.com/en-us/windows/win32/ad/service-principal-names) * [MIT Kerberos Documentation: Realm configuration decisions](http://web.mit.edu/Kerberos/krb5-1.12/doc/admin/realm_config.html) * [MIT Kerberos Documentation: Principal names and DNS](http://web.mit.edu/Kerberos/krb5-1.12/doc/admin/princ_dns.html) Creating Users -------------- To create a user account via `[CREATE USER](../create-user/index)`, specify the name of the plugin in the `[IDENTIFIED VIA](../create-user/index#identified-viawith-authentication_plugin)` clause. For example: ``` CREATE USER username@hostname IDENTIFIED VIA gssapi; ``` If `[SQL\_MODE](../sql-mode/index)` does not have `NO_AUTO_CREATE_USER` set, then you can also create the user account via `[GRANT](../grant/index)`. For example: ``` GRANT SELECT ON db.* TO username@hostname IDENTIFIED VIA gssapi; ``` You can also specify the user's [realm](https://docs.microsoft.com/en-us/windows-server/networking/technologies/nps/nps-crp-realm-names) for MariaDB with the `USING` clause. For example: ``` CREATE USER username@hostname IDENTIFIED VIA gssapi USING '[email protected]'; ``` The format of the realm depends on the specific authentication mechanism that is used. For example, the format would need to be `machine\\username` for Windows users authenticating with NTLM. If the realm is not provided in the user account's definition, then the realm is **not** used for comparison. Therefore, '[email protected]', '[email protected]' and 'mymachine\usr1' would all identify as the following user account: ``` CREATE USER usr1@hostname IDENTIFIED VIA gssapi; ``` ### Creating users identified via group membership or SID (Windows-specific) Since 10.6.0, on Windows only, it is possible to login using a AD or local group-membership. This is achieved by using GROUP prefix in IDENTIFIED ... AS ``` CREATE USER root IDENTIFIED VIA gssapi as 'GROUP:Administrators' CREATE USER root IDENTIFIED VIA gssapi as 'GROUP:BUILTIN\\Administrators' ``` Effect of the above definition is that every user that identifies as member of group Administrators can login using user name root, passwordless. User can also login using own or group [SID](https://en.wikipedia.org/wiki/Security_Identifier) ``` CREATE USER root IDENTIFIED VIA gssapi as 'SID:S-1-5-32-544' ``` Using SIDs will perform slightly faster than using name (since it will spare translation between SID and name which is otherwise done), also SIDs immune against user or group renaming. Client Authentication Plugins ----------------------------- For clients that use the `libmysqlclient` or [MariaDB Connector/C](../mariadb-connector-c/index) libraries, MariaDB provides one client authentication plugin that is compatible with the `gssapi` authentication plugin: * `auth_gssapi_client` When connecting with a [client or utility](../clients-utilities/index) to a server as a user account that authenticates with the `gssapi` authentication plugin, you may need to tell the client where to find the relevant client authentication plugin by specifying the `--plugin-dir` option. For example: ``` mysql --plugin-dir=/usr/local/mysql/lib64/mysql/plugin --user=alice ``` ### `auth_gssapi_client` The `auth_gssapi_client` client authentication plugin receives the principal name from the server, and then uses either the `[gss\_init\_sec\_context](https://web.mit.edu/kerberos/krb5-devel/doc/appdev/gssapi.html#initiator-credentials)` function (on Unix) or the `[InitializeSecurityContext](https://docs.microsoft.com/en-us/windows/desktop/api/sspi/nf-sspi-initializesecuritycontexta)` function (on Windows) to establish a security context on the client. Support in Client Libraries --------------------------- ### Using the Plugin with MariaDB Connector/C [MariaDB Connector/C](../mariadb-connector-c/index) supports `gssapi` authentication using the [client authentication plugins](#client-authentication-plugins) mentioned in the previous section since MariaDB Connector/C 3.0.1. ### Using the Plugin with MariaDB Connector/ODBC [MariaDB Connector/ODBC](../mariadb-connector-odbc/index) supports `gssapi` authentication using the [client authentication plugins](#client-authentication-plugins) mentioned in the previous section since MariaDB Connector/ODBC 3.0.0. ### Using the Plugin with MariaDB Connector/J [MariaDB Connector/J](../mariadb-connector-j/index) supports `gssapi` authentication since MariaDB Connector/J 1.4.0. Current documentation can be found [here](../gssapi-authentication-with-mariadb-connectorj/index). ### Using the Plugin with MariaDB Connector/Node.js [MariaDB Connector/Node.js](../nodejs-connector/index) does not yet support `gssapi` authentication. See [CONJS-72](https://jira.mariadb.org/browse/CONJS-72) for more information. ### Using the Plugin with MySqlConnector for .NET [MySqlConnector for ADO.NET](../mysqlconnector-for-adonet/index) supports `gssapi` authentication since MySqlConnector 0.47.0. The support is transparent. Normally, the connector only needs to be provided the correct user name, and no other parameters are required. However, this connector also supports the `[ServerSPN](https://mysql-net.github.io/MySqlConnector/connection-options)` connection string parameter, which can be used for mutual authentication. #### .NET specific problems/workarounds When connecting from Unix client to Windows server with ADO.NET, in an Active Directory domain environment, be aware that .NET Core on Unix does not support principal names in UPN(User Principal Name) form, which is default on Windows (e.g [email protected]) . Thus, upon encountering an authentication exception with "server not found in Kerberos database", use one of workarounds below * Force host-based SPN on server side. + For example, this can be done by setting the `[gssapi\_principal\_name](#gssapi_principal_name)` system variable to `HOST/machine` in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). * Pass host-based SPN on client side. + For example, this can be done by setting the connector's `[ServerSPN](https://mysql-net.github.io/MySqlConnector/connection-options)` connection string parameter to `HOST/machine`. Versions -------- | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Stable | [MariaDB 10.1.15](https://mariadb.com/kb/en/mariadb-10115-release-notes/) | | 1.0 | Beta | [MariaDB 10.1.11](https://mariadb.com/kb/en/mariadb-10111-release-notes/) | System Variables ---------------- ### `gssapi_keytab_path` * **Description:** Defines the path to the server's keytab file. + This system variable is only meaningful on **Unix**. + See [Creating a Keytab File on Unix](#creating-a-keytab-file) and [Configuring the Path to the Keytab File on Unix](#configuring-the-path-to-the-keytab-file-on-unix) for more information. * **Commandline:** `--gssapi-keytab-path` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** '' * **Introduced:** [MariaDB 10.1.11](https://mariadb.com/kb/en/mariadb-10111-release-notes/) --- ### `gssapi_principal_name` * **Description:** Name of the service principal. + See [Configuring the Service Principal Name](#configuring-the-service-principal-name) for more information. * **Commandline:** `--gssapi-principal-name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** '' * **Introduced:** [MariaDB 10.1.11](https://mariadb.com/kb/en/mariadb-10111-release-notes/) --- ### `gssapi_mech_name` * **Description:** Name of the SSPI package used by server. Can be either 'Kerberos' or 'Negotiate'. Set it to 'Kerberos', to prevent less secure NTLM in domain environments, but leave it as default (Negotiate) to allow non-domain environments (e.g if server does not run in a domain environment). + This system variable is only meaningful on **Windows**. * **Commandline:** `--gssapi-mech-name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `enumerated` * **Default Value:** `Negotiate` * **Valid Values:** `Kerberos`, `Negotiate` * **Introduced:** [MariaDB 10.1.11](https://mariadb.com/kb/en/mariadb-10111-release-notes/) --- Options ------- ### `gssapi` * **Description:** Controls how the server should treat the plugin when the server starts up. + Valid values are: - `OFF` - Disables the plugin without removing it from the `[mysql.plugins](../mysqlplugin-table/index)` table. - `ON` - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled. - `FORCE` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. - `FORCE_PLUS_PERMANENT` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with `[UNINSTALL SONAME](../uninstall-soname/index)` or `[UNINSTALL PLUGIN](../uninstall-plugin/index)` while the server is running. + See [Plugin Overview: Configuring Plugin Activation at Server Startup](../plugin-overview/index#configuring-plugin-activation-at-server-startup) for more information. * **Commandline:** `--gssapi=value` * **Data Type:** `enumerated` * **Default Value:** `ON` * **Valid Values:** `OFF`, `ON`, `FORCE`, `FORCE_PLUS_PERMANENT` * **Introduced:** [MariaDB 10.1.11](https://mariadb.com/kb/en/mariadb-10111-release-notes/) --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SUBDATE SUBDATE ======= Syntax ------ ``` SUBDATE(date,INTERVAL expr unit), SUBDATE(expr,days) ``` Description ----------- When invoked with the `INTERVAL` form of the second argument, `SUBDATE()` is a synonym for `[DATE\_SUB()](../date_sub/index)`. See [Date and Time Units](../date-and-time-units/index) for a complete list of permitted units. The second form allows the use of an integer value for days. In such cases, it is interpreted as the number of days to be subtracted from the date or datetime expression expr. Examples -------- ``` SELECT DATE_SUB('2008-01-02', INTERVAL 31 DAY); +-----------------------------------------+ | DATE_SUB('2008-01-02', INTERVAL 31 DAY) | +-----------------------------------------+ | 2007-12-02 | +-----------------------------------------+ SELECT SUBDATE('2008-01-02', INTERVAL 31 DAY); +----------------------------------------+ | SUBDATE('2008-01-02', INTERVAL 31 DAY) | +----------------------------------------+ | 2007-12-02 | +----------------------------------------+ ``` ``` SELECT SUBDATE('2008-01-02 12:00:00', 31); +------------------------------------+ | SUBDATE('2008-01-02 12:00:00', 31) | +------------------------------------+ | 2007-12-02 12:00:00 | +------------------------------------+ ``` ``` CREATE TABLE t1 (d DATETIME); INSERT INTO t1 VALUES ("2007-01-30 21:31:07"), ("1983-10-15 06:42:51"), ("2011-04-21 12:34:56"), ("2011-10-30 06:31:41"), ("2011-01-30 14:03:25"), ("2004-10-07 11:19:34"); ``` ``` SELECT d, SUBDATE(d, 10) from t1; +---------------------+---------------------+ | d | SUBDATE(d, 10) | +---------------------+---------------------+ | 2007-01-30 21:31:07 | 2007-01-20 21:31:07 | | 1983-10-15 06:42:51 | 1983-10-05 06:42:51 | | 2011-04-21 12:34:56 | 2011-04-11 12:34:56 | | 2011-10-30 06:31:41 | 2011-10-20 06:31:41 | | 2011-01-30 14:03:25 | 2011-01-20 14:03:25 | | 2004-10-07 11:19:34 | 2004-09-27 11:19:34 | +---------------------+---------------------+ SELECT d, SUBDATE(d, INTERVAL 10 MINUTE) from t1; +---------------------+--------------------------------+ | d | SUBDATE(d, INTERVAL 10 MINUTE) | +---------------------+--------------------------------+ | 2007-01-30 21:31:07 | 2007-01-30 21:21:07 | | 1983-10-15 06:42:51 | 1983-10-15 06:32:51 | | 2011-04-21 12:34:56 | 2011-04-21 12:24:56 | | 2011-10-30 06:31:41 | 2011-10-30 06:21:41 | | 2011-01-30 14:03:25 | 2011-01-30 13:53:25 | | 2004-10-07 11:19:34 | 2004-10-07 11:09:34 | +---------------------+--------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Package Testing with Buildbot and KVM Package Testing with Buildbot and KVM ===================================== Buildbot testing of binary MariaDB packages ------------------------------------------- This part of the Buildbot setup uses KVM virtual machines to build packages on a wide range of Linux distributions and test the different packages in various ways. The builds run on a single host, which has an Intel Core i7 860 @ 2.80GHz CPU, 8 GByte of RAM, and a 500GByte disk. The build host is installed with Ubuntu 9.04 Server 64-bit. The current box is capable of running up to 3 builds in parallel. The entire set of 19 builds take around 3.5 hours to complete. The build host has no virtual machines that are kept running when idle. Instead each build boots up and shuts down virtual machines on the fly as needed, using the [runvm](../runvm/index) tool. The details of the setup (installation) of the virtual machines are [here](../buildbot-setup/index). ### Builds (Please check the Buildbot configuration for details, in case this information becomes out of date). At the time of writing, the builds done are these: * Source tarball build (on a 32-bit Ubuntu 9.04 VM) * Binary tarballs, i386 and amd64, on Ubuntu 8.04 VMs. * Ubuntu, i386 and amd64: 8.04, 8.10, 9.04, 9.10, 10.04 (alpha). * Debian, i386 and amd64, Debian 4 and Debian 5. * Centos 5, i386 and amd64. The builds use the packaging scripts from [OurDelta](https://launchpad.net/ourdelta). In all builds (except for source tarball), the binary package is built, and subsequently attempted installed. The build is done on a virtual machine with compilers and other necessary build tools installed. The virtual machines are cloned from a reference image before each build (using the --base-image option to runvm). This way, the original images are not modified in any way, so there is no risk of "pollution" from previous builds, and no need to carefully clean up after a build or test. The source tarball build is done in a virtual machine that is not reset after every build. This is to preserve the bzr shared repository setup inside the virtual machine. This way it is only necessary in each build to download new changes from Launchpad, which saves significant amounts of time (and Launchpad bandwidth). Since this particular build only works inside the source checkout directory, the risk of cross-build pollution is minimal. The source tarball build is the only one that is triggered by bzr commits. After it has successfully built a source tarball, the tarball is uploaded to the Buildbot master, and all of the other builders are triggered to start building. Each will download the source tarball from the master and build from that rather than from a bzr checkout (this is the correct way, as we want to ensure that users building from the source tarball themselves get the same results as the packages built by us). Since we use the OurDelta scripts, which use a "bakery" for the build scripts similar to a source tarball, there is a bakery tarball similarly generated from bzr and uploaded to the master. Because of this triggering, it is not possible to manually force a Buildbot run on "latest bzr version" on the non-tarball builders. Instead to force a build, it is necessary to set the build properties for source tarball and bakery manually to the files one wants to tests. But it is often easier just to pick an existing build (with correct tarball) and use the "resubmit build" feature instead. Another option is to force build on the tarball build only; it will then in turn trigger all of the other builds. ### Basic install test On all builds (except source tarball), after the build a test is performed where the resulting package is installed in a virtual machine and basic testing is done. The install test is done in a separate virtual machine from the one in which it was built, with no build tools and a very minimal install (to check that we have no hidden dependencies). The install test is currently *very* basic, basically just create a table and insert a row (it would be a nice ToDo to extend this testing to a more complete "smoke test"). Note that for .deb (Debian and Ubuntu), we set up a small fake local apt repository, so that we can properly test that ''apt-get install'' is able to pull in any extra dependencies without anything special needed on the part of the user. ### Upgrade tests for .deb packages On .deb builders (Debian and Ubuntu), we do three additional upgrade tests. Two of them install the newly built MariaDB packages on top of an already installed MySQL package (the default MySQL package on that particular distro version), as well as on top of an earlier version of the MariaDB packages. For this, separate virtual machine images are used, based on the one used in the install test, but in addition with MySQL/MariaDB pre-installed. The third test is performed on a clean image without any pre-installed MySQL or MariaDB packages. The test installs the latest available release of the same major version from MariaDB public repo, and then runs dist-upgrade using the local repo as a source of the new packages. The main goal of this test is to check that regular system upgrades performed via dist-upgrade work as expected in regard to MariaDB server. In all tests, some very basic test data is also created in the installation, so we can test that replacing the old server installation with our new MariaDB package does not nuke the user's existing data! The test is also useful to check that the upgrade runs correctly with respect to dependencies etc, something that is quite complex to get right with the .deb packaging. ### Upgrade tests for .rpm packages On .rpm builders (CentOS, Fedora, RHEL, SLES, openSUSE) we have numerous upgrade tests, although only a small portion of them is run for every branch. All tests upgrade an already existing installation to the new MariaDB packages. The variables are: - what kind of existing installation is being upgraded: MariaDB server, MariaDB Galera, MySQL, Percona server, or mysql/mariadb installations provided by distributions; - which command is used for upgrade: it can either be performed via upgrade/update (depending on the package manager), or install, or dist-upgrade; - which packages are installed and upgraded: it can be a minimal set, server + client (plus whatever dependencies they bring), or a full set of packages. In some cases, the tests can also set additional command-line options or environment variables for the package manager. It is normally done when the default installation does not work, and the package manager suggests using a different set of parameters. Each test uses a clean VM image, installs an initial set of packages, and then uses one of the commands to upgrade the installation. It further checks that the server is upgraded, restarted and is reachable. ### mysql-test-run.pl test On the .deb builders (Debian and Ubuntu), we additionally do a full mysql-test-run.pl test run. This is done using the package *mariadb-test*. Note that currently, due to [Bug #491349](https://bugs.launchpad.net/bugs/491349), on newer Ubuntus the default apparmor profile prevents running mysql-test-run.pl. Until this is fixed, the tests need to uninstall apparmor before running the test suite. See also -------- * [Buildbot Setup for Virtual Machines](../buildbot-setup-for-virtual-machines/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Building MariaDB on Gentoo Building MariaDB on Gentoo ========================== MariaDB is in Gentoo, so the steps to build it are: 1. Synchronize your tree with ``` emerge --sync ``` 2. Build MariaDB using ``` emerge mariadb ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_GeomCollFromText ST\_GeomCollFromText ==================== Syntax ------ ``` ST_GeomCollFromText(wkt[,srid]) ST_GeometryCollectionFromText(wkt[,srid]) GeomCollFromText(wkt[,srid]) GeometryCollectionFromText(wkt[,srid]) ``` Description ----------- Constructs a [GEOMETRYCOLLECTION](../geometrycollection/index) value using its [WKT](../wkt-definition/index) representation and [SRID](../srid/index). `ST_GeomCollFromText()`, `ST_GeometryCollectionFromText()`, `GeomCollFromText()` and `GeometryCollectionFromText()` are all synonyms. Example ------- ``` CREATE TABLE gis_geometrycollection (g GEOMETRYCOLLECTION); SHOW FIELDS FROM gis_geometrycollection; INSERT INTO gis_geometrycollection VALUES (GeomCollFromText('GEOMETRYCOLLECTION(POINT(0 0), LINESTRING(0 0,10 10))')), (GeometryFromWKB(AsWKB(GeometryCollection(Point(44, 6), LineString(Point(3, 6), Point(7, 9)))))), (GeomFromText('GeometryCollection()')), (GeomFromText('GeometryCollection EMPTY')); ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Certificate Creation with OpenSSL Certificate Creation with OpenSSL ================================= **Warning**: the instructions below generate version 1 certificates only. These work fine with servers and clients using OpenSSL, but fail if WolfSSL is used instead, as is the case for our Windows MSI packages and our binary tarballs for Linux. WolfSSL requires version 3 certificates instead when using TLS v1.2 or higher, and so won't work with certificates generated as shown here when using two-way TLS with explicit client certificates. Generating version 3 certificates requires a few more minor steps, we will upgrade the instructions below soon to include these. See also: [MDEV-25701](https://jira.mariadb.org/browse/MDEV-25701) In order to secure communications with the MariaDB Server using TLS, you need to create a private key and an X509 certificate for the server. You may also want to create additional private keys and X509 certificates for any clients that need to connect to the server with TLS. This guide covers how to create a private key and a self-signed X509 certificate with OpenSSL. Certificate Creation -------------------- The [OpenSSL](https://www.openssl.org/) library provides a command-line tool called `[openssl](https://www.openssl.org/docs/man1.1.1/man1/openssl.html)`, which can be used for performing various tasks with the library, such as generating private keys, creating X509 certificate requests, signing X509 certificates as a Certificate Authority (CA), and verifying X509 certificates. ### Creating a Certificate Authority Private Key and Certificate The Certificate Authority (CA) is typically an organization (such as [Let's Encrypt](https://letsencrypt.org/)) that signs the X509 certificate and validates ownership of the domain. However, when you would like to use self-signed certificates, you need to create the private key and certificate for the CA yourself, and then you can use them to sign your own X509 certificates. To start, generate a private key for the CA using the `[openssl genrsa](https://www.openssl.org/docs/man1.1.1/man1/genrsa.html)` command. For example: ``` # openssl genrsa 2048 > ca-key.pem ``` After that, you can use the private key to generate the X509 certificate for the CA using the `[openssl req](https://www.openssl.org/docs/man1.1.1/man1/req.html)` command. For example: ``` # openssl req -new -x509 -nodes -days 365000 \ -key ca-key.pem -out ca.pem ``` The above commands create two files in the working directory: The `ca-key.pem` private key and the `ca.pem` X509 certificate are both are used by the CA to create self-signed X509 certificates below. ### Creating a Private Key and a Self-signed Certificate Once you have the CA's private key and X509 certificate, you can create the self-signed X509 certificates to use for the MariaDB Server, client, replication and other purposes. To start, generate a private key and create a certificate request using the `[openssl req](https://www.openssl.org/docs/man1.1.1/man1/req.html)` command. For example: ``` # openssl req -newkey rsa:2048 -days 365000 \ -nodes -keyout server-key.pem -out server-req.pem ``` After that, process the key to remove the passphrase using the `[openssl rsa](https://www.openssl.org/docs/man1.1.1/man1/rsa.html)` command. For example: ``` # openssl rsa -in server-key.pem -out server-key.pem ``` Lastly, using the certificate request and the CA's private key and X509 certificate, you can generate a self-signed X509 certificate from the certificate request using the `[openssl x509](https://www.openssl.org/docs/man1.1.1/man1/x509.html)` command. For example: ``` # openssl x509 -req -in server-req.pem -days 365000 \ -CA ca.pem -CAkey ca-key.pem -set_serial 01 \ -out server-cert.pem ``` This creates a `server-cert.pem` file, which is the self-signed X509 certificate. Certificate Verification ------------------------ Once you have created the CA's X509 certificate and a self-signed X509 certificate, you can verify that the X509 certificate was correctly generated using the `[openssl verify](https://www.openssl.org/docs/man1.1.1/man1/openssl-verify.html)` command. For example: ``` # openssl verify -CAfile ca.pem server-cert.pem server-cert.pem: OK ``` You can add as many X509 certificates to check against the CA's X509 certificate as you want to verify. A value of `OK` indicates that you can use it was correctly generated and is ready for use with MariaDB. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mariadb-access mariadb-access ============== **MariaDB starting with [10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/)**From [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), `mariadb-access` is a symlink to `mysqlaccess`, the tool for checking access privileges. **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), `mariadb-access` is the name of the tool, with `mysqlaccess` a symlink . See [mysqlaccess](../mysqlaccess/index) for details. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DEC, NUMERIC, FIXED DEC, NUMERIC, FIXED =================== Syntax ------ ``` DEC[(M[,D])] [SIGNED | UNSIGNED | ZEROFILL] NUMERIC[(M[,D])] [SIGNED | UNSIGNED | ZEROFILL] FIXED[(M[,D])] [SIGNED | UNSIGNED | ZEROFILL] ``` Description ----------- These types are synonyms for [DECIMAL](../decimal/index). The `FIXED` synonym is available for compatibility with other database systems. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema MyRocks Tables Information Schema MyRocks Tables ================================== List of Information Schema tables specifically related to [MyRocks](../myrocks/index). | Title | Description | | --- | --- | | [Information Schema ROCKSDB\_CFSTATS Table](../information-schema-rocksdb_cfstats-table/index) | The Information Schema ROCKSDB\_CFSTATS table is included as part of the MyR... | | [Information Schema ROCKSDB\_CF\_OPTIONS Table](../information-schema-rocksdb_cf_options-table/index) | Information about MyRocks Column Families. | | [Information Schema ROCKSDB\_COMPACTION\_STATS Table](../information-schema-rocksdb_compaction_stats-table/index) | The Information Schema ROCKSDB\_COMPACTION\_STATS table is included as part o... | | [Information Schema ROCKSDB\_DBSTATS Table](../information-schema-rocksdb_dbstats-table/index) | The Information Schema ROCKSDB\_DBSTATS table is included as part of the MyR... | | [Information Schema ROCKSDB\_DDL Table](../information-schema-rocksdb_ddl-table/index) | The Information Schema ROCKSDB\_DDL table is included as part of the MyRocks... | | [Information Schema ROCKSDB\_DEADLOCK Table](../information-schema-rocksdb_deadlock-table/index) | The Information Schema ROCKSDB\_DEADLOCK table is included as part of the My... | | [Information Schema ROCKSDB\_GLOBAL\_INFO Table](../information-schema-rocksdb_global_info-table/index) | The Information Schema ROCKSDB\_GLOBAL\_INFO table is included as part of the... | | [Information Schema ROCKSDB\_INDEX\_FILE\_MAP Table](../information-schema-rocksdb_index_file_map-table/index) | The Information Schema ROCKSDB\_INDEX\_FILE\_MAP table is included as part of ... | | [Information Schema ROCKSDB\_LOCKS Table](../information-schema-rocksdb_locks-table/index) | The Information Schema ROCKSDB\_LOCKS table is included as part of the MyRoc... | | [Information Schema ROCKSDB\_PERF\_CONTEXT Table](../information-schema-rocksdb_perf_context-table/index) | Per-table/partition counters. | | [Information Schema ROCKSDB\_PERF\_CONTEXT\_GLOBAL Table](../information-schema-rocksdb_perf_context_global-table/index) | Global counters. | | [Information Schema ROCKSDB\_SST\_PROPS Table](../information-schema-rocksdb_sst_props-table/index) | The Information Schema ROCKSDB\_SST\_PROPS table is included as part of the M... | | [Information Schema ROCKSDB\_TRX Table](../information-schema-rocksdb_trx-table/index) | The Information Schema ROCKSDB\_TRX table is included as part of the MyRocks... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb JSON_VALUE JSON\_VALUE =========== **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**JSON functions were added in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). Syntax ------ ``` JSON_VALUE(json_doc, path) ``` Description ----------- Given a JSON document, returns the scalar specified by the path. Returns NULL if not given a valid JSON document, or if there is no match. Examples -------- ``` select json_value('{"key1":123}', '$.key1'); +--------------------------------------+ | json_value('{"key1":123}', '$.key1') | +--------------------------------------+ | 123 | +--------------------------------------+ select json_value('{"key1": [1,2,3], "key1":123}', '$.key1'); +-------------------------------------------------------+ | json_value('{"key1": [1,2,3], "key1":123}', '$.key1') | +-------------------------------------------------------+ | 123 | +-------------------------------------------------------+ ``` In the SET statement below, two escape characters are needed, as a single escape character would be applied by the SQL parser in the SET statement, and the escaped character would not form part of the saved value. ``` SET @json = '{"key1":"60\\" Table", "key2":"1"}'; SELECT JSON_VALUE(@json,'$.key1') AS Name , json_value(@json,'$.key2') as ID; +-----------+------+ | Name | ID | +-----------+------+ | 60" Table | 1 | +-----------+------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb aria_s3_copy aria\_s3\_copy ============== **MariaDB starting with [10.5](../what-is-mariadb-105/index)**The [S3 storage engine](../s3-storage-engine/index) has been available since [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/). `aria_s3_copy` is a tool for copying an [Aria](../aria/index) table to and from [S3](../s3-storage-engine/index). The Aria table must be non transactional and have [ROW\_FORMAT=PAGE](../aria-storage-formats/index#page). For `aria_s3_copy` to work reliably, the table should not be changed by the MariaDB server during the copy, and one should have first performed [FLUSH TABLES](../flush/index) to ensure that the table is properly closed. Example of properly created Aria table: ``` create table test1 (a int) transactional=0 row_format=PAGE engine=aria; ``` Note that [ALTER TABLE table\_name ENGINE=S3](../using-the-s3-storage-engine/index) will work for any kind of table. This internally converts the table to an Aria table and then moves it to S3 storage. ### Main Arguments | Option | Description | | --- | --- | | -?, --help | Display this help and exit. | | -k, --s3-access-key=name | AWS access key ID | | -r, --s3-region=name | AWS region | | -K, --s3-secret-key=name | AWS secret access key ID | | -b, --s3-bucket=name | AWS prefix for tables | | -h, --s3-host-name=name | Host name to S3 provider | | -c, --compress | Use compression | | -o, --op=name | Operation to execute. One of 'from\_s3', 'to\_s3' or 'delete\_from\_s3' | | -d, --database=name | Database for copied table (second prefix). If not given, the directory of the table file is used | | -B, --s3-block-size=# | Block size for data/index blocks in s3 | | -L, --s3-protocol-version=name | Protocol used to communication with S3. One of "Amazon" or "Original". | | -f, --force | Force copy even if target exists | | -v, --verbose | Write more information | | -V, --version | Print version and exit. | | -#, --debug[=name] | Output debug log. Often this is 'd:t:o,filename'. | | --s3-debug | Output debug log from marias3 to stdout | | | | | --- | --- | | -p, --s3-port=# | Port number to connect to (0 means use default) | | -P, --s3-use-http | If true, force use of HTTP protocol | ### Typical Configuration in a my.cnf File ``` [aria_s3_copy] s3-bucket=mariadb s3-access-key=xxxx s3-secret-key=xxx s3-region=eu-north-1 #s3-host-name=s3.amazonaws.com #s3-protocol-version=Amazon verbose=1 op=to ``` ### Example Usage The following code will copy an existing Aria table named `test1` to S3. If the `--database` option is not given, then the directory name where the table files exist will be used as the database. ``` shell> aria_s3_copy --force --op=to --database=foo --compress --verbose --s3_block_size=4M test1 Delete of aria table: foo.test1 Delete of index information foo/test1/index Delete of data information foo/test1/data Delete of base information and frm Copying frm file test1.frm Copying aria table: foo.test1 to s3 Creating aria table information foo/test1/aria Copying index information foo/test1/index . Copying data information foo/test1/data . ``` When using `--verbose`, `aria_s3_copy` will write a dot for each #/79 part of the file copied. See Also -------- [Using the S3 storage engine](../using-the-s3-storage-engine/index#aria_s3_copy). This pages has examples of .my.cnf entries for using `aria_s3_copy`. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Creating a Vagrantfile Creating a Vagrantfile ====================== In this page we discuss how to create a Vagrantfile, which you can use to create new boxes or machines. This content is specifically written to address the needs of MariaDB users. A Basic Vagrantfile ------------------- A Vagrantfile is a Ruby file that instructs Vagrant to create, depending on how it is executed, new Vagrant machines or boxes. You can see a box as a compiled Vagrantfile. It describes a type of Vagrant machines. From a box, we can create new Vagrant machines. However, while a box is easy to distribute to a team or to a wider public, a Vagrantfile can also directly create one or more Vagrant machines, without generating any box. Here is a simple Vagrantfile example: ``` Vagrant.configure("2") do |config| config.vm.box = "hashicorp/bionic64" config.vm.provider "virtualbox" config.vm.provision :shell, path: "bootstrap.sh" end ``` `Vagrant.configure("2")` returns the Vagrant configuration object for the new box. In the block, we'll use the `config` alias to refer this object. We are going to use version 2 of Vagrant API. `vm.box` is the base box that we are going to use. It is Ubuntu BionicBeaver (18.04 LTS), 64-bit version, provided by HashiCorp. The schema for box names is simple: the maintainer account in [Vagrant Cloud](https://app.vagrantup.com/boxes/search) followed by the box name. We use `vm.provision` to specify the name of the file that is going to be executed at the machine creation, to provision the machine. `bootstrap.sh` is the conventional name used in most cases. To create new Vagrant machines from the Vagrantfile, move to the directory that contains the Vagrant project and run: ``` vagrant up ``` To compile the Vagrantfile into a box: ``` vagrant package ``` These operations can take time. To preventively check if the Vagrantfile contains syntax errors or certain types of bugs: ``` vagrant validate ``` Providers --------- A provider allows Vagrant to create a Vagrant machine using a certain technology. Different providers may enable a virtual machine manager ([VirtualBox](https://www.vagrantup.com/docs/providers/virtualbox), [VMWare](https://www.vagrantup.com/docs/providers/vmware), [Hyper-V](https://www.vagrantup.com/docs/providers/hyperv)...), a container manager ([Docker](https://www.vagrantup.com/docs/providers/docker)), or remote cloud hosts ([AWS](https://github.com/mitchellh/vagrant-aws), [Google Compute Engine](https://github.com/mitchellh/vagrant-google)...). Some providers are developed by third parties. [app.vagrant.com](https://app.vagrantup.com/) supports search for boxes that support the most important third parties providers. To find out how to develop a new provider, see [Plugin Development: Providers](https://www.vagrantup.com/docs/plugins/providers). Provider options can be specified. Options affect the type of Vagrant machine that is created, like the number of virtual CPUs. Different providers support different options. It is possible to specify multiple providers. In this case, Vagrant will try to use them in the order they appear in the Vagrantfile. It will try the first provider; if it is not available it will try the second; and so on. Here is an example of providers usage: ``` Vagrant.configure("2") do |config| config.vm.box = "hashicorp/bionic64" config.vm.provider "virtualbox" do |vb| vb.customize ["modifyvm", :id, "--memory", 1024 * 4] end config.vm.provider "vmware_fusion" end ``` In this example, we try to use VirtualBox to create a virtual machine. We specify that this machine must have 4G of RAM (1024M \* 4). If VirtualBox is not available, Vagrant will try to use VMWare. This mechanism is useful for at least a couple of reasons: * Different users may use different systems, and maybe they don't have the same virtualization technologies installed. * We can gradually move from one provider to another. For a period of time, some users will have the new virtualization technology installed, and they will use it; other users will only have the old technology installed, but they will still be able to create machines with Vagrant. Provisioners ------------ We can use different methods for provisioning. The simplest provisioner is `shell`, that allows one to run a Bash file to provision a machine. Other provisioners allow setting up the machines using automation software, including Ansible, Puppet, Chef and Salt. To find out how to develop a new provisioner, see [Plugin Development: Provisioners](https://www.vagrantup.com/docs/plugins/provisioners). ### The `shell` Provisioner In the example above, the [shell](https://www.vagrantup.com/docs/provisioning/shell) provisioner runs boostrap.sh inside the Vagrant machine to provision it. A simple bootstrap.sh may look like the following: ``` #!/bin/bash apt-get update apt-get install -y ``` To find out the steps to install MariaDB on your system of choice, see the [Getting, Installing, and Upgrading MariaDB](../getting-installing-and-upgrading-mariadb/index) section. You may also want to restore a database backup in the new Vagrant machine. In this way, you can have the database needed by the application you are developing. To find out how to do it, see [Backup and Restore Overview](../backup-and-restore-overview/index). The most flexible type of backup (meaning that it works between different MariaDB versions, and in some cases even between MariaDB and different DBMSs) is a [dump](../mysqldump/index). On Linux machines, the `shell` provisioner uses the default shell. On Windows machines, it uses PowerShell. ### Uploading Files If we use the `shell` provisioner, we need a way to upload files to the new machine when it is created. We could use the `file` provisioner, but it works by connecting the machine via ssh, and the default user doesn't have permissions for any directory except for the synced folders. We could change the target directory owner, or we could add the default user to a group with the necessary privileges, but these are not considered good practices. Instead, we can just put the file we need to upload somewhere in the synced folder, and then copy it with a shell command: ``` cp ./files/my.cnf /etc/mysql/conf.d/ ``` ### Provisioning Vagrant with Ansible Here is an example of how to provision a Vagrant machine or box by running Ansible: ``` Vagrant.configure("2") do |config| ... config.vm.provision "ansible" do |ansible| ansible.playbook = "vagrant.yml" end end ``` With the [Ansible provisioner](https://www.vagrantup.com/docs/provisioning/ansible), Ansible runs in the host system and applies a playbook in the guest system. In this example, it runs a playbook called `vagrant.yml`. The [Ansible Local provisioner](https://www.vagrantup.com/docs/provisioning/ansible_local) runs the playbook in the vagrant machine. For more information, see [Using Vagrant and Ansible](https://docs.ansible.com/ansible/2.3/guide_vagrant.html) in the Ansible documentation. For an introduction to Ansible for MariaDB users, see [Ansible and MariaDB](../ansible-and-mariadb/index). ### Provisioning Vagrant with Puppet To provision a Vagrant machine or box by running Puppet: ``` Vagrant.configure("2") do |config| ... config.vm.provision "puppet" do |puppet| puppet.manifests_path = "manifests" puppet.manifest_file = "default.pp" end end ``` In this example, Puppet Apply runs in the host system and no Puppet Server is needed. Puppet expects to find a `manifests` directory in the project directory. It expects it to contain `default.pp`, which will be used as an entry point. Note that `puppet.manifests_path` and `puppet.manifest_file` are set to their default values. Puppet needs to be installed in the guest machine. To use a Puppet server, the `puppet_server` provisioner can be used: ``` Vagrant.configure("2") do |config| ... config.vm.provision "puppet_server" do |puppet| puppet.puppet_server = "puppet.example.com" end end ``` See the [Puppet Apply provisioner](https://www.vagrantup.com/docs/provisioning/puppet_apply) and the [Puppet Agent Provisioner](https://www.vagrantup.com/docs/provisioning/puppet_agent). For an introduction to Puppet for MariaDB users, see [Puppet and MariaDB](../automated-mariadb-deployment-and-administration-puppet-and-mariadb/index). Sharing Files Between the Host and a Guest System ------------------------------------------------- To restore a backup into MariaDB, in most cases we need to be able to copy it from the host system to the box. We may also want to occasionally copy MariaDB logs from the box to the host system, to be able to investigate problems. The project directory (the one that contains the Vagrantfile) by default is shared with the virtual machine and mapped to the `/vagrant` directory (the synced folder). It is a good practice to put there all files that should be shared with the box when it is started. Those files should normally be versioned. The synced folder can be changed. In the above example, we could simply add one line: ``` config.vm.synced_folder "/host/path", "/guest/path" ``` The synced folder can also be disabled: ``` config.vm.synced_folder '.', '/vagrant', disabled: true ``` Note that multiple Vagrant machines may have synced folders that point to the same directory on the host system. This can be useful in some cases, if you prefer to test some functionalities quickly, rather that replicating production environment as faithfully as possible. For example, to test if you're able to take a backup from one machine and restore it to another, you can store the backup in a common directory. Network Communications ---------------------- It is often desirable for a machine to be able to communicate with "the outside". This can be done in several ways: * Private networks; * Public networks; * Exposing ports to the host. Remembers that Vagrant doesn't create machines, but it asks a provisioner to create machines. Some provisioners support all of these communication methods, others may support some of them, or even none of them. When you create a Vagrantfile that starts machines using one of these features, it is implicit that this can only happen if the provisioner you are using supports the features you need. Check your provisioner documentation to find out which features it supports. The default provisioner, VirtualBox, supports all these communication methods, including multiple networks. ### Private Networks A private network is a networks that can only be accesses by machines that run on the same host. Usually this also means that the machines must run on the same provisioner (for example, they all must be VirtualBox virtual machines). Some provisioners support multiple private networks. This means that every network has a different name and can be accessed by different machines. The following line shows how to create or join a private network called "example", where this machine's IP is assigned by the provisioner via DHCP: ``` config.vm.network 'private_network', name: 'example', type: 'dhcp' ``` While this is very convenient to avoid IP conflicts, sometimes you prefer to assign some IP's manually, in this way: ``` config.vm.network 'private_network', name: 'example', ip: '111.222.111.222' ``` ### Public Networks As explained above, public networks are networks that can be accessed by machines that don't run on the same host with the same provider. To let a machine join a public network: ``` # use provisioner DHCP: config.vm.network "public_network", use_dhcp_assigned_default_route: true # assign ip manually: config.vm.network "public_network", ip: "111.222.111.222" ``` To improve security, you may want to configure a gateway: ``` config.vm.provision "shell", run: "always", inline: "route add default gw 111.222.111.222" ``` ### Exposing Ports Vagrant allows us to map a TCP or UDP port in a guest system to a TCP or UDP port in the host system. For example, you can map a virtual machine port 3306 to the host port 12345. Then you can connect MariaDB in this way: ``` mariadb -hlocalhost -P12345 -u<user> -p<password> ``` You are not required to map a port to a port with a different number. In the above example, if the port 3306 in your host is not in use, you are free to map the guest port 3306 to the host port 3306. There are a couple of caveats: * You can't map a single host port to multiple guest ports. If you want to expose the port 3306 from multiple Vagrant machines, you'll have to map them to different host ports. When running many machines this can be hard to maintain. * Ports with numbers below 1024 are privileged ports. Mapping privileged ports requires root privileges. To expose a port: ``` config.vm.network 'forwarded_port', guest: 3306, host: 3306 ``` ### Use Cases Suppose you run MariaDB and an application server in two separate Vagrant machines. It's usually best to let them communicate via a private network, because this greatly increases your security. The application server will still need to expose ports to the host, so the application can be tested with a web browser. Suppose you have multiple environments of the same type, like the one described above. They run different applications that don't communicate with each other. In this case, if your provisioner supports this, you will run multiple private networks. You will need to expose the applications servers ports, mapping them to different host ports. You may even want to implement different private networks to create an environment that reflects production complexity. Maybe in production you have [a cluster](../galera-cluster/index) of three MariaDB servers, and the application servers communicate with them via a proxy layer (ProxySQL, HAProxy, or [MaxScale](../maxscale/index)). So the applications can communicate with the proxies, but have no way to reach MariaDB directly. So there is a private network called "database" that can be accessed by the MariaDB servers and the proxy servers, and another private network called "application" that can be accessed by the proxy servers and the application servers. This requires that your provisioner supports multiple private networks. Using public networks instead of private one will allow VMs that run on different hosts to be part of your topology. In general this is considered as an insecure practice, so you should probably ask yourself if you really need to do this. References ---------- The [vagrant-mariadb-examples](https://github.com/Vettabase/vagrant-mariadb-examples) repository is an example of a Vagrantfile that creates a box containing MariaDB and some useful tools for developers. Further information can be found in Vagrant documentation. * [Vagrantfile](https://www.vagrantup.com/docs/vagrantfile). * [Providers](https://www.vagrantup.com/docs/providers). * [Synced Folders](https://www.vagrantup.com/docs/synced-folders). * [Ansible Provisioner](https://www.vagrantup.com/docs/provisioning/ansible). * [Puppet Apply Provisioner](https://www.vagrantup.com/docs/provisioning/puppet_apply). * [Puppet Agent Provisioner](https://www.vagrantup.com/docs/provisioning/puppet_agent). See also [Ruby documentation](http://www.ruby-lang.org/en/documentation/). --- Content initially contributed by [Vettabase Ltd](https://vettabase.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Temporal Tables Temporal Tables ================ MariaDB supports temporal data tables in the form of system-versioning tables (allowing you to query and operate on historic data), application-time periods (allow you to query and operate on a temporal range of data), and bitemporal tables (which combine both system-versioning and application-time periods). | Title | Description | | --- | --- | | [System-Versioned Tables](../system-versioned-tables/index) | System-versioned tables record the history of all changes to table data. | | [Application-Time Periods](../application-time-periods/index) | Application-time period tables, defined by a range between two temporal columns. | | [Bitemporal Tables](../bitemporal-tables/index) | Bitemporal tables use versioning both at the system and application-time period levels. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DuplicateWeedout Strategy DuplicateWeedout Strategy ========================= `DuplicateWeedout` is an execution strategy for [Semi-join subqueries](../semi-join-subquery-optimizations/index). The idea -------- The idea is to run the semi-join as if it were a regular inner join, and then eliminate the duplicate record combinations using a temporary table. Suppose, you have a query where you're looking for countries which have more than 33% percent of their population in one big city: ``` select * from Country where Country.code IN (select City.Country from City where City.Population > 0.33 * Country.Population and City.Population > 1*1000*1000); ``` First, we run a regular inner join between the `City` and `Country` tables: The Inner join produces duplicates. We have Germany three times, because it has three big cities. Now, lets put `DuplicateWeedout` into the picture: Here one can see that a temporary table with a primary key was used to avoid producing multiple records with 'Germany'. DuplicateWeedout in action -------------------------- The `Start temporary` and `End temporary` from the last diagram are shown in the `EXPLAIN` output: ``` explain select * from Country where Country.code IN (select City.Country from City where City.Population > 0.33 * Country.Population and City.Population > 1*1000*1000)\G *************************** 1. row *************************** id: 1 select_type: PRIMARY table: City type: range possible_keys: Population,Country key: Population key_len: 4 ref: NULL rows: 238 Extra: Using index condition; Start temporary *************************** 2. row *************************** id: 1 select_type: PRIMARY table: Country type: eq_ref possible_keys: PRIMARY key: PRIMARY key_len: 3 ref: world.City.Country rows: 1 Extra: Using where; End temporary 2 rows in set (0.00 sec) ``` This query will read 238 rows from the `City` table, and for each of them will make a primary key lookup in the `Country` table, which gives another 238 rows. This gives a total of 476 rows, and you need to add 238 lookups in the temporary table (which are typically \*much\* cheaper since the temporary table is in-memory). If we run the same EXPLAIN in MySQL, we'll get: ``` explain select * from Country where Country.code IN (select City.Country from City where City.Population > 0.33 * Country.Population and City.Population > 1*1000*1000)\G *************************** 1. row *************************** id: 1 select_type: PRIMARY table: Country type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 239 Extra: Using where *************************** 2. row *************************** id: 2 select_type: DEPENDENT SUBQUERY table: City type: index_subquery possible_keys: Population,Country key: Country key_len: 3 ref: func rows: 18 Extra: Using where 2 rows in set (0.00 sec) ``` This plan will read `(239 + 239*18) = 4541` rows, which is much slower. Factsheet --------- * `DuplicateWeedout` is shown as "Start temporary/End temporary" in `EXPLAIN`. * The strategy can handle correlated subqueries. * But it cannot be applied if the subquery has meaningful `GROUP BY` and/or aggregate functions. * `DuplicateWeedout` allows the optimizer to freely mix a subquery's tables and the parent select's tables. * There is no separate @@optimizer\_switch flag for `DuplicateWeedout`. The strategy can be disabled by switching off all semi-join optimizations with `SET @@optimizer_switch='optimizer_semijoin=off'` command. See Also -------- * [What is MariaDB 5.3](../what-is-mariadb-53/index) * [Subquery Optimizations Map](../subquery-optimizations-map/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb GPG GPG === The MariaDB project signs their MariaDB packages for Debian, Ubuntu, Fedora, CentOS, and Red Hat. Debian / Ubuntu key ------------------- Our repositories for Debian "Sid" and the Ubuntu 16.04 and beyond "Xenial" use the following GPG signing key. As detailed in [MDEV-9781](https://jira.mariadb.org/browse/MDEV-9781), APT 1.2.7 (and later) prefers SHA2 GPG keys and now prints warnings when a repository is signed using a SHA1 key like our previous GPG key. We have created a SHA2 key for use with these. Information about this key: * The short Key ID is: `0xC74CD1D8` * The long Key ID is: `0xF1656F24C74CD1D8` * The full fingerprint of the key is: `177F 4010 FE56 CA33 3630 0305 F165 6F24 C74C D1D8` * The key can be added on Debian-based systems using the following command: ``` sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8 ``` The instructions in the repository configuration tool for Ubuntu 16.04 "Xenial" and Debian "Stretch" and higher have been updated to reference this new key. Repositories for previous versions of Debian and Ubuntu still use the old key, so no changes are needed there. RPM / Source key ---------------- The GPG Key ID of the MariaDB signing key we use for yum/dnf/zypper repositories and to sign our source code tarballs is `0xCBCB082A1BB943DB`. The short form of the id is `0x1BB943DB` and the full key fingerprint is: ``` 1993 69E5 404B D5FC 7D2F E43B CBCB 082A 1BB9 43DB ``` This key is used by the yum/dnf/zypper repositories for RedHat, CentOS, Fedora, openSUSE, and SLES. If you configure the mariadb.org rpm repositories using the repository configuration tool (see below) then your package manager will prompt you to import the key the first time you install a package from the repository. You can also import the key directly using the following command: ``` sudo rpmkeys --import https://supplychain.mariadb.com/MariaDB-Server-GPG-KEY ``` Configuring ----------- See the [repository configuration tool](https://downloads.mariadb.org/mariadb/repositories/) for details on configuring repositories that use these keys. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb VARCHAR VARCHAR ======= Syntax ------ ``` [NATIONAL] VARCHAR(M) [CHARACTER SET charset_name] [COLLATE collation_name] ``` Description ----------- A variable-length string. M represents the maximum column length in characters. The range of M is 0 to 65,532. The effective maximum length of a VARCHAR is subject to the maximum row size and the character set used. For example, utf8 characters can require up to three bytes per character, so a VARCHAR column that uses the utf8 character set can be declared to be a maximum of 21,844 characters. **Note:** For the [ColumnStore](../columnstore/index) engine, M represents the maximum column length in bytes. MariaDB stores VARCHAR values as a one-byte or two-byte length prefix plus data. The length prefix indicates the number of bytes in the value. A VARCHAR column uses one length byte if values require no more than 255 bytes, two length bytes if values may require more than 255 bytes. MariaDB follows the standard SQL specification, and does not remove trailing spaces from VARCHAR values. VARCHAR(0) columns can contain 2 values: an empty string or NULL. Such columns cannot be part of an index. The [CONNECT](../connect/index) storage engine does not support VARCHAR(0). VARCHAR is shorthand for CHARACTER VARYING. NATIONAL VARCHAR is the standard SQL way to define that a VARCHAR column should use some predefined character set. MariaDB uses utf8 as this predefined character set, as does MySQL 4.1 and up. NVARCHAR is shorthand for NATIONAL VARCHAR. Before [MariaDB 10.2](../what-is-mariadb-102/index), all MariaDB [collations](../character-sets/index) were of type `PADSPACE`, meaning that VARCHAR (as well as [CHAR](../char/index) and [TEXT](../text/index) values) are compared without regard for trailing spaces. This does not apply to the [LIKE](../like/index) pattern-matching operator, which takes into account trailing spaces. From [MariaDB 10.2](../what-is-mariadb-102/index), a number of [NO PAD collations](../supported-character-sets-and-collations/index#no-pad-collations) are available. If a unique index consists of a column where trailing pad characters are stripped or ignored, inserts into that column where values differ only by the number of trailing pad characters will result in a duplicate-key error. Examples -------- The following are equivalent: ``` VARCHAR(30) CHARACTER SET utf8 NATIONAL VARCHAR(30) NVARCHAR(30) NCHAR VARCHAR(30) NATIONAL CHARACTER VARYING(30) NATIONAL CHAR VARYING(30) ``` Trailing spaces: ``` CREATE TABLE strtest (v VARCHAR(10)); INSERT INTO strtest VALUES('Maria '); SELECT v='Maria',v='Maria ' FROM strtest; +-----------+--------------+ | v='Maria' | v='Maria ' | +-----------+--------------+ | 1 | 1 | +-----------+--------------+ SELECT v LIKE 'Maria',v LIKE 'Maria ' FROM strtest; +----------------+-------------------+ | v LIKE 'Maria' | v LIKE 'Maria ' | +----------------+-------------------+ | 0 | 1 | +----------------+-------------------+ ``` Truncation ---------- * Depending on whether or not [strict sql mode](../sql-mode/index#strict-mode) is set, you will either get a warning or an error if you try to insert a string that is too long into a VARCHAR column. If the extra characters are spaces, the spaces that can't fit will be removed and you will always get a warning, regardless of the [sql mode](../sql_mode/index) setting. Difference Between VARCHAR and [TEXT](../text/index) ---------------------------------------------------- * VARCHAR columns can be fully indexed. [TEXT](../text/index) columns can only be indexed over a specified length. * Using [TEXT](../text/index) or [BLOB](../blob/index) in a [SELECT](../select/index) query that uses temporary tables for storing intermediate results will force the temporary table to be disk based (using the [Aria storage engine](../aria-storage-engine/index) instead of the [memory storage engine](../memory-storage-engine/index), which is a bit slower. This is not that bad as the [Aria storage engine](../aria-storage-engine/index) caches the rows in memory. To get the benefit of this, one should ensure that the [aria\_pagecache\_buffer\_size](../aria-system-variables/index#aria_pagecache_buffer_size) variable is big enough to hold most of the row and index data for temporary tables. Oracle Mode ----------- **MariaDB starting with [10.3](../what-is-mariadb-103/index)**In [Oracle mode from MariaDB 10.3](../sql_modeoracle-from-mariadb-103/index#synonyms-for-basic-sql-types), `VARCHAR2` is a synonym. ### For Storage Engine Developers * Internally the full length of the VARCHAR column is allocated inside each TABLE objects record[] structure. As there are three such buffers, each open table will allocate 3 times max-length-to-store-varchar bytes of memory. * [TEXT](../text/index) and [BLOB](../blob/index) columns are stored with a pointer (4 or 8 bytes) + a 1-4 bytes length. The [TEXT](../text/index) data is only stored once. This means that internally `TEXT` uses less memory for each open table but instead has the additional overhead that each `TEXT` object needs to be allocated and freed for each row access (with some caching in between). See Also -------- * [VARBINARY](../varbinary/index) * [TEXT](../text/index) * [CHAR](../char/index) * [Character Sets and Collations](../data-types-character-sets-and-collations/index) * [Data Type Storage Requirements](../data-type-storage-requirements/index) * [Oracle mode from MariaDB 10.3](../sql_modeoracle-from-mariadb-103/index#synonyms-for-basic-sql-types) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb OmniDB OmniDB ====== OmniDB is a browser-based tool that simplifies MariaDB database management focusing on interactivity, designed to be powerful and lightweight. Characteristics: * Browser-based Tool: Accessible from any platform, using a browser as a medium. * Responsive Interface: All available functions in a single page. * Unified workspace: Different technologies managed in a single workspace. * Simplified Editing: Easy to add and remove connections. * Safety: Multi-user support with encrypted personal information. * Interactive Tables: All functionalities use interactive tables, allowing copying and pasting in blocks. * Smart SQL Editor: Contextual SQL code completion. * Beautiful SQL Editor: You can choose between many available color themes. * Tabbed SQL Editor: Easily add, rename or delete editor tabs. OmniDB Web Page: <https://omnidb.org/en/> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_TABLESPACES_ENCRYPTION Table Information Schema INNODB\_TABLESPACES\_ENCRYPTION Table ======================================================== The [Information Schema](../information_schema/index) `INNODB_TABLESPACES_ENCRYPTION` table contains metadata about [encrypted InnoDB tablespaces](../encrypting-data-for-innodb-xtradb/index). When you [enable encryption for an InnoDB tablespace](../encrypting-data-for-innodb-xtradb/index#enabling-encryption), an entry for the tablespace is added to this table. If you later [disable encryption for the InnoDB tablespace](../encrypting-data-for-innodb-xtradb/index#disabling-encryption), then the row still remains in this table, but the `ENCRYPTION_SCHEME` and `CURRENT_KEY_VERSION` columns will be set to `0`. Viewing this table requires the [PROCESS](../grant/index#global-privileges) privilege, although a bug in versions before [MariaDB 10.1.46](https://mariadb.com/kb/en/mariadb-10146-release-notes/), [10.2.33](https://mariadb.com/kb/en/mariadb-10233-release-notes/), [10.3.24](https://mariadb.com/kb/en/mariadb-10324-release-notes/), [10.4.14](https://mariadb.com/kb/en/mariadb-10414-release-notes/) and [10.5.5](https://mariadb.com/kb/en/mariadb-1055-release-notes/) mean the [SUPER](../grant/index#global-privileges) privilege was required ([MDEV-23003](https://jira.mariadb.org/browse/MDEV-23003)). It has the following columns: | Column | Description | Added | | --- | --- | --- | | `SPACE` | InnoDB tablespace ID. | | | `NAME` | Path to the InnoDB tablespace file, without the extension. | | | `ENCRYPTION_SCHEME` | Key derivation algorithm. Only `1` is currently used to represent an algorithm. If this value is `0`, then the tablespace is unencrypted. | | | `KEYSERVER_REQUESTS` | Number of times InnoDB has had to request a key from the [encryption key management plugin](../encryption-key-management/index). The three most recent keys are cached internally. | | | `MIN_KEY_VERSION` | Minimum key version used to encrypt a page in the tablespace. Different pages may be encrypted with different key versions. | | | `CURRENT_KEY_VERSION` | Key version that will be used to encrypt pages. If this value is `0`, then the tablespace is unencrypted. | | | `KEY_ROTATION_PAGE_NUMBER` | Page that a [background encryption thread](../encrypting-data-for-innodb-xtradb/index#background-encryption-threads) is currently rotating. If key rotation is not enabled, then the value will be `NULL`. | | | `KEY_ROTATION_MAX_PAGE_NUMBER` | When a [background encryption thread](../encrypting-data-for-innodb-xtradb/index#background-encryption-threads) starts rotating a tablespace, the field contains its current size. If key rotation is not enabled, then the value will be `NULL`. | | | `CURRENT_KEY_ID` | Key ID for the encryption key currently in use. | [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/) | | `ROTATING_OR_FLUSHING` | Current key rotation status. If this value is `1`, then the [background encryption threads](../encrypting-data-for-innodb-xtradb/index#background-encryption-threads) are working on the tablespace. See [MDEV-11738](https://jira.mariadb.org/browse/MDEV-11738). | [MariaDB 10.2.5](https://mariadb.com/kb/en/mariadb-1025-release-notes/), [MariaDB 10.1.23](https://mariadb.com/kb/en/mariadb-10123-release-notes/) | When the [InnoDB system tablespace](../innodb-system-tablespaces/index) is encrypted, it is represented in this table with the special name: `innodb_system`. Example ------- ``` SELECT * FROM information_schema.INNODB_TABLESPACES_ENCRYPTION WHERE NAME LIKE 'db_encrypt%'; +-------+----------------------------------------------+-------------------+--------------------+-----------------+---------------------+--------------------------+------------------------------+ | SPACE | NAME | ENCRYPTION_SCHEME | KEYSERVER_REQUESTS | MIN_KEY_VERSION | CURRENT_KEY_VERSION | KEY_ROTATION_PAGE_NUMBER | KEY_ROTATION_MAX_PAGE_NUMBER | +-------+----------------------------------------------+-------------------+--------------------+-----------------+---------------------+--------------------------+------------------------------+ | 18 | db_encrypt/t_encrypted_existing_key | 1 | 1 | 1 | 1 | NULL | NULL | | 19 | db_encrypt/t_not_encrypted_existing_key | 1 | 0 | 1 | 1 | NULL | NULL | | 20 | db_encrypt/t_not_encrypted_non_existing_key | 1 | 0 | 4294967295 | 4294967295 | NULL | NULL | | 21 | db_encrypt/t_default_encryption_existing_key | 1 | 1 | 1 | 1 | NULL | NULL | | 22 | db_encrypt/t_encrypted_default_key | 1 | 1 | 1 | 1 | NULL | NULL | | 23 | db_encrypt/t_not_encrypted_default_key | 1 | 0 | 1 | 1 | NULL | NULL | | 24 | db_encrypt/t_defaults | 1 | 1 | 1 | 1 | NULL | NULL | +-------+----------------------------------------------+-------------------+--------------------+-----------------+---------------------+--------------------------+------------------------------+ 7 rows in set (0.00 sec) ``` See Also -------- * [Encrypting Data for InnoDB / XtraDB](../encrypting-data-for-innodb-xtradb/index) * [Data at Rest Encryption](../data-at-rest-encryption/index) * [Why Encrypt MariaDB Data?](../why-encrypt-mariadb-data/index) * [Encryption Key Management](../encryption-key-management/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb InnoDB Redo Log InnoDB Redo Log =============== Overview -------- The redo log is used by [InnoDB](../innodb/index) during crash recovery. The redo log files have names like `ib_logfileN`, where `N` is an integer. From [MariaDB 10.5](../what-is-mariadb-105/index), there is only one redo log, so the file will always be named `ib_logfile0`. If the [innodb\_log\_group\_home\_dir](../innodb-system-variables/index#innodb_log_group_home_dir) system variable is configured, then the redo log files will be created in that directory. Otherwise, they will be created in the directory defined by the [datadir](../server-system-variables/index#datadir) system variable. Flushing Effects on Performance and Consistency ----------------------------------------------- The [innodb\_flush\_log\_at\_trx\_commit](../innodb-system-variables/index#innodb_flush_log_at_trx_commit) system variable determines how often the transactions are flushed to the redo log, and it is important to achieve a good balance between speed and reliability. ### Binary Log Group Commit and Redo Log Flushing In [MariaDB 10.0](../what-is-mariadb-100/index) and above, when both [innodb\_flush\_log\_at\_trx\_commit=1](../innodb-system-variables/index#innodb_flush_log_at_trx_commit) (the default) is set and the [binary log](../binary-log/index) is enabled, there is now one less sync to disk inside InnoDB during commit (2 syncs shared between a group of transactions instead of 3). See [Binary Log Group Commit and InnoDB Flushing Performance](../binary-log-group-commit-and-innodb-flushing-performance/index) for more information. Redo Log Group Capacity ----------------------- The redo log group capacity is the total combined size of all InnoDB redo logs. The relevant factors are: * From [MariaDB 10.5](../what-is-mariadb-105/index), there is 1 redo log. For [MariaDB 10.4](../what-is-mariadb-104/index) and before, the number of redo log files is configured by the [innodb\_log\_files\_in\_group](../innodb-system-variables/index#innodb_log_files_in_group) system variable. * The size of each redo log file is configured by the [innodb\_log\_file\_size](../innodb-system-variables/index#innodb_log_file_size) system variable. This can safely be set to a much higher value from [MariaDB 10.5](../what-is-mariadb-105/index). Before [MariaDB 10.9](../what-is-mariadb-109/index), resizing required the server to be restarted. From [MariaDB 10.9](../what-is-mariadb-109/index) the variable can be set dynamically. The redo log group capacity is determined by the following calculation: `innodb_log_group_capacity` = `[innodb\_log\_file\_size](../innodb-system-variables/index#innodb_log_file_size)` \* `[innodb\_log\_files\_in\_group](../innodb-system-variables/index#innodb_log_files_in_group)` For example, if [innodb\_log\_file\_size](../innodb-system-variables/index#innodb_log_file_size) is set to `2G` and [innodb\_log\_files\_in\_group](../innodb-system-variables/index#innodb_log_files_in_group) is set to `2`, then we would have the following: * `innodb_log_group_capacity` = `[innodb\_log\_file\_size](../innodb-system-variables/index#innodb_log_file_size)` \* `[innodb\_log\_files\_in\_group](../innodb-system-variables/index#innodb_log_files_in_group)` * = `2G` \* `2` * = `4G` ### Changing the Redo Log Group Capacity The number (until [MariaDB 10.4](../what-is-mariadb-104/index) only - from [MariaDB 10.5](../what-is-mariadb-105/index) there is only 1 redo log) or size of redo log files can be changed with the following process: * Stop the server. * To change the log file size, configure [innodb\_log\_file\_size](../innodb-system-variables/index#innodb_log_file_size). To increase the number of log files (until [MariaDB 10.4](../what-is-mariadb-104/index) only), configure [innodb\_log\_files\_in\_group](../innodb-system-variables/index#innodb_log_files_in_group). * Start the server. Log Sequence Number (LSN) ------------------------- Records within the InnoDB redo log are identified via a log sequence number (LSN). Checkpoints ----------- When InnoDB performs a checkpoint, it writes the LSN of the oldest dirty page in the [InnoDB buffer pool](../innodb-buffer-pool/index) to the InnoDB redo log. If a page is the oldest dirty page in the [InnoDB buffer pool](../innodb-buffer-pool/index), then that means that all pages with lower LSNs have been flushed to the physical InnoDB tablespace files. If the server were to crash, then InnoDB would perform crash recovery by only applying log records with LSNs that are greater than or equal to the LSN of the oldest dirty page written in the last checkpoint. Checkpoints are one of the tasks performed by the InnoDB master background thread. This thread schedules checkpoints 7 seconds apart when the server is very active, but checkpoints can happen more frequently when the server is less active. Dirty pages are not actually flushed from the buffer pool to the physical InnoDB tablespace files during a checkpoint. That process happens asynchronously on a continuous basis by InnoDB's write I/O background threads configured by the [innodb\_write\_io\_threads](../innodb-system-variables/index#innodb_write_io_threads) system variable. If you want to make this process more aggressive, then you can decrease the value of the [innodb\_max\_dirty\_pages\_pct](../innodb-system-variables/index#innodb_max_dirty_pages_pct) system variable. You may also need to better tune InnoDB's I/O capacity on your system by setting the [innodb\_io\_capacity](../innodb-system-variables/index#innodb_io_capacity) system variable. ### Determining the Checkpoint Age The checkpoint age is the amount of data written to the InnoDB redo log since the last checkpoint. #### Determining the Checkpoint Age in InnoDB **MariaDB starting with [10.2](../what-is-mariadb-102/index)**In [MariaDB 10.2](../what-is-mariadb-102/index) and later, MariaDB uses InnoDB. In those versions, the checkpoint age can be determined by the process shown below. To determine the InnoDB checkpoint age, do the following: * Query [SHOW ENGINE INNODB STATUS](../show-engine-innodb-status/index). * Find the `LOG` section. For example: ``` --- LOG --- Log sequence number 252794398789379 Log flushed up to 252794398789379 Pages flushed up to 252792767756840 Last checkpoint at 252792767756840 0 pending log flushes, 0 pending chkp writes 23930412 log i/o's done, 2.03 log i/o's/second ``` * Perform the following calculation: `innodb_checkpoint_age` = `Log sequence number` - `Last checkpoint at` In the example above, that would be: * `innodb_checkpoint_age` = `Log sequence number` - `Last checkpoint at` * = 252794398789379 - 252792767756840 * = 1631032539 bytes * = 1631032539 byes / (1024 \* 1024 \* 1024) (GB/bytes) * = 1.5 GB of redo log written since last checkpoint #### Determining the Checkpoint Age in XtraDB **MariaDB until [10.1](../what-is-mariadb-101/index)**In [MariaDB 10.1](../what-is-mariadb-101/index) and before, MariaDB uses XtraDB by default. In those versions, the checkpoint age can be determined by the [Innodb\_checkpoint\_age](../innodb-status-variables/index#innodb_checkpoint_age) status variable. Determining the Redo Log Occupancy ---------------------------------- The redo log occupancy is the percentage of the InnoDB redo log capacity that is taken up by dirty pages that have not yet been flushed to the physical InnoDB tablespace files in a checkpoint. Therefore, it's determined by the following calculation: `innodb_log_occupancy` = `[innodb\_checkpoint\_age](#determining-the-checkpoint-age)` / `[innodb\_log\_group\_capacity](#redo-log-group-capacity)` For example, if `[innodb\_checkpoint\_age](#determining-the-checkpoint-age)` is `1.5G` and `[innodb\_log\_group\_capacity](#redo-log-group-capacity)` is `4G`, then we would have the following: * `innodb_log_occupancy` = `[innodb\_checkpoint\_age](#determining-the-checkpoint-age)` / `[innodb\_log\_group\_capacity](#redo-log-group-capacity)` * = `1.5G` / `4G` * = `0.375` If the calculated value for redo log occupancy is too close to `1.0`, then the InnoDB redo log capacity may be too small for the current workload. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Importing Data into MariaDB Importing Data into MariaDB =========================== When a MariaDB developer first creates a MariaDB database for a client, often times the client has already accumulated data in other, simpler applications. Being able to convert data easily to MariaDB is critical. In the previous two articles of this MariaDB series, we explored how to set up a database and how to query one. In this third installment, we will introduce some methods and tools for bulk importing of data into MariaDB. This isn't an overly difficult task, but the processing of large amounts of data can be intimidating for a newcomer and and as a result it can be a barrier to getting started with MariaDB. Additionally, for intermediate developers, there are many nuances to consider for a clean import, which is especially important for automating regularly scheduled imports. There are also restraints to deal with that may be imposed on a developer when using a web hosting company. #### Foreign Data Basics Clients sometimes give developers raw data in formats created by simple database programs like MS Access ®. Since non-technical clients don't typically understand database concepts, new clients often give me their initial data in Excel spreadsheets. Let's first look at a simple method for importing data. The simplest way to deal with incompatible data in any format is to load it up in its original software and to export it out to a delimited text file. Most applications have the ability to export data to a text format and will allow the user to set the delimiters. We like to use the bar (i.e., `|`, a.k.a. pipe) to separate fields and the line-feed to separate records. For the examples in this article, we will assume that a fictitious client's data was in Excel and that the exported text file will be named `prospects.txt`. It contains contact information about prospective customers for the client's sales department, located on the client's intranet site. The data is to be imported into a MariaDB table called `prospect_contact`, in a database called `sales_dept`. To make the process simpler, the order and number of columns in MS Excel ® (the format of the data provided by the client) should be the same as the table into which the data is going to be imported. So if prospect\_contact has columns that are not included in the spreadsheet, one would make a copy of the spreadsheet and add the missing columns and leave them blank. If there are columns in the spreadsheet that aren't in `prospect_contact`, one would either add them to the MariaDB table, or, if they're not to be imported, one would delete the extra columns from the spreadsheet. One should also delete any headings and footnotes from the spreadsheet. After this is completed then the data can be exported. Since this is Unix Review, we'll skip how one would export data in Excel and assume that the task was accomplished easily enough using its export wizard. The next step is to upload the data text file to the client's web site by FTP. It should be uploaded in ASCII mode. Binary mode may send binary hard-returns for row-endings. Also, it's a good security habit to upload data files to non-public directories. Many web hosting companies provide virtual domains with a directory like `/public_html`, which is the document root for the Apache web server; it typically contains the site's web pages. In such a situation, `/` is a virtual root containing logs and other files that are inaccessible to the public. We usually create a directory called `tmp` in the virtual root directory to hold data files temporarily for importing into MariaDB. Once that's done, all that's required is to log into MariaDB with the [mysql](../mysql-client/index) client as an administrative user (if not root, then a user with `FILE` privileges), and run the proper SQL statement to import the data. #### Loading Data Basics The [LOAD DATA INFILE](../load-data-infile/index) statement is the easiest way to import data from a plain text file into MariaDB. Below is what one would enter in the [mysql](../mysql-client/index) client to load the data in the file called prospects.txt into the table `prospect_contact`: ``` LOAD DATA INFILE '/tmp/prospects.txt' INTO TABLE prospect_contact FIELDS TERMINATED BY '|'; ``` Before entering the statement above, the MariaDB session would, of course, be switched to the sales\_dept database with a [USE](../use/index) statement. It is possible, though, to specify the database along with the table name (e.g., `sales_dept.prospect_contact`). If the server is running Windows, the forward slashes are still used for the text file's path, but a drive may need to be specified at the beginning of the path: '`c:/tmp/prospects.txt`'. Notice that the SQL statement above has `|` as the field delimiter. If the delimiter was [TAB]—which is common—then one would replace `|` with `\t` here. A line-feed (`\n`) isn't specified as the record delimiter since it's assumed. If the rows start and end with something else, though, then they will need to be stated. For instance, suppose the rows in the text file start with a double-quote and end with a double-quote and a Windows hard-return (i.e., a return and a line-feed). The statement would need to read like this: ``` LOAD DATA INFILE '/tmp/prospects.txt' INTO TABLE prospect_contact FIELDS TERMINATED BY '|' LINES STARTING BY '"' TERMINATED BY '"\r\n'; ``` Notice that the starting double-quote is inside of single-quotes. If one needs to specify a single-quote as the start of a line, one could either put the one single-quote within double-quotes or one could escape the inner single-quote with a back-slash, thus telling MariaDB that the single-quote that follows is to be taken literally and is not part of the statement, per se: ``` ... LINES STARTING BY '\'' ... ``` #### Duplicate Rows If the table prospect\_contact already contains some of the records that are about to be imported from prospects.txt (that is to say, records with the same primary key), then a decision should be made as to what MariaDB is to do about the duplicates. The SQL statement, as it stands above, will cause MariaDB to try to import the duplicate records and to create duplicate rows in prospect\_contact for them. If the table's properties are set not to allow duplicates, then MariaDB will kick out errors. To get MariaDB to replace the duplicate existing rows with the ones being imported in, one would add the `REPLACE` just before the `INTO TABLE` clause like this: ``` LOAD DATA INFILE '/tmp/prospects.txt' REPLACE INTO TABLE prospect_contact FIELDS TERMINATED BY '|' LINES STARTING BY '"' TERMINATED BY '"\n'; ``` To import only records for prospects that are not already in prospect\_contact, one would substitute REPLACE with the `IGNORE` flag. This instructs MariaDB to ignore records read from the text file that already exist in the table. #### Live Data For importing data into a table while it's in use, table access needs to be addressed. If access to the table by other users may not be interrupted, then a `LOW_PRIORITY` flag can be added to the [LOAD DATA INFILE](../load-data-infile/index) statement. This tells MariaDB that the loading of this data is a low priority. One would only need to change the first line of the SQL statement above to set its priority to low: ``` LOAD DATA LOW_PRIORITY INFILE '/tmp/prospects.txt' ... ``` If the `LOW_PRIORITY` flag isn't included, the table will be locked temporarily during the import and other users will be prevented from accessing it. #### Being Difficult I mentioned earlier that uploading of the text file should not be done in binary mode so as to avoid the difficulties associated with Windows line endings. If this is unavoidable, however, there is an easy way to import binary row-endings with MariaDB. One would just specify the appropriate hexadecimals for a carriage-return combined with a line-feed (i.e., `CRLF`) as the value of `TERMINATED BY`: ``` ... TERMINATED BY 0x0d0a; ``` Notice that there are intentionally no quotes around the binary value. If there were, MariaDB would take the value for text and not a binary code. The semi-colon is not part of the value; it's the SQL statement terminator. Earlier we also stated that the first row in the spreadsheet containing the column headings should be deleted before exporting to avoid the difficulty of importing the headings as a record. It's actually pretty easy to tell MariaDB to just skip the top line. One would add the following line to the very end of the [LOAD DATA INFILE](../load-data-infile/index) statement: ``` ... IGNORE 1 LINES; ``` The number of lines for MariaDB to ignore can, of course, be more than one. Another difficulty arises when some Windows application wizards export data with each field surrounded by double-quotes, as well as around the start and end of records. This can be a problem when a field contains a double-quote. To deal with this, some applications use back-slash (\) to escape embedded double-quotes, to indicate that a particular double-quote is not a field ending but part of the field's content. However, some applications will use a different character (like a pound-sign) to escape embedded quotes. This can cause problems if MariaDB isn't prepared for the odd escape-character. MariaDB will think the escape character is actually text and the embedded quote-mark, although it's escaped, is a field ending. The unenclosed text that follows will be imported into the next column and the remaining columns will be one column off, leaving the last column not imported. As maddening as this can be, it's quite manageable in MariaDB by adding an `ENCLOSED BY` and an `ESCAPED BY` clause: ``` LOAD DATA LOW_PRIORITY INFILE '/tmp/prospects.txt' REPLACE INTO TABLE prospect_contact FIELDS TERMINATED BY '"' ENCLOSED BY '"' ESCAPED BY '#' LINES STARTING BY '"' TERMINATED BY '"\n' IGNORE 1 LINES; ``` In the *Foreign Data Basics* section above, we said that the columns in the spreadsheet should be put in the same order and quantity as the receiving table. This really isn't necessary if MariaDB is cued in as to what it should expect. To illustrate, let's assume that prospect\_contact has four columns in the following order: `row_id`, `name_first`, `name_last`, `telephone`. Whereas, the spreadsheet has only three columns, differently named, in this order: `Last Name`, `First Name`, `Telephone`. If the spreadsheet isn't adjusted, then the SQL statement will need to be changed to tell MariaDB the field order: ``` LOAD DATA LOW_PRIORITY INFILE '/tmp/prospects.txt' REPLACE INTO TABLE sales_dept.prospect_contact FIELDS TERMINATED BY 0x09 ENCLOSED BY '"' ESCAPED BY '#' TERMINATED BY 0x0d0a IGNORE 1 LINES (name_last, name_first, telephone); ``` This SQL statement tells MariaDB the name of each table column associated with each spreadsheet column in the order that they appear in the text file. From there it will naturally insert the data into the appropriate columns in the table. As for columns that are missing like row\_id, MariaDB will fill in those fields with the default value if one has been supplied in the table's properties. If not, it will leave the field as NULL. Incidentally, we slipped in the binary `[TAB] (0x09)` as a field delimiter. #### mariadb-import/mysqlimport For some clients and for certain situations it may be of value to be able to import data into MariaDB without using the [mysql](../mysql-client/index) client. This could be necessary when constructing a shell script to import text files on an automated, regular schedule. To accomplish this, the [mariadb-import](../mysqlimport/index) (`mysqlimport` before [MariaDB 10.5](../what-is-mariadb-105/index)) utility may be used as it encompasses the [LOAD DATA INFILE](../load-data-infile/index) statement and can easily be run from a script. So if one wants to enter the involved SQL statement at the end of the last section above, the following could be entered from the command-line (i.e., not in the [mysql](../mysql-client/index) client): ``` mysqlimport --user='marie_dyer' --password='angelle1207' \ --fields-terminated-by=0x09 --lines-terminated-by=0x0d0a \ --replace --low-priority --fields-enclosed-by='"' \ --fields-escaped-by='#' --ignore-lines='1' --verbose \ --columns='name_last, name_first, telephone' \ sales_dept '/tmp/prospect_contact.txt' ``` Although this statement is written over several lines here, it either has to be on the same line when entered or a space followed by a back-slash has to be entered at the end of each line (as seen here) to indicate that more follows. Since the above is entered at the command-line prompt, the user isn't logged into MariaDB. Therefore the first line contains the user name and password for [mariadb-import/mysqlimport](../mysqlimport/index) to give to MariaDB. The password itself is optional, but the directive `--password` (without the equal sign) isn't. If the password value is not given in the statement, then the user will be prompted for it. Notice that the order of directives doesn't matter after the initial command, except that the database and file name go last. Regarding the file name, its prefix must be the same as the table—the dot and the extension are ignored. This requires that `prospects.txt` be renamed to `prospect_contact.txt`. If the file isn't renamed, then MariaDB would create a new table called prospects and the `--replace` option would be pointless. After the file name, incidentally, one could list more text files, separated by a space, to process using [mariadb-import/mysqlimport](../mysqlimport/index). We've added the `--verbose` directive so as to be able to see what's going on. One probably would leave this out in an automated script. By the way, `--low-priority` and `--ignore-lines` are available. #### Web Hosting Restraints Some web hosting companies do not allow the use of [LOAD DATA INFILE](../load-data-infile/index) or [mariadb-import/mysqlimport](../mysqlimport/index) statements due to security vulnerabilities in these statements for them. To get around this, some extra steps are necessary to avoid having to manually enter the data one row at a time. First, one needs to have MariaDB installed on one's local workstation. For simplicity, we'll assume this is done and is running Linux on the main partition and MS Windows® on an extra partition. Recapping the on-going example of this article based on these new circumstances, one would boot up into Windows and start MS Excel®, load the client's spreadsheet into it and then run the export wizard as before—saving the file prospects.txt to the 'My Documents' directory. Then one would reboot into Linux and mount the Windows partition and copy the data text file to `/tmp` in Linux, locally. Next one would log into the local (not the client's) MariaDB server and import the text file using a [LOAD DATA INFILE](../load-data-infile/index) as we've extensively outline above. From there one would exit MariaDB and export the data out of MariaDB using the [mysqldump](../mysqldump/index) utility locally, from the command-line like this: ``` mysqldump --user='root' --password='geronimo' sales_dept prospect_contact > /tmp/prospects.sql ``` This creates an interesting text file complete with all of the SQL commands necessary to insert the data back into MariaDB one record, one [INSERT](../insert/index) at a time. When you run [mariadb-import/mysqlimport](../mysqlimport/index), it's very educational to open up it in a text editor to see what it generates. After creating this table dump, one would upload the resulting file (in ASCII mode) to the `/tmp` directory on the client's web server. From the command prompt on the client's server one would enter the following: ``` mysql --user='marie_dyer' --password='angelle12107' sales_dept < '/tmp/prospects.sql' ``` This line along with the [mysqldump](../mysqldump/index) line show above are simple approaches. Like the Windows application wizard, with mysqldump one can specify the format of the output file and several other factors. One important factor related to the scenario used in this article is the [CREATE TABLE](../create-table/index) statement that will be embedded in the [mysqldump](../mysqldump/index) output file. This will fail and kick out an error because of the existing table prospect\_contact in the client's database. To limit the output to only [INSERT](../insert/index) statements and no [CREATE TABLE](../create-table/index) statements, the [mysqldump](../mysqldump/index) line would look like this: ``` mysqldump -u marie_dyer -p --no-create-info sales_dept prospect_contact > /tmp/prospects.sql ``` Notice that we've used acceptable abbreviations for the user name and the password directives. Since the password was given here, the user will be prompted for it. The [mysqldump](../mysqldump/index) utility usually works pretty well. However, one feature it's lacking at this time is a `REPLACE` flag as is found in the [LOAD DATA INFILE](../load-data-infile/index) statement and with the [mariadb-import/mysqlimport](../mysqlimport/index) tool. So if a record already exists in the `prospect_contact`, it won't be imported. Instead it will kick out an error message and stop at that record, which can be a mess if one has imported several hundred rows and have several hundred more to go. One easy fix for this is to open up `prospects.sql` in a text editor and do a search on the word `INSERT` and replace it with `REPLACE`. The syntax of both of these statements are the same, fortunately. So one would only need to replace the keyword for new records to be inserted and for existing records to be replaced. #### Concluding Observations and Admissions It's always amazing to me how much can be involved in the simplest of statements in MariaDB. MariaDB is deceptively powerful and feature rich. One can keep the statements pretty minimal or one can develop a fairly detailed, single statement to allow for accuracy of action. There are many other aspects of importing data into MariaDB that we did not address—in particular dealing with utilities. We also didn't talk about the Perl modules that could be used to convert data files. These can be useful in scripting imports. There are many ways in which one can handle importing data. Hopefully, this article has presented most of the basics and pertinent advanced details that may be of use to most MariaDB developers. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Information Schema INNODB_FT_INDEX_CACHE Table Information Schema INNODB\_FT\_INDEX\_CACHE Table ================================================= The [Information Schema](../information_schema/index) `INNODB_FT_INDEX_CACHE` table contains information about rows that have recently been inserted into an InnoDB [fulltext index](../full-text-indexes/index). To avoid re-organizing the fulltext index each time a change is made, which would be very expensive, new changes are stored separately and only integrated when an [OPTIMIZE TABLE](../optimize-table/index) is run. The `SUPER` [privilege](../grant/index) is required to view the table, and it also requires the [innodb\_ft\_aux\_table](../xtradbinnodb-server-system-variables/index#innodb_ft_aux_table) system variable to be set. It has the following columns: | Column | Description | | --- | --- | | `WORD` | Word from the text of a newly added row. Words can appear multiple times in the table, once per `DOC_ID` and `POSITION` combination. | | `FIRST_DOC_ID` | First document ID where this word appears in the index. | | `LAST_DOC_ID` | Last document ID where this word appears in the index. | | `DOC_COUNT` | Number of rows containing this word in the index. | | `DOC_ID` | Document ID of the newly added row, either an appropriate ID column or an internal InnoDB value. | | `POSITION` | Position of this word instance within the `DOC_ID`, as an offset added to the previous `POSITION` instance. | Note that for `OPTIMIZE TABLE` to process InnoDB fulltext index data, the [innodb\_optimize\_fulltext\_only](../xtradbinnodb-server-system-variables/index#innodb_optimize_fulltext_only) system variable needs to be set to `1`. When this is done, and an `OPTIMIZE TABLE` statement run, the `INNODB_FT_INDEX_CACHE` table will be emptied, and the [INNODB\_FT\_INDEX\_TABLE](../information-schema-innodb_ft_index_table-table/index) table will be updated. Examples -------- ``` SELECT * FROM INNODB_FT_INDEX_CACHE; +------------+--------------+-------------+-----------+--------+----------+ | WORD | FIRST_DOC_ID | LAST_DOC_ID | DOC_COUNT | DOC_ID | POSITION | +------------+--------------+-------------+-----------+--------+----------+ | and | 4 | 4 | 1 | 4 | 0 | | arrived | 4 | 4 | 1 | 4 | 20 | | ate | 1 | 1 | 1 | 1 | 4 | | everybody | 1 | 1 | 1 | 1 | 8 | | goldilocks | 4 | 4 | 1 | 4 | 9 | | hungry | 3 | 3 | 1 | 3 | 8 | | then | 4 | 4 | 1 | 4 | 4 | | wicked | 2 | 2 | 1 | 2 | 4 | | witch | 2 | 2 | 1 | 2 | 11 | +------------+--------------+-------------+-----------+--------+----------+ 9 rows in set (0.00 sec) INSERT INTO test.ft_innodb VALUES(3,'And she ate a pear'); SELECT * FROM INNODB_FT_INDEX_CACHE; +------------+--------------+-------------+-----------+--------+----------+ | WORD | FIRST_DOC_ID | LAST_DOC_ID | DOC_COUNT | DOC_ID | POSITION | +------------+--------------+-------------+-----------+--------+----------+ | and | 4 | 5 | 2 | 4 | 0 | | and | 4 | 5 | 2 | 5 | 0 | | arrived | 4 | 4 | 1 | 4 | 20 | | ate | 1 | 5 | 2 | 1 | 4 | | ate | 1 | 5 | 2 | 5 | 8 | | everybody | 1 | 1 | 1 | 1 | 8 | | goldilocks | 4 | 4 | 1 | 4 | 9 | | hungry | 3 | 3 | 1 | 3 | 8 | | pear | 5 | 5 | 1 | 5 | 14 | | she | 5 | 5 | 1 | 5 | 4 | | then | 4 | 4 | 1 | 4 | 4 | | wicked | 2 | 2 | 1 | 2 | 4 | | witch | 2 | 2 | 1 | 2 | 11 | +------------+--------------+-------------+-----------+--------+----------+ ``` ``` OPTIMIZE TABLE test.ft_innodb\G *************************** 1. row *************************** Table: test.ft_innodb Op: optimize Msg_type: note Msg_text: Table does not support optimize, doing recreate + analyze instead *************************** 2. row *************************** Table: test.ft_innodb Op: optimize Msg_type: status Msg_text: OK 2 rows in set (2.24 sec) SELECT * FROM INNODB_FT_INDEX_CACHE; +------------+--------------+-------------+-----------+--------+----------+ | WORD | FIRST_DOC_ID | LAST_DOC_ID | DOC_COUNT | DOC_ID | POSITION | +------------+--------------+-------------+-----------+--------+----------+ | and | 4 | 5 | 2 | 4 | 0 | | and | 4 | 5 | 2 | 5 | 0 | | arrived | 4 | 4 | 1 | 4 | 20 | | ate | 1 | 5 | 2 | 1 | 4 | | ate | 1 | 5 | 2 | 5 | 8 | | everybody | 1 | 1 | 1 | 1 | 8 | | goldilocks | 4 | 4 | 1 | 4 | 9 | | hungry | 3 | 3 | 1 | 3 | 8 | | pear | 5 | 5 | 1 | 5 | 14 | | she | 5 | 5 | 1 | 5 | 4 | | then | 4 | 4 | 1 | 4 | 4 | | wicked | 2 | 2 | 1 | 2 | 4 | | witch | 2 | 2 | 1 | 2 | 11 | +------------+--------------+-------------+-----------+--------+----------+ 13 rows in set (0.00 sec) ``` The `OPTIMIZE TABLE` statement has no effect, because the [innodb\_optimize\_fulltext\_only](innodb-server-system-variables#innodb_optimize_fulltext_only) variable wasn't set: ``` SHOW VARIABLES LIKE 'innodb_optimize_fulltext_only'; +-------------------------------+-------+ | Variable_name | Value | +-------------------------------+-------+ | innodb_optimize_fulltext_only | OFF | +-------------------------------+-------+ SET GLOBAL innodb_optimize_fulltext_only =1; OPTIMIZE TABLE test.ft_innodb; +----------------+----------+----------+----------+ | Table | Op | Msg_type | Msg_text | +----------------+----------+----------+----------+ | test.ft_innodb | optimize | status | OK | +----------------+----------+----------+----------+ SELECT * FROM INNODB_FT_INDEX_CACHE; Empty set (0.00 sec) ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ITERATE ITERATE ======= Syntax ------ ``` ITERATE label ``` `ITERATE` can appear only within [LOOP](../loop/index), [REPEAT](../repeat-loop/index), and [WHILE](../while/index) statements. `ITERATE` means "do the loop again", and uses the statement's [label](../labels/index) to determine which statements to repeat. The label must be in the same stored program, not in a caller procedure. If you try to use `ITERATE` with a non-existing label, or if the label is associated to a construct which is not a loop, the following error will be produced: ``` ERROR 1308 (42000): ITERATE with no matching label: <label_name> ``` Below is an example of how `ITERATE` might be used: ``` CREATE PROCEDURE doiterate(p1 INT) BEGIN label1: LOOP SET p1 = p1 + 1; IF p1 < 10 THEN ITERATE label1; END IF; LEAVE label1; END LOOP label1; SET @x = p1; END ``` See Also -------- * [LEAVE](../leave/index) - Exits a loop (or any labeled code block) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb JOIN Syntax JOIN Syntax =========== Description ----------- MariaDB supports the following `JOIN` syntaxes for the `table_references` part of `[SELECT](../select/index)` statements and multiple-table `[DELETE](../delete/index)` and `[UPDATE](../update/index)` statements: ``` table_references: table_reference [, table_reference] ... table_reference: table_factor | join_table table_factor: tbl_name [PARTITION (partition_list)] [query_system_time_period_specification] [[AS] alias] [index_hint_list] | table_subquery [query_system_time_period_specification] [AS] alias | ( table_references ) | { ON table_reference LEFT OUTER JOIN table_reference ON conditional_expr } join_table: table_reference [INNER | CROSS] JOIN table_factor [join_condition] | table_reference STRAIGHT_JOIN table_factor | table_reference STRAIGHT_JOIN table_factor ON conditional_expr | table_reference {LEFT|RIGHT} [OUTER] JOIN table_reference join_condition | table_reference NATURAL [{LEFT|RIGHT} [OUTER]] JOIN table_factor join_condition: ON conditional_expr | USING (column_list) query_system_time_period_specification: FOR SYSTEM_TIME AS OF point_in_time | FOR SYSTEM_TIME BETWEEN point_in_time AND point_in_time | FOR SYSTEM_TIME FROM point_in_time TO point_in_time | FOR SYSTEM_TIME ALL point_in_time: [TIMESTAMP] expression | TRANSACTION expression index_hint_list: index_hint [, index_hint] ... index_hint: USE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] ([index_list]) | IGNORE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] (index_list) | FORCE {INDEX|KEY} [{FOR {JOIN|ORDER BY|GROUP BY}] (index_list) index_list: index_name [, index_name] ... ``` A table reference is also known as a join expression. Each table can also be specified as `db_name`.`tabl_name`. This allows to write queries which involve multiple databases. See [Identifier Qualifiers](../identifier-qualifiers/index) for syntax details. The syntax of `table_factor` is extended in comparison with the SQL Standard. The latter accepts only `table_reference`, not a list of them inside a pair of parentheses. This is a conservative extension if we consider each comma in a list of table\_reference items as equivalent to an inner join. For example: ``` SELECT * FROM t1 LEFT JOIN (t2, t3, t4) ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c) ``` is equivalent to: ``` SELECT * FROM t1 LEFT JOIN (t2 CROSS JOIN t3 CROSS JOIN t4) ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c) ``` In MariaDB, `CROSS JOIN` is a syntactic equivalent to `INNER JOIN` (they can replace each other). In standard SQL, they are not equivalent. `INNER JOIN` is used with an `ON` clause, `CROSS JOIN` is used otherwise. In general, parentheses can be ignored in join expressions containing only inner join operations. MariaDB also supports nested joins (see <http://dev.mysql.com/doc/refman/5.1/en/nested-join-optimization.html>). See [System-versioned tables](../system-versioned-tables/index) for more information about `FOR SYSTEM_TIME` syntax. Index hints can be specified to affect how the MariaDB optimizer makes use of indexes. For more information, see [How to force query plans](../how-to-force-query-plans/index). Examples -------- ``` SELECT left_tbl.* FROM left_tbl LEFT JOIN right_tbl ON left_tbl.id = right_tbl.id WHERE right_tbl.id IS NULL; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb WKB WKB ==== WKB stands for Well-Known Binary, a standard representation for geometric values. | Title | Description | | --- | --- | | [Well-Known Binary (WKB) Format](../well-known-binary-wkb-format/index) | Well-Known Binary format for representing geometric data. | | [AsBinary](../wkb-asbinary/index) | Synonym for ST\_AsBinary. | | [AsWKB](../aswkb/index) | Synonym for ST\_AsBinary. | | [MLineFromWKB](../mlinefromwkb/index) | Constructs a MULTILINESTRING. | | [MPointFromWKB](../mpointfromwkb/index) | Constructs a MULTIPOINT value using its WKB representation and SRID. | | [MPolyFromWKB](../mpolyfromwkb/index) | Constructs a MULTIPOLYGON value using its WKB representation and SRID. | | [GeomCollFromWKB](../wkb-geomcollfromwkb/index) | Synonym for ST\_GeomCollFromWKB. | | [GeometryCollectionFromWKB](../geometrycollectionfromwkb/index) | Synonym for ST\_GeomCollFromWKB. | | [GeometryFromWKB](../geometryfromwkb/index) | Synonym for ST\_GeomFromWKB. | | [GeomFromWKB](../wkb-geomfromwkb/index) | Synonym for ST\_GeomFromWKB. | | [LineFromWKB](../wkb-linefromwkb/index) | Synonym for ST\_LineFromWKB. | | [LineStringFromWKB](../linestringfromwkb/index) | Synonym for ST\_LineFromWKB. | | [MultiLineStringFromWKB](../multilinestringfromwkb/index) | A synonym for MLineFromWKB. | | [MultiPointFromWKB](../multipointfromwkb/index) | Synonym for MPointFromWKB. | | [MultiPolygonFromWKB](../multipolygonfromwkb/index) | Synonym for MPolyFromWKB. | | [PointFromWKB](../wkb-pointfromwkb/index) | Synonym for PointFromWKB. | | [PolyFromWKB](../wkb-polyfromwkb/index) | Synonym for ST\_PolyFromWKB. | | [PolygonFromWKB](../polygonfromwkb/index) | Synonym for ST\_PolyFromWKB. | | [ST\_AsBinary](../st_asbinary/index) | Converts a value to its WKB representation. | | [ST\_AsWKB](../st_aswkb/index) | Synonym for ST\_AsBinary. | | [ST\_GeomCollFromWKB](../st_geomcollfromwkb/index) | Constructs a GEOMETRYCOLLECTION value from a WKB. | | [ST\_GeometryCollectionFromWKB](../st_geometrycollectionfromwkb/index) | Synonym for ST\_GeomCollFromWKB. | | [ST\_GeometryFromWKB](../st_geometryfromwkb/index) | Synonym for ST\_GeomFromWKB. | | [ST\_GeomFromWKB](../st_geomfromwkb/index) | Constructs a geometry value using its WKB representation and SRID. | | [ST\_LineFromWKB](../st_linefromwkb/index) | Constructs a LINESTRING using its WKB and SRID. | | [ST\_LineStringFromWKB](../st_linestringfromwkb/index) | Synonym for ST\_LineFromWKB. | | [ST\_PointFromWKB](../st_pointfromwkb/index) | Constructs POINT using its WKB and SRID. | | [ST\_PolyFromWKB](../st_polyfromwkb/index) | Constructs POLYGON value using its WKB representation and SRID. | | [ST\_PolygonFromWKB](../st_polygonfromwkb/index) | Synonym for ST\_PolyFromWKB. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CONNECT Table Types Overview CONNECT Table Types Overview ============================ CONNECT can handle very many table formats; it is indeed one of its main features. The Type option specifies the type and format of the table. The Type options available values and their descriptions are listed in the following table: | Type | Description | | --- | --- | | [BIN](../connect-bin-table-type/index) | Binary file with numeric values in platform representation, also with columns at fixed offset within records and fixed record length. | | BSON | (Temporary) JSON table handled by the new JSON handling. | | [CSV](../connect-csv-and-fmt-table-types/index)\*$ | "Comma Separated Values" file in which each variable length record contains column values separated by a specific character (defaulting to the comma) | | [DBF](../connect-dbf-table-type/index)\* | File having the dBASE format. | | [DOS](../connect-dos-and-fix-table-types/index) | The table is contained in one or several files. The file format can be refined by some other options of the command or more often using a specific type as many of those described below. Otherwise, it is a flat text file where columns are placed at a fixed offset within each record, the last column being of variable length. | | [DIR](../connect-table-types-special-virtual-tables/index#dir-type) | Virtual table that returns a file list like the Unix `ls` or DOS `dir` command. | | [FIX](../connect-dos-and-fix-table-types/index) | Text file arranged like DOS but with fixed length records. | | [FMT](../connect-csv-and-fmt-table-types/index) | File in which each record contains the column values in a non-standard format (the same for each record) This format is specified in the column definition. | | [INI](../connect-ini-table-type/index) | File having the format of the initialization or configuration files used by many applications. | | [JDBC](../connect-jdbc-table-type-accessing-tables-from-other-dbms/index)\* | Table accessed via a JDBC driver. | | [JSON](../connect-json-table-type/index)\*$ | File having the JSON format. | | [MAC](../connect-table-types-special-virtual-tables/index#mac-address-table-type-mac) | Virtual table returning information about the machine and network cards (Windows only). | | [MONGO](../connect-mongo-table-type/index)\* | Table accessed via the MongoDB C Driver API. | | [MYSQL](../connect-table-types-mysql-table-type-accessing-mysqlmariadb-tables/index)\* | Table accessed using the MySQL API like the FEDERATED engine. | | [OCCUR](../connect-table-types-occur-table-type/index)\* | A table based on another table existing on the current server, several columns of the object table containing values that can be grouped in only one column. | | [ODBC](../connect-table-types-odbc-table-type-accessing-tables-from-other-dbms/index)\* | Table extracted from an application accessible via ODBC or unixODBC. For example from another DBMS or from an Excel spreadsheet. | | [OEM](../connect-table-types-oem-type-table-type-implemented-in-an-external-lib/index)\* | Table of any other formats not directly handled by CONNECT but whose access is implemented by an external FDW (foreign data wrapper) written in C++ (as a DLL or Shared Library). | | [PIVOT](../connect-table-types-pivot-table-type/index)\* | Used to "pivot" the display of an existing table or view. | | [PROXY](../connect-table-types-proxy-table-type/index)\* | A table based on another table existing on the current server. | | [TBL](../connect-table-types-tbl-table-type-table-list/index)\* | Accessing a collection of tables as one table (like the MERGE engine does for MyIsam tables) | | [VEC](../connect-vec-table-type/index) | Binary file organized in vectors, in which column values are grouped consecutively, either split in separate files or in a unique file. | | [VIR\*](../connect-table-types-vir/index) | Virtual table containing only special and virtual columns. | | [WMI](../connect-table-types-special-virtual-tables/index#windows-management-instrumentation-table-type-wmi)\* | Windows Management Instrumentation table displaying information coming from a WMI provider. This type enables to get in tabular format all sorts of information about the machine hardware and operating system (Windows only). | | [XCOL](../connect-table-types-xcol-table-type/index)\* | A table based on another table existing on the current server with one of its columns containing comma separated values. | | [XML](../connect-xml-table-type/index)\*$ | File having the XML or HTML format. | | [ZIP](../connect-zipped-file-tables/index) | Table giving information about the contents of a zip file. | Catalog Tables -------------- For all table types marked with a '\*' in the table above, CONNECT is able to analyze the data source to retrieve the column definition. This can be used to define a “catalog” table that display the column description of the source, or to create a table without specifying the column definition that will be automatically constructed by CONNECT when creating the table. When marked with a ‘$’ the file can be the result returned by a REST query. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb USING CONNECT - Offline Documentation USING CONNECT - Offline Documentation ===================================== Note: You can download a [PDF version of the CONNECT documentation](https://mariadb.com/kb/en/connect-table-types/+attachment/connect_1_7_03) (1.7.0003). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Authentication Plugin - Unix Socket Authentication Plugin - Unix Socket =================================== **MariaDB starting with [10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/)**In [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) and later, the `unix_socket` authentication plugin is installed by default, and it is used by the `'root'@'localhost'` user account by default. See [Authentication from MariaDB 10.4](../authentication-from-mariadb-104/index) for more information. The `unix_socket` authentication plugin allows the user to use operating system credentials when connecting to MariaDB via the local Unix socket file. This Unix socket file is defined by the [socket](../server-system-variables/index#socket) system variable. The `unix_socket` authentication plugin works by calling the [getsockopt](http://man7.org/linux/man-pages/man7/socket.7.html) system call with the `SO_PEERCRED` socket option, which allows it to retrieve the `uid` of the process that is connected to the socket. It is then able to get the user name associated with that `uid`. Once it has the user name, it will authenticate the connecting user as the MariaDB account that has the same user name. The `unix_socket` authentication plugin is not suited to multiple Unix users accessing a single MariaDB user account. Security -------- A `unix_socket` authentication plugin is a passwordless security mechanism. Its security is in the strength of the access to the Unix user rather than the complexity and the secrecy of the password. As the security is different from passwords, the strengths and weaknesses need to be considered, and these aren't the same in every installation. ### Strengths * Access is limited to the Unix user so, for example, a `www-data` user cannot access `root` with the `unix_socket` authentication plugin. * There is no password to brute force. * There is no password that can be accidentally exposed by user accident, poor security on backups, or poor security on passwords in configuration files. * Default Unix user security is usually strong on preventing remote access and password brute force attempts. ### Weaknesses The strength of a `unix_socket` authentication plugin is effectively the strength of the security of the Unix users on the system. The Unix user default installation in most cases is sufficiently secure, however, business requirements or unskilled management may expose risks. The following is a non-exhaustive list of potential Unix user security issues that may arise. * Common access areas without screen locks, where an unauthorized user accesses the logged in Unix user of an authorized user. * Extensive sudo access grants that provide users with access to execute commands of a different Unix user. * Scripts writable by Unix users other than the Unix user that are executed (cron or directly) by the unix user. * Web pages that are susceptible to command injection, where the Unix user running the web page has elevated privileges in the database that weren't intended to be used. * Poor Unix user password practices including weak user passwords, password exposure and password reuse accompanied by an access vulnerability/mechanism of an unauthorized user to exploit this weakness. * Weak remote access mechanisms and network file system privileges. * Poor user security behavior including running untrusted scripts and software. In some of these scenarios a database password may prevent these security exploits, however it will remove all the strengths of the `unix_socket` authentication plugin previously mentioned. Disabling the Plugin -------------------- **MariaDB starting with [10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/)**In [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) and later, the `unix_socket` authentication plugin is installed by default, so **if you do not want it to be available by default on those versions, then you will need to disable it**. The `unix_socket` authentication plugin is also installed by default in **new installations** that use the `[.deb](../installing-mariadb-deb-files/index)` packages provided by Debian's default repositories in Debian 9 and later and Ubuntu's default repositories in Ubuntu 15.10 and later, so **if you do not want it to be available by default on those systems when those packages are used, then you will need to disable it**. See [Differences in MariaDB in Debian (and Ubuntu)](../differences-in-mariadb-in-debian-and-ubuntu/index) for more information. The `unix_socket` authentication plugin can be disabled by starting the server with the `[unix\_socket](#unix_socket)` option set to `OFF`. This can be specified as a command-line argument to `[mysqld](../mysqld-options/index)` or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... unix_socket=OFF ``` As an alternative, the `[unix\_socket](#unix_socket)` option can also be set to `OFF` by pairing the option with the `disable` [option prefix](../configuring-mariadb-with-option-files/index#option-prefixes). For example: ``` [mariadb] ... disable_unix_socket ``` Installing the Plugin --------------------- **MariaDB starting with [10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/)**In [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) and later, the `unix_socket` authentication plugin is installed by default, so **this step can be skipped on those versions**. The `unix_socket` authentication plugin is also installed by default in **new installations** that use the `[.deb](../installing-mariadb-deb-files/index)` packages provided by Debian's default repositories in Debian 9 and later and Ubuntu's default repositories in Ubuntu 15.10 and later, so **this step can be skipped on those systems when those packages are used**. See [Differences in MariaDB in Debian (and Ubuntu)](../differences-in-mariadb-in-debian-and-ubuntu/index) for more information. In other systems, although the plugin's shared library is distributed with MariaDB by default as `auth_socket.so`, the plugin is not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB. The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing `[INSTALL SONAME](../install-soname/index)` or `[INSTALL PLUGIN](../install-plugin/index)`. For example: ``` INSTALL SONAME 'auth_socket'; ``` The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the `[--plugin-load](../mysqld-options/index#-plugin-load)` or the `[--plugin-load-add](../mysqld-options/index#-plugin-load-add)` options. This can be specified as a command-line argument to `[mysqld](../mysqld-options/index)` or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... plugin_load_add = auth_socket ``` Uninstalling the Plugin ----------------------- You can uninstall the plugin dynamically by executing `[UNINSTALL SONAME](../uninstall-soname/index)` or `[UNINSTALL PLUGIN](../uninstall-plugin/index)`. For example: ``` UNINSTALL SONAME 'auth_socket'; ``` If you installed the plugin by providing the `[--plugin-load](../mysqld-options/index#-plugin-load)` or the `[--plugin-load-add](../mysqld-options/index#-plugin-load-add)` options in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), then those options should be removed to prevent the plugin from being loaded the next time the server is restarted. Creating Users -------------- To create a user account via `[CREATE USER](../create-user/index)`, specify the name of the plugin in the `[IDENTIFIED VIA](../create-user/index#identified-viawith-authentication_plugin)` clause. For example: ``` CREATE USER username@hostname IDENTIFIED VIA unix_socket; ``` If `[SQL\_MODE](../sql-mode/index)` does not have `NO_AUTO_CREATE_USER` set, then you can also create the user account via `[GRANT](../grant/index)`. For example: ``` GRANT SELECT ON db.* TO username@hostname IDENTIFIED VIA unix_socket; ``` Switching to Password-based Authentication ------------------------------------------ Sometimes Unix socket authentication does not meet your needs, so it can be desirable to switch a user account back to password-based authentication. This can easily be done by telling MariaDB to use another [authentication plugin](../authentication-plugins/index) for the account by executing the `[ALTER USER](../alter-user/index)` statement. The specific authentication plugin is specified with the `[IDENTIFIED VIA](../alter-user/index#identified-viawith-authentication_plugin)` clause. For example, if you wanted to switch to the `[mysql\_native\_password](../authentication-plugin-mysql_native_password/index)` authentication plugin, then you could execute: ``` ALTER USER root@localhost IDENTIFIED VIA mysql_native_password; SET PASSWORD = PASSWORD('foo'); ``` Note that if your operating system has scripts that require password-less access to MariaDB, then this may break those scripts. You may be able to fix that by setting a password in the `[client]` [option group](../configuring-mariadb-with-option-files/index#option-groups) in your /root/.my.cnf [option file](../configuring-mariadb-with-option-files/index). For example: ``` [client] password=foo ``` Client Authentication Plugins ----------------------------- The `unix_socket` authentication plugin does not require any specific client authentication plugins. It should work with all clients. Support in Client Libraries --------------------------- The `unix_socket` authentication plugin does not require any special support in client libraries. It should work with all client libraries. Example ------- ``` $ mysql -uroot MariaDB []> CREATE USER serg IDENTIFIED VIA unix_socket; MariaDB []> CREATE USER monty IDENTIFIED VIA unix_socket; MariaDB []> quit Bye $ whoami serg $ mysql --user=serg Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 2 Server version: 5.2.0-MariaDB-alpha-debug Source distribution MariaDB []> quit Bye $ mysql --user=monty ERROR 1045 (28000): Access denied for user 'monty'@'localhost' (using password: NO) ``` In this example, a user `serg` is already logged into the operating system and has full shell access. He has already authenticated with the operating system and his MariaDB account is configured to use the `unix_socket` authentication plugin, so he does not need to authenticate again for the database. MariaDB accepts his operating system credentials and allows him to connect. However, any attempt to connect to the database as another operating system user will be denied. Versions -------- | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Stable | [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) | | 1.0 | Beta | [MariaDB 5.2.0](https://mariadb.com/kb/en/mariadb-520-release-notes/) | Options ------- ### `unix_socket` * **Description:** Controls how the server should treat the plugin when the server starts up. + Valid values are: - `OFF` - Disables the plugin without removing it from the `[mysql.plugin](../mysqlplugin-table/index)` table. - `ON` - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled. - `FORCE` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. - `FORCE_PLUS_PERMANENT` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with `[UNINSTALL SONAME](../uninstall-soname/index)` or `[UNINSTALL PLUGIN](../uninstall-plugin/index)` while the server is running. + See [Plugin Overview: Configuring Plugin Activation at Server Startup](../plugin-overview/index#configuring-plugin-activation-at-server-startup) for more information. * **Commandline:** `--unix-socket=value` * **Data Type:** `enumerated` * **Default Value:** `ON` * **Valid Values:** `OFF`, `ON`, `FORCE`, `FORCE_PLUS_PERMANENT` --- See Also -------- * [Differences in MariaDB in Debian (and Ubuntu)](../differences-in-mariadb-in-debian-and-ubuntu/index) * [Authentication from MariaDB 10.4](../authentication-from-mariadb-104/index) * [Authentication from MariaDB 10 4 video tutorial](https://www.youtube.com/watch?v=aWFG4uLbimM) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SQL Error Log Plugin SQL Error Log Plugin ==================== The `SQL_ERROR_LOG` plugin collects errors sent to clients in a log file defined by [sql\_error\_log\_filename](#sql_error_log_filename), so that they can later be analyzed. The log file can be rotated if [sql\_error\_log\_rotate](#sql_error_log_rotate) is set. Errors are logged as they happen and an error will be logged even if it was handled by a [condition handler](../declare-handler/index) and was never technically *sent* to the client. Comments are also logged, which can make the log easier to search. But this is only possible if the client does not strip the comments away. For example, [mysql](../mysql-command-line-client/index) command-line client only leaves comments when started with the [--comments](../mysql-command-line-client/index#mysql-options) option. Installing the Plugin --------------------- Although the plugin's shared library is distributed with MariaDB by default, the plugin is not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB. The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing [INSTALL SONAME](../install-soname/index) or [INSTALL PLUGIN](../install-plugin/index). For example: ``` INSTALL SONAME 'sql_errlog'; ``` The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the [--plugin-load](../mysqld-options/index#-plugin-load) or the [--plugin-load-add](../mysqld-options/index#-plugin-load-add) options. This can be specified as a command-line argument to [mysqld](../mysqld-options/index) or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... plugin_load_add = sql_errlog ``` Uninstalling the Plugin ----------------------- You can uninstall the plugin dynamically by executing [UNINSTALL SONAME](../uninstall-soname/index) or [UNINSTALL PLUGIN](../uninstall-plugin/index). For example: ``` UNINSTALL SONAME 'sql_errlog'; ``` If you installed the plugin by providing the [--plugin-load](../mysqld-options/index#-plugin-load) or the [--plugin-load-add](../mysqld-options/index#-plugin-load-add) options in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), then those options should be removed to prevent the plugin from being loaded the next time the server is restarted. Example ------- ``` install plugin SQL_ERROR_LOG soname 'sql_errlog'; Query OK, 0 rows affected (0.00 sec) use test; Database changed set sql_mode='STRICT_ALL_TABLES,NO_ENGINE_SUBSTITUTION'; Query OK, 0 rows affected (0.00 sec) CREATE TABLE foo2 (id int) ENGINE=WHOOPSIE; ERROR 1286 (42000): Unknown storage engine 'WHOOPSIE' \! cat data/sql_errors.log 2013-03-19 9:38:40 msandbox[msandbox] @ localhost [] ERROR 1286: Unknown storage engine 'WHOOPSIE' : CREATE TABLE foo2 (id int) ENGINE=WHOOPSIE ``` Versions -------- | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Stable | [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/) | | 1.0 | Gamma | [MariaDB 10.0.10](https://mariadb.com/kb/en/mariadb-10010-release-notes/) | | 1.0 | Alpha | [MariaDB 5.5.22](https://mariadb.com/kb/en/mariadb-5522-release-notes/) | System Variables ---------------- ### `sql_error_log_filename` * **Description:** The name of the logfile. Rotation of it will be named like `*sql\_error\_log\_filename*.001` * **Commandline:** `--sql-error-log-filename=value` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** `sql_errors.log` --- ### `sql_error_log_rate` * **Description:** The rate of logging. `SET sql_error_log_rate=300;` means that one of 300 errors will be written to the log. If `sql_error_log_rate` is `0` the logging is disabled. The default rate is `1` (every error is logged). * **Commandline:** `--sql-error-log-rate=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` --- ### `sql_error_log_rotate` * **Description:** This is the 'write-only' variable. Assigning TRUE to this variable forces the log rotation. * **Commandline:** `--sql-error-log-rotate={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- ### `sql_error_log_rotations` * **Description:** The number of rotations. When rotated, the current log file is stored and the new empty one created. The sql\_error\_log\_rotations logs are stored, older are removed. The default number of rotations is `9`. * **Commandline:** `--sql-error-log-rotations` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `9` * **Range:** `1` to `999` --- ### `sql_error_log_size_limit` * **Description:** The limitation for the size of the log file. After reaching the specified limit, the log file is rotated. 1M limit set by default. * **Commandline:** `--sql-error-log-size-limit=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `1000000` * **Range:** `100` to `9223372036854775807` --- Options ------- ### `sql_error_log` * **Description:** Controls how the server should treat the plugin when the server starts up. + Valid values are: - `OFF` - Disables the plugin without removing it from the [mysql.plugins](../mysqlplugin-table/index) table. - `ON` - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled. - `FORCE` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. - `FORCE_PLUS_PERMANENT` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with [UNINSTALL SONAME](../uninstall-soname/index) or [UNINSTALL PLUGIN](../uninstall-plugin/index) while the server is running. + See [Plugin Overview: Configuring Plugin Activation at Server Startup](../plugin-overview/index#configuring-plugin-activation-at-server-startup) for more information. * **Commandline:** `--sql-error-log=value` * **Data Type:** `enumerated` * **Default Value:** `ON` * **Valid Values:** `OFF`, `ON`, `FORCE`, `FORCE_PLUS_PERMANENT` --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Mariabackup and BACKUP STAGE Commands Mariabackup and BACKUP STAGE Commands ===================================== **MariaDB starting with [10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/)**The `[BACKUP STAGE](../backup-stage/index)` commands were introduced in [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/). The `[BACKUP STAGE](../backup-stage/index)` commands are a set of commands to make it possible to make an efficient external backup tool. How Mariabackup uses these commands depends on whether you are using the version that is bundled with MariaDB Community Server or the version that is bundled with [MariaDB Enterprise Server](https://mariadb.com/docs/products/mariadb-enterprise-server/). Mariabackup and `BACKUP STAGE` Commands in MariaDB Community Server ------------------------------------------------------------------- **MariaDB starting with [10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/)**In MariaDB Community Server, Mariabackup first supported `[BACKUP STAGE](../backup-stage/index)` commands in [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/). In [MariaDB 10.3](../what-is-mariadb-103/index) and before, the `[BACKUP STAGE](../backup-stage/index)` commands are **not** supported, so Mariabackup executes the `[FLUSH TABLES WITH READ LOCK](../flush/index)` command to lock the database. When the backup is complete, it executes the `[UNLOCK TABLES](../transactions-unlock-tables/index)` command to unlock the database. In [MariaDB 10.4](../what-is-mariadb-104/index) and later, the `[BACKUP STAGE](../backup-stage/index)` commands are supported. However, the version of Mariabackup that is bundled with MariaDB Community Server does not yet use the `[BACKUP STAGE](../backup-stage/index)` commands in the most efficient way. Mariabackup simply executes the following `[BACKUP STAGE](../backup-stage/index)` commands to lock the database: ``` BACKUP STAGE START; BACKUP STAGE BLOCK_COMMIT; ``` When the backup is complete, it executes the following `[BACKUP STAGE](../backup-stage/index)` command to unlock the database: ``` BACKUP STAGE END; ``` If you would like to use a version of Mariabackup that uses the `[BACKUP STAGE](../backup-stage/index)` commands in the most efficient way, then your best option is to use [MariaDB Enterprise Backup](https://mariadb.com/docs/usage/mariadb-enterprise-backup/) that is bundled with [MariaDB Enterprise Server](https://mariadb.com/docs/products/mariadb-enterprise-server/). ### Tasks Performed Prior to `BACKUP STAGE` in MariaDB Community Server * Copy some transactional tables. + [InnoDB](../innodb/index) (i.e. `ibdataN` and file extensions `.ibd` and `.isl`) * Copy the tail of some transaction logs. + The tail of the [InnoDB redo log](../innodb-redo-log/index) (i.e. `ib_logfileN` files) will be copied for [InnoDB](../innodb/index) tables. ### `BACKUP STAGE START` in MariaDB Community Server Mariabackup from MariaDB Community Server does not currently perform any tasks in the `START` stage. ### `BACKUP STAGE FLUSH` in MariaDB Community Server Mariabackup from MariaDB Community Server does not currently perform any tasks in the `FLUSH` stage. ### `BACKUP STAGE BLOCK_DDL` in MariaDB Community Server Mariabackup from MariaDB Community Server does not currently perform any tasks in the `BLOCK_DDL` stage. ### `BACKUP STAGE BLOCK_COMMIT` in MariaDB Community Server Mariabackup from MariaDB Community Server performs the following tasks in the `BLOCK_COMMIT` stage: * Copy other files. + i.e. file extensions `.frm`, `.isl`, `.TRG`, `.TRN`, `.opt`, `.par` * Copy some transactional tables. + [Aria](../aria/index) (i.e. `aria_log_control` and file extensions `.MAD` and `.MAI`) * Copy the non-transactional tables. + [MyISAM](../myisam/index) (i.e. file extensions `.MYD` and `.MYI`) + [MERGE](../merge/index) (i.e. file extensions `.MRG`) + [ARCHIVE](../archive/index) (i.e. file extensions `.ARM` and `.ARZ`) + [CSV](../csv/index) (i.e. file extensions `.CSM` and `.CSV`) * Create a [MyRocks](../myrocks/index) checkpoint using the `[rocksdb\_create\_checkpoint](../myrocks-system-variables/index#rocksdb_create_checkpoint)` system variable. * Copy the tail of some transaction logs. + The tail of the [InnoDB redo log](../innodb-redo-log/index) (i.e. `ib_logfileN` files) will be copied for [InnoDB](../innodb/index) tables. * Save the [binary log](../binary-log/index) position to `[xtrabackup\_binlog\_info](../files-created-by-mariabackup/index#xtrabackup_binlog_info)`. * Save the [Galera Cluster](../galera/index) state information to `[xtrabackup\_galera\_info](../files-created-by-mariabackup/index#xtrabackup_galera_info)`. ### `BACKUP STAGE END` in MariaDB Community Server Mariabackup from MariaDB Community Server performs the following tasks in the `END` stage: * Copy the [MyRocks](../myrocks/index) checkpoint into the backup. Mariabackup and `BACKUP STAGE` Commands in MariaDB Enterprise Server -------------------------------------------------------------------- **MariaDB starting with [10.2.25](https://mariadb.com/kb/en/mariadb-10225-release-notes/)**[MariaDB Enterprise Backup](https://mariadb.com/docs/usage/mariadb-enterprise-backup/) first supported `[BACKUP STAGE](../backup-stage/index)` commands in [MariaDB Enterprise Server 10.4.6-1](https://mariadb.com/docs/appendix/release-notes/mariadb-enterprise-server-10-4-6-1-release-notes/), [MariaDB Enterprise Server 10.3.16-1](https://mariadb.com/docs/appendix/release-notes/mariadb-enterprise-server-10-3-16-1-release-notes/), and [MariaDB Enterprise Server 10.2.25-1](https://mariadb.com/docs/appendix/release-notes/mariadb-enterprise-server-10-2-25-1-release-notes/). The following sections describe how the [MariaDB Enterprise Backup](https://mariadb.com/docs/usage/mariadb-enterprise-backup/) version of Mariabackup that is bundled with [MariaDB Enterprise Server](https://mariadb.com/docs/products/mariadb-enterprise-server/) uses each `[BACKUP STAGE](../backup-stage/index)` command in an efficient way. ### `BACKUP STAGE START` in MariaDB Enterprise Server Mariabackup from MariaDB Enterprise Server performs the following tasks in the `START` stage: * Copy all transactional tables. + [InnoDB](../innodb/index) (i.e. `ibdataN` and file extensions `.ibd` and `.isl`) + [Aria](../aria/index) (i.e. `aria_log_control` and file extensions `.MAD` and `.MAI`) * Copy the tail of all transaction logs. + The tail of the [InnoDB redo log](../innodb-redo-log/index) (i.e. `ib_logfileN` files) will be copied for [InnoDB](../innodb/index) tables. + The tail of the Aria redo log (i.e. `aria_log.N` files) will be copied for [Aria](../aria/index) tables. ### `BACKUP STAGE FLUSH` in MariaDB Enterprise Server Mariabackup from MariaDB Enterprise Server performs the following tasks in the `FLUSH` stage: * Copy all non-transactional tables that are not in use. This list of used tables is found with `[SHOW OPEN TABLES](../show-open-tables/index)`. + [MyISAM](../myisam/index) (i.e. file extensions `.MYD` and `.MYI`) + [MERGE](../merge/index) (i.e. file extensions `.MRG`) + [ARCHIVE](../archive/index) (i.e. file extensions `.ARM` and `.ARZ`) + [CSV](../csv/index) (i.e. file extensions `.CSM` and `.CSV`) * Copy the tail of all transaction logs. + The tail of the [InnoDB redo log](../innodb-redo-log/index) (i.e. `ib_logfileN` files) will be copied for [InnoDB](../innodb/index) tables. + The tail of the Aria redo log (i.e. `aria_log.N` files) will be copied for [Aria](../aria/index) tables. ### `BACKUP STAGE BLOCK_DDL` in MariaDB Enterprise Server Mariabackup from MariaDB Enterprise Server performs the following tasks in the `BLOCK_DDL` stage: * Copy other files. + i.e. file extensions `.frm`, `.isl`, `.TRG`, `.TRN`, `.opt`, `.par` * Copy the non-transactional tables that were in use during `BACKUP STAGE FLUSH`. + [MyISAM](../myisam/index) (i.e. file extensions `.MYD` and `.MYI`) + [MERGE](../merge/index) (i.e. file extensions `.MRG`) + [ARCHIVE](../archive/index) (i.e. file extensions `.ARM` and `.ARZ`) + [CSV](../csv/index) (i.e. file extensions `.CSM` and `.CSV`) * Check `ddl.log` for DDL executed before the `BLOCK DDL` stage. + The file names of newly created tables can be read from `ddl.log`. + The file names of dropped tables can also be read from `ddl.log`. + The file names of renamed tables can also be read from `ddl.log`, so the files can be renamed instead of re-copying them. * Copy changes to system log tables. + `[mysql.general\_log](../mysqlgeneral_log-table/index)` + `[mysql.slow\_log](../mysqlslow_log-table/index)` + This is easy as these are append only. * Copy the tail of all transaction logs. + The tail of the [InnoDB redo log](../innodb-redo-log/index) (i.e. `ib_logfileN` files) will be copied for [InnoDB](../innodb/index) tables. + The tail of the Aria redo log (i.e. `aria_log.N` files) will be copied for [Aria](../aria/index) tables. ### `BACKUP STAGE BLOCK_COMMIT` in MariaDB Enterprise Server Mariabackup from MariaDB Enterprise Server performs the following tasks in the `BLOCK_COMMIT` stage: * Create a [MyRocks](../myrocks/index) checkpoint using the `[rocksdb\_create\_checkpoint](../myrocks-system-variables/index#rocksdb_create_checkpoint)` system variable. * Copy changes to system log tables. + `[mysql.general\_log](../mysqlgeneral_log-table/index)` + `[mysql.slow\_log](../mysqlslow_log-table/index)` + This is easy as these are append only. * Copy changes to statistics tables. + `[mysql.table\_stats](../mysqltable_stats-table/index)` + `[mysql.column\_stats](../mysqlcolumn_stats-table/index)` + `[mysql.index\_stats](../mysqlindex_stats-table/index)` * Copy the tail of all transaction logs. + The tail of the [InnoDB redo log](../innodb-redo-log/index) (i.e. `ib_logfileN` files) will be copied for [InnoDB](../innodb/index) tables. + The tail of the Aria redo log (i.e. `aria_log.N` files) will be copied for [Aria](../aria/index) tables. * Save the [binary log](../binary-log/index) position to `[xtrabackup\_binlog\_info](../files-created-by-mariabackup/index#xtrabackup_binlog_info)`. * Save the [Galera Cluster](../galera/index) state information to `[xtrabackup\_galera\_info](../files-created-by-mariabackup/index#xtrabackup_galera_info)`. ### `BACKUP STAGE END` in MariaDB Enterprise Server Mariabackup from MariaDB Enterprise Server performs the following tasks in the `END` stage: * Copy the [MyRocks](../myrocks/index) checkpoint into the backup. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_waits_current Table Performance Schema events\_waits\_current Table =============================================== The `events_waits_current` table contains the status of a thread's most recently monitored wait event, listing one event per thread. The table contains the following columns: | Column | Description | | --- | --- | | `THREAD_ID` | Thread associated with the event. Together with `EVENT_ID` uniquely identifies the row. | | `EVENT_ID` | Thread's current event number at the start of the event. Together with `THREAD_ID` uniquely identifies the row. | | `END_EVENT_ID` | `NULL` when the event starts, set to the thread's current event number at the end of the event. | | `EVENT_NAME` | Event instrument name and a `NAME` from the `setup_instruments` table | | `SOURCE` | Name and line number of the source file containing the instrumented code that produced the event. | | `TIMER_START` | Value in picoseconds when the event timing started or `NULL` if timing is not collected. | | `TIMER_END` | Value in picoseconds when the event timing ended, or `NULL` if the event has not ended or timing is not collected. | | `TIMER_WAIT` | Value in picoseconds of the event's duration or `NULL` if the event has not ended or timing is not collected. | | `SPINS` | Number of spin rounds for a mutex, or `NULL` if spin rounds are not used, or spinning is not instrumented. | | `OBJECT_SCHEMA` | Name of the schema that contains the table for table I/O objects, otherwise `NULL` for file I/O and synchronization objects. | | `OBJECT_NAME` | File name for file I/O objects, table name for table I/O objects, the socket's `IP:PORT` value for a socket object or `NULL` for a synchronization object. | | `INDEX NAME` | Name of the index, `PRIMARY` for the primary key, or `NULL` for no index used. | | `OBJECT_TYPE` | FILE for a file object, `TABLE` or `TEMPORARY TABLE` for a table object, or `NULL` for a synchronization object. | | `OBJECT_INSTANCE_BEGIN` | Address in memory of the object. | | `NESTING_EVENT_ID` | `EVENT_ID` of event within which this event nests. | | `NESTING_EVENT_TYPE` | Nesting event type. Either `statement`, `stage` or `wait`. | | `OPERATION` | Operation type, for example read, write or lock | | `NUMBER_OF_BYTES` | Number of bytes that the operation read or wrote, or `NULL` for table I/O waits. | | `FLAGS` | Reserved for use in the future. | It is possible to empty this table with a `TRUNCATE TABLE` statement. The related tables, [events\_waits\_history](../performance-schema-events_waits_history-table/index) and [events\_waits\_history\_long](../performance-schema-events_waits_history_long-table/index) derive their values from the current events. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb REPLACE...RETURNING REPLACE...RETURNING =================== **MariaDB starting with [10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)**REPLACE ... RETURNING was added in [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/), and returns a resultset of the replaced rows. Syntax ------ ``` REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION (partition_list)] [(col,...)] {VALUES | VALUE} ({expr | DEFAULT},...),(...),... [RETURNING select_expr [, select_expr ...]] ``` Or: ``` REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION (partition_list)] SET col={expr | DEFAULT}, ... [RETURNING select_expr [, select_expr ...]] ``` Or: ``` REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION (partition_list)] [(col,...)] SELECT ... [RETURNING select_expr [, select_expr ...]] ``` Description ----------- `REPLACE ... RETURNING` returns a resultset of the replaced rows. This returns the listed columns for all the rows that are replaced, or alternatively, the specified SELECT expression. Any SQL expressions which can be calculated can be used in the select expression for the RETURNING clause, including virtual columns and aliases, expressions which use various operators such as bitwise, logical and arithmetic operators, string functions, date-time functions, numeric functions, control flow functions, secondary functions and stored functions. Along with this, statements which have subqueries and prepared statements can also be used. Examples -------- Simple REPLACE statement ``` REPLACE INTO t2 VALUES (1,'Leopard'),(2,'Dog') RETURNING id2, id2+id2 as Total ,id2|id2, id2&&id2; +-----+-------+---------+----------+ | id2 | Total | id2|id2 | id2&&id2 | +-----+-------+---------+----------+ | 1 | 2 | 1 | 1 | | 2 | 4 | 2 | 1 | +-----+-------+---------+----------+ ``` Using stored functions in RETURNING ``` DELIMITER | CREATE FUNCTION f(arg INT) RETURNS INT BEGIN RETURN (SELECT arg+arg); END| DELIMITER ; PREPARE stmt FROM "REPLACE INTO t2 SET id2=3, animal2='Fox' RETURNING f2(id2), UPPER(animal2)"; EXECUTE stmt; +---------+----------------+ | f2(id2) | UPPER(animal2) | +---------+----------------+ | 6 | FOX | +---------+----------------+ ``` Subqueries in the statement ``` REPLACE INTO t1 SELECT * FROM t2 RETURNING (SELECT id2 FROM t2 WHERE id2 IN (SELECT id2 FROM t2 WHERE id2=1)) AS new_id; +--------+ | new_id | +--------+ | 1 | | 1 | | 1 | | 1 | +--------+ ``` Subqueries in the RETURNING clause that return more than one row or column cannot be used.. Aggregate functions cannot be used in the RETURNING clause. Since aggregate functions work on a set of values and if the purpose is to get the row count, ROW\_COUNT() with SELECT can be used, or it can be used in REPLACE...SELECT...RETURNING if the table in the RETURNING clause is not the same as the REPLACE table. See Also -------- * [INSERT ... RETURNING](../insertreturning/index) * [DELETE ... RETURNING](../delete/index#returning) * [Returning clause](https://www.youtube.com/watch?v=n-LTdEBeAT4) (video) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Differences Between FederatedX and Federated Differences Between FederatedX and Federated ============================================ The main differences are: New features in FederatedX -------------------------- * Transactions (beta feature) * Supports partitions (alpha feature) * New class structure which allows developers to write connection classes for other RDBMSs without having to modify base classes for FederatedX * Actively developed! Different behavior ------------------ * FederatedX is statically compiled into MariaDB by default. * When you create a table with FederatedX, the connection will be tested. The `CREATE` will fail if MariaDB can't connect to the remote host or if the remote table doesn't exist. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema XTRADB_READ_VIEW Table Information Schema XTRADB\_READ\_VIEW Table =========================================== **MariaDB starting with [10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/)**The `XTRADB_READ_VIEW` table was added in [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/). The [Information Schema](../information_schema/index) `XTRADB_READ_VIEW` table contains information about the oldest active transaction in the system. The `PROCESS` [privilege](../grant/index) is required to view the table. It has the following columns: | Column | Description | | --- | --- | | `READ_VIEW_UNDO_NUMBER` | | | `READ_VIEW_LOW_LIMIT_TRX_NUMBER` | Highest transaction number at the time the view was created. | | `READ_VIEW_UPPER_LIMIT_TRX_ID` | Highest transaction ID at the time the view was created. Should not see newer transactions with IDs equal to or greater than the value. | | `READ_VIEW_LOW_LIMIT_TRX_ID` | Latest committed transaction ID at the time the oldest view was created. Should see all transactions with IDs equal to or less than the value. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Memory Allocation MariaDB Memory Allocation ========================= Allocating RAM for MariaDB - The Short Answer --------------------------------------------- If only using [MyISAM](../myisam/index), set [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) to 20% of **available** RAM. (Plus [innodb\_buffer\_pool\_size=0](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_size)) If only using InnoDB, set [innodb\_buffer\_pool\_size](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_size) to 70% of **available** RAM. (Plus [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) = 10M, small, but not zero.) Rule of thumb for tuning: * Start with released copy of my.cnf / my.ini. * Change [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) and [innodb\_buffer\_pool\_size](../innodb-system-variables/index#innodb_buffer_pool_size) according to engine usage and RAM. * Slow queries can usually be 'fixed' via indexes, schema changes, or SELECT changes, not by tuning. * Don't get carried away with the [query cache](../query-cache/index) until you understand what it can and cannot do. * Don't change anything else unless you run into trouble (eg, max connections). * Be sure the changes are under the [mysqld] section, not some other section. The 20%/70% assumes you have at least 4GB of RAM. If you have a tiny antique, or a tiny VM, then those percentages are too high. Now for the gory details. How to troubleshoot out-of-memory issues ---------------------------------------- If the MariaDB server is crashing because of 'out-of-memory' then it is probably wrongly configured. There are two kind of buffers in MariaDB: * Global ones that are only allocated once during the lifetime of the server: + Storage engine buffers ([innodb\_buffer\_pool\_size](../innodb-system-variables/index#innodb_buffer_pool_size), [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size), [aria\_pagecache\_buffer\_size](../aria-system-variables/index#aria_pagecache_buffer_size), etc) + Query cache [query\_cache\_size](../server-system-variables/index#query_cache_size). * Global caches onces that grow and shrink dynamically on demand up to max limit: + [max\_user\_connections](../server-system-variables/index#max_user_connections) + [table\_open\_cache](../server-system-variables/index#table_open_cache) + [table\_definition\_cache](../server-system-variables/index#table_definition_cache) + [thread\_cache\_size](../server-system-variables/index#thread_cache_size) * Local buffers that are allocated on demand whenever needed + Internal ones used during engine index creation ([myisam\_sort\_buffer\_size](../myisam-system-variables/index#myisam_sort_buffer_size), [aria\_sort\_buffer\_size).](../aria-system-variables/index#aria_sort_buffer_size) + Internal buffers for storing blobs. - Some storage engine will keep a temporary cache to store the largest blob seen so far when scanning a table. This will be freed at end of query. Note that temporary blob storage is **not** included in the memory information in [information\_schema.processlist](../information-schema-processlist-table/index) but only in the total memory used (`show global status like "memory_used"`). + Buffers and caches used during query execution: | Variable | Description | | --- | --- | | [join\_buffer\_size](../server-system-variables/index#join_buffer_size) | Used when no keys can be used to find a row in next table | | [mrr\_buffer\_size](../server-system-variables/index#mrr_buffer_size) | Size of buffer to use when using multi-range read with range access | | [net\_buffer\_length](../server-system-variables/index#net_buffer_length) | Max size of network packet | | [read\_buffer\_size](../server-system-variables/index#read_buffer_size) | Used by some storage engines when doing bulk insert | | [sort\_buffer\_size](../server-system-variables/index#sort_buffer_size) | When doing ORDER BY or GROUP BY | | [max\_heap\_table\_size](../server-system-variables/index#max_heap_table_size) | Used to store temporary tables in memory. See [Optimizing memory tables](../optimizing-memory-tables/index) | If any variables in the last group is very large and you have a lot of simultaneous users that are executing queries that are using these buffers then you can run into trouble. In a default MariaDB installation the default of most of the above variables are quite small to ensure that one does not run out of memory. You can check which variables that have been changed in your setup by executing the following sql statement. If you are running into out-of-memory issues, it is very likely that the problematic variable is in this list! ``` select information_schema.system_variables.variable_name, information_schema.system_variables.default_value, global_variables.variable_value from information_schema.system_variables,information_schema.global_variables where system_variables.variable_name=global_variables.variable_name and system_variables.default_value <> global_variables.variable_value and system_variables.default_value <> 0 ``` What is the Key Buffer? ----------------------- [MyISAM](../myisam/index) does two different things for caching. * Index blocks (1KB each, BTree structured, from .MYI file) live in the "key buffer". * Data block caching (from .MYD file) is left to the OS, so be sure to leave a bunch of free space for this. Caveat: Some flavors of OS always claim to be using over 90%, even when there is really lots of free space. ``` SHOW GLOBAL STATUS LIKE 'Key%'; ``` then calculate [Key\_read\_requests](../server-status-variables/index#key_read_requests) / [Key\_reads](../server-status-variables/index#key_reads). If it is high (say, over 10), then the key buffer is big enough, otherwise you should adjust the [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) value. What is the Buffer Pool? ------------------------ InnoDB does all its caching in a the [buffer pool](../xtradbinnodb-buffer-pool/index), whose size is controlled by [innodb\_buffer\_pool\_size](../innodb-system-variables/index#innodb_buffer_pool_size). By default it contains 16KB data and index blocks from the open tables (see [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size)), plus some maintenance overhead. From [MariaDB 5.5](../what-is-mariadb-55/index), multiple buffer pools are permitted; this can help because there is one mutex per pool, thereby relieving some of the mutex bottleneck. [More on InnoDB tuning](http://www.mysqlperformanceblog.com/2007/11/01/innodb-performance-optimization-basics/) Another Algorithm ----------------- This will set the main cache settings to the minimum; it could be important to systems with lots of other processes and/or RAM is 2GB or smaller. Do [SHOW TABLE STATUS](../show-table-status/index) for all the tables in all the databases. Add up Index\_length for all the MyISAM tables. Set [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) no larger than that size. Add up Data\_length + Index\_length for all the InnoDB tables. Set [innodb\_buffer\_pool\_size](../innodb-system-variables/index#innodb_buffer_pool_size) to no more than 110% of that total. If that leads to swapping, cut both settings back. Suggest cutting them down proportionately. Run this to see the values for your system. (If you have a lot of tables, it can take minute(s).) ``` SELECT ENGINE, ROUND(SUM(data_length) /1024/1024, 1) AS "Data MB", ROUND(SUM(index_length)/1024/1024, 1) AS "Index MB", ROUND(SUM(data_length + index_length)/1024/1024, 1) AS "Total MB", COUNT(*) "Num Tables" FROM INFORMATION_SCHEMA.TABLES WHERE table_schema not in ("information_schema", "PERFORMANCE_SCHEMA", "SYS_SCHEMA", "ndbinfo") GROUP BY ENGINE; ``` Query Memory Allocation ----------------------- There are two variables that dictates how memory are allocated by MariaDB while parsing and executing a query. [query\_prealloc\_size](../server-system-variables/index#query_prealloc_size) defines the standard buffer for memory used for query execution and [query\_alloc\_block\_size](../server-system-variables/index#query_alloc_block_size) that is size of memory blocks if `query_prealloc_size` was not big enough. Getting these variables right will reduce memory fragmentation in the server. Mutex Bottleneck ---------------- MySQL was designed in the days of single-CPU machines, and designed to be easily ported to many different architectures. Unfortunately, that lead to some sloppiness in how to interlock actions. There are a small number (too small) of "mutexes" to gain access to several critical processes. Of note: * MyISAM's key\_buffer * The Query Cache * InnoDB's buffer\_pool With multi-core boxes, the mutex problem is causing performance problems. In general, past 4-8 cores, MySQL gets slower, not faster. MySQL 5.5 and Percona's XtraDB made that somewhat better in InnoDB; the practical limit for cores is more like 32, and performance tends plateaus after that rather than declining. 5.6 claims to scale up to about 48 cores. HyperThreading and Multiple Cores (CPUs) ---------------------------------------- Short answers (for older versions of MySQL and MariaDB): * Turn off HyperThreading * Turn off any cores beyond 8 * HyperThreading is mostly a thing of the past, so this section may not apply. HyperThreading is great for marketing, lousy for performance. It involves having two processing units sharing a single hardware cache. If both units are doing the same thing, the cache will be reasonably useful. If the units are doing different things, they will be clobbering each other's cache entries. Furthermore MySQL is not great on using multiple cores. So, if you turn off HT, the remaining cores run a little faster. 32-bit OS and MariaDB --------------------- First, the OS (and the hardware?) may conspire to not let you use all 4GB, if that is what you have. If you have more than 4GB of RAM, the excess beyond 4GB is \_totally\_ inaccessable and unusable on a 32-bit OS. Secondly, the OS probably has a limit on how much RAM it will allow any process to use. Example: FreeBSD's maxdsiz, which defaults to 512MB. Example: ``` $ ulimit -a ... max memory size (kbytes, -m) 524288 ``` So, once you have determined how much RAM is available to mysqld, then apply the 20%/70%, but round down some. If you get an error like `[ERROR] /usr/libexec/mysqld: Out of memory (Needed xxx bytes)`, it probably means that MySQL exceeded what the OS is willing to give it. Decrease the cache settings. 64-bit OS with 32-bit MariaDB ----------------------------- The OS is not limited by 4GB, but MariaDB is. If you have at least 4GB of RAM, then maybe these would be good: * [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) = 20% of \_all\_ of RAM, but not more than 3G * [innodb\_buffer\_pool\_size](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_size) = 3G You should probably upgrade MariaDB to 64-bit. 64-bit OS and MariaDB --------------------- MyISAM only: [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size): Use about 20% of RAM. Set (in my.cnf / my.ini) [innodb\_buffer\_pool\_size=0](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_size) = 0. InnoDB only: [innodb\_buffer\_pool\_size=0](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_size) = 70% of RAM. If you have lots of RAM and are using 5.5 (or later), then consider having multiple pools. Recommend 1-16 [innodb\_buffer\_pool\_instances](../innodb-system-variables/index#innodb_buffer_pool_instances), such that each one is no smaller than 1GB. (Sorry, no metric on how much this will help; probably not a lot.) Meanwhile, set [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) = 20M (tiny, but non-zero) If you have a mixture of engines, lower both numbers. max\_connections, thread\_stack Each "thread" takes some amount of RAM. This used to be about 200KB; 100 threads would be 20MB, not a significant size. If you have [max\_connections](../server-system-variables/index#max_connections) = 1000, then you are talking about 200MB, maybe more. Having that many connections probably implies other issues that should be addressed. In 5.6 (or [MariaDB 5.5](../what-is-mariadb-55/index)), optional thread pooling interacts with [max\_connections](../server-system-variables/index#max_connections). This is a more advanced topic. Thread stack overrun rarely happens. If it does, do something like thread\_stack=256K [More on max\_connections, wait\_timeout, connection pooling, etc](http://www.mysqlperformanceblog.com/2013/11/28/mysql-error-too-many-connections/) table\_open\_cache ------------------ (In older versions this was called table\_cache) The OS has some limit on the number of open files it will let a process have. Each table needs 1 to 3 open files. Each PARTITION is effectively a table. Most operations on a partitioned table open \_all\_ partitions. In \*nix, ulimit tells you what the file limit is. The maximum value is in the tens of thousands, but sometimes it is set to only 1024. This limits you to about 300 tables. More discussion on ulimit (This paragraph is in disputed.) On the other side, the table cache is (was) inefficiently implemented -- lookups were done with a linear scan. Hence, setting table\_cache in the thousands could actually slow down mysql. (Benchmarks have shown this.) You can see how well your system is performing via [SHOW GLOBAL STATUS](../show-status/index); and computing the opens/second via [Opened\_files](../server-status-variables/index#opened_files) / [Uptime](../server-status-variables/index#uptime) If this is more than, say, 5, [table\_open\_cache](../server-system-variables/index#table_open_cache) should be increased. If it is less than, say, 1, you might get improvement by decreasing [table\_open\_cache](../server-system-variables/index#table_open_cache). From [MariaDB 10.1](../what-is-mariadb-101/index), [table\_open\_cache](../server-system-variables/index#table_open_cache) defaults to 2000. Query Cache ----------- Short answer: [query\_cache\_type](../server-system-variables/index#query_cache_type) = OFF and [query\_cache\_size](../server-system-variables/index#query_cache_size) = 0 The [Query Cache](../query-cache/index) (QC) is effectively a hash mapping SELECT statements to resultsets. Long answer... There are many aspects of the "Query cache"; many are negative. * Novice Alert! The QC is totally unrelated to the key\_buffer and buffer\_pool. * When it is useful, the QC is blazingly fast. It would not be hard to create a benchmark that runs 1000x faster. * There is a single mutex controlling the QC. * The QC, unless it is OFF & 0, is consulted for \_every\_ SELECT. * Yes, the mutex is hit even if [query\_cache\_type](../server-system-variables/index#query_cache_type) = DEMAND (2). * Yes, the mutex is hit even for [SQL\_NO\_CACHE](../query-cache/index#sql_no_cache-and-sql_cache). * Any change to a query (even adding a space) leads (potentially) to a different entry in the QC. * If my.cnf says type=ON and you later turn it OFF, it is not fully OFF. Ref: <https://bugs.mysql.com/bug.php?id=60696> "Pruning" is costly and frequent: * When \_any\_ write happens on a table, \_all\_ entries in the QC for \_that\_ table are removed. * It happens even on a readonly Slave. * Purges are performed with a linear algorithm, so a large QC (even 200MB) can be noticeably slow. To see how well your QC is performing, SHOW GLOBAL STATUS LIKE 'Qc%'; then compute the read hit rate: [Qcache\_hits](../server-status-variables/index#qcache_hits) / [Qcache\_inserts](../server-status-variables/index#qcache_inserts) If it is over, say, 5, the QC might be worth keeping. If you decide the QC is right for you, then I recommend * [query\_cache\_size](../server-system-variables/index#query_cache_size) = no more than 50M * [query\_cache\_type](../server-system-variables/index#query_cache_type) = DEMAND * [SQL\_CACHE or SQL\_NO\_CACHE](%5bquery-cache/index#sql_no_cache-and-sql_cache) in all SELECTs, based on which queries are likely to benefit from caching. * [Why to turn off the QC](http://dba.stackexchange.com/a/136814/1876) * [Discussion about size](https://haydenjames.io/mysql-query-cache-size-performance/) thread\_cache\_size ------------------- It is not necessary to tune [thread\_cache\_size](../server-system-variables/index#thread_cache_size) from [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/). Previously, it was minor tunable variable. Zero will slow down thread (connection) creation. A small (say, 10), non-zero number is good. The setting has essentially no impact on RAM usage. It is the number of extra processes to hang onto. It does not restrict the number of threads; [max\_connections](../server-system-variables/index#max_connections) does. Binary Logs ----------- If you have turned on [binary logging](../binary-log/index) (via [log\_bin](../replication-and-binary-log-system-variables/index#log_bin)) for replication and/or point-in-time recovery, the system will create binary logs forever. That is, they can slowly fill up the disk. Suggest setting [expire\_logs\_days](../replication-and-binary-log-system-variables/index#expire_logs_days) = 14 to keep only 14 days' worth of logs. Swappiness ---------- RHEL, in its infinite wisdom, decided to let you control how aggressively the OS will pre-emptively swap RAM. This is good in general, but lousy for MariaDB. MariaDB would love for RAM allocations to be reasonably stable -- the caches are (mostly) pre-allocated; the threads, etc, are (mostly) of limited scope. ANY swapping is likely to severely hurt performance of MariaDB. With a high value for swappiness, you lose some RAM because the OS is trying to keep a lot of space free for future allocations (that MySQL is not likely to need). With swappiness = 0, the OS will probably crash rather than swap. I would rather have MariaDB limping than die. The latest recommendation is swappiness = 1. (2015) [More confirmation](http://www.mysqlperformanceblog.com/2014/04/28/oom-relation-vm-swappiness0-new-kernel/) Somewhere in between (say, 5?) might be a good value for a MariaDB-only server. NUMA ---- OK, it's time to complicate the architecture of how a CPU talks to RAM. NUMA (Non-Uniform Memory Access) enters the picture. Each CPU (or maybe socket with several cores) has a part of the RAM hanging off each. This leads to memory access being faster for local RAM, but slower (tens of cycles slower) for RAM hanging off other CPUs. Then the OS enters the picture. In at least one case (RHEL?), two things seem to be done: * OS allocations are pinned to the 'first' CPU's RAM.] * Other allocations go by default to the first CPU until it is full. Now for the problem. * The OS and MariaDB have allocated all the 'first' RAM. * MariaDB has allocated some of the second RAM. * The OS needs to allocate something. Ouch -- it is out of room in the one CPU where it is willing to allocate its stuff, so it swaps out some of MariaDB. Bad. dmesg | grep -i numa # to see if you have numa Probable solution: Configure the BIOS to "interleave" the RAM allocations. This should prevent the premature swapping, at the cost of off-CPU RAM accesses half the time. Well, you have the costly accesses anyway, since you really want to use all of RAM. Older MySQL versions: numactl --interleave=all. Or: [innodb\_numa\_interleave](../innodb-system-variables/index#innodb_numa_interleave)=1 Another possible solution: Turn numa off (if the OS has a way of doing that) Overall performance loss/gain: A few percent. Huge Pages ---------- This is another hardware performance gimmick. For a CPU to access RAM, especially mapping a 64-bit address to somewhere in, say, 128GB or 'real' RAM, the TLB is used. (TLB = Translation Lookup Buffer.) Think of the TLB as a hardware associative memory lookup table; given a 64-bit virtual address, what is the real address. Because it is an associative memory of finite size, sometimes there will be "misses" that require reaching into real RAM to resolve the lookup. This is costly, so should be avoided. Normally, RAM is 'paged' in 4KB pieces; the TLB actually maps the top (64-12) bits into a specific page. Then the bottom 12 bits of the virtual address are carried over intact. For example, 128GB of RAM broken 4KB pages means 32M page-table entries. This is a lot, and probably far exceeds the capacity of the TLB. So, enter the "Huge page" trick. With the help of both the hardware and the OS, it is possible to have some of RAM in huge pages, of say 4MB (instead of 4KB). This leads to far fewer TLB entries, but it means the unit of paging is 4MB for such parts of RAM. Hence, huge pages tend to be non-pagable. Now RAM is broken into pagable and non pagable parts; what parts can reasonably be non pagable? In MariaDB, the [Innodb Buffer Pool](../xtradbinnodb-buffer-pool/index) is a perfect candidate. So, by correctly configuring these, InnoDB can run a little faster: * Huge pages enabled * Tell the OS to allocate the right amount (namely to match the buffer\_pool) * Tell MariaDB to use huge pages * [innodb memory usage vs swap](http://forums.mysql.com/read.php?22,384707,385002) That thread has more details on what to look for and what to set. Overall performance gain: A few percent. Yawn. Too much hassle for too little benefit. Jumbo Pages? Turn off. ENGINE=MEMORY ------------- The [Memory Storage Engine](../memory-storage-engine/index) is a little-used alternative to [MyISAM](../myisam/index) and [InnoDB](../innodb/index). The data is not persistent, so it has limited uses. The size of a MEMORY table is limited to [max\_heap\_table\_size](../server-system-variables/index#max_heap_table_size), which defaults to 16MB. I mention it in case you have changed the value to something huge; this would stealing from other possible uses of RAM. How to Set Variables -------------------- In the text file my.cnf (my.ini on Windows), add or modify a line to say something like [innodb\_buffer\_pool\_size](../innodb-system-variables/index#innodb_buffer_pool_size) = 5G That is, VARIABLE name, "=", and a value. Some abbreviations are allowed, such as M for million (1048576), G for billion. For the server to see it, the settings must be in the "[mysqld]" section of the file. The settings in my.cnf or my.ini will not take effect until you restart the server. Most settings can be changed on the live system by connecting as user root (or other user with SUPER privilege) and doing something like ``` SET @@global.key_buffer_size = 77000000; ``` Note: No M or G suffix is allowed here. To see the setting a global VARIABLE do something like ``` SHOW GLOBAL VARIABLES LIKE "key_buffer_size"; +-----------------+----------+ | Variable_name | Value | +-----------------+----------+ | key_buffer_size | 76996608 | +-----------------+----------+ ``` Note that this particular setting was rounded down to some multiple that MariaDB liked. You may want to do both (SET, and modify my.cnf) in order to make the change immediately and have it so that the next restart (for whatever reason) will again get the value. Web Server ---------- A web server like Apache runs multiple threads. If each thread opens a connection to MariaDB, you could run out of connections. Make sure MaxClients (or equivalent) is set to some civilized number (under 50). Tools ----- * MySQLTuner * TUNING-PRIMER There are several tools that advise on memory. One misleading entry they come up with Maximum possible memory usage: 31.3G (266% of installed RAM) Don't let it scare you -- the formulas used are excessively conservative. They assume all of [max\_connections](../server-system-variables/index#max_connections) are in use and active, and doing something memory-intensive. Total fragmented tables: 23 This implies that OPTIMIZE TABLE \_might\_ help. I suggest it for tables with either a high percentage of "free space" (see SHOW TABLE STATUS) or where you know you do a lot of DELETEs and/or UPDATEs. Still, don't bother to OPTIMIZE too often. Once a month might suffice. MySQL 5.7 --------- 5.7 stores a lot more information in RAM, leading to the footprint being perhaps half a GB more than 5.6. See [Memory increase in 5.7](https://blogs.oracle.com/svetasmirnova/entry/memory_summary_tables_in_performance). Postlog ------- Created 2010; Refreshed Oct, 2012, Jan, 2014 The tips in this document apply to MySQL, MariaDB, and Percona. See Also -------- * [Configuring MariaDB for Optimal Performance](../configuring-mariadb-for-optimal-performance/index) * More in-depth: Tocker's tuning for 5.6 * Irfan's InnoDB performance optimization basics (redux) * 10 MySQL settings to tune after installation * Magento * Peter Zaitsev's take on such (5/2016) Rick James graciously allowed us to use this article in the Knowledge Base. [Rick James' site](http://mysql.rjweb.org/) has other useful tips, how-tos, optimizations, and debugging tips. Original source: <http://mysql.rjweb.org/doc.php/random> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb MINUS MINUS ===== **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**`MINUS` was introduced as a synonym for [EXCEPT](../except/index) from [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_transactions_current Table Performance Schema events\_transactions\_current Table ====================================================== **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**The events\_transactions\_current table was introduced in [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). The `events_transactions_current` table contains current transaction events for each thread. The table size cannot be figured, and always stores one row for each thread, showing the current status of the thread's most recent monitored transaction event. The table contains the following columns: | Column | Type | Description | | --- | --- | --- | | THREAD\_ID | bigint(20) unsigned | The thread associated with the event. | | EVENT\_ID | bigint(20) unsigned | The event id associated with the event. | | END\_EVENT\_ID | bigint(20) unsigned | This column is set to NULL when the event starts and updated to the thread current event number when the event ends. | | EVENT\_NAME | varchar(128) | The name of the instrument from which the event was collected. This is a NAME value from the setup\_instruments table. | | STATE | enum('ACTIVE', 'COMMITTED', 'ROLLED BACK') | The current transaction state. The value is ACTIVE (after START TRANSACTION or BEGIN), COMMITTED (after COMMIT), or ROLLED BACK (after ROLLBACK). | | TRX\_ID | bigint(20) unsigned | Unused. | | GTID | varchar(64) | Transaction [GTID](../gtid/index), using the format DOMAIN-SERVER\_ID-SEQUENCE\_NO. | | XID\_FORMAT\_ID | int(11) | XA transaction format ID for GTRID and BQUAL values. | | XID\_GTRID | varchar(130) | XA global transaction ID. | | XID\_BQUAL | varchar(130) | XA transaction branch qualifier. | | XA\_STATE | varchar(64) | The state of the XA transaction. The value is ACTIVE (after XA START), IDLE (after XA END), PREPARED (after XA PREPARE), ROLLED BACK (after XA ROLLBACK), or COMMITTED (after XA COMMIT). | | SOURCE | varchar(64) | The name of the source file containing the instrumented code that produced the event and the line number in the file at which the instrumentation occurs. | | TIMER\_START | bigint(20) unsigned | The unit is picoseconds. When event timing started. NULL if event has no timing information. | | TIMER\_END | bigint(20) unsigned | The unit is picoseconds. When event timing ended. NULL if event has no timing information. | | TIMER\_WAIT | bigint(20) unsigned | The unit is picoseconds. Event duration. NULL if event has not timing information. | | ACCESS\_MODE | enum('READ ONLY', 'READ WRITE') | Transaction access mode. | | ISOLATION\_LEVEL | varchar(64) | Transaction isolation level. One of: REPEATABLE READ, READ COMMITTED, READ UNCOMMITTED, or SERIALIZABLE. | | AUTOCOMMIT | enum('YES','NO') | Whether autcommit mode was enabled when the transaction started. | | NUMBER\_OF\_SAVEPOINTS | bigint(20) unsigned | The number of SAVEPOINT statements issued during the transaction. | | NUMBER\_OF\_ROLLBACK\_TO\_SAVEPOINT | bigint(20) unsigned | The number of ROLLBACK\_TO\_SAVEPOINT statements issued during the transaction. | | NUMBER\_OF\_RELEASE\_SAVEPOINT | bigint(20) unsigned | The number of RELEASE\_SAVEPOINT statements issued during the transaction. | | OBJECT\_INSTANCE\_BEGIN | bigint(20) unsigned | Unused. | | NESTING\_EVENT\_ID | bigint(20) unsigned | The EVENT\_ID value of the event within which this event is nested. | | NESTING\_EVENT\_TYPE | enum('TRANSACTION', 'STATEMENT', 'STAGE', 'WAIT') | The nesting event type. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema table_io_waits_summary_by_table Table Performance Schema table\_io\_waits\_summary\_by\_table Table ============================================================= The `table_io_waits_summary_by_table` table records table I/O waits by table. | Column | Description | | --- | --- | | `OBJECT_TYPE` | Since this table records waits by table, always set to `TABLE`. | | `OBJECT_SCHEMA` | Schema name. | | `OBJECT_NAME` | Table name. | | `COUNT_STAR` | Number of summarized events and the sum of the `x_READ` and `x_WRITE` columns. | | `SUM_TIMER_WAIT` | Total wait time of the summarized events that are timed. | | `MIN_TIMER_WAIT` | Minimum wait time of the summarized events that are timed. | | `AVG_TIMER_WAIT` | Average wait time of the summarized events that are timed. | | `MAX_TIMER_WAIT` | Maximum wait time of the summarized events that are timed. | | `COUNT_READ` | Number of all read operations, and the sum of the equivalent `x_FETCH` columns. | | `SUM_TIMER_READ` | Total wait time of all read operations that are timed. | | `MIN_TIMER_READ` | Minimum wait time of all read operations that are timed. | | `AVG_TIMER_READ` | Average wait time of all read operations that are timed. | | `MAX_TIMER_READ` | Maximum wait time of all read operations that are timed. | | `COUNT_WRITE` | Number of all write operations, and the sum of the equivalent `x_INSERT`, `x_UPDATE` and `x_DELETE` columns. | | `SUM_TIMER_WRITE` | Total wait time of all write operations that are timed. | | `MIN_TIMER_WRITE` | Minimum wait time of all write operations that are timed. | | `AVG_TIMER_WRITE` | Average wait time of all write operations that are timed. | | `MAX_TIMER_WRITE` | Maximum wait time of all write operations that are timed. | | `COUNT_FETCH` | Number of all fetch operations. | | `SUM_TIMER_FETCH` | Total wait time of all fetch operations that are timed. | | `MIN_TIMER_FETCH` | Minimum wait time of all fetch operations that are timed. | | `AVG_TIMER_FETCH` | Average wait time of all fetch operations that are timed. | | `MAX_TIMER_FETCH` | Maximum wait time of all fetch operations that are timed. | | `COUNT_INSERT` | Number of all insert operations. | | `SUM_TIMER_INSERT` | Total wait time of all insert operations that are timed. | | `MIN_TIMER_INSERT` | Minimum wait time of all insert operations that are timed. | | `AVG_TIMER_INSERT` | Average wait time of all insert operations that are timed. | | `MAX_TIMER_INSERT` | Maximum wait time of all insert operations that are timed. | | `COUNT_UPDATE` | Number of all update operations. | | `SUM_TIMER_UPDATE` | Total wait time of all update operations that are timed. | | `MIN_TIMER_UPDATE` | Minimum wait time of all update operations that are timed. | | `AVG_TIMER_UPDATE` | Average wait time of all update operations that are timed. | | `MAX_TIMER_UPDATE` | Maximum wait time of all update operations that are timed. | | `COUNT_DELETE` | Number of all delete operations. | | `SUM_TIMER_DELETE` | Total wait time of all delete operations that are timed. | | `MIN_TIMER_DELETE` | Minimum wait time of all delete operations that are timed. | | `AVG_TIMER_DELETE` | Average wait time of all delete operations that are timed. | | `MAX_TIMER_DELETE` | Maximum wait time of all delete operations that are timed. | You can [TRUNCATE](../truncate-table/index) the table, which will reset all counters to zero. Truncating this table will also truncate the [table\_io\_waits\_summary\_by\_index\_usage](../performance-schema-table_io_waits_summary_by_index_usage-table/index) table. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb JSON_QUOTE JSON\_QUOTE =========== **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**JSON functions were added in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). Syntax ------ ``` JSON_QUOTE(json_value) ``` Description ----------- Quotes a string as a JSON value, usually for producing valid JSON string literals for inclusion in JSON documents. Wraps the string with double quote characters and escapes interior quotes and other special characters, returning a utf8mb4 string. Returns NULL if the argument is NULL. Examples -------- ``` SELECT JSON_QUOTE('A'), JSON_QUOTE("B"), JSON_QUOTE('"C"'); +-----------------+-----------------+-------------------+ | JSON_QUOTE('A') | JSON_QUOTE("B") | JSON_QUOTE('"C"') | +-----------------+-----------------+-------------------+ | "A" | "B" | "\"C\"" | +-----------------+-----------------+-------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Archive Archive ======== The `ARCHIVE` storage engine is a storage engine that uses gzip to compress rows. It is mainly used for storing large amounts of data, without indexes, with only a very small footprint. A table using the `ARCHIVE` storage engine is stored in two files on disk. There's a table definition file with an extension of .frm, and a data file with the extension .ARZ. At times during optimization, a .ARN file will appear. New rows are inserted into a compression buffer and are flushed to disk when needed. SELECTs cause a flush. Sometimes, rows created by multi-row inserts are not visible until the statement is complete. `ARCHIVE` allows a maximum of one key. The key must be on an `[AUTO\_INCREMENT](../auto_increment/index)` column, and can be a `PRIMARY KEY` or a non-unique key. However, it has a limitation: it is not possible to insert a value which is lower than the next `AUTO_INCREMENT` value. Installing the Plugin --------------------- Although the plugin's shared library is distributed with MariaDB by default, the plugin is not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB. The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing `[INSTALL SONAME](../install-soname/index)` or `[INSTALL PLUGIN](../install-plugin/index)`. For example: ``` INSTALL SONAME 'ha_archive'; ``` The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the `[--plugin-load](../mysqld-options/index#-plugin-load)` or the `[--plugin-load-add](../mysqld-options/index#-plugin-load-add)` options. This can be specified as a command-line argument to `[mysqld](../mysqld-options/index)` or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... plugin_load_add = ha_archive ``` Uninstalling the Plugin ----------------------- You can uninstall the plugin dynamically by executing `[UNINSTALL SONAME](../uninstall-soname/index)` or `[UNINSTALL PLUGIN](../uninstall-plugin/index)`. For example: ``` UNINSTALL SONAME 'ha_archive'; ``` If you installed the plugin by providing the `[--plugin-load](../mysqld-options/index#-plugin-load)` or the `[--plugin-load-add](../mysqld-options/index#-plugin-load-add)` options in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), then those options should be removed to prevent the plugin from being loaded the next time the server is restarted. Characteristics --------------- * Supports [INSERT](../insert/index) and [SELECT](../select/index), but not [DELETE](../delete/index), [UPDATE](../update/index) or [REPLACE](../replace/index). * Data is compressed with zlib as it is inserted, making it very small. * Data is slow the select, as it needs to be uncompressed, and, besides the [query cache](../query-cache/index), there is no cache. * Supports AUTO\_INCREMENT (since MariaDB/MySQL 5.1.6), which can be a unique or a non-unique index. * Since MariaDB/MySQL 5.1.6, selects scan past BLOB columns unless they are specifically requested, making these queries much more efficient. * Does not support [spatial](../spatial/index) data types. * Does not support [transactions](../transactions/index). * Does not support foreign keys. * Does not support [virtual columns](../virtual-columns/index). * No storage limit. * Supports row locking. * Supports [table discovery](../table-discovery/index), and the server can access ARCHIVE tables even if the corresponding `.frm` file is missing. * [OPTIMIZE TABLE](../optimize-table/index) and [REPAIR TABLE](../repair-table/index) can be used to compress the table in its entirety, resulting in slightly better compression. * With MariaDB, it is possible to upgrade from the MySQL 5.0 format without having to dump the tables. * [INSERT DELAYED](../insert-delayed/index) is supported. * Running many SELECTs during the insertions can deteriorate the compression, unless only multi-rows INSERTs and INSERT DELAYED are used. | Title | Description | | --- | --- | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Performance Module ColumnStore Performance Module ============================== The Performance Module performs I/O operations in support of read and write processing. It doesn't see the query itself, but only a set of instructions given to it by a [User Module](../columnstore-user-module/index). There are three critical tasks key to scaling out database behavior: * **Distributed Scans** * **Distributed Hash Joins** * **Distributed Aggregation** The combination of these enables massive parallel processing (MPP) for query-intensive environments. Processes --------- The Performance Module is composed of a number of processes ### Managing and Monitoring Processes The Process Manager, or ProcMgr, is the process responsible for starting, monitoring and restarting all MariaDB ColumnStore processes on the Performance Module. In order to accomplish this, ProcMgr uses the Process Monitor, or ProcMon on each Performance Module to keep track of MariaDB ColumnStore processes. ### Processing Queries The Primary Process, or PrimProc, handles query execution. The [User Modules](../columnstore-user-module/index) process queries from the application into instructions that are sent to the Performance Module. PrimProc executes these instructions as block oriented I/O operations to perform predicate filtering, join processing, and the initial aggregation of data, after which PrimProc sends the data back to the User Module. ### Performing Loads and Writes The Performance Module processes loads and writes to the underlying persistent storage. It uses two processes to handle this: WriteEngineServer and cpimport. WriteEngineServer coordinates DML, DDL and imports on each Performance Module. DDL changes are made persistent within the System Catalog, which keeps track of all ColumnStore metadata. User and Performance modules both use cpimport. On the Performance Module it updates database files when loading bulk data. This allows ColumnStore to support fully parallel loads. Shared Nothing Data Cache ------------------------- The Performance Module uses a shared nothing data cache. When it first accesses data, it operates on data as instructed by the [User Module](../columnstore-user-module/index) and caches it in an LRU-based buffer for subsequent access. When the Performance Module runs on a dedicated server, you can dedicate the majority of the available to this data cache. As the Performance Module cache is shared nothing design: * There is no data block pinging between participating Performance Module nodes, (as sometimes occurs in other multi-instance/shared disk database systems). * More Performance Module nodes added to a system, the larger the overall cache size for the database. Failover -------- When deploying MariaDB ColumnStore with multiple Performance Module nodes, a heartbeat mechanism ensures that all nodes are online and there is transparent failover in the event that a particular node fails. If a node abnormally terminates, in-process queries return an error. Users that receive an error due to Performance Module can resubmit the query. ColumnStore then does the work using the remaining Performance Modules. In cases of failover where the underlying storage data is externally mounted, (such as with EC2 EBS or SAN), the mapping of data blocks to Performance Modules is re-organized across working Performance Modules, and the Extent Maps on the User Modules are re-evaluated, so that queries are sent to the appropriate nodes. That is, the DB Roots attached to the failed Performance Module are attached to working Performance Modules. This process is transparent to the user and does not require manual intervention. When the failed Performance Module is brought back online, ColumnStore auto-adopts it back into the configuration and begins using it for work. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb UPDATE UPDATE ====== Syntax ------ Single-table syntax: ``` UPDATE [LOW_PRIORITY] [IGNORE] table_reference [PARTITION (partition_list)] [FOR PORTION OF period FROM expr1 TO expr2] SET col1={expr1|DEFAULT} [,col2={expr2|DEFAULT}] ... [WHERE where_condition] [ORDER BY ...] [LIMIT row_count] ``` Multiple-table syntax: ``` UPDATE [LOW_PRIORITY] [IGNORE] table_references SET col1={expr1|DEFAULT} [, col2={expr2|DEFAULT}] ... [WHERE where_condition] ``` Description ----------- For the single-table syntax, the `UPDATE` statement updates columns of existing rows in the named table with new values. The `SET` clause indicates which columns to modify and the values they should be given. Each value can be given as an expression, or the keyword `DEFAULT` to set a column explicitly to its default value. The `WHERE` clause, if given, specifies the conditions that identify which rows to update. With no `WHERE` clause, all rows are updated. If the [ORDER BY](../order-by/index) clause is specified, the rows are updated in the order that is specified. The [LIMIT](../limit/index) clause places a limit on the number of rows that can be updated. Until [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/), for the multiple-table syntax, `UPDATE` updates rows in each table named in table\_references that satisfy the conditions. In this case, [ORDER BY](../order-by/index) and [LIMIT](../limit/index) cannot be used. This restriction was lifted in [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) and both clauses can be used with multiple-table updates. An `UPDATE` can also reference tables which are located in different databases; see [Identifier Qualifiers](../identifier-qualifiers/index) for the syntax. `where_condition` is an expression that evaluates to true for each row to be updated. `table_references` and `where_condition` are as specified as described in [SELECT](../select/index). For single-table updates, assignments are evaluated in left-to-right order, while for multi-table updates, there is no guarantee of a particular order. If the `SIMULTANEOUS_ASSIGNMENT` [sql\_mode](../sql-mode/index) (available from [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/)) is set, UPDATE statements evaluate all assignments simultaneously. You need the `UPDATE` privilege only for columns referenced in an `UPDATE` that are actually updated. You need only the [SELECT](../select/index) privilege for any columns that are read but not modified. See [GRANT](../grant/index). The `UPDATE` statement supports the following modifiers: * If you use the `LOW_PRIORITY` keyword, execution of the `UPDATE` is delayed until no other clients are reading from the table. This affects only storage engines that use only table-level locking (MyISAM, MEMORY, MERGE). See [HIGH\_PRIORITY and LOW\_PRIORITY clauses](../high_priority-and-low_priority-clauses/index) for details. * If you use the `IGNORE` keyword, the update statement does not abort even if errors occur during the update. Rows for which duplicate-key conflicts occur are not updated. Rows for which columns are updated to values that would cause data conversion errors are updated to the closest valid values instead. ### PARTITION See [Partition Pruning and Selection](../partition-pruning-and-selection/index) for details. ### FOR PORTION OF **MariaDB starting with [10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/)**See [Application Time Periods - Updating by Portion](../application-time-periods/index#updating-by-portion). ### UPDATE Statements With the Same Source and Target **MariaDB starting with [10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/)**From [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/), UPDATE statements may have the same source and target. For example, given the following table: ``` DROP TABLE t1; CREATE TABLE t1 (c1 INT, c2 INT); INSERT INTO t1 VALUES (10,10), (20,20); ``` Until [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), the following UPDATE statement would not work: ``` UPDATE t1 SET c1=c1+1 WHERE c2=(SELECT MAX(c2) FROM t1); ERROR 1093 (HY000): Table 't1' is specified twice, both as a target for 'UPDATE' and as a separate source for data ``` From [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/), the statement executes successfully: ``` UPDATE t1 SET c1=c1+1 WHERE c2=(SELECT MAX(c2) FROM t1); SELECT * FROM t1; +------+------+ | c1 | c2 | +------+------+ | 10 | 10 | | 21 | 20 | +------+------+ ``` Example ------- Single-table syntax: ``` UPDATE table_name SET column1 = value1, column2 = value2 WHERE id=100; ``` Multiple-table syntax: ``` UPDATE tab1, tab2 SET tab1.column1 = value1, tab1.column2 = value2 WHERE tab1.id = tab2.id; ``` See Also -------- * [How IGNORE works](../ignore/index) * [SELECT](../select/index) * [ORDER BY](../order-by/index) * [LIMIT](../limit/index) * [Identifier Qualifiers](../identifier-qualifiers/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Optimizer Quality Optimizer Quality ================= Generating the Queries ---------------------- As of Nov 2010, there are 5 primary SQL grammars available for testing the Optimizer: * `optimizer_nosubquery.yy` generates random queries with no subselects, with up to 3-way join and with various SQL clauses such as aggregates, GROUP BY , HAVING, LIMIT; * `optimizer_subquery.yy` generates queries with subselects with up to 2 levels of nesting. Subqueries are placed in various locations, such as in the `SELECT` list, in the `ON` clause, etc. Aggregates, LIMIT, HAVING, etc. are used if allowed by the server; * `optimizer_subquery.yy` generates outer joins of various depths; * `range_optimizer.yy` tests the range optimizer by joinging several tables and generating various conditions on which range optimization is likely to be applied; * `range_optimizer2.yy` tests the range optimizer by generating single-table queries that contain a lot of range-optimizable clauses. Avoiding joins allows the single table to be arbitrarily large, this allowing for more interesting range overlaps; Validating the Results ---------------------- As of Nov 2010, the RQG has two primary modes for validating the results: * by using a reference implementation. This can be a PostgreSQL, JavaDB or another version or flavor of MySQL/Maria/Drizzle. Testing this way requires trusting external software that is not under our control. Also, it is sometimes difficult to determine which implementation has returned the correct result. Technically, 3 implementations can "vote" as to which is the correct result, but this is not reliable if the implementations all derive from one another. * by executing the generated query using a different execution plan. This is usually achieved by disabling particular optimizations and thus "downgrading" the plan to a more basic, presumed stable one. It is assumed that a nested-loop-join that takes no advantage of indexes would always provide the correct result. The advantage of this approach is that there is no need for a reference implementation and the source of the wrong result can be obtained by diffing the original and the downgraded execution plan. In addition to result set validation, there is a module which executes each generated `SELECT` in various contexts, such as as part of a union, stored procedure, trigger, etc. and makes sure that the query returns a correct result. This is most often used for testing subselects. Running a Complete Test Cycle ----------------------------- A test cycle is described in a configuration file called the CC file. The CC file contains a list of mysqld options to use, the list of grammars to use and other settings (e.g. Engines, table sizes, etc.). The testing framework will then take a random permutation from the settings described in the file and run them as a RQG test for a predefined time, such as 10 minutes. This is repeated up to 100 times, each with a different random permutation. The PRNG seed for each run will also be different, so different queries will be generated for each run, in addition to using different mysqld options, engine, etc. By default, all cycles include MyISAM, Aria and InnoDB, and some percentage are run under Valgrind. Cycles run with both NULL and NOT NULL fields and with and without simple views. ### Configuration for Join Cache Testing `outer_join_with_cache` is always ON. ``--`join_cache_level` varies from 0 to 8. ``--`join_buffer_size` varies between 1, 100, 1K, 10K and 100K. The `optimizer_no_subquery.yy`, `outer_join.yy` and `range_access.yy` grammars are used. Once semijoin is stable, join\_cache + semijoin will be tested with `optimizer_subquery.yy`. ### Configuration for MRR/ICP/DS-MRR-CPK Testing ``--`optimizer_use_mrr` is ON, `mrr_sort_keys` is both ON and OFF, `index_condition_pushdown` is both ON and OFF, `join_cache_level` is between 0 and 8, `join_buffer_size` and `mrr_buffer_size` are 1, 100, 1K, 10K and 100K. `optimizer_no_subquery.yy`, `outer_join.yy`, `range_access.yy` and `range_access2.yy` grammars are used. ### Configuration for Subquery Testing The `optimizer_no_subquery.yy` grammar is used. Each individual `optimizer_switch` related to subquery optimization may be disabled so that the "second best" plan is generated. #### Testing [MWL#89](http://askmonty.org/worklog/?tid=89) When testing [MWL#89](http://askmonty.org/worklog/?tid=89), the following `optimizer_switch` are used: `in_to_exists=ON,materialization=OFF`, `in_to_exists=OFF,materialization=ON` and `in_to_exists=ON,materialization=ON`. In addition `semijoin` is always OFF to force more queries to use materialization/in\_to\_exists. `subquery_cache` is OFF to prevent subquery cache bugs from showing up during the test. See Also -------- * [RQG Documentation](http://github.com/RQG/RQG-Documentation/wiki/Category:RandomQueryGenerator) * [RQG Performance Comparisons](../rqg-performance-comparisons/index) * [RQG Extensions for MariaDB Features](../rqg-extensions-for-mariadb-features/index) * [QA Tools](../qa-tools/index) * [Worklog Quality Checklist Template](../worklog-quality-checklist-template/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb TRUNCATE TABLE TRUNCATE TABLE ============== Syntax ------ ``` TRUNCATE [TABLE] tbl_name [WAIT n | NOWAIT] ``` Description ----------- `TRUNCATE TABLE` empties a table completely. It requires the `DROP` privilege. See [GRANT](../grant/index). `tbl_name` can also be specified in the form `db_name`.`tbl_name` (see [Identifier Qualifiers](../identifier-qualifiers/index)). Logically, `TRUNCATE TABLE` is equivalent to a [DELETE](../delete/index) statement that deletes all rows, but there are practical differences under some circumstances. `TRUNCATE TABLE` will fail for an [InnoDB table](../innodb/index) if any FOREIGN KEY constraints from other tables reference the table, returning the error: ``` ERROR 1701 (42000): Cannot truncate a table referenced in a foreign key constraint ``` Foreign Key constraints between columns in the same table are permitted. For an InnoDB table, if there are no `FOREIGN KEY` constraints, InnoDB performs fast truncation by dropping the original table and creating an empty one with the same definition, which is much faster than deleting rows one by one. The [AUTO\_INCREMENT](../auto_increment/index) counter is reset by `TRUNCATE TABLE`, regardless of whether there is a `FOREIGN KEY` constraint. The count of rows affected by `TRUNCATE TABLE` is accurate only when it is mapped to a `DELETE` statement. For other storage engines, `TRUNCATE TABLE` differs from `DELETE` in the following ways: * Truncate operations drop and re-create the table, which is much faster than deleting rows one by one, particularly for large tables. * Truncate operations cause an implicit commit. * Truncation operations cannot be performed if the session holds an active table lock. * Truncation operations do not return a meaningful value for the number of deleted rows. The usual result is "0 rows affected," which should be interpreted as "no information." * As long as the table format file `tbl_name.frm` is valid, the table can be re-created as an empty table with `TRUNCATE TABLE`, even if the data or index files have become corrupted. * The table handler does not remember the last used [AUTO\_INCREMENT](../auto_increment/index) value, but starts counting from the beginning. This is true even for MyISAM and InnoDB, which normally do not reuse sequence values. * When used with partitioned tables, `TRUNCATE TABLE` preserves the partitioning; that is, the data and index files are dropped and re-created, while the partition definitions (.par) file is unaffected. * Since truncation of a table does not make any use of `DELETE`, the `TRUNCATE` statement does not invoke `ON DELETE` triggers. * `TRUNCATE TABLE` will only reset the values in the [Performance Schema summary tables](../list-of-performance-schema-tables/index) to zero or null, and will not remove the rows. For the purposes of binary logging and [replication](../replication/index), `TRUNCATE TABLE` is treated as [DROP TABLE](../drop-table/index) followed by [CREATE TABLE](../create-table/index) (DDL rather than DML). `TRUNCATE TABLE` does not work on [views](../views/index). Currently, `TRUNCATE TABLE` drops all historical records from a [system-versioned table](../system-versioned-tables/index). **MariaDB starting with [10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/)**#### WAIT/NOWAIT Set the lock wait timeout. See [WAIT and NOWAIT](../wait-and-nowait/index). ### Oracle-mode [Oracle-mode](../sql_modeoracle/index) from [MariaDB 10.3](../what-is-mariadb-103/index) permits the optional keywords REUSE STORAGE or DROP STORAGE to be used. ``` TRUNCATE [TABLE] tbl_name [{DROP | REUSE} STORAGE] [WAIT n | NOWAIT] ``` These have no effect on the operation. ### Performance `TRUNCATE TABLE` is faster than [DELETE](delete-table), because it drops and re-creates a table. With [InnoDB](../innodb/index), `TRUNCATE TABLE` is slower if [innodb\_file\_per\_table=ON](../innodb-system-variables/index#innodb_file_per_table) is set (the default). This is because `TRUNCATE TABLE` unlinks the underlying tablespace file, which can be an expensive operation. See [MDEV-8069](https://jira.mariadb.org/browse/MDEV-8069) for more details. The performance issues with [innodb\_file\_per\_table=ON](../innodb-system-variables/index#innodb_file_per_table) can be exacerbated in cases where the [InnoDB buffer pool](../innodb-buffer-pool/index) is very large and [innodb\_adaptive\_hash\_index=ON](../innodb-system-variables/index#innodb_adaptive_hash_index) is set. In that case, using [DROP TABLE](../drop-table/index) followed by [CREATE TABLE](../create-table/index) instead of `TRUNCATE TABLE` may perform better. Setting [innodb\_adaptive\_hash\_index=OFF](../innodb-system-variables/index#innodb_adaptive_hash_index) (it defaults to ON before [MariaDB 10.5](../what-is-mariadb-105/index)) can also help. In [MariaDB 10.2](../what-is-mariadb-102/index) only, from [MariaDB 10.2.19](https://mariadb.com/kb/en/mariadb-10219-release-notes/), this performance can also be improved by setting [innodb\_safe\_truncate=OFF](../innodb-system-variables/index#innodb_safe_truncate). See [MDEV-9459](https://jira.mariadb.org/browse/MDEV-9459) for more details. Setting [innodb\_adaptive\_hash\_index=OFF](../innodb-system-variables/index#innodb_adaptive_hash_index) can also improve `TRUNCATE TABLE` performance in general. See [MDEV-16796](https://jira.mariadb.org/browse/MDEV-16796) for more details. See Also -------- * [TRUNCATE function](../truncate/index) * [innodb\_safe\_truncate](../innodb-system-variables/index#innodb_safe_truncate) system variable * [Oracle mode from MariaDB 10.3](../sql_modeoracle-from-mariadb-103/index#simple-syntax-compatibility) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DROP USER DROP USER ========= Syntax ------ ``` DROP USER [IF EXISTS] user_name [, user_name] ... ``` Description ----------- The `DROP USER` statement removes one or more MariaDB accounts. It removes privilege rows for the account from all grant tables. To use this statement, you must have the global [CREATE USER](../grant/index#create-user) privilege or the [DELETE](../grant/index#table-privileges) privilege for the mysql database. Each account is named using the same format as for the `CREATE USER` statement; for example, `'jeffrey'@'localhost'`. If you specify only the user name part of the account name, a host name part of `'%'` is used. For additional information about specifying account names, see [CREATE USER](../create-user/index). Note that, if you specify an account that is currently connected, it will not be deleted until the connection is closed. The connection will not be automatically closed. If any of the specified user accounts do not exist, `ERROR 1396 (HY000)` results. If an error occurs, `DROP USER` will still drop the accounts that do not result in an error. Only one error is produced for all users which have not been dropped: ``` ERROR 1396 (HY000): Operation DROP USER failed for 'u1'@'%','u2'@'%' ``` Failed `CREATE` or `DROP` operations, for both users and roles, produce the same error code. #### IF EXISTS If the `IF EXISTS` clause is used, MariaDB will return a note instead of an error if the user does not exist. Examples -------- ``` DROP USER bob; ``` `IF EXISTS`: ``` DROP USER bob; ERROR 1396 (HY000): Operation DROP USER failed for 'bob'@'%' DROP USER IF EXISTS bob; Query OK, 0 rows affected, 1 warning (0.00 sec) SHOW WARNINGS; +-------+------+---------------------------------------------+ | Level | Code | Message | +-------+------+---------------------------------------------+ | Note | 1974 | Can't drop user 'bob'@'%'; it doesn't exist | +-------+------+---------------------------------------------+ ``` See Also -------- * [CREATE USER](../create-user/index) * [ALTER USER](../alter-user/index) * [GRANT](../grant/index) * [SHOW CREATE USER](../show-create-user/index) * [mysql.user table](../mysqluser-table/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DROP TABLESPACE DROP TABLESPACE =============== The `DROP TABLESPACE` statement is not supported by MariaDB. It was originally inherited from MySQL NDB Cluster. In MySQL 5.7 and later, the statement is also supported for InnoDB. However, MariaDB has chosen not to include that specific feature. See [MDEV-19294](https://jira.mariadb.org/browse/MDEV-19294) for more information. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Migrating to MariaDB from SQL Server Migrating to MariaDB from SQL Server ===================================== This section is a guide to help you migrate from SQL Server to MariaDB. This includes a general understanding of MariaDB, information to help plan the migration, and differences in the configuration and syntax. | Title | Description | | --- | --- | | [Understanding MariaDB Architecture](../understanding-mariadb-architecture/index) | An overview of MariaDB server architecture, especially where it differs from SQL Server. | | [SQL Server Features Not Available in MariaDB](../sql-server-features-not-available-in-mariadb/index) | List of SQL Server features not available in MariaDB. | | [SQL Server Features Implemented Differently in MariaDB](../sql-server-features-implemented-differently-in-mariadb/index) | List of SQL Server features that MariaDB implements in a different way. | | [MariaDB Features Not Available in SQL Server](../mariadb-features-not-available-in-sql-server/index) | List of MariaDB features not available in SQL Server. | | [Setting Up MariaDB for Testing for SQL Server Users](../setting-up-mariadb-for-testing-for-sql-server-users/index) | Hints for SQL Server users to setup MariaDB for testing. | | [Syntax Differences between MariaDB and SQL Server](../syntax-differences-between-mariadb-and-sql-server/index) | MariaDB syntax hints for SQL Server users. | | [SQL Server and MariaDB Types Comparison](../sql-server-and-mariadb-types-comparison/index) | Comparison tables between SQL Server types and MariaDB types. | | [MariaDB Transactions and Isolation Levels for SQL Server Users](../mariadb-transactions-and-isolation-levels-for-sql-server-users/index) | How MariaDB transactions and isolation levels differ from SQL Server. | | [MariaDB Authorization and Permissions for SQL Server Users](../mariadb-authorization-and-permissions-for-sql-server-users/index) | MariaDB handles users and permissions quite differently to SQL Server. | | [Repairing MariaDB Tables for SQL Server Users](../repairing-mariadb-tables-for-sql-server-users/index) | MariaDB table repair explained to SQL Server users. | | [MariaDB Backups Overview for SQL Server Users](../mariadb-backups-overview-for-sql-server-users/index) | An overview of MariaDB backup tools and techniques for SQL Server users. | | [MariaDB Replication Overview for SQL Server Users](../mariadb-replication-overview-for-sql-server-users/index) | An overview of MariaDB replication types for SQL Server users. | | [Moving Data Between SQL Server and MariaDB](../moving-data-between-sql-server-and-mariadb/index) | Information and some advice on how to import SQL Server data into MariaDB. | | [SQL\_MODE=MSSQL](../sql_modemssql/index) | Microsoft SQL Server compatibility mode. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema COLUMNS Table Information Schema COLUMNS Table ================================ The [Information Schema](../information_schema/index) `COLUMNS` table provides information about columns in each table on the server. It contains the following columns: | Column | Description | Introduced | | --- | --- | --- | | `TABLE_CATALOG` | Always contains the string 'def'. | | | `TABLE_SCHEMA` | Database name. | | | `TABLE_NAME` | Table name. | | | `COLUMN_NAME` | Column name. | | | `ORDINAL_POSITION` | Column position in the table. Can be used for ordering. | | | `COLUMN_DEFAULT` | Default value for the column. From [MariaDB 10.2.7](https://mariadb.com/kb/en/mariadb-1027-release-notes/), literals are quoted to distinguish them from expressions. `NULL` means that the column has no default. In [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) and earlier, no quotes were used for any type of default and `NULL` can either mean that there is no default, or that the default column value is `NULL`. | | | `IS_NULLABLE` | Whether the column can contain `NULL`s. | | | `DATA_TYPE` | The column's [data type](../data-types/index). | | | `CHARACTER_MAXIMUM_LENGTH` | Maximum length. | | | `CHARACTER_OCTET_LENGTH` | Same as the `CHARACTER_MAXIMUM_LENGTH` except for multi-byte [character sets](../data-types-character-sets-and-collations/index). | | | `NUMERIC_PRECISION` | For numeric types, the precision (number of significant digits) for the column. `NULL` if not a numeric field. | | | `NUMERIC_SCALE` | For numeric types, the scale (significant digits to the right of the decimal point). NULL if not a numeric field. | | | `DATETIME_PRECISION` | Fractional-seconds precision, or `NULL` if not a [time data type](../date-and-time-data-types/index). | | | `CHARACTER_SET_NAME` | [Character set](../data-types-character-sets-and-collations/index) if a non-binary [string data type](../string-data-types/index), otherwise NULL. | | | `COLLATION_NAME` | [Collation](../data-types-character-sets-and-collations/index) if a non-binary [string data type](../string-data-types/index), otherwise NULL. | | | `COLUMN_TYPE` | Column definition, a MySQL and MariaDB extension. | | | `COLUMN_KEY` | Index type. `PRI` for primary key, `UNI` for unique index, `MUL` for multiple index. A MySQL and MariaDB extension. | | | `EXTRA` | Additional information about a column, for example whether the column is an [invisible column](../invisible-columns/index), or, from [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/), `WITHOUT SYSTEM VERSIONING` if the table is not a [system-versioned table](../system-versioned-tables/index). A MySQL and MariaDB extension. | | | `PRIVILEGES` | Which privileges you have for the column. A MySQL and MariaDB extension. | | | `COLUMN_COMMENT` | Column comments. | | | `IS_GENERATED` | Indicates whether the column value is [generated (virtual, or computed)](../virtual-computed-columns/index). Can be `ALWAYS` or `NEVER`. | [MariaDB 10.2.5](https://mariadb.com/kb/en/mariadb-1025-release-notes/) | | `GENERATION_EXPRESSION` | The expression used for computing the column value in a [generated (virtual, or computed)](../virtual-computed-columns/index) column. | [MariaDB 10.2.5](https://mariadb.com/kb/en/mariadb-1025-release-notes/) | It provides information similar to, but more complete, than `[SHOW COLUMNS](../show-columns/index)` and `[mysqlshow](../mysqlshow/index)`. Examples -------- ``` SELECT * FROM information_schema.COLUMNS\G ... *************************** 9. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: test TABLE_NAME: t2 COLUMN_NAME: j ORDINAL_POSITION: 1 COLUMN_DEFAULT: NULL IS_NULLABLE: YES DATA_TYPE: longtext CHARACTER_MAXIMUM_LENGTH: 4294967295 CHARACTER_OCTET_LENGTH: 4294967295 NUMERIC_PRECISION: NULL NUMERIC_SCALE: NULL DATETIME_PRECISION: NULL CHARACTER_SET_NAME: utf8mb4 COLLATION_NAME: utf8mb4_bin COLUMN_TYPE: longtext COLUMN_KEY: EXTRA: PRIVILEGES: select,insert,update,references COLUMN_COMMENT: IS_GENERATED: NEVER GENERATION_EXPRESSION: NULL ... ``` ``` CREATE TABLE t ( s1 VARCHAR(20) DEFAULT 'ABC', s2 VARCHAR(20) DEFAULT (concat('A','B')), s3 VARCHAR(20) DEFAULT ("concat('A','B')"), s4 VARCHAR(20), s5 VARCHAR(20) DEFAULT NULL, s6 VARCHAR(20) NOT NULL, s7 VARCHAR(20) DEFAULT 'NULL' NULL, s8 VARCHAR(20) DEFAULT 'NULL' NOT NULL ); SELECT table_name, column_name, ordinal_position, column_default, column_default IS NULL FROM information_schema.COLUMNS WHERE table_schema=DATABASE() AND TABLE_NAME='t'; ``` From [MariaDB 10.2.7](https://mariadb.com/kb/en/mariadb-1027-release-notes/): ``` +------------+-------------+------------------+-----------------------+------------------------+ | table_name | column_name | ordinal_position | column_default | column_default IS NULL | +------------+-------------+------------------+-----------------------+------------------------+ | t | s1 | 1 | 'ABC' | 0 | | t | s2 | 2 | concat('A','B') | 0 | | t | s3 | 3 | 'concat(''A'',''B'')' | 0 | | t | s4 | 4 | NULL | 0 | | t | s5 | 5 | NULL | 0 | | t | s6 | 6 | NULL | 1 | | t | s7 | 7 | 'NULL' | 0 | | t | s8 | 8 | 'NULL' | 0 | +------------+-------------+------------------+-----------------------+------------------------+ ``` In the results above, the two single quotes in `concat(''A'',''B'')` indicate an escaped single quote - see [string-literals](../string-literals/index). Note that while [mysql-command-line-client](../mysql-command-line-client/index) appears to show the same default value for columns `s5` and `s6`, the first is a 4-character string "NULL", while the second is the SQL NULL value. [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) and before: ``` +------------+-------------+------------------+-----------------+------------------------+ | table_name | column_name | ordinal_position | column_default | column_default IS NULL | +------------+-------------+------------------+-----------------+------------------------+ | t | s1 | 1 | ABC | 0 | | t | s2 | 2 | concat('A','B') | 0 | | t | s3 | 3 | concat('A','B') | 0 | | t | s4 | 4 | NULL | 1 | | t | s5 | 5 | NULL | 1 | | t | s6 | 6 | NULL | 1 | | t | s7 | 7 | NULL | 0 | | t | s8 | 8 | NULL | 0 | +------------+-------------+------------------+-----------------+------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb MariaDB Audit Plugin - Log Settings MariaDB Audit Plugin - Log Settings =================================== Events that are logged by the MariaDB Audit Plugin are grouped generally into different types: connect, query, and table events. To log based on these types of events, set the variable, [server\_audit\_events](../server_audit-system-variables/index#server_audit_events) to `CONNECT`, `QUERY`, or `TABLE`. To have the Audit Plugin log more than one type of event, put them in a comma-separated list like so: ``` SET GLOBAL server_audit_events = 'CONNECT,QUERY,TABLE'; ``` You can put the equivalent of this in the configuration file like so: ``` [mysqld] ... server_audit_events=connect,query ``` By default, logging is set to `OFF`. To enable it, set the [server\_audit\_logging](../server_audit-system-variables/index#server_audit_logging) variable to `ON`. Note that if the [query cache](../query-cache/index) is enabled, and a query is returned from the query cache, no `TABLE` records will appear in the log since the server didn't open or access any tables and instead relied on the cached results. So you may want to disable query caching. There are actually a few types of events that may be logged, not just the three common ones mentioned above. A full list of related system variables is detailed on the [Server\_Audit System Variables](../server_audit-system-variables/index) page, and status variables on the [Server\_Audit Status Variables](../server_audit-status-variables/index) page of this documentation. Some of the major ones are highlighted below: | Type | Description | | --- | --- | | CONNECT | Connects, disconnects and failed connects—including the error code | | | QUERY | Queries executed and their results in plain text, including failed queries due to syntax or permission errors | | | TABLE | Tables affected by query execution | | | QUERY\_DDL | Similar to `QUERY`, but filters only DDL-type queries (`CREATE`, `ALTER`, `DROP`, `RENAME` and `TRUNCATE`). There are some exceptions however. `RENAME USER` is not logged, while `CREATE/DROP [PROCEDURE / FUNCTION / USER]` are only logged from [MariaDB 10.2.38](https://mariadb.com/kb/en/mariadb-10238-release-notes/), [MariaDB 10.3.29](https://mariadb.com/kb/en/mariadb-10329-release-notes/), [MariaDB 10.4.22](https://mariadb.com/kb/en/mariadb-10422-release-notes/), [MariaDB 10.5.13](https://mariadb.com/kb/en/mariadb-10513-release-notes/) and [MariaDB 10.6.5](https://mariadb.com/kb/en/mariadb-1065-release-notes/). In earlier versions they are not logged. See [MDEV-23457](https://jira.mariadb.org/browse/MDEV-23457). | | QUERY\_DML | Similar to `QUERY`, but filters only DML-type queries (`DO`, `CALL`, `LOAD DATA/XML`, `DELETE`, `INSERT`, `SELECT`, `UPDATE`, `HANDLER` and `REPLACE` statements) | | QUERY\_DML\_NO\_SELECT | Similar to `QUERY_DML`, but doesn't log SELECT queries. (since version 1.4.4) (`DO`, `CALL`, `LOAD DATA/XML`, `DELETE`, `INSERT`, `UPDATE`, `HANDLER` and `REPLACE` statements) | | QUERY\_DCL | Similar to `QUERY`, but filters only DCL-type queries (`CREATE USER`, `DROP USER`, `RENAME USER`, `GRANT`, `REVOKE` and `SET PASSWORD` statements) | Since there are other types of queries besides DDL and DML, using the `QUERY_DDL` and `QUERY_DML` options together is not equivalent to using `QUERY`. Starting in version 1.3.0 of the Audit Plugin, there is the `QUERY_DCL` option for logging DCL types of queries (e.g., `GRANT` and `REVOKE` statements). In the same version, the [server\_audit\_query\_log\_limit](../server_audit-system-variables/index#server_audit_query_log_limit) variable was added to be able to set the length of a log record. Previously, a log entry would be truncated due to long query strings. Logging Connect Events ---------------------- If the Audit Plugin has been configured to log connect events, it will log connects, disconnects, and failed connects. For a failed connection, the log includes the error code. It's possible to define a list of users for which events can be excluded or included for tracing their database activities. This list will be ignored, though, for the loggings of connect events. This is because auditing standards distinguish between technical and physical users. Connects need to be logged for all types of users; access to objects need to be logged only for physical users. Logging Query Events -------------------- If `QUERY`, `QUERY_DDL`, `QUERY_DML`, `QUERY_DML_NO_SELECT`, and/or `QUERY_DCL` event types are enabled, then the corresponding types of queries that are executed will be logged for defined users. The queries will be logged exactly as they are executed, in plain text. This is a security vulnerability: anyone who has access to the log files will be able to read the queries. So make sure that only trusted users have access to the log files and that the files are in a protected location. An alternative is to use `TABLE` event type instead of the query-related event types. Queries are also logged if they cannot be executed, if they're unsuccessful. For example, a query will be logged because of a syntax error or because the user doesn't have the privileges necessary to access an object. These queries can be parsed by the error code that's provided in the log. You may find failed queries to be more interesting: They can reveal problems with applications (e.g., an SQL statement in an application that doesn't match the current schema). They can also reveal if a malicious user is guessing at the names of tables and columns to try to get access to data. Below is an example in which a user attempts to execute an `UPDATE` statement on a table for which he does not have permission: ``` UPDATE employees SET salary = salary * 1.2 WHERE emp_id = 18236; ERROR 1142 (42000): UPDATE command denied to user 'bob'@'localhost' for table 'employees' ``` Looking in the Audit Plugin log (`server_audit.log`) for this entry, you can see the following entry: ``` 20170817 11:07:18,ip-172-30-0-38,bob,localhost,15,46,QUERY,company, 'UPDATE employees SET salary = salary * 1.2 WHERE emp_id = 18236',1142 ``` This log entry would be on one line, but it's reformatted here for better rendering. Looking at this log entry, you can see the date and time of the query, followed by the server host, the user and host for the account. Next is the connection and query identification numbers (i.e., `15` and `46`). After the log event type (i.e., `QUERY`), the database name (i.e., `company`), the query, and the error number is recorded. Notice that the last value in the log entry is `1142`. That's the error number for the query. To find failed queries, you would look for two elements: the notation indicating that it's a `QUERY` entry, and the last value for the entry. If the query is successful, the value will be `0`. ### Queries Not Included in Subordinate Query Event Types Note that the `QUERY` event type will log queries that are not included in any of the subordinate `QUERY_*` event types, such as: * CREATE FUNCTION * DROP FUNCTION * CREATE PROCEDURE * DROP PROCEDURE * SET * CHANGE MASTER TO * FLUSH * KILL * CHECK * OPTIMIZE * LOCK * UNLOCK * ANALYZE * INSTALL PLUGIN * UNINSTALL PLUGIN * INSTALL SONAME * UNINSTALL SONAME * EXPLAIN Logging Table Events -------------------- MariaDB has the ability to record table events in the logs—this is not a feature of MySQL. This feature is the only way to log which tables have been accessed through a view, a stored procedure, a stored function, or a trigger. Without this feature, a log entry for a query shows only the view, stored procedure or function used, not the underlying tables. Of course, you could create a custom application to parse each query executed to find the SQL statements used and the tables accessed, but that would be a drain on system resources. Table event logging is much simpler: it adds a line to the log for each table accessed, without any parsing. It includes notes as to whether it was a read or a write. If you want to monitor user access to specific databases or tables (e.g., `mysql.user`), you can search the log for them. Then if you want to see a query which accessed a certain table, the audit log entry will include the query identificaiton number. You can use it to search the same log for the query entry. This can be useful when searching a log containing tens of thousands of entries. Because of the `TABLE` option, you may disable query logging and still know who accessed which tables. You might want to disable `QUERY` event logging to prevent sensitive data from being logged. Since *table* event logging will log who accessed which table, you can still watch for malicious activities with the log. This is often enough to fulfill auditing requirements. Below is an example with both `TABLE` and `QUERY` events logging. For this scenario, suppose there is a [VIEW](../create-view/index) in which columns are selected from a few tables in a `company` database. The underlying tables are related to sensitive employee information, in particular salaries. Although we may have taken precautions to ensure that only certain user accounts have access to those tables, we will monitor the Audit Plugin logs for anyone who queries them—directly or indirectly through a view. ``` 20170817 16:04:33,ip-172-30-0-38,root,localhost,29,913,READ,company,employees, 20170817 16:04:33,ip-172-30-0-38,root,localhost,29,913,READ,company,employees_salaries, 20170817 16:04:33,ip-172-30-0-38,root,localhost,29,913,READ,company,ref_job_titles, 20170817 16:04:33,ip-172-30-0-38,root,localhost,29,913,READ,company,org_departments, 20170817 16:04:33,ip-172-30-0-38,root,localhost,29,913,QUERY,company, 'SELECT * FROM employee_pay WHERE title LIKE \'%Executive%\' OR title LIKE \'%Manager%\'',0 ``` Although the user executed only one [SELECT](../select/index) statement, there are multiple entries to the log: one for each table accessed and one entry for the query on the view, (i.e., `employee_pay`). We know primarily this is all for one query because they all have the same connection and query identification numbers (i.e., `29` and `913`). Logging User Activities ----------------------- The Audit Plugin will log the database activities of all users, or only the users that you specify. A database activity is defined as a *query* event or a *table* event. *Connect* events are logged for all users. You may specify users to include in the log with the `server_audit_incl_users` variable or exclude users with the `server_audit_excl_users` variable. This can be useful if you would like to log entries, but are not interested in entries from trusted applications and would like to exclude them from the logs. You would typically use either the `server_audit_incl_users` variable or the `server_audit_excl_users` variable. You may, though, use both variables. If a username is inadvertently listed in both variables, database activities for that user will be logged because `server_audit_incl_users` takes priority. Although MariaDB considers a user as the combination of the username and hostname, the Audit Plugin logs only based on the username. MariaDB uses both the username and hostname so as to grant privileges relevant to the location of the user. Privileges are not relevant though for tracing the access to database objects. The host name is still recorded in the log, but logging is not determined based on that information. The following example shows how to add a new username to the `server_audit_incl_users` variable without removing previous usernames: ``` SET GLOBAL server_audit_incl_users = CONCAT(@@global.server_audit_incl_users, ',Maria'); ``` Remember to add also any new users to be included in the logs to the same variable in MariaDB configuration file. Otherwise, when the server restarts it will discard the setting. Excluding or Including Users ---------------------------- By default events from all users are logged, but certain users can be excluded from logging by using the [server\_audit\_excl\_users](../server_audit-system-variables/index#server_audit_excl_users) variable. For example, to exclude users *valerianus* and *rocky* from having their events logged: ``` server_audit_excl_users=valerianus,rocky ``` This option is primarily used to exclude the activities of trusted applications. Alternatively, [server\_audit\_incl\_users](../server_audit-system-variables/index#server_audit_incl_users) can be used to specifically include users. Both variables can be used, but if a user appears on both lists, [server\_audit\_incl\_users](../server_audit-system-variables/index#server_audit_incl_users) has a higher priority, and their activities will be logged. Note that `CONNECT` events are always logged for all users, regardless of these two settings. Logging is also based on username only, not the username and hostname combination that MariaDB uses to determine privileges. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Automated MariaDB Deployment and Administration Automated MariaDB Deployment and Administration ================================================ It is possible to automate the deployment and administration of MariaDB servers and related technologies by using third-party software. This is especially useful when deploying and administering a large number of servers, but it also has benefits for small environments. This section describes some automation technologies from MariaDB users perspective. | Title | Description | | --- | --- | | [Why to Automate MariaDB Deployments and Management](../why-to-automate-mariadb-deployments-and-management/index) | The reasons to automate deployment and configuration of MariaDB. | | [A Comparison Between Automation Systems](../a-comparison-between-automation-systems/index) | A summary of the differences between automation systems, to help evaluating them. | | [Ansible and MariaDB](../ansible-and-mariadb/index) | General information and hints on automating MariaDB deployments with Ansible. | | [Puppet and MariaDB](../automated-mariadb-deployment-and-administration-puppet-and-mariadb/index) | General information on how to automate MariaDB deployments and configuration with Puppet. | | [Vagrant and MariaDB](../vagrant-and-mariadb/index) | General information on how to setup development MariaDB servers with Vagrant. | | [Docker and MariaDB](../docker-and-mariadb/index) | General information on how to setup MariaDB containers with Docker. | | [Kubernetes and MariaDB](../kubernetes-and-mariadb/index) | General information and tips on deploying MariaDB on Kubernetes. | | [Automating Upgrades with MariaDB.Org Downloads REST API](../automating-upgrades-with-mariadborg-downloads-rest-api/index) | How to use MariaDB.Org Downloads APIs to automate upgrades. | | [HashiCorp Vault and MariaDB](../hashicorp-vault-and-mariadb/index) | An overview of secret management with Vault for MariaDB users. | | [Orchestrator Overview](../orchestrator-overview/index) | Using Orchestrator to automate failover and replication operations. | | [Rotating Logs on Unix and Linux](../rotating-logs-on-unix-and-linux/index) | Rotating logs on Unix and Linux with logrotate. | | [Automating MariaDB Tasks with Events](../automating-mariadb-tasks-with-events/index) | Using MariaDB events for automating tasks. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql_install_db mysql\_install\_db ================== **MariaDB starting with [10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/)**From [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), `mariadb-install-db` is a symlink to `mysql_install_db`. **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), `mysql_install_db` is the symlink, and `mariadb-install-db` the binary name. **This page is for the `mysql_install_db` script for Linux/Unix only** For the Windows specific tool of similar name and purpose see [mysql\_install\_db.exe](../mysql_install_dbexe/index). The Windows version shares the common theme (creating system tables), yet has a lot of functionality specific to Windows systems, for example creating a Windows service. The Windows version does \*not\* share command line parameters with the Unix shell script. `mysql_install_db` initializes the MariaDB data directory and creates the [system tables](../system-tables/index) in the `[mysql](../the-mysql-database-tables/index)` database, if they do not exist. MariaDB uses these tables to manage [privileges](../grant/index#privilege-levels), [roles](../roles/index), and [plugins](../plugins/index). It also uses them to provide the data for the `[help](../help-command/index)` command in the `[mysql](../mysql-command-line-client/index)` client. `mysql_install_db` works by starting MariaDB Server's `mysqld` process in `[--bootstrap](../mysqld-options/index#-bootstrap)` mode and sending commands to create the [system tables](../system-tables/index) and their content. Using mysql\_install\_db ------------------------ To invoke `mysql_install_db`, use the following syntax: ``` $ mysql_install_db [options] ``` Because the MariaDB server, `mysqld`, needs to access the data directory when it runs later, you should either run `mysql_install_db` from the same account that will be used for running `mysqld` or run it as root and use the `--user` option to indicate the user name that `mysqld` will run as. It might be necessary to specify other options such as `--basedir` or `--datadir` if `mysql_install_db` does not use the correct locations for the installation directory or data directory. For example: ``` $ scripts/mysql_install_db --user=mysql \ --basedir=/opt/mysql/mysql \ --datadir=/opt/mysql/mysql/data ``` ### Options `mysql_install_db` supports the following options: | Option | Description | | --- | --- | | `--auth-root-authentication-method={normal `|` socket}` | If set to `normal`, it creates a `root@localhost` account that authenticates with the `[mysql\_native\_password](../authentication-plugin-mysql_native_password/index)` authentication plugin and that has no initial password set, which can be insecure. If set to `socket`, it creates a `root@localhost` account that authenticates with the `[unix\_socket](../authentication-plugin-unix-socket/index)` authentication plugin. Set to `socket` by default from [MariaDB 10.4](../what-is-mariadb-104/index) (see [Authentication from MariaDB 10.4](../authentication-from-mariadb-104/index)), or `normal` by default in earlier versions. Available since [MariaDB 10.1](../what-is-mariadb-101/index). | | `--auth-root-socket-user=USER` | Used with `--auth-root-authentication-method=socket`. It specifies the name of the second account to create with `[SUPER](../grant/index#global-privileges)` privileges in addition to `root`, as well as of the system account allowed to access it. Defaults to the value of `--user`. | | `--basedir=path` | The path to the MariaDB installation directory. | | `--builddir=path` | If using `--srcdir` with out-of-directory builds, you will need to set this to the location of the build directory where built files reside. | | `--cross-bootstrap` | For internal use. Used when building the MariaDB system tables on a different host than the target. | | `--datadir=path`, `--ldata=path` | The path to the MariaDB data directory. | | `--defaults-extra-file=name` | Read this file after the global files are read. Must be given as the first option. | | `--defaults-file=name` | Only read default options from the given file *name* Must be given as the first option. | | `--defaults-group-suffix=name` | In addition to the given groups, read also groups with this suffix. From [MariaDB 10.1.31](https://mariadb.com/kb/en/mariadb-10131-release-notes/), [MariaDB 10.2.13](https://mariadb.com/kb/en/mariadb-10213-release-notes/) and [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/). | | `--force` | Causes `mysql_install_db` to run even if DNS does not work. In that case, grant table entries that normally use host names will use IP addresses. | | `--no-defaults` | Don't read default options from any option file. Must be given as the first option. | | `--print-defaults` | Print the program argument list and exit. Must be given as the first option. | | `--rpm` | For internal use. This option is used by RPM files during the MariaDB installation process. | | `--skip-auth-anonymous-user` | Do not create the anonymous user. | | `--skip-name-resolve` | Uses IP addresses rather than host names when creating grant table entries. This option can be useful if your DNS does not work. | | `--skip-test-db` | Don't install the test database. | | `--srcdir=path` | For internal use. The path to the MariaDB source directory. This option uses the compiled binaries and support files within the source tree, useful for if you don't want to install MariaDB yet and just want to create the system tables. The directory under which `mysql_install_db` looks for support files such as the error message file and the file for populating the help tables. | | `--user=user_name` | The login user name to use for running `mysqld`. Files and directories created by `mysqld` will be owned by this user. You must be `root` to use this option. By default, `mysqld` runs using your current login name and files and directories that it creates will be owned by you. | | `--verbose` | Verbose mode. Print more information about what the program does. | | `--windows` | For internal use. This option is used for creating Windows distributions. | ### Option Files In addition to reading options from the command-line, `mysql_install_db` can also read options from [option files](../configuring-mariadb-with-option-files/index). If an unknown option is provided to `mysql_install_db` in an option file, then it is ignored. The following options relate to how MariaDB command-line tools handles option files. They must be given as the first argument on the command-line: | Option | Description | | --- | --- | | `--print-defaults` | Print the program argument list and exit. | | `--no-defaults` | Don't read default options from any option file. | | `--defaults-file=#` | Only read default options from the given file #. | | `--defaults-extra-file=#` | Read this file after the global files are read. | | `--defaults-group-suffix=#` | In addition to the default option groups, also read option groups with this suffix. | #### Option Groups `mysql_install_db` reads options from the following [option groups](../configuring-mariadb-with-option-files/index#option-groups) from [option files](../configuring-mariadb-with-option-files/index): | Group | Description | | --- | --- | | `[mysql_install_db]` | Options read by `mysqld_safe`, which includes both MariaDB Server and MySQL Server. | `mysql_install_db` also reads options from the following server [option groups](../configuring-mariadb-with-option-files/index#option-groups) from [option files](../configuring-mariadb-with-option-files/index): | Group | Description | | --- | --- | | `[mysqld]` | Options read by `mysqld`, which includes both MariaDB Server and MySQL Server. | | `[server]` | Options read by MariaDB Server. | | `[mysqld-X.Y]` | Options read by a specific version of `mysqld`, which includes both MariaDB Server and MySQL Server. For example, `[mysqld-5.5]`. | | `[mariadb]` | Options read by MariaDB Server. | | `[mariadb-X.Y]` | Options read by a specific version of MariaDB Server. | | `[client-server]` | Options read by all MariaDB [client programs](../clients-utilities/index) and the MariaDB Server. This is useful for options like socket and port, which is common between the server and the clients. | | `[galera]` | Options read by a galera-capable MariaDB Server. Available on systems compiled with Galera support. | Installing System Tables ------------------------ ### Installing System Tables From a Source Tree If you have just [compiled MariaDB from source](../compiling-mariadb-from-source/index), and if you want to use `mysql_install_db` from your source tree, then that can be done without having to actually install MariaDB. This is very useful if you want to test your changes to MariaDB without disturbing any existing installations of MariaDB. To do so, you would have to provide the `--srcdir` option. For example: ``` ./scripts/mysql_install_db --srcdir=. --datadir=path-to-temporary-data-dir ``` ### Installing System Tables From a Binary Tarball If you install a [binary tarball](../installing-mariadb-binary-tarballs/index) package in a non standard path, like your home directory, and if you already have a MariaDB / MySQL package installed, then you may get conflicts with the default `/etc/my.cnf`. This often results in permissions errors. One possible solution is to use the `--no-defaults` option, so that it does not read any [option files](../configuring-mariadb-with-option-files/index). For example: ``` ./scripts/mysql_install_db --no-defaults --basedir=. --datadir=data ``` Another possible solution is to use the `defaults-file` option, so that you can specify your own [option file](../configuring-mariadb-with-option-files/index). For example: ``` ./scripts/mysql_install_db --defaults-file=~/.my.cnf ``` User Accounts Created by Default -------------------------------- **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, `mysql_install_db` sets `--auth-root-authentication-method=socket` by default. When this is set, the default `root@localhost` user account is created with the ability to use two [authentication plugins](../authentication-plugins/index): * First, it is configured to try to use the `[unix\_socket](../authentication-plugin-unix-socket/index)` authentication plugin. This allows the the `root@localhost` user to login without a password via the local Unix socket file defined by the `[socket](../server-system-variables/index#socket)` system variable, as long as the login is attempted from a process owned by the operating system `root` user account. * Second, if authentication fails with the `[unix\_socket](../authentication-plugin-unix-socket/index)` authentication plugin, then it is configured to try to use the `[mysql\_native\_password](../authentication-plugin-mysql_native_password/index)` authentication plugin. The definition of the default `root@localhost` user account is: ``` CREATE USER 'root'@'localhost' IDENTIFIED VIA unix_socket OR mysql_native_password USING 'invalid'; GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION; GRANT PROXY ON ''@'%' TO 'root'@'localhost' WITH GRANT OPTION; ``` Since `mysql_install_db` sets `--auth-root-authentication-method=socket` by default, the following additional user accounts are **not** created by default: * `[email protected]` * `root@::1` * `root@${current_hostname}` However, an additional user account that is defined by the `--auth-root-socket-user` option is created. If this option is not set, then the value defaults to the value of the `--user` option. On most systems, the `--user` option will use the value of `mysql` by default, so this additional user account would be called `mysql@localhost`. The definition of this `mysql@localhost` user account is similar to the `root@localhost` user account: ``` CREATE USER 'mysql'@'localhost' IDENTIFIED VIA unix_socket OR mysql_native_password USING 'invalid'; GRANT ALL PRIVILEGES ON *.* TO 'mysql'@'localhost' WITH GRANT OPTION; ``` An invalid password is initially set for both of these user accounts. This means that before a password can be used to authenticate as either of these user accounts, the accounts must first be given a valid password by executing the `[SET PASSWORD](../set-password/index)` statement. For example, here is an example of setting the password for the `root@localhost` user account immediately after installation: ``` $ sudo yum install MariaDB-server $ sudo systemctl start mariadb $ sudo mysql ... MariaDB> SET PASSWORD = PASSWORD('XH4VmT3_jt'); ``` You may notice in the above example that the [mysql](../mysql-command-line-client/index) command-line client is executed via [sudo](https://linux.die.net/man/8/sudo). This allows the `root@localhost` user account to successfully authenticate via the [unix\_socket](../authentication-plugin-unix-socket/index) authentication plugin. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, `mysql_install_db` sets `--auth-root-authentication-method=normal` by default. When this is set, the following default accounts are created with no password: * `root@localhost` * `[email protected]` * `root@::1` * `root@${current_hostname}` The definition of the default `root@localhost` user account is: ``` CREATE USER 'root'@'localhost'; GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION; GRANT PROXY ON ''@'%' TO 'root'@'localhost' WITH GRANT OPTION; ``` The definition of the other default `root` accounts is similar. A password should be set for these user accounts immediately after installation. This can be done either by executing the `[SET PASSWORD](../set-password/index)` statement or by running `[mysql\_secure\_installation](../mysql_secure_installation/index)`. For example, here is an example of setting the password for the `root@localhost` user account immediately after installation: ``` $ sudo yum install MariaDB-server $ sudo systemctl start mariadb $ mysql -u root ... MariaDB> SET PASSWORD = PASSWORD('XH4VmT3_jt'); ``` Since `mysql_install_db` sets `--auth-root-authentication-method=normal` by default, the `--auth-root-socket-user` option is ignored by default. Troubleshooting Issues ---------------------- ### Checking the Error Log If `mysql_install_db` fails, you should examine the [error log](../error-log/index) in the data directory, which is the directory specified with `--datadir` option. This should provide a clue about what went wrong. ### Testing With mysqld You can also test that this is not a general fault of MariaDB Server by trying to start the `mysqld` process. The `[-skip-grant-tables](../mysqld-options/index#-skip-grant-tables)` option will tell it to ignore the [system tables](../system-tables/index). Enabling the [general query log](../general-query-log/index) can help you determine what queries are being run on the server. For example: ``` mysqld --skip-grant-tables --general-log ``` At this point, you can use the `[mysql](../mysql-command-line-client/index)` client to connect to the `[mysql](../the-mysql-database-tables/index)` database and look at the [system tables](../system-tables/index). For example: ``` $ /usr/local/mysql/bin/mysql -u root mysql MariaDB [mysql]> show tables ``` Using a Server Compiled With --disable-grant-options ---------------------------------------------------- The following only apply in the exceptional case that you are using a mysqld server which is configured with the `--disable-grant-options` option: `mysql_install_db` needs to invoke `mysqld` with the `--bootstrap` and `--skip-grant-tables` options. A MariaDB configured with the `--disable-grant-options` option has `--bootstrap` and `--skip-grant-tables` disabled. To handle this case, set the `MYSQLD_BOOTSTRAP` environment variable to the full path name of a mysqld server that is configured without `--disable-grant-options`. `mysql_install_db` will use that server. The test and test\_% Databases ------------------------------ When calling the `mysql_install_db` script, a new folder called `test` is created in the data directory. It only has the single `db.opt` file, which sets the client options `default-character-set` and `default-collation` only. If you run `mysql` as an anonymous user, `mysql -u''@localhost`, and look for the grants and databases you are able to work with, you will get the following: ``` SELECT current_user; +--------------+ | current_user | +--------------+ | @localhost | +--------------+ SHOW GRANTS FOR current_user; +--------------------------------------+ | Grants for @localhost | +--------------------------------------+ | GRANT USAGE ON *.* TO ``@`localhost` | +--------------------------------------+ SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | test | +--------------------+ ``` Shown are the `information_schema` as well as `test` databases that are built in databases. But looking from [SHOW GRANTS](../show-grants/index) appears to be a paradox; how can the current user see something if they don't have privileges for that? Let's go a step further. Now, use the `root`/`unix` user, which has all rights, in order to create a new database with the prefix `test_` , something like: ``` CREATE DATABASE test_electricity; ``` With the above change, a new directory will be created in the data directory. Now login again with the anonymous user and run [SHOW DATABASES](../show-databases/index): ``` SHOW DATABASES +--------------------+ | Database | +--------------------+ | information_schema | | test | | test_electricity | +--------------------+ ``` Again we are able to see the newly created database, without any rights? We have an anonymous user that has no privileges, but still can see the `test` and `test_electricity` databases. **Where does this come from?** --- Login with the `root`/`unix` user to find out all privileges that the anonymous user has: ``` SELECT * FROM mysql.user WHERE user='' AND host='localhost'\G *************************** 1. row *************************** Host: localhost User: Password: Select_priv: N Insert_priv: N Update_priv: N Delete_priv: N Create_priv: N Drop_priv: N Reload_priv: N Shutdown_priv: N Process_priv: N File_priv: N Grant_priv: N References_priv: N Index_priv: N Alter_priv: N Show_db_priv: N Super_priv: N Create_tmp_table_priv: N Lock_tables_priv: N Execute_priv: N Repl_slave_priv: N Repl_client_priv: N Create_view_priv: N Show_view_priv: N Create_routine_priv: N Alter_routine_priv: N Create_user_priv: N Event_priv: N Trigger_priv: N Create_tablespace_priv: N Delete_history_priv: N ssl_type: ssl_cipher: x509_issuer: x509_subject: max_questions: 0 max_updates: 0 max_connections: 0 max_user_connections: 0 plugin: authentication_string: password_expired: N is_role: N default_role: max_statement_time: 0.000000 ``` As seen above from the [mysql.user](../mysqluser-table/index) table, the anonymous user doesn't have any global privileges. Still, the anonymous user can see databases, so there must be a way so that anonymous user can see the `test` and `test_electricity` databases. Let's check for grants on the database level. That information can be found in the [mysql.db](../mysqldb-table/index) table. Looking at the `mysql.db` table, it already contains 2 rows created when the `mysql_install_db` script was invoked. The anonymous user has database privileges (without `grant`, `alter_routine` and `execute`) on `test` and `test_%` databases: ``` SELECT * FROM mysql.db\G *************************** 1. row *************************** Host: % Db: test User: Select_priv: Y Insert_priv: Y Update_priv: Y Delete_priv: Y Create_priv: Y Drop_priv: Y Grant_priv: N References_priv: Y Index_priv: Y Alter_priv: Y Create_tmp_table_priv: Y Lock_tables_priv: Y Create_view_priv: Y Show_view_priv: Y Create_routine_priv: Y Alter_routine_priv: N Execute_priv: N Event_priv: Y Trigger_priv: Y Delete_history_priv: Y *************************** 2. row *************************** Host: % Db: test\_% User: Select_priv: Y Insert_priv: Y Update_priv: Y Delete_priv: Y Create_priv: Y Drop_priv: Y Grant_priv: N References_priv: Y Index_priv: Y Alter_priv: Y Create_tmp_table_priv: Y Lock_tables_priv: Y Create_view_priv: Y Show_view_priv: Y Create_routine_priv: Y Alter_routine_priv: N Execute_priv: N Event_priv: Y Trigger_priv: Y Delete_history_priv: Y ``` The first row is reserved for explicit usage for the `test` database, which is automatically created with `mysql_install_db`. Since database `test_electricity` satisfies the `test_%` pattern where `test_` is a prefix, we can understand why the user has the right to work with the newly-created database. As long as records in `mysql.db` for the anonymous user exists, each new user created will have the privileges for the `test` and `test_%` databases. Other databases privileges **are not automatically granted** for the newly created user. We have to grant privileges, which will be visible in `mysql.db` table. ### Not Creating the test Database and Anonymous User If you run `mysql_install_db` with the `--skip-test-db` option, no `test` database will be created, which we can see as follows: ``` SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | +--------------------+ SELECT * FROM mysql.db; Empty set (0.001 sec) ``` Also, no anonymous user is created (only `unix`/`mariadb.sys`/`root` users): ``` SELECT user,host FROM mysql.user; +-------------+-----------+ | User | Host | +-------------+-----------+ | anel | localhost | | mariadb.sys | localhost | | root | localhost | +-------------+-----------+ ``` See Also -------- * [Installing system tables (mysql\_install\_db)](../installing-system-tables-mysql_install_db/index) * The Windows version of `mysql_install_db`: `[mysql\_install\_db.exe](../mysql_install_dbexe/index)` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Event Scheduler Thread States Event Scheduler Thread States ============================= This article documents thread states that are related to [event](../events/index) scheduling and execution. These include the Event Scheduler thread, threads that terminate the Event Scheduler, and threads for executing events. These correspond to the `STATE` values listed by the [SHOW PROCESSLIST](../show-processlist/index) statement or in the [Information Schema PROCESSLIST Table](../information-schema-processlist-table/index) as well as the `PROCESSLIST_STATE` value listed in the [Performance Schema threads Table](../performance-schema-threads-table/index) | Value | Description | | --- | --- | | Clearing | Thread is terminating. | | Initialized | Thread has be initialized. | | Waiting for next activation | The event queue contains items, but the next activation is at some time in the future. | | Waiting for scheduler to stop | Waiting for the event scheduler to stop after issuing `SET GLOBAL event_scheduler=OFF`. | | Waiting on empty queue | Sleeping, as the event scheduler's queue is empty. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Understanding the Relational Database Model Understanding the Relational Database Model =========================================== The relational database model was a huge leap forward from the [network database model](../understanding-the-network-database-model/index). Instead of relying on a parent-child or owner-member relationship, the relational model allows any file to be related to any other by means of a common field. Suddenly, the complexity of the design was greatly reduced because changes could be made to the database schema without affecting the system's ability to access data. And because access was not by means of paths to and from files, but from a direct relationship between files, new relations between these files could easily be added. In 1970, when E.F. Codd developed the model, it was thought to be impractical. The increased ease of use comes at a large performance penalty, and the hardware in those days was not able to implement the model. Since then, of course, hardware has taken huge strides to where today, even the simplest computers can run sophisticated relational database management systems. Relational databases go hand-in-hand with the development of SQL. The simplicity of SQL - where even a novice can learn to perform basic queries in a short period of time - is a large part of the reason for the popularity of the relational model. The two tables below relate to each other through the *product\_code* field. Any two tables can relate to each other simply by creating a field they have in common. ### Table 1 | *Product\_code* | Description | Price | | --- | --- | --- | | A416 | Nails, box | $0.14 | | C923 | Drawing pins, box | $0.08 | ### Table 2 | Invoice\_code | Invoice\_line | *Product\_code* | Quantity | | --- | --- | --- | --- | | 3804 | 1 | A416 | 10 | | 3804 | 2 | C923 | 15 | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb RTRIM RTRIM ===== Syntax ------ ``` RTRIM(str) ``` Description ----------- Returns the string `str` with trailing space characters removed. Returns NULL if given a NULL argument. If the result is empty, returns either an empty string, or, from [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/) with [SQL\_MODE=Oracle](../sql_modeoracle-from-mariadb-103/index), NULL. The Oracle mode version of the function can be accessed outside of Oracle mode by using `RTRIM_ORACLE` as the function name. Examples -------- ``` SELECT QUOTE(RTRIM('MariaDB ')); +-----------------------------+ | QUOTE(RTRIM('MariaDB ')) | +-----------------------------+ | 'MariaDB' | +-----------------------------+ ``` Oracle mode version from [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/): ``` SELECT RTRIM(''),RTRIM_ORACLE(''); +-----------+------------------+ | RTRIM('') | RTRIM_ORACLE('') | +-----------+------------------+ | | NULL | +-----------+------------------+ ``` See Also -------- * [LTRIM](../ltrim/index) - leading spaces removed * [TRIM](../trim/index) - removes all given prefixes or suffixes Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Audit Plugin - Versions MariaDB Audit Plugin - Versions =============================== Below is a list of the releases of the MariaDB Audit Plugin, the most recent version first, and in which versions of MariaDB each plugin version was included. | Version | Introduced | | --- | --- | | 1.4.13 | [MariaDB 10.2.38](https://mariadb.com/kb/en/mariadb-10238-release-notes/), [MariaDB 10.3.29](https://mariadb.com/kb/en/mariadb-10329-release-notes/), [MariaDB 10.4.19](https://mariadb.com/kb/en/mariadb-10419-release-notes/), [MariaDB 10.5.10](https://mariadb.com/kb/en/mariadb-10510-release-notes/) | | 1.4.10 | [MariaDB 10.2.35](https://mariadb.com/kb/en/mariadb-10235-release-notes/), [MariaDB 10.3.26](https://mariadb.com/kb/en/mariadb-10326-release-notes/), [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/) | | 1.4.7 | [MariaDB 10.1.41](https://mariadb.com/kb/en/mariadb-10141-release-notes/), [MariaDB 10.2.26](https://mariadb.com/kb/en/mariadb-10226-release-notes/), [MariaDB 10.3.17](https://mariadb.com/kb/en/mariadb-10317-release-notes/), [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/) | | 1.4.5 | [MariaDB 10.2.24](https://mariadb.com/kb/en/mariadb-10224-release-notes/), [MariaDB 10.3.15](https://mariadb.com/kb/en/mariadb-10315-release-notes/), [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/) | | 1.4.4 | [MariaDB 5.5.61](https://mariadb.com/kb/en/mariadb-5561-release-notes/), [MariaDB 10.0.36](https://mariadb.com/kb/en/mariadb-10036-release-notes/), [MariaDB 10.1.34](https://mariadb.com/kb/en/mariadb-10134-release-notes/), [MariaDB 10.2.15](https://mariadb.com/kb/en/mariadb-10215-release-notes/), [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/), [MariaDB 10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/) | | 1.4.0 | [MariaDB 5.5.48](https://mariadb.com/kb/en/mariadb-5548-release-notes/), [MariaDB 10.0.24](https://mariadb.com/kb/en/mariadb-10024-release-notes/), [MariaDB 10.1.11](https://mariadb.com/kb/en/mariadb-10111-release-notes/) | | 1.3.0 | [MariaDB 5.5.43](https://mariadb.com/kb/en/mariadb-5543-release-notes/), [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/), [MariaDB 10.1.5](https://mariadb.com/kb/en/mariadb-1015-release-notes/) | | 1.2.0 | [MariaDB 5.5.42](https://mariadb.com/kb/en/mariadb-5542-release-notes/), [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/), [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [1.1.7](https://mariadb.com/kb/en/mariadb-audit-plugin-117-release-notes/) | [MariaDB 5.5.38](https://mariadb.com/kb/en/mariadb-5538-release-notes/), [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/), [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [1.1.6](https://mariadb.com/kb/en/mariadb-audit-plugin-116-release-notes/) | [MariaDB 5.5.37](https://mariadb.com/kb/en/mariadb-5537-release-notes/), [MariaDB 10.0.10](https://mariadb.com/kb/en/mariadb-10010-release-notes/) | | [1.1.5](https://mariadb.com/kb/en/mariadb-audit-plugin-115-release-notes/) | [MariaDB 10.0.09](https://mariadb.com/kb/en/mariadb-10009-release-notes/) | | [1.1.4](https://mariadb.com/kb/en/mariadb-audit-plugin-114-release-notes/) | [MariaDB 5.5.36](https://mariadb.com/kb/en/mariadb-5536-release-notes/) | | [1.1.3](https://mariadb.com/kb/en/mariadb-audit-plugin-113-release-notes/) | [MariaDB 5.5.34](https://mariadb.com/kb/en/mariadb-5534-release-notes/), [MariaDB 10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/) | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb InnoDB Online DDL Operations with the NOCOPY Alter Algorithm InnoDB Online DDL Operations with the NOCOPY Alter Algorithm ============================================================ Supported Operations by Inheritance ----------------------------------- When the [ALGORITHM](../alter-table/index#algorithm) clause is set to `NOCOPY`, the supported operations are a superset of the operations that are supported when the [ALGORITHM](../alter-table/index#algorithm) clause is set to `INSTANT`. Therefore, when the [ALGORITHM](../alter-table/index#algorithm) clause is set to `NOCOPY`, some operations are supported by inheritance. See the following additional pages for more information about these supported operations: * [InnoDB Online DDL Operations with ALGORITHM=INSTANT](../innodb-online-ddl-operations-with-algorithminstant/index) Column Operations ----------------- ### `ALTER TABLE ... ADD COLUMN` In [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/) and later, InnoDB supports adding columns to a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... ADD COLUMN](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-add-column) for more information. This applies to [ALTER TABLE ... ADD COLUMN](../alter-table/index#add-column) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... DROP COLUMN` In [MariaDB 10.4](../what-is-mariadb-104/index) and later, InnoDB supports dropping columns from a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... DROP COLUMN](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-drop-column) for more information. This applies to [ALTER TABLE ... DROP COLUMN](../alter-table/index#drop-column) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... MODIFY COLUMN` This applies to [ALTER TABLE ... MODIFY COLUMN](../alter-table/index#modify-column) for [InnoDB](../innodb/index) tables. #### Reordering Columns In [MariaDB 10.4](../what-is-mariadb-104/index) and later, InnoDB supports reordering columns within a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Reordering Columns](../innodb-online-ddl-operations-with-algorithminstant/index#reordering-columns) for more information. #### Changing the Data Type of a Column InnoDB does **not** support modifying a column's data type with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in most cases. There are a few exceptions in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Changing the Data Type of a Column](../innodb-online-ddl-operations-with-algorithminstant/index#changing-the-data-type-of-a-column) for more information. #### Changing a Column to NULL In [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/) and later, InnoDB supports modifying a column to allow [NULL](../create-table/index#null-and-not-null) values with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Changing a Column to NULL](../innodb-online-ddl-operations-with-algorithminstant/index#changing-a-column-to-null) for more information. #### Changing a Column to NOT NULL InnoDB does **not** support modifying a column to **not** allow [NULL](../create-table/index#null-and-not-null) values with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ) ROW_FORMAT=REDUNDANT; SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab MODIFY COLUMN c varchar(50) NOT NULL; ERROR 1845 (0A000): ALGORITHM=NOCOPY is not supported for this operation. Try ALGORITHM=INPLACE ``` #### Adding a New `ENUM` Option InnoDB supports adding a new [ENUM](../enum/index) option to a column with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Adding a New ENUM Option](../innodb-online-ddl-operations-with-algorithminstant/index#adding-a-new-enum-option) for more information. #### Adding a New `SET` Option InnoDB supports adding a new [SET](../set-data-type/index) option to a column with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Adding a New SET Option](../innodb-online-ddl-operations-with-algorithminstant/index#adding-a-new-set-option) for more information. #### Removing System Versioning from a Column In [MariaDB 10.3.8](https://mariadb.com/kb/en/mariadb-1038-release-notes/) and later, InnoDB supports removing [system versioning](../system-versioned-tables/index) from a column with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Removing System Versioning from a Column](../innodb-online-ddl-operations-with-algorithminstant/index#removing-system-versioning-from-a-column) for more information. ### `ALTER TABLE ... ALTER COLUMN` This applies to [ALTER TABLE ... ALTER COLUMN](../alter-table/index#alter-column) for [InnoDB](../innodb/index) tables. #### Setting a Column's Default Value InnoDB supports modifying a column's [DEFAULT](../create-table/index#default-column-option) value with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Setting a Column's Default Value](../innodb-online-ddl-operations-with-algorithminstant/index#setting-a-columns-default-value) for more information. #### Removing a Column's Default Value InnoDB supports removing a column's [DEFAULT](../create-table/index#default-column-option) value with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: Removing a Column's Default Value](../innodb-online-ddl-operations-with-algorithminstant/index#removing-a-columns-default-value) for more information. ### `ALTER TABLE ... CHANGE COLUMN` InnoDB supports renaming a column with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... CHANGE COLUMN](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-change-column) for more information. This applies to [ALTER TABLE ... CHANGE COLUMN](../alter-table/index#change-column) for [InnoDB](../innodb/index) tables. Index Operations ---------------- ### `ALTER TABLE ... ADD PRIMARY KEY` InnoDB does **not** support adding a primary key to a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int, b varchar(50), c varchar(50) ); SET SESSION sql_mode='STRICT_TRANS_TABLES'; SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab ADD PRIMARY KEY (a); ERROR 1845 (0A000): ALGORITHM=NOCOPY is not supported for this operation. Try ALGORITHM=INPLACE ``` This applies to [ALTER TABLE ... ADD PRIMARY KEY](../alter-table/index#add-primary-key) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... DROP PRIMARY KEY` InnoDB does **not** support dropping a primary key with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab DROP PRIMARY KEY; ERROR 1846 (0A000): ALGORITHM=NOCOPY is not supported. Reason: Dropping a primary key is not allowed without also adding a new primary key. Try ALGORITHM=COPY ``` This applies to [ALTER TABLE ... DROP PRIMARY KEY](../alter-table/index#drop-primary-key) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... ADD INDEX` and `CREATE INDEX` This applies to [ALTER TABLE ... ADD INDEX](../alter-table/index#add-index) and [CREATE INDEX](../create-index/index) for [InnoDB](../innodb/index) tables. #### Adding a Plain Index InnoDB supports adding a plain index to a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. This operation supports the non-locking strategy. This strategy can be explicitly chosen by setting the [LOCK](../alter-table/index#lock) clause to `NONE`. When this strategy is used, all concurrent DML is permitted. For example, this succeeds: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab ADD INDEX b_index (b); Query OK, 0 rows affected (0.009 sec) ``` And this succeeds: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SET SESSION alter_algorithm='NOCOPY'; CREATE INDEX b_index ON tab (b); Query OK, 0 rows affected (0.009 sec) ``` #### Adding a Fulltext Index InnoDB supports adding a [FULLTEXT](../full-text-indexes/index) index to a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. However, there are some limitations, such as: * Adding a [FULLTEXT](../full-text-indexes/index) index to a table that does not have a user-defined `FTS_DOC_ID` column will require the table to be rebuilt once. When the table is rebuilt, the system adds a hidden `FTS_DOC_ID` column. This initial operation will have to be performed with [ALGORITHM](../alter-table/index#algorithm) set to `INPLACE`.From that point forward, adding additional [FULLTEXT](../full-text-indexes/index) indexes to the same table will not require the table to be rebuilt, and [ALGORITHM](../alter-table/index#algorithm) can be set to `NOCOPY`. * Only one [FULLTEXT](../full-text-indexes/index) index may be added at a time when [ALGORITHM](../alter-table/index#algorithm) is set to `NOCOPY`. This operation supports a read-only locking strategy. This strategy can be explicitly chosen by setting the [LOCK](../alter-table/index#lock) clause to `SHARED`. When this strategy is used, read-only concurrent DML is permitted. For example, this succeeds, but the first operation requires the table to be rebuilt [ALGORITHM](../alter-table/index#algorithm) set to `INPLACE`, so that the hidden `FTS_DOC_ID` column can be added: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SET SESSION alter_algorithm='INPLACE'; ALTER TABLE tab ADD FULLTEXT INDEX b_index (b); Query OK, 0 rows affected (0.043 sec) SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab ADD FULLTEXT INDEX c_index (c); Query OK, 0 rows affected (0.017 sec) ``` And this succeeds in the same way as above: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SET SESSION alter_algorithm='INPLACE'; CREATE FULLTEXT INDEX b_index ON tab (b); Query OK, 0 rows affected (0.048 sec) SET SESSION alter_algorithm='NOCOPY'; CREATE FULLTEXT INDEX c_index ON tab (c); Query OK, 0 rows affected (0.016 sec) ``` But this second command fails, because only one [FULLTEXT](../full-text-indexes/index) index can be added at a time: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50), d varchar(50) ); SET SESSION alter_algorithm='INPLACE'; ALTER TABLE tab ADD FULLTEXT INDEX b_index (b); Query OK, 0 rows affected (0.041 sec) SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab ADD FULLTEXT INDEX c_index (c), ADD FULLTEXT INDEX d_index (d); ERROR 1846 (0A000): ALGORITHM=NOCOPY is not supported. Reason: InnoDB presently supports one FULLTEXT index creation at a time. Try ALGORITHM=COPY ``` #### Adding a Spatial Index InnoDB supports adding a [SPATIAL](../spatial-index/index) index to a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. This operation supports a read-only locking strategy. This strategy can be explicitly chosen by setting the [LOCK](../alter-table/index#lock) clause to `SHARED`. When this strategy is used, read-only concurrent DML is permitted. For example, this succeeds: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c GEOMETRY NOT NULL ); SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab ADD SPATIAL INDEX c_index (c); Query OK, 0 rows affected (0.005 sec) ``` And this succeeds in the same way as above: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c GEOMETRY NOT NULL ); SET SESSION alter_algorithm='NOCOPY'; CREATE SPATIAL INDEX c_index ON tab (c); Query OK, 0 rows affected (0.005 sec) ``` ### `ALTER TABLE ... DROP INDEX` and `DROP INDEX` InnoDB supports dropping indexes from a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... DROP INDEX and DROP INDEX](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-drop-index-and-drop-index) for more information. This applies to [ALTER TABLE ... DROP INDEX](../alter-table/index#drop-index) and [DROP INDEX](../drop-index/index) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... ADD FOREIGN KEY` InnoDB does supports adding foreign key constraints to a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. In order to add a new foreign key constraint to a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`, the [foreign\_key\_checks](../server-system-variables/index#foreign_key_checks) system variable needs to be set to `OFF`. If it is set to `ON`, then `ALGORITHM=COPY` is required. This operation supports the non-locking strategy. This strategy can be explicitly chosen by setting the [LOCK](../alter-table/index#lock) clause to `NONE`. When this strategy is used, all concurrent DML is permitted. For example, this fails: ``` CREATE OR REPLACE TABLE tab1 ( a int PRIMARY KEY, b varchar(50), c varchar(50), d int ); CREATE OR REPLACE TABLE tab2 ( a int PRIMARY KEY, b varchar(50) ); SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab1 ADD FOREIGN KEY tab2_fk (d) REFERENCES tab2 (a); ERROR 1846 (0A000): ALGORITHM=NOCOPY is not supported. Reason: Adding foreign keys needs foreign_key_checks=OFF. Try ALGORITHM=COPY ``` But this succeeds: ``` CREATE OR REPLACE TABLE tab1 ( a int PRIMARY KEY, b varchar(50), c varchar(50), d int ); CREATE OR REPLACE TABLE tab2 ( a int PRIMARY KEY, b varchar(50) ); SET SESSION foreign_key_checks=OFF; SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab1 ADD FOREIGN KEY tab2_fk (d) REFERENCES tab2 (a); Query OK, 0 rows affected (0.011 sec) ``` This applies to [ALTER TABLE ... ADD FOREIGN KEY](../alter-table/index#add-foreign-key) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... DROP FOREIGN KEY` InnoDB supports dropping foreign key constraints from a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... DROP FOREIGN KEY](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-drop-foreign-key) for more information. This applies to [ALTER TABLE ... DROP FOREIGN KEY](../alter-table/index#drop-foreign-key) for [InnoDB](../innodb/index) tables. Table Operations ---------------- ### `ALTER TABLE ... AUTO_INCREMENT=...` InnoDB supports changing a table's [AUTO\_INCREMENT](../auto_increment/index) value with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... AUTO\_INCREMENT=...](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-auto_increment) for more information. This applies to [ALTER TABLE ... AUTO\_INCREMENT=...](../create-table/index#auto_increment) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... ROW_FORMAT=...` InnoDB does **not** support changing a table's [row format](../innodb-storage-formats/index) with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ) ROW_FORMAT=DYNAMIC; SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab ROW_FORMAT=COMPRESSED; ERROR 1846 (0A000): ALGORITHM=NOCOPY is not supported. Reason: Changing table options requires the table to be rebuilt. Try ALGORITHM=INPLACE ``` This applies to [ALTER TABLE ... ROW\_FORMAT=...](../create-table/index#row_format) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... KEY_BLOCK_SIZE=...` InnoDB does **not** support changing a table's [KEY\_BLOCK\_SIZE](../innodb-storage-formats/index#using-the-compressed-row-format) with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ) ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=4; SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab KEY_BLOCK_SIZE=2; ERROR 1846 (0A000): ALGORITHM=NOCOPY is not supported. Reason: Changing table options requires the table to be rebuilt. Try ALGORITHM=INPLACE ``` This applies to [KEY\_BLOCK\_SIZE=...](../create-table/index#key_block_size) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... PAGE_COMPRESSED=1` and `ALTER TABLE ... PAGE_COMPRESSION_LEVEL=...` In [MariaDB 10.3.10](https://mariadb.com/kb/en/mariadb-10310-release-notes/) and later, InnoDB supports setting a table's [PAGE\_COMPRESSED](../create-table/index#page_compressed) value to `1` with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. InnoDB does **not** support changing a table's [PAGE\_COMPRESSED](../create-table/index#page_compressed) value from `1` to `0` with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. In these versions, InnoDB also supports changing a table's [PAGE\_COMPRESSION\_LEVEL](../create-table/index#page_compression_level) value with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause is set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... PAGE\_COMPRESSED=1 and ALTER TABLE ... PAGE\_COMPRESSION\_LEVEL=...](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-page_compressed1-and-alter-table-page_compression_level) for more information. This applies to [ALTER TABLE ... PAGE\_COMPRESSED=...](../create-table/index#page_compressed) and [ALTER TABLE ... PAGE\_COMPRESSION\_LEVEL=...](../create-table/index#page_compression_level) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... DROP SYSTEM VERSIONING` InnoDB does **not** support dropping [system versioning](../system-versioned-tables/index) from a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ) WITH SYSTEM VERSIONING; SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab DROP SYSTEM VERSIONING; ERROR 1845 (0A000): ALGORITHM=NOCOPY is not supported for this operation. Try ALGORITHM=INPLACE ``` This applies to [ALTER TABLE ... DROP SYSTEM VERSIONING](../alter-table/index#drop-system-versioning) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... DROP CONSTRAINT` In [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/) and later, InnoDB supports dropping a [CHECK](../constraint/index#check-constraints) constraint from a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... DROP CONSTRAINT](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-drop-constraint) for more information. This applies to [ALTER TABLE ... DROP CONSTRAINT](../alter-table/index#drop-constraint) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... FORCE` InnoDB does **not** support forcing a table rebuild with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab FORCE; ERROR 1845 (0A000): ALGORITHM=NOCOPY is not supported for this operation. Try ALGORITHM=INPLACE ``` This applies to [ALTER TABLE ... FORCE](../alter-table/index#force) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... ENGINE=InnoDB` InnoDB does **not** support forcing a table rebuild with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SET SESSION alter_algorithm='NOCOPY'; ALTER TABLE tab ENGINE=InnoDB; ERROR 1845 (0A000): ALGORITHM=NOCOPY is not supported for this operation. Try ALGORITHM=INPLACE ``` This applies to [ALTER TABLE ... ENGINE=InnoDB](../create-table/index#storage-engine) for [InnoDB](../innodb/index) tables. ### `OPTIMIZE TABLE ...` InnoDB does **not** support optimizing a table with with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY`. For example: ``` CREATE OR REPLACE TABLE tab ( a int PRIMARY KEY, b varchar(50), c varchar(50) ); SHOW GLOBAL VARIABLES WHERE Variable_name IN('innodb_defragment', 'innodb_optimize_fulltext_only'); +-------------------------------+-------+ | Variable_name | Value | +-------------------------------+-------+ | innodb_defragment | OFF | | innodb_optimize_fulltext_only | OFF | +-------------------------------+-------+ 2 rows in set (0.001 sec) SET SESSION alter_algorithm='NOCOPY'; OPTIMIZE TABLE tab; +---------+----------+----------+-----------------------------------------------------------------------------+ | Table | Op | Msg_type | Msg_text | +---------+----------+----------+-----------------------------------------------------------------------------+ | db1.tab | optimize | note | Table does not support optimize, doing recreate + analyze instead | | db1.tab | optimize | error | ALGORITHM=NOCOPY is not supported for this operation. Try ALGORITHM=INPLACE | | db1.tab | optimize | status | Operation failed | +---------+----------+----------+-----------------------------------------------------------------------------+ 3 rows in set, 1 warning (0.002 sec) ``` This applies to [OPTIMIZE TABLE](../optimize-table/index) for [InnoDB](../innodb/index) tables. ### `ALTER TABLE ... RENAME TO` and `RENAME TABLE ...` InnoDB supports renaming a table with [ALGORITHM](../alter-table/index#algorithm) set to `NOCOPY` in the cases where the operation supports having the [ALGORITHM](../alter-table/index#algorithm) clause set to `INSTANT`. See [InnoDB Online DDL Operations with ALGORITHM=INSTANT: ALTER TABLE ... RENAME TO and RENAME TABLE ...](../innodb-online-ddl-operations-with-algorithminstant/index#alter-table-rename-to-and-rename-table) for more information. This applies to [ALTER TABLE ... RENAME TO](../alter-table/index#rename-to) and [RENAME TABLE](../rename-table/index) for [InnoDB](../innodb/index) tables. Limitations ----------- ### Limitations Related to Generated (Virtual and Persistent/Stored) Columns [Generated columns](../generated-columns/index) do not currently support online DDL for all of the same operations that are supported for "real" columns. See [Generated (Virtual and Persistent/Stored) Columns: Statement Support](../generated-columns/index#statement-support) for more information on the limitations. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Upgrading MariaDB ColumnStore from 1.0.1 to 1.0.2 Upgrading MariaDB ColumnStore from 1.0.1 to 1.0.2 ================================================= MariaDB ColumnStore single server software upgrade from 1.0.1 to 1.0.2 ---------------------------------------------------------------------- Note: Calpont.xml modifications you manually made are not automatically carried forward on an upgrade. These modifications will need to be incorporated back into .XML once the upgrade has occurred. The previous configuration file will be saved as /usr/local/MariaDB/Columnstore/etc/Calpont.xml.rpmsave. In 1.0.2, the configuration file name was changed to Columnstore.xml. Check the 1.0.2 Release Notes on how to perform the upgrade from the 1.0.1 to the 1.0.2. There is a work-around procedure to follow. ### Upgrade workaround After you have completed the part of the package upgrade process (removing the old package and installing the 1.0.2 package), the following file will exist: /usr/local/mariadb/columnstore/etc/Calpont.xml.rpmsave Run the following commands, this is the work-around part that is only required when going from 1.0.0/1.0.1 to 1.0.2 1. cd /usr/local/mariadb/columnstore/etc/ 2. cp Calpont.xml.rpmsave Columnstore.xml.rpmsave 3. sed -i 's/Calpont Version/Columnstore Version/g' Columnstore.xml.rpmsave 4. sed -i 's/Calpont.xml/Columnstore.xml/g' Columnstore.xml.rpmsave 5. sed -i 's/<\/Calpont>/<\/Columnstore>/g' Columnstore.xml.rpmsave Then you can run the install script to upgrade the system: 6. /usr/local/mariadb/columnstore/bin/postConfigure -u ### Choosing the type of upgrade #### Root User Installs #### Upgrading MariaDB ColumnStore using RPMs Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Download the package mariadb-columnstore-1.0.2-1-centos#.x86\_64.rpm.tar.gz to the server where you are installing MariaDB ColumnStore.** Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate a set of RPMs that will reside in the /root/ directory. `tar -zxf mariadb-columnstore-1.0.2-1-centos#.x86_64.rpm.tar.gz` * Upgrade the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. Note: If another version of MariaDB is currently running, this service will need to be stopped before running this command. After the rpm command has been executed, you can restart the service. ``` rpm -Uvh mariadb-columnstore*.rpm ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` # /usr/local/MariaDB/Columnstore/bin/postConfigure -u ``` For RPM Upgrade, the previous configuration file will be saved as: /usr/local/MariaDB/Columnstore/etc/Columnstore.xml.rpmsave ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /usr/local directory -mariadb-columnstore-release#.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: `cc shutdownsystem y` * Run pre-uninstall script `/usr/local/MariaDB/Columnstore/bin/pre-uninstall` * Unpack the tarball, which will generate the /usr/local/ directory. `tar -zxvf -mariadb-columnstore-release#.x86_64.bin.tar.gz` * Run post-install scripts `/usr/local/MariaDB/Columnstore/bin/post-install` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave `/usr/local/MariaDB/Columnstore/bin/postConfigure -u` ### Upgrading MariaDB ColumnStore using the DEB package A DEB upgrade would be done on a system that supports DEBs like Debian or Ubuntu systems. Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /root directory ``` mariadb-columnstore-release#.amd64.deb.tar.gz ``` (DEB 64-BIT) to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` cc shutdownsystem y ``` * Unpack the tarball, which will generate DEBs. ``` tar -zxf mariadb-columnstore-release#.amd64.deb.tar.gz ``` * Remove, purge and install all MariaDB ColumnStore debs ``` cd /root/ dpkg -r mariadb-columnstore*deb dpkg -P mariadb-columnstore*deb ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Calpont.xml,rpmsave ``` /usr/local/MariaDB/Columnstore/bin/postConfigure -u ``` #### Non-Root User Installs ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /home/'non-root-user" directory mariadb-columnstore-release#.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: `cc shutdownsystem y` * Run pre-uninstall script `$HOME/MariaDB/Columnstore/bin/pre-uninstall` * Unpack the tarball, which will generate the $HOME/ directory. `tar -zxvf -mariadb-columnstore-release#.x86_64.bin.tar.gz` * Run post-install scripts 1. $HOME/MariaDB/Columnstore/bin/post-install * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave `$HOME*MariaDB/Columnstore/bin/postConfigure -n*` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CONNECT JSON Table Type CONNECT JSON Table Type ======================= Overview -------- JSON (JavaScript Object Notation) is a lightweight data-interchange format widely used on the Internet. Many applications, generally written in JavaScript or PHP use and produce JSON data, which are exchanged as files of different physical formats. JSON data is often returned from REST queries. It is also possible to query, create or update such information in a database-like manner. MongoDB does it using a JavaScript-like language. PostgreSQL includes these facilities by using a specific data type and related functions like dynamic columns. The CONNECT engine adds this facility to MariaDB by supporting tables based on JSON data files. This is done like for XML tables by creating tables describing what should be retrieved from the file and how it should be processed. Starting with 1.07.0002, the internal way JSON was parsed and handled was changed. The main advantage of the new way is to reduce the memory required to parse JSON. It was from 6 to 10 times the size of the JSON source and is now only 2 to 4 times. However, this is in Beta mode and JSON tables are still handled using the old mode. To use the new mode, tables should be created with TABLE\_TYPE=BSON. Another way is the set the [connect\_force\_bson](../connect-system-variables/index#connect_force_bson) session variable to 1 or ON. Then all JSON tables will be handled as BSON. Of course, this is temporary and when successfully tested, the new way will replace the old way and all tables be created as JSON. Let us start from the file “biblio3.json” that is the JSON equivalent of the XML Xsample file described in the XML table chapter: ``` [ { "ISBN": "9782212090819", "LANG": "fr", "SUBJECT": "applications", "AUTHOR": [ { "FIRSTNAME": "Jean-Christophe", "LASTNAME": "Bernadac" }, { "FIRSTNAME": "François", "LASTNAME": "Knab" } ], "TITLE": "Construire une application XML", "PUBLISHER": { "NAME": "Eyrolles", "PLACE": "Paris" }, "DATEPUB": 1999 }, { "ISBN": "9782840825685", "LANG": "fr", "SUBJECT": "applications", "AUTHOR": [ { "FIRSTNAME": "William J.", "LASTNAME": "Pardi" } ], "TITLE": "XML en Action", "TRANSLATED": { "PREFIX": "adapté de l'anglais par", "TRANSLATOR": { "FIRSTNAME": "James", "LASTNAME": "Guerin" } }, "PUBLISHER": { "NAME": "Microsoft Press", "PLACE": "Paris" }, "DATEPUB": 1999 } ] ``` This file contains the different items existing in JSON. * `Arrays`: They are enclosed in square brackets and contain a list of comma separated values. * `Objects`: They are enclosed in curly brackets. They contain a comma separated list of pairs, each pair composed of a key name between double quotes, followed by a ‘:’ character and followed by a value. * `Values`: Values can be an array or an object. They also can be a string between double quotes, an integer or float number, a Boolean value or a null value. The simplest way for CONNECT to locate a table in such a file is by an array containing a list of objects (this is what MongoDB calls a collection of documents). Each array value will be a table row and each pair of the row objects will represent a column, the key being the column name and the value the column value. A first try to create a table on this file will be to take the outer array as the table: ``` create table jsample ( ISBN char(15), LANG char(2), SUBJECT char(32), AUTHOR char(128), TITLE char(32), TRANSLATED char(80), PUBLISHER char(20), DATEPUB int(4)) engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` If we execute the query: ``` select isbn, author, title, publisher from jsample; ``` We get the result: | isbn | author | title | publisher | | --- | --- | --- | --- | | 9782212090819 | Jean-Christophe Bernadac | Construire une application XML | Eyrolles Paris | | 9782840825685 | William J. Pardi | XML en Action | Microsoft Press Pari | Note that by default, column values that are objects have been set to the concatenation of all the string values of the object separated by a blank. When a column value is an array, only the first item of the array is retrieved (This will change in later versions of Connect). However, things are generally more complicated. If JSON files do not contain attributes (although object pairs are similar to attributes) they contain a new item, arrays. We have seen that they can be used like XML multiple nodes, here to specify several authors, but they are more general because they can contain objects of different types, even it may not be advisable to do so. This is why CONNECT enables the specification of a column field\_format option “JPATH” (FIELD\_FORMAT until Connect 1.6) that is used to describe exactly where the items to display are and how to handles arrays. Here is an example of a new table that can be created on the same file, allowing choosing the column names, to get some sub-objects and to specify how to handle the author array. Until Connect 1.5: ``` create table jsampall ( ISBN char(15), Language char(2) field_format='LANG', Subject char(32) field_format='SUBJECT', Author char(128) field_format='AUTHOR:[" and "]', Title char(32) field_format='TITLE', Translation char(32) field_format='TRANSLATOR:PREFIX', Translator char(80) field_format='TRANSLATOR', Publisher char(20) field_format='PUBLISHER:NAME', Location char(16) field_format='PUBLISHER:PLACE', Year int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` From Connect 1.6: ``` create table jsampall ( ISBN char(15), Language char(2) field_format='LANG', Subject char(32) field_format='SUBJECT', Author char(128) field_format='AUTHOR.[" and "]', Title char(32) field_format='TITLE', Translation char(32) field_format='TRANSLATOR.PREFIX', Translator char(80) field_format='TRANSLATOR', Publisher char(20) field_format='PUBLISHER.NAME', Location char(16) field_format='PUBLISHER.PLACE', Year int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` From Connect 1.07.0002 ``` create table jsampall ( ISBN char(15), Language char(2) jpath='$.LANG', Subject char(32) jpath='$.SUBJECT', Author char(128) jpath='$.AUTHOR[" and "]', Title char(32) jpath='$.TITLE', Translation char(32) jpath='$.TRANSLATOR.PREFIX', Translator char(80) jpath='$.TRANSLATOR', Publisher char(20) jpath='$.PUBLISHER.NAME', Location char(16) jpath='$.PUBLISHER.PLACE', Year int(4) jpath='$.DATEPUB') engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` Given the query: ``` select title, author, publisher, location from jsampall; ``` The result is: | title | author | publisher | location | | --- | --- | --- | --- | | Construire une application XML | Jean-Christophe Bernadac and François Knab | Eyrolles | Paris | | XML en Action | William J. Pardi | Microsoft Press | Paris | Note: The JPATH was not specified for column ISBN because it defaults to the column name. Here is another example showing that one can choose what to extract from the file and how to “expand” an array, meaning to generate one row for each array value: Until Connect 1.5: ``` create table jsampex ( ISBN char(15), Title char(32) field_format='TITLE', AuthorFN char(128) field_format='AUTHOR:[X]:FIRSTNAME', AuthorLN char(128) field_format='AUTHOR:[X]:LASTNAME', Year int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` From Connect 1.6: ``` create table jsampex ( ISBN char(15), Title char(32) field_format='TITLE', AuthorFN char(128) field_format='AUTHOR.[X].FIRSTNAME', AuthorLN char(128) field_format='AUTHOR.[X].LASTNAME', Year int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` From Connect 1.06.006: ``` create table jsampex ( ISBN char(15), Title char(32) field_format='TITLE', AuthorFN char(128) field_format='AUTHOR[*].FIRSTNAME', AuthorLN char(128) field_format='AUTHOR[*].LASTNAME', Year int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` From Connect 1.07.0002 ``` create table jsampex ( ISBN char(15), Title char(32) jpath='TITLE', AuthorFN char(128) jpath='AUTHOR[*].FIRSTNAME', AuthorLN char(128) jpath='AUTHOR[*].LASTNAME', Year int(4) jpath='DATEPUB') engine=CONNECT table_type=JSON File_name='biblio3.json'; ``` It is displayed as: | ISBN | Title | AuthorFN | AuthorLN | Year | | --- | --- | --- | --- | --- | | 9782212090819 | Construire une application XML | Jean-Christophe | Bernadac | 1999 | | 9782212090819 | Construire une application XML | François | Knab | 1999 | | 9782840825685 | XML en Action | William J. | Pardi | 1999 | Note: The example above shows that the ‘$.’, that means the beginning of the path, can be omitted. The Jpath Specification ----------------------- From Connect 1.6, the Jpath specification has changed to be the one of the native JSON functions and more compatible with what is generally used. It is close to the standard definition and compatible to what MongoDB and other products do. The ‘:’ separator is replaced by ‘.’. Position in array is accepted MongoDB style with no square brackets. Array specification specific to CONNECT are still accepted but [\*] is used for expanding and [x] for multiply. However, tables created with the previous syntax can still be used by adding SEP\_CHAR=’:’ (can be done with alter table). Also, it can be now specified as JPATH (was FIELD\_FORMAT) but FIELD\_FORMAT is still accepted. Until Connect 1.5, it is the description of the path to follow to reach the required item. Each step is the key name (case sensitive) of the pair when crossing an object, and the number of the value between square brackets when crossing an array. Each specification is separated by a ‘:’ character. From Connect 1.6, It is the description of the path to follow to reach the required item. Each step is the key name (case sensitive) of the pair when crossing an object, and the position number of the value when crossing an array. Key specifications are separated by a ‘.’ character. For instance, in the above file, the last name of the second author of a book is reached by: $.AUTHOR[1].LASTNAME *standard style $AUTHOR.1.LASTNAME* MongoDB style AUTHOR:[1]:LASTNAME *old style when SEP\_CHAR=’:’ or until Connect 1.5* The ‘$’ or “$.” prefix specifies the root of the path and can be omitted with CONNECT. The array specification can also indicate how it must be processed: For instance, in the above file, the last name of the second author of a book is reached by: ``` AUTHOR:[1]:LASTNAME ``` The array specification can also indicate how it must be processed: | Specification | Array Type | Limit | Description | | --- | --- | --- | --- | | n (Connect >= 1.6) or [n][[1](#_note-0)] | All | N.A | Take the nth value of the array. | | [\*] (Connect >= 1.6), [X] or [x] (Connect <= 1.5) | All | | Expand. Generate one row for each array value. | | ["string"] | String | | Concatenate all values separated by the specified string. | | [+] | Numeric | | Make the sum of all the non-null array values. | | [x] (Connect >= 1.6), [\*] (Connect <= 1.5) | Numeric | | Make the product of all non-null array values. | | [!] | Numeric | | Make the average of all the non-null array values. | | [>] or [<] | All | | Return the greatest or least non-null value of the array. | | [#] | All | N.A | Return the number of values in the array. | | [] | All | | Expand if under an expanded object. Otherwise sum if numeric, else concatenation separated by “, “. | | | All | | Between two separators, if an array, expand it if under an expanded object or take the first value of it. | Note 1: When the LIMIT restriction is applicable, only the first *m* array items are used, *m* being the value of the LIMIT option (to be specified in option\_list). The LIMIT default value is 10. Note 2: An alternative way to indicate what is to be expanded is to use the expand option in the option list, for instance: ``` OPTION_LIST='Expand=AUTHOR' ``` `AUTHOR` is here the key of the pair that has the array as a value (case sensitive). Expand is limited to only one branch (expanded arrays must be under the same object). Let us take as an example the file `expense.json` ([found here](../json-sample-files/index)). The table jexpall expands all under and including the week array: From Connect 1.07.0002 ``` create table jexpall ( WHO char(12), WEEK int(2) jpath='$.WEEK[*].NUMBER', WHAT char(32) jpath='$.WEEK[*].EXPENSE[*].WHAT', AMOUNT double(8,2) jpath='$.WEEK[*].EXPENSE[*].AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` From Connect.1.6 ``` create table jexpall ( WHO char(12), WEEK int(2) field_format='$.WEEK[*].NUMBER', WHAT char(32) field_format='$.WEEK[*].EXPENSE[*].WHAT', AMOUNT double(8,2) field_format='$.WEEK[*].EXPENSE[*].AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` Until Connect 1.5: ``` create table jexpall ( WHO char(12), WEEK int(2) field_format='WEEK:[x]:NUMBER', WHAT char(32) field_format='WEEK:[x]:EXPENSE:[x]:WHAT', AMOUNT double(8,2) field_format='WEEK:[x]:EXPENSE:[x]:AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` | WHO | WEEK | WHAT | AMOUNT | | --- | --- | --- | --- | | Joe | 3 | Beer | 18.00 | | Joe | 3 | Food | 12.00 | | Joe | 3 | Food | 19.00 | | Joe | 3 | Car | 20.00 | | Joe | 4 | Beer | 19.00 | | Joe | 4 | Beer | 16.00 | | Joe | 4 | Food | 17.00 | | Joe | 4 | Food | 17.00 | | Joe | 4 | Beer | 14.00 | | Joe | 5 | Beer | 14.00 | | Joe | 5 | Food | 12.00 | | Beth | 3 | Beer | 16.00 | | Beth | 4 | Food | 17.00 | | Beth | 4 | Beer | 15.00 | | Beth | 5 | Food | 12.00 | | Beth | 5 | Beer | 20.00 | | Janet | 3 | Car | 19.00 | | Janet | 3 | Food | 18.00 | | Janet | 3 | Beer | 18.00 | | Janet | 4 | Car | 17.00 | | Janet | 5 | Beer | 14.00 | | Janet | 5 | Car | 12.00 | | Janet | 5 | Beer | 19.00 | | Janet | 5 | Food | 12.00 | The table `jexpw` shows what was bought and the sum and average of amounts for each person and week: From Connect 1.07.0002 ``` create table jexpw ( WHO char(12) not null, WEEK int(2) not null jpath='$.WEEK[*].NUMBER', WHAT char(32) not null jpath='$.WEEK[].EXPENSE[", "].WHAT', SUM double(8,2) not null jpath='$.WEEK[].EXPENSE[+].AMOUNT', AVERAGE double(8,2) not null jpath='$.WEEK[].EXPENSE[!].AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` From Connect 1.6: ``` create table jexpw ( WHO char(12) not null, WEEK int(2) not null field_format='$.WEEK[*].NUMBER', WHAT char(32) not null field_format='$.WEEK[].EXPENSE[", "].WHAT', SUM double(8,2) not null field_format='$.WEEK[].EXPENSE[+].AMOUNT', AVERAGE double(8,2) not null field_format='$.WEEK[].EXPENSE[!].AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` Until Connect 1.5: ``` create table jexpw ( WHO char(12) not null, WEEK int(2) not null field_format='WEEK:[x]:NUMBER', WHAT char(32) not null field_format='WEEK::EXPENSE:[", "]:WHAT', SUM double(8,2) not null field_format='WEEK::EXPENSE:[+]:AMOUNT', AVERAGE double(8,2) not null field_format='WEEK::EXPENSE:[!]:AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` | WHO | WEEK | WHAT | SUM | AVERAGE | | --- | --- | --- | --- | --- | | Joe | 3 | Beer, Food, Food, Car | 69.00 | 17.25 | | Joe | 4 | Beer, Beer, Food, Food, Beer | 83.00 | 16.60 | | Joe | 5 | Beer, Food | 26.00 | 13.00 | | Beth | 3 | Beer | 16.00 | 16.00 | | Beth | 4 | Food, Beer | 32.00 | 16.00 | | Beth | 5 | Food, Beer | 32.00 | 16.00 | | Janet | 3 | Car, Food, Beer | 55.00 | 18.33 | | Janet | 4 | Car | 17.00 | 17.00 | | Janet | 5 | Beer, Car, Beer, Food | 57.00 | 14.25 | Let us see what the table `jexpz` does: From Connect 1.6: ``` create table jexpz ( WHO char(12) not null, WEEKS char(12) not null field_format='WEEK[", "].NUMBER', SUMS char(64) not null field_format='WEEK["+"].EXPENSE[+].AMOUNT', SUM double(8,2) not null field_format='WEEK[+].EXPENSE[+].AMOUNT', AVGS char(64) not null field_format='WEEK["+"].EXPENSE[!].AMOUNT', SUMAVG double(8,2) not null field_format='WEEK[+].EXPENSE[!].AMOUNT', AVGSUM double(8,2) not null field_format='WEEK[!].EXPENSE[+].AMOUNT', AVERAGE double(8,2) not null field_format='WEEK[!].EXPENSE[*].AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` From Connect 1.07.0002 ``` create table jexpz ( WHO char(12) not null, WEEKS char(12) not null jpath='WEEK[", "].NUMBER', SUMS char(64) not null jpath='WEEK["+"].EXPENSE[+].AMOUNT', SUM double(8,2) not null jpath='WEEK[+].EXPENSE[+].AMOUNT', AVGS char(64) not null jpath='WEEK["+"].EXPENSE[!].AMOUNT', SUMAVG double(8,2) not null jpath='WEEK[+].EXPENSE[!].AMOUNT', AVGSUM double(8,2) not null jpath='WEEK[!].EXPENSE[+].AMOUNT', AVERAGE double(8,2) not null jpath='WEEK[!].EXPENSE[*].AMOUNT') engine=CONNECT table_type=JSON File_name='expense.json'; ``` Until Connect 1.5: ``` create table jexpz ( WHO char(12) not null, WEEKS char(12) not null field_format='WEEK:[", "]:NUMBER', SUMS char(64) not null field_format='WEEK:["+"]:EXPENSE:[+]:AMOUNT', SUM double(8,2) not null field_format='WEEK:[+]:EXPENSE:[+]:AMOUNT', AVGS char(64) not null field_format='WEEK:["+"]:EXPENSE:[!]:AMOUNT', SUMAVG double(8,2) not null field_format='WEEK:[+]:EXPENSE:[!]:AMOUNT', AVGSUM double(8,2) not null field_format='WEEK:[!]:EXPENSE:[+]:AMOUNT', AVERAGE double(8,2) not null field_format='WEEK:[!]:EXPENSE:[x]:AMOUNT') engine=CONNECT table_type=JSON File_name='E:/Data/Json/expense2.json'; ``` | WHO | WEEKS | SUMS | SUM | AVGS | SUMAVG | AVGSUM | AVERAGE | | --- | --- | --- | --- | --- | --- | --- | --- | | Joe | 3, 4, 5 | 69.00+83.00+26.00 | 178.00 | 17.25+16.60+13.00 | 46.85 | 59.33 | 16.18 | | Beth | 3, 4, 5 | 16.00+32.00+32.00 | 80.00 | 16.00+16.00+16.00 | 48.00 | 26.67 | 16.00 | | Janet | 3, 4, 5 | 55.00+17.00+57.00 | 129.00 | 18.33+17.00+14.25 | 49.58 | 43.00 | 16.12 | For all persons: * Column 1 show the person name. * Column 2 shows the weeks for which values are calculated. * Column 3 lists the sums of expenses for each week. * Column 4 calculates the sum of all expenses by person. * Column 5 shows the week’s expense averages. * Column 6 calculates the sum of these averages. * Column 7 calculates the average of the week’s sum of expenses. * Column 8 calculates the average expense by person. It would be very difficult, if even possible, to obtain this result from table `jexpall` using an SQL query. Handling of NULL Values ----------------------- Json has a null explicit value that can be met in arrays or object key values. When regarding json as a relational table, a column value can be null because the corresponding json item is explicitly null, or implicitly because the corresponding item is missing in an array or object. CONNECT does not make any distinction between explicit and implicit nulls. However, it is possible to specify how nulls are handled and represented. This is done by setting the string session variable [connect\_json\_null](../connect-system-variables/index#connect_json_null). The default value of connect\_json\_null is “<null>”; it can be changed, for instance, by: ``` SET connect_json_null='NULL'; ``` This changes its representation when a column displays the text of an object or the concatenation of the values of an array. It is also possible to tell CONNECT to ignore nulls by: ``` SET connect_json_null=NULL; ``` When doing so, nulls do not appear in object text or array lists. However, this does not change the behavior of array calculation nor the result of array count. Having Columns defined by Discovery ----------------------------------- It is possible to let the MariaDB discovery process do the job of column specification. When columns are not defined in the create table statement, CONNECT endeavors to analyze the JSON file and to provide the column specifications. This is possible only for tables represented by an array of objects because CONNECT retrieves the column names from the object pair keys and their definition from the object pair values. For instance, the jsample table could be created saying: ``` create table jsample engine=connect table_type=JSON file_name='biblio3.json'; ``` Let’s check how it was actually specified using the show create table statement: ``` CREATE TABLE `jsample` ( `ISBN` char(13) NOT NULL, `LANG` char(2) NOT NULL, `SUBJECT` char(12) NOT NULL, `AUTHOR` varchar(256) DEFAULT NULL, `TITLE` char(30) NOT NULL, `TRANSLATED` varchar(256) DEFAULT NULL, `PUBLISHER` varchar(256) DEFAULT NULL, `DATEPUB` int(4) NOT NULL ) ENGINE=CONNECT DEFAULT CHARSET=latin1 `TABLE_TYPE`='JSON' `FILE_NAME`='biblio3.json'; ``` It is equivalent except for the column sizes that have been calculated from the file as the maximum length of the corresponding column when it was a normal value. For columns that are json arrays or objects, the column is specified as a varchar string of length 256, supposedly big enough to contain the sub-object's concatenated values. Nullable is set to true if the column is null or missing in some rows or if its JPATH contains arrays. If a more complex definition is desired, you can ask CONNECT to analyse the JPATH up to a given depth using the DEPTH or LEVEL option in the option list. Its default value is 0 but can be changed setting the [connect\_default\_depth](../connect-system-variables/index#connect_default_depth) session variable (in future versions the default will be 5). The depth value is the number of sub-objects that are taken in the JPATH2 (this is different from what is defined and returned by the native [Json\_Depth](../json_depth/index) function). For instance: ``` create table jsampall2 engine=connect table_type=JSON file_name='biblio3.json' option_list='level=1'; ``` This will define the table as: From Connect 1.07.0002 ``` CREATE TABLE `jsampall2` ( `ISBN` char(13) NOT NULL, `LANG` char(2) NOT NULL, `SUBJECT` char(12) NOT NULL, `AUTHOR_FIRSTNAME` char(15) NOT NULL `JPATH`='$.AUTHOR.[0].FIRSTNAME', `AUTHOR_LASTNAME` char(8) NOT NULL `JPATH`='$.AUTHOR.[0].LASTNAME', `TITLE` char(30) NOT NULL, `TRANSLATED_PREFIX` char(23) DEFAULT NULL `JPATH`='$.TRANSLATED.PREFIX', `TRANSLATED_TRANSLATOR` varchar(256) DEFAULT NULL `JPATH`='$.TRANSLATED.TRANSLATOR', `PUBLISHER_NAME` char(15) NOT NULL `JPATH`='$.PUBLISHER.NAME', `PUBLISHER_PLACE` char(5) NOT NULL `JPATH`='$.PUBLISHER.PLACE', `DATEPUB` int(4) NOT NULL ) ENGINE=CONNECT DEFAULT CHARSET=latin1 `TABLE_TYPE`='JSON' `FILE_NAME`='biblio3.json' `OPTION_LIST`='depth=1'; ``` From Connect 1.6: ``` CREATE TABLE `jsampall2` ( `ISBN` char(13) NOT NULL, `LANG` char(2) NOT NULL, `SUBJECT` char(12) NOT NULL, `AUTHOR_FIRSTNAME` char(15) NOT NULL `FIELD_FORMAT`='AUTHOR..FIRSTNAME', `AUTHOR_LASTNAME` char(8) NOT NULL `FIELD_FORMAT`='AUTHOR..LASTNAME', `TITLE` char(30) NOT NULL, `TRANSLATED_PREFIX` char(23) DEFAULT NULL `FIELD_FORMAT`='TRANSLATED.PREFIX', `TRANSLATED_TRANSLATOR` varchar(256) DEFAULT NULL `FIELD_FORMAT`='TRANSLATED.TRANSLATOR', `PUBLISHER_NAME` char(15) NOT NULL `FIELD_FORMAT`='PUBLISHER.NAME', `PUBLISHER_PLACE` char(5) NOT NULL `FIELD_FORMAT`='PUBLISHER.PLACE', `DATEPUB` int(4) NOT NULL ) ENGINE=CONNECT DEFAULT CHARSET=latin1 `TABLE_TYPE`='JSON' `FILE_NAME`='biblio3.json' `OPTION_LIST`='level=1'; ``` Until Connect 1.5: ``` CREATE TABLE `jsampall2` ( `ISBN` char(13) NOT NULL, `LANG` char(2) NOT NULL, `SUBJECT` char(12) NOT NULL, `AUTHOR_FIRSTNAME` char(15) NOT NULL `FIELD_FORMAT`='AUTHOR::FIRSTNAME', `AUTHOR_LASTNAME` char(8) NOT NULL `FIELD_FORMAT`='AUTHOR::LASTNAME', `TITLE` char(30) NOT NULL, `TRANSLATED_PREFIX` char(23) DEFAULT NULL `FIELD_FORMAT`='TRANSLATED:PREFIX', `TRANSLATED_TRANSLATOR` varchar(256) DEFAULT NULL `FIELD_FORMAT`='TRANSLATED:TRANSLATOR', `PUBLISHER_NAME` char(15) NOT NULL `FIELD_FORMAT`='PUBLISHER:NAME', `PUBLISHER_PLACE` char(5) NOT NULL `FIELD_FORMAT`='PUBLISHER:PLACE', `DATEPUB` int(4) NOT NULL ) ENGINE=CONNECT DEFAULT CHARSET=latin1 `TABLE_TYPE`='JSON' ` FILE_NAME`='biblio3.json' `OPTION_LIST`='level=1'; ``` For columns that are a simple value, the Json path is the column name. This is the default when the Jpath option is not specified, so it was not specified for such columns. However, you can force discovery to specify it by setting the connect\_all\_path variable to 1 or ON. This can be useful if you plan to change the name of such columns and relieves you of manually specifying the path (otherwise it would default to the new name and cause the column to not or wrongly be found). Another problem is that CONNECT cannot guess what you want to do with arrays. Here the AUTHOR array is set to 0, which means that only its first value will be retrieved unless you also had specified “Expand=AUTHOR” in the option list. But of course, you can replace it with anything else. This method can be used as a quick way to make a “template” table definition that can later be edited to make the desired definition. In particular, column names are constructed from all the object keys of their path in order to have distinct column names. This can be manually edited to have the desired names, provided their JPATH key names are not modified. DEPTH can also be given the value -1 to create only columns that are simple values (no array or object). It normally defaults to 0 but this can be modified setting the [connect\_default\_depth](../connect-system-variables/index#connect_default_depth) variable. Note: Since version 1.6.4, CONNECT eliminates columns that are “void” or whose type cannot be determined. For instance given the file sresto.json: ``` {"_id":1,"name":"Corner Social","cuisine":"American","grades":[{"grade":"A","score":6}]} {"_id":2,"name":"La Nueva Clasica Antillana","cuisine":"Spanish","grades":[]} ``` Previously, when using discovery, creating the table by: ``` create table sjr0 engine=connect table_type=JSON file_name='sresto.json' option_list='Pretty=0,Depth=1' lrecl=128; ``` The table was previously created as: ``` CREATE TABLE `sjr0` ( `_id` bigint(1) NOT NULL, `name` char(26) NOT NULL, `cuisine` char(8) NOT NULL, `grades` char(1) DEFAULT NULL, `grades_grade` char(1) DEFAULT NULL `JPATH`='$.grades[0].grade', `grades_score` bigint(1) DEFAULT NULL `JPATH`='$.grades[0].score' ) ENGINE=CONNECT DEFAULT CHARSET=latin1 `TABLE_TYPE`='JSON' `FILE_NAME`='sresto.json' `OPTION_LIST`='Pretty=0,Depth=1,Accept=1' `LRECL`=128; ``` The column “grades” was added because of the void array in line 2. Now this column is skipped and does not appear anymore (unless the option `Accept=1` is added in the option list). JSON Catalogue Tables --------------------- Another way to see JSON table column specifications is to use a catalogue table. For instance: ``` create table bibcol engine=connect table_type=JSON file_name='biblio3.json' option_list='level=2' catfunc=columns; select column_name, type_name type, column_size size, jpath from bibcol; ``` which returns: From Connect 1.07.0002: | column\_name | type | size | jpath | | --- | --- | --- | --- | | ISBN | CHAR | 13 | $.ISBN | | LANG | CHAR | 2 | $.LANG | | SUBJECT | CHAR | 12 | $.SUBJECT | | AUTHOR\_FIRSTNAME | CHAR | 15 | $.AUTHOR[0].FIRSTNAME | | AUTHOR\_LASTNAME | CHAR | 8 | $.AUTHOR[0].LASTNAME | | TITLE | CHAR | 30 | $.TITLE | | TRANSLATED\_PREFIX | CHAR | 23 | $.TRANSLATED.PREFIX | | TRANSLATED\_TRANSLATOR\_FIRSTNAME | CHAR | 5 | $TRANSLATED.TRANSLATOR.FIRSTNAME | | TRANSLATED\_TRANSLATOR\_LASTNAME | CHAR | 6 | $.TRANSLATED.TRANSLATOR.LASTNAME | | PUBLISHER\_NAME | CHAR | 15 | $.PUBLISHER.NAME | | PUBLISHER\_PLACE | CHAR | 5 | $.PUBLISHER.PLACE | | DATEPUB | INTEGER | 4 | $.DATEPUB | From Connect 1.6: | column\_name | type | size | jpath | | --- | --- | --- | --- | | ISBN | CHAR | 13 | | | LANG | CHAR | 2 | | | SUBJECT | CHAR | 12 | | | AUTHOR\_FIRSTNAME | CHAR | 15 | AUTHOR..FIRSTNAME | | AUTHOR\_LASTNAME | CHAR | 8 | AUTHOR..LASTNAME | | TITLE | CHAR | 30 | | | TRANSLATED\_PREFIX | CHAR | 23 | TRANSLATED.PREFIX | | TRANSLATED\_TRANSLATOR\_FIRSTNAME | CHAR | 5 | TRANSLATED.TRANSLATOR.FIRSTNAME | | TRANSLATED\_TRANSLATOR\_LASTNAME | CHAR | 6 | TRANSLATED.TRANSLATOR.LASTNAME | | PUBLISHER\_NAME | CHAR | 15 | PUBLISHER.NAME | | PUBLISHER\_PLACE | CHAR | 5 | PUBLISHER.PLACE | | DATEPUB | INTEGER | 4 | | Until Connect 1.5: | column\_name | type | size | jpath | | --- | --- | --- | --- | | ISBN | CHAR | 13 | | | LANG | CHAR | 2 | | | SUBJECT | CHAR | 12 | | | AUTHOR\_FIRSTNAME | CHAR | 15 | AUTHOR::FIRSTNAME | | AUTHOR\_LASTNAME | CHAR | 8 | AUTHOR::LASTNAME | | TITLE | CHAR | 30 | | | TRANSLATED\_PREFIX | CHAR | 23 | TRANSLATED:PREFIX | | TRANSLATED\_TRANSLATOR\_FIRSTNAME | CHAR | 5 | TRANSLATED:TRANSLATOR:FIRSTNAME | | TRANSLATED\_TRANSLATOR\_LASTNAME | CHAR | 6 | TRANSLATED:TRANSLATOR:LASTNAME | | PUBLISHER\_NAME | CHAR | 15 | PUBLISHER:NAME | | PUBLISHER\_PLACE | CHAR | 5 | PUBLISHER:PLACE | | DATEPUB | INTEGER | 4 | | All this is mostly useful when creating a table on a remote file that you cannot easily see. Finding the table within a JSON file ------------------------------------ Given the file “facebook.json”: ``` { "data": [ { "id": "X999_Y999", "from": { "name": "Tom Brady", "id": "X12" }, "message": "Looking forward to 2010!", "actions": [ { "name": "Comment", "link": "http://www.facebook.com/X999/posts/Y999" }, { "name": "Like", "link": "http://www.facebook.com/X999/posts/Y999" } ], "type": "status", "created_time": "2010-08-02T21:27:44+0000", "updated_time": "2010-08-02T21:27:44+0000" }, { "id": "X998_Y998", "from": { "name": "Peyton Manning", "id": "X18" }, "message": "Where's my contract?", "actions": [ { "name": "Comment", "link": "http://www.facebook.com/X998/posts/Y998" }, { "name": "Like", "link": "http://www.facebook.com/X998/posts/Y998" } ], "type": "status", "created_time": "2010-08-02T21:27:44+0000", "updated_time": "2010-08-02T21:27:44+0000" } ] } ``` The table we want to analyze is represented by the array value of the “data” object. Here is how this is specified in the create table statement: From Connect 1.07.0002: ``` create table jfacebook ( `ID` char(10) jpath='id', `Name` char(32) jpath='from.name', `MyID` char(16) jpath='from.id', `Message` varchar(256) jpath='message', `Action` char(16) jpath='actions..name', `Link` varchar(256) jpath='actions..link', `Type` char(16) jpath='type', `Created` datetime date_format='YYYY-MM-DD\'T\'hh:mm:ss' jpath='created_time', `Updated` datetime date_format='YYYY-MM-DD\'T\'hh:mm:ss' jpath='updated_time') engine=connect table_type=JSON file_name='facebook.json' option_list='Object=data,Expand=actions'; ``` From Connect 1.6: ``` create table jfacebook ( `ID` char(10) field_format='id', `Name` char(32) field_format='from.name', `MyID` char(16) field_format='from.id', `Message` varchar(256) field_format='message', `Action` char(16) field_format='actions..name', `Link` varchar(256) field_format='actions..link', `Type` char(16) field_format='type', `Created` datetime date_format='YYYY-MM-DD\'T\'hh:mm:ss' field_format='created_time', `Updated` datetime date_format='YYYY-MM-DD\'T\'hh:mm:ss' field_format='updated_time') engine=connect table_type=JSON file_name='facebook.json' option_list='Object=data,Expand=actions'; ``` Until Connect 1.5: ``` create table jfacebook ( `ID` char(10) field_format='id', `Name` char(32) field_format='from:name', `MyID` char(16) field_format='from:id', `Message` varchar(256) field_format='message', `Action` char(16) field_format='actions::name', `Link` varchar(256) field_format='actions::link', `Type` char(16) field_format='type', `Created` datetime date_format='YYYY-MM-DD\'T\'hh:mm:ss' field_format='created_time', `Updated` datetime date_format='YYYY-MM-DD\'T\'hh:mm:ss' field_format='updated_time') engine=connect table_type=JSON file_name='facebook.json' option_list='Object=data,Expand=actions'; ``` This is the object option that gives the Jpath of the table. Note also an alternate way to declare the array to be expanded by the expand option of the option\_list. Because some string values contain a date representation, the corresponding columns are declared as datetime and the date format is specified for them. The Jpath of the object option has the same syntax as the column Jpath but of course all array steps must be specified using the [n] (until Connect 1.5) or n (from Connect 1.6) format. Note: This applies to the whole document for tables having `PRETTY = 2` (see below). Otherwise, it applies to the document objects of each file records. JSON File Formats ----------------- The examples we have seen so far are files that, even they can be formatted in different ways (blanks, tabs, carriage return and line feed are ignored when parsing them), respect the JSON syntax and are made of only one item (Object or Array). Like for XML files, they are entirely parsed and a memory representation is made used to process them. This implies that they are of reasonable size to avoid an out of memory condition. Tables based on such files are recognized by the option Pretty=2 that we did not specify above because this is the default. An alternate format, which is the format of exported MongoDB files, is a file where each row is physically stored in one file record. For instance: ``` { "_id" : "01001", "city" : "AGAWAM", "loc" : [ -72.622739, 42.070206 ], "pop" : 15338, "state" : "MA" } { "_id" : "01002", "city" : "CUSHMAN", "loc" : [ -72.51564999999999, 42.377017 ], "pop" : 36963, "state" : "MA" } { "_id" : "01005", "city" : "BARRE", "loc" : [ -72.1083540000001, 42.409698 ], "pop" : 4546, "state" : "MA" } { "_id" : "01007", "city" : "BELCHERTOWN", "loc" : [ -72.4109530000001, 42.275103 ], "pop" : 10579, "state" : "MA" } … { "_id" : "99929", "city" : "WRANGELL", "loc" : [ -132.352918, 56.433524 ], "pop" : 2573, "state" : "AK" } { "_id" : "99950", "city" : "KETCHIKAN", "loc" : [ -133.18479, 55.942471 ], "pop" : 422, "state" : "AK" } ``` The original file, “cities.json”, has 29352 records. To base a table on this file we must specify the option Pretty=0 in the option list. For instance: From Connect 1.07.0002: ``` create table cities ( `_id` char(5) key, `city` char(32), `lat` double(12,6) jpath='loc.0', `long` double(12,6) jpath='loc.1', `pop` int(8), `state` char(2) distrib='clustered') engine=CONNECT table_type=JSON file_name='cities.json' lrecl=128 option_list='pretty=0'; ``` From Connect 1.6: ``` create table cities ( `_id` char(5) key, `city` char(32), `lat` double(12,6) field_format='loc.0', `long` double(12,6) field_format='loc.1', `pop` int(8), `state` char(2) distrib='clustered') engine=CONNECT table_type=JSON file_name='cities.json' lrecl=128 option_list='pretty=0'; ``` Until Connect 1.5: ``` create table cities ( `_id` char(5) key, `city` char(32), `long` double(12,6) field_format='loc:[0]', `lat` double(12,6) field_format='loc:[1]', `pop` int(8), `state` char(2) distrib='clustered') engine=CONNECT table_type=JSON file_name='cities.json' lrecl=128 option_list='pretty=0'; ``` Note the use of [n] (until Connect 1.5) or n (from Connect 1.6) array specifications for the longitude and latitude columns. When using this format, the table is processed by CONNECT like a DOS, CSV or FMT table. Rows are retrieved and parsed by records and the table can be very large. Another advantage is that such a table can be indexed, which can be of great value for very large tables. The “distrib” option of the “state” column tells CONNECT to use block indexing when possible. For such tables – as well as for *pretty=1* ones – the record size must be specified using the LRECL option. Be sure you don’t specify it too small as it is used to allocate the read/write buffers and the memory used for parsing the rows. If in doubt, be generous as it does not cost much in memory allocation. Another format exists, noted by Pretty=1, which is similar to this one but has some additions to represent a JSON array. A header and a trailer records are added containing the opening and closing square bracket, and all records but the last are followed by a comma. It has the same advantages for reading and updating, but inserting and deleting are executed in the pretty=2 way. Alternate Table Arrangement --------------------------- We have seen that the most natural way to represent a table in a JSON file is to make it on an array of objects. However, other possibilities exist. A table can be an array of arrays, a one column table can be an array of values, or a one row table can be just one object or one value. Single row tables are internally handled by adding a one value array around them. Let us see how to handle, for instance, a table that is an array of arrays. The file: ``` [ [56, "Coucou", 500.00], [[2,0,1,4], "Hello World", 2.0316], ["1784", "John Doo", 32.4500], [1914, ["Nabucho","donosor"], 5.12], [7, "sept", [0.77,1.22,2.01]], [8, "huit", 13.0] ] ``` A table can be created on this file as: From Connect 1.07.0002: ``` create table xjson ( `a` int(6) jpath='1', `b` char(32) jpath='2', `c` double(10,4) jpath='3') engine=connect table_type=JSON file_name='test.json' option_list='Pretty=1,Jmode=1,Base=1' lrecl=128; ``` From Connect 1.6: ``` create table xjson ( `a` int(6) field_format='1', `b` char(32) field_format='2', `c` double(10,4) field_format='3') engine=connect table_type=JSON file_name='test.json' option_list='Pretty=1,Jmode=1,Base=1' lrecl=128; ``` Until Connect 1.5: ``` create table xjson ( `a` int(6) field_format='[1]', `b` char(32) field_format='[2]', `c` double(10,4) field_format='[3]') engine=connect table_type=JSON file_name='test.json' option_list='Pretty=1,Jmode=1,Base=1' lrecl=128; ``` Columns are specified by their position in the row arrays. By default, this is zero-based but for this table the base was set to 1 by the *Base* option of the option list. Another new option in the option list is Jmode=1. It indicates what type of table this is. The Jmode values are: 1. An array of objects. This is the default. 2. An array of Array. Like this one. 3. An array of values. When reading, this is not required as the type of the array items is specified for the columns; however, it is required when inserting new rows so CONNECT knows what to insert. For instance: ``` insert into xjson values(25, 'Breakfast', 1.414); ``` After this, it is displayed as: | a | b | c | | --- | --- | --- | | 56 | Coucou | 500.0000 | | 2 | Hello World | 2.0316 | | 1784 | John Doo | 32.4500 | | 1914 | Nabucho | 5.1200 | | 7 | sept | 0.7700 | | 8 | huit | 13.0000 | | 25 | Breakfast | 1.4140 | Unspecified array values are represented by their first element. Getting and Setting JSON Representation of a Column --------------------------------------------------- We have seen that columns corresponding to a Json object or array are retrieved by default as the concatenation of all its values separated by a blank. It is also possible to retrieve and display such column contains as the full JSON string corresponding to it in the JSON file. This is specified in the JPATH by a “\*” where the object or array would be specified. Note: When having columns generated by discovery, this can be specified by adding the STRINGIFY option to ON or 1 in the option list. For instance: From Connect 1.07.0002: ``` create table jsample2 ( ISBN char(15), Lng char(2) jpath='LANG', json_Author char(255) jpath='AUTHOR.*', Title char(32) jpath='TITLE', Year int(4) jpath='DATEPUB') engine=CONNECT table_type=JSON file_name='biblio3.json'; ``` From Connect 1.6: ``` create table jsample2 ( ISBN char(15), Lng char(2) field_format='LANG', json_Author char(255) field_format='AUTHOR.*', Title char(32) field_format='TITLE', Year int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON file_name='biblio3.json'; ``` Until Connect 1.5: ``` create table jsample2 ( ISBN char(15), Lng char(2) field_format='LANG', json_Author char(255) field_format='AUTHOR:*', Title char(32) field_format='TITLE', Year int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON file_name='biblio3.json'; ``` Now the query: ``` select json_Author from jsample2; ``` will return and display : | json\_Author | | --- | | [{"FIRSTNAME":"Jean-Christophe","LASTNAME":"Bernadac"},{"FIRSTNAME":"François","LASTNAME":"Knab"}] | | [{"FIRSTNAME":"William J.","LASTNAME":"Pardi"}] | Note: Prefixing the column name by *json\_* is optional but is useful when using the column as argument to Connect UDF functions, making it to be surely recognized as valid Json without aliasing. This also works on input, a column specified so that it can be directly set to a valid JSON string. This feature is of great value as we will see below. Create, Read, Update and Delete Operations on JSON Tables --------------------------------------------------------- The SQL commands INSERT, UPDATE and DELETE are fully supported for JSON tables except those returned by REST queries. For INSERT and UPDATE, if the target values are simple values, there are no problems. However, there are some issues when the added or modified values are objects or arrays. Concerning objects, the same problems exist that we have already seen with the XML type. The added or modified object will have the format described in the table definition, which can be different from the one of the JSON file. Modifications should be done using a file specifying the full path of modified objects. New problems are raised when trying to modify the values of an array. Only updates can be done on the original table. First of all, for the values of the array to be distinct values, all update operations concerning array values must be done using a table expanding this array. For instance, to modify the authors of the `biblio.json` based table, the `jsampex` table must be used. Doing so, updating and deleting authors is possible using standard SQL commands. For example, to change the first name of Knab from François to John: ``` update jsampex set authorfn = 'John' where authorln = 'Knab'; ``` However It would be wrong to do: ``` update jsampex set authorfn = 'John' where isbn = '9782212090819'; ``` Because this would change the first name of both authors as they share the same ISBN. Where things become more difficult is when trying to delete or insert an author of a book. Indeed, a delete command will delete the whole book and an insert command will add a new complete row instead of adding a new author in the same array. Here we are penalized by the SQL language that cannot give us a way to specify this. Something like: ``` update jsampex add authorfn = 'Charles', authorln = 'Dickens' where title = 'XML en Action'; ``` However this does not exist in SQL. Does this mean that it is impossible to do it? No, but it requires us to use a table specified on the same file but adapted to this task. One way to do it is to specify a table for which the authors are no more an expanded array. Supposing we want to add an author to the “XML en Action” book. We will do it on a table containing just the author(s) of that book, which is the second book of the table. From Connect 1.6: ``` create table jauthor ( FIRSTNAME char(64), LASTNAME char(64)) engine=CONNECT table_type=JSON File_name='biblio3.json' option_list='Object=1.AUTHOR'; ``` Until Connect 1.5 ``` create table jauthor ( FIRSTNAME char(64), LASTNAME char(64)) engine=CONNECT table_type=JSON File_name='biblio3.json' option_list='Object=[1]:AUTHOR'; ``` The command: ``` select * from jauthor; ``` replies: | FIRSTNAME | LASTNAME | | --- | --- | | William J. | Pardi | It is a standard JSON table that is an array of objects in which we can freely insert or delete rows. ``` insert into jauthor values('Charles','Dickens'); ``` We can check that this was done correctly by: ``` select * from jsampex; ``` This will display: | ISBN | Title | AuthorFN | AuthorLN | Year | | --- | --- | --- | --- | --- | | 9782212090819 | Construire une application XML | Jean-Christophe | Bernadac | 1999 | | 9782212090819 | Construire une application XML | John | Knab | 1999 | | 9782840825685 | XML en Action | William J. | Pardi | 1999 | | 9782840825685 | XML en Action | Charles | Dickens | 1999 | Note: If this table were a big table with many books, it would be difficult to know what the order of a specific book is in the table. This can be found by adding a special ROWID column in the table. However, an alternate way to do it is by using direct JSON column representation as in the `JSAMPLE2` table. This can be done by: ``` update jsample2 set json_Author = '[{"FIRSTNAME":"William J.","LASTNAME":"Pardi"}, {"FIRSTNAME":"Charles","LASTNAME":"Dickens"}]' where isbn = '9782840825685'; ``` Here, we didn't have to find the index of the sub array to modify. However, this is not quite satisfying because we had to manually write the whole JSON value to set to the json\_Author column. Therefore we need specific functions to do so. They are introduced now. JSON User Defined Functions --------------------------- Although such functions written by other parties do exist,[[2](#_note-1)] CONNECT provides its own UDFs that are specifically adapted to the JSON table type and easily available because, being inside the CONNECT library or DLL, they require no additional module to be loaded (see [CONNECT - Compiling JSON UDFs in a Separate Library](../connect-compiling-json-udfs-in-a-separate-library/index) to make these functions in a separate library module). In particular, [MariaDB 10.2](../what-is-mariadb-102/index) and 10.3 feature native JSON functions. In some cases, it is possible that these native functions can be used. However, mixing native and UDF JSON functions in the same query often does not work because the way they recognize their arguments is different and might even cause a server crash. Here is the list of the CONNECT functions; more can be added if required. | Name | Type | Return | Description | Added | | --- | --- | --- | --- | --- | | jbin\_array | Function | STRING\* | Make a JSON array containing its arguments. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_array\_add | Function | STRING\* | Adds to its first array argument its second arguments. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_array\_add\_values | Function | STRING\* | Adds to its first array argument all following arguments. | | | jbin\_array\_delete | Function | STRING\* | Deletes the nth element of its first array argument. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_file | Function | STRING\* | Returns of a (json) file contain. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_get\_item | Function | STRING\* | Access and returns a json item by a JPATH key. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_insert\_item | Function | STRING | Insert item values located to paths. | | | jbin\_item\_merge | Function | STRING\* | Merges two arrays or two objects. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_object | Function | STRING\* | Make a JSON object containing its arguments. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_object\_nonull | Function | STRING\* | Make a JSON object containing its not null arguments. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_object\_add | Function | STRING\* | Adds to its first object argument its second argument. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_object\_delete | Function | STRING\* | Deletes the nth element of its first object argument. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_object\_key | Function | STRING\* | Make a JSON object for key/value pairs. | | | jbin\_object\_list | Function | STRING\* | Returns the list of object keys as an array. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jbin\_set\_item | Function | STRING | Set item values located to paths. | | | jbin\_update\_item | Function | STRING | Update item values located to paths. | | | jfile\_bjson | Function | STRING | Convert a pretty=0 file to another BJson file. | [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/), [MariaDB 10.4.18](https://mariadb.com/kb/en/mariadb-10418-release-notes/), [MariaDB 10.3.28](https://mariadb.com/kb/en/mariadb-10328-release-notes/), [MariaDB 10.2.36](https://mariadb.com/kb/en/mariadb-10236-release-notes/) | | jfile\_convert | Function | STRING | Convert a Json file to another pretty=0 file. | [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/), [MariaDB 10.4.18](https://mariadb.com/kb/en/mariadb-10418-release-notes/), [MariaDB 10.3.28](https://mariadb.com/kb/en/mariadb-10328-release-notes/), [MariaDB 10.2.36](https://mariadb.com/kb/en/mariadb-10236-release-notes/) | | jfile\_make | Function | STRING | Make a json file from its json item first argument. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_array | Function | STRING | Make a JSON array containing its arguments. | [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) until Connect 1.5 | | json\_array\_add | Function | STRING | Adds to its first array argument its second arguments (before [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/), all following arguments). | | | json\_array\_add\_values | Function | STRING | Adds to its first array argument all following arguments. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_array\_delete | Function | STRING | Deletes the nth element of its first array argument. | | | json\_array\_grp | Aggregate | STRING | Makes JSON arrays from coming argument. | | | json\_file | Function | STRING | Returns the contains of (json) file. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_get\_item | Function | STRING | Access and returns a json item by a JPATH key. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_insert\_item | Function | STRING | Insert item values located to paths. | | | json\_item\_merge | Function | STRING | Merges two arrays or two objects. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_locate\_all | Function | STRING | Returns the JPATH’s of all occurrences of an element. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_make\_array | Function | STRING | Make a JSON array containing its arguments. | From Connect 1.6 | | json\_make\_object | Function | STRING | Make a JSON object containing its arguments. | From Connect 1.6 | | json\_object | Function | STRING | Make a JSON object containing its arguments. | [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) until Connect 1.5 | | json\_object\_delete | Function | STRING | Deletes the nth element of its first object argument. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_object\_grp | Aggregate | STRING | Makes JSON objects from coming arguments. | | | json\_object\_list | Function | STRING | Returns the list of object keys as an array. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_object\_nonull | Function | STRING | Make a JSON object containing its not null arguments. | | | json\_serialize | Function | STRING | Serializes the return of a “Jbin” function. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | json\_set\_item | Function | STRING | Set item values located to paths. | | | json\_update\_item | Function | STRING | Update item values located to paths. | | | jsonvalue | Function | STRING | Make a JSON value from its unique argument. Called json\_value until [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) and [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) | | jsoncontains | Function | INTEGER | Returns 0 or 1 if an element is contained in the document. | | | jsoncontains\_path | Function | INTEGER | Returns 0 or 1 if a JPATH is contained in the document. | | | jsonget\_string | Function | STRING | Access and returns a string element by a JPATH key. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jsonget\_int | Function | INTEGER | Access and returns an integer element by a JPATH key. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jsonget\_real | Function | REAL | Access and returns a real element by a JPATH key. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | | jsonlocate | Function | STRING | Returns the JPATH to access one element. | [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) | String values are mapped to JSON strings. These strings are automatically escaped to conform to the JSON syntax. The automatic escaping is bypassed when the value has an alias beginning with ‘json\_’. This is automatically the case when a JSON UDF argument is another JSON UDF whose name begins with “json\_” (not case sensitive). This is why all functions that do not return a Json item are not prefixed by “json\_”. Argument string values, for some functions, can alternatively be json file names. When this is ambiguous, alias them as *jfile\_*. Full path should be used because UDF functions has no means to know what the current database is. Apparently, when the file name path is not full, it is based on the MariaDB data directory but I am not sure it is always true. Numeric values are (big) integers, double floating point values or decimal values. Decimal values are character strings containing a numeric representation and are treated as strings. Floating point values contain a decimal point and/or an exponent. Integers are written without decimal points. To install these functions execute the following commands :[[3](#_note-2)] Note: Json function names are often written on this page with leading upper case letters for clarity. It is possible to do so in SQL queries because function names are case insensitive. However, when creating or dropping them, their names must match the case they are in the library module (lower case from [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)). On Unix systems (from Connect 1.7.02): ``` create function jsonvalue returns string soname 'ha_connect.so'; create function json_make_array returns string soname 'ha_connect.so'; create function json_array_add_values returns string soname 'ha_connect.so'; create function json_array_add returns string soname 'ha_connect.so'; create function json_array_delete returns string soname 'ha_connect.so'; create function json_make_object returns string soname 'ha_connect.so'; create function json_object_nonull returns string soname 'ha_connect.so'; create function json_object_key returns string soname 'ha_connect.so'; create function json_object_add returns string soname 'ha_connect.so'; create function json_object_delete returns string soname 'ha_connect.so'; create function json_object_list returns string soname 'ha_connect.so'; create function json_object_values returns string soname 'ha_connect.so'; create function jsonset_grp_size returns integer soname 'ha_connect.so'; create function jsonget_grp_size returns integer soname 'ha_connect.so'; create aggregate function json_array_grp returns string soname 'ha_connect.so'; create aggregate function json_object_grp returns string soname 'ha_connect.so'; create function jsonlocate returns string soname 'ha_connect.so'; create function json_locate_all returns string soname 'ha_connect.so'; create function jsoncontains returns integer soname 'ha_connect.so'; create function jsoncontains_path returns integer soname 'ha_connect.so'; create function json_item_merge returns string soname 'ha_connect.so'; create function json_get_item returns string soname 'ha_connect.so'; create function jsonget_string returns string soname 'ha_connect.so'; create function jsonget_int returns integer soname 'ha_connect.so'; create function jsonget_real returns real soname 'ha_connect.so'; create function json_set_item returns string soname 'ha_connect.so'; create function json_insert_item returns string soname 'ha_connect.so'; create function json_update_item returns string soname 'ha_connect.so'; create function json_file returns string soname 'ha_connect.so'; create function jfile_make returns string soname 'ha_connect.so'; create function jfile_convert returns string soname 'ha_connect.so'; create function jfile_bjson returns string soname 'ha_connect.so'; create function json_serialize returns string soname 'ha_connect.so'; create function jbin_array returns string soname 'ha_connect.so'; create function jbin_array_add_values returns string soname 'ha_connect.so'; create function jbin_array_add returns string soname 'ha_connect.so'; create function jbin_array_delete returns string soname 'ha_connect.so'; create function jbin_object returns string soname 'ha_connect.so'; create function jbin_object_nonull returns string soname 'ha_connect.so'; create function jbin_object_key returns string soname 'ha_connect.so'; create function jbin_object_add returns string soname 'ha_connect.so'; create function jbin_object_delete returns string soname 'ha_connect.so'; create function jbin_object_list returns string soname 'ha_connect.so'; create function jbin_item_merge returns string soname 'ha_connect.so'; create function jbin_get_item returns string soname 'ha_connect.so'; create function jbin_set_item returns string soname 'ha_connect.so'; create function jbin_insert_item returns string soname 'ha_connect.so'; create function jbin_update_item returns string soname 'ha_connect.so'; create function jbin_file returns string soname 'ha_connect.so'; ``` On Unix systems (from Connect 1.6): ``` create function jsonvalue returns string soname 'ha_connect.so'; create function json_make_array returns string soname 'ha_connect.so'; create function json_array_add_values returns string soname 'ha_connect.so'; create function json_array_add returns string soname 'ha_connect.so'; create function json_array_delete returns string soname 'ha_connect.so'; create function json_make_object returns string soname 'ha_connect.so'; create function json_object_nonull returns string soname 'ha_connect.so'; create function json_object_key returns string soname 'ha_connect.so'; create function json_object_add returns string soname 'ha_connect.so'; create function json_object_delete returns string soname 'ha_connect.so'; create function json_object_list returns string soname 'ha_connect.so'; create function jsonset_grp_size returns integer soname 'ha_connect.so'; create function jsonget_grp_size returns integer soname 'ha_connect.so'; create aggregate function json_array_grp returns string soname 'ha_connect.so'; create aggregate function json_object_grp returns string soname 'ha_connect.so'; create function jsonlocate returns string soname 'ha_connect.so'; create function json_locate_all returns string soname 'ha_connect.so'; create function jsoncontains returns integer soname 'ha_connect.so'; create function jsoncontains_path returns integer soname 'ha_connect.so'; create function json_item_merge returns string soname 'ha_connect.so'; create function json_get_item returns string soname 'ha_connect.so'; create function jsonget_string returns string soname 'ha_connect.so'; create function jsonget_int returns integer soname 'ha_connect.so'; create function jsonget_real returns real soname 'ha_connect.so'; create function json_set_item returns string soname 'ha_connect.so'; create function json_insert_item returns string soname 'ha_connect.so'; create function json_update_item returns string soname 'ha_connect.so'; create function json_file returns string soname 'ha_connect.so'; create function jfile_make returns string soname 'ha_connect.so'; create function json_serialize returns string soname 'ha_connect.so'; create function jbin_array returns string soname 'ha_connect.so'; create function jbin_array_add_values returns string soname 'ha_connect.so'; create function jbin_array_add returns string soname 'ha_connect.so'; create function jbin_array_delete returns string soname 'ha_connect.so'; create function jbin_object returns string soname 'ha_connect.so'; create function jbin_object_nonull returns string soname 'ha_connect.so'; create function jbin_object_key returns string soname 'ha_connect.so'; create function jbin_object_add returns string soname 'ha_connect.so'; create function jbin_object_delete returns string soname 'ha_connect.so'; create function jbin_object_list returns string soname 'ha_connect.so'; create function jbin_item_merge returns string soname 'ha_connect.so'; create function jbin_get_item returns string soname 'ha_connect.so'; create function jbin_set_item returns string soname 'ha_connect.so'; create function jbin_insert_item returns string soname 'ha_connect.so'; create function jbin_update_item returns string soname 'ha_connect.so'; create function jbin_file returns string soname 'ha_connect.so'; ``` On Unix systems (from [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/) until Connect 1.5): ``` create function jsonvalue returns string soname 'ha_connect.so'; create function json_array returns string soname 'ha_connect.so'; create function json_array_add_values returns string soname 'ha_connect.so'; create function json_array_add returns string soname 'ha_connect.so'; create function json_array_delete returns string soname 'ha_connect.so'; create function json_object returns string soname 'ha_connect.so'; create function json_object_nonull returns string soname 'ha_connect.so'; create function json_object_key returns string soname 'ha_connect.so'; create function json_object_add returns string soname 'ha_connect.so'; create function json_object_delete returns string soname 'ha_connect.so'; create function json_object_list returns string soname 'ha_connect.so'; create function jsonset_grp_size returns integer soname 'ha_connect.so'; create function jsonget_grp_size returns integer soname 'ha_connect.so'; create aggregate function json_array_grp returns string soname 'ha_connect.so'; create aggregate function json_object_grp returns string soname 'ha_connect.so'; create function jsonlocate returns string soname 'ha_connect.so'; create function json_locate_all returns string soname 'ha_connect.so'; create function jsoncontains returns integer soname 'ha_connect.so'; create function jsoncontains_path returns integer soname 'ha_connect.so'; create function json_item_merge returns string soname 'ha_connect.so'; create function json_get_item returns string soname 'ha_connect.so'; create function jsonget_string returns string soname 'ha_connect.so'; create function jsonget_int returns integer soname 'ha_connect.so'; create function jsonget_real returns real soname 'ha_connect.so'; create function json_set_item returns string soname 'ha_connect.so'; create function json_insert_item returns string soname 'ha_connect.so'; create function json_update_item returns string soname 'ha_connect.so'; create function json_file returns string soname 'ha_connect.so'; create function jfile_make returns string soname 'ha_connect.so'; create function json_serialize returns string soname 'ha_connect.so'; create function jbin_array returns string soname 'ha_connect.so'; create function jbin_array_add_values returns string soname 'ha_connect.so'; create function jbin_array_add returns string soname 'ha_connect.so'; create function jbin_array_delete returns string soname 'ha_connect.so'; create function jbin_object returns string soname 'ha_connect.so'; create function jbin_object_nonull returns string soname 'ha_connect.so'; create function jbin_object_key returns string soname 'ha_connect.so'; create function jbin_object_add returns string soname 'ha_connect.so'; create function jbin_object_delete returns string soname 'ha_connect.so'; create function jbin_object_list returns string soname 'ha_connect.so'; create function jbin_item_merge returns string soname 'ha_connect.so'; create function jbin_get_item returns string soname 'ha_connect.so'; create function jbin_set_item returns string soname 'ha_connect.so'; create function jbin_insert_item returns string soname 'ha_connect.so'; create function jbin_update_item returns string soname 'ha_connect.so'; create function jbin_file returns string soname 'ha_connect.so'; ``` On WIndows (from Connect 1.7.02): ``` create function jsonvalue returns string soname 'ha_connect'; create function json_make_array returns string soname 'ha_connect'; create function json_array_add_values returns string soname 'ha_connect'; create function json_array_add returns string soname 'ha_connect'; create function json_array_delete returns string soname 'ha_connect'; create function json_make_object returns string soname 'ha_connect'; create function json_object_nonull returns string soname 'ha_connect'; create function json_object_key returns string soname 'ha_connect'; create function json_object_add returns string soname 'ha_connect'; create function json_object_delete returns string soname 'ha_connect'; create function json_object_list returns string soname 'ha_connect'; create function json_object_values returns string soname 'ha_connect'; create function jsonset_grp_size returns integer soname 'ha_connect'; create function jsonget_grp_size returns integer soname 'ha_connect'; create aggregate function json_array_grp returns string soname 'ha_connect'; create aggregate function json_object_grp returns string soname 'ha_connect'; create function jsonlocate returns string soname 'ha_connect'; create function json_locate_all returns string soname 'ha_connect'; create function jsoncontains returns integer soname 'ha_connect'; create function jsoncontains_path returns integer soname 'ha_connect'; create function json_item_merge returns string soname 'ha_connect'; create function json_get_item returns string soname 'ha_connect'; create function jsonget_string returns string soname 'ha_connect'; create function jsonget_int returns integer soname 'ha_connect'; create function jsonget_real returns real soname 'ha_connect'; create function json_set_item returns string soname 'ha_connect'; create function json_insert_item returns string soname 'ha_connect'; create function json_update_item returns string soname 'ha_connect'; create function json_file returns string soname 'ha_connect'; create function jfile_make returns string soname 'ha_connect'; create function jfile_convert returns string soname 'ha_connect'; create function jfile_bjson returns string soname 'ha_connect'; create function json_serialize returns string soname 'ha_connect'; create function jbin_array returns string soname 'ha_connect'; create function jbin_array_add_values returns string soname 'ha_connect'; create function jbin_array_add returns string soname 'ha_connect'; create function jbin_array_delete returns string soname 'ha_connect'; create function jbin_object returns string soname 'ha_connect'; create function jbin_object_nonull returns string soname 'ha_connect'; create function jbin_object_key returns string soname 'ha_connect'; create function jbin_object_add returns string soname 'ha_connect'; create function jbin_object_delete returns string soname 'ha_connect'; create function jbin_object_list returns string soname 'ha_connect'; create function jbin_item_merge returns string soname 'ha_connect'; create function jbin_get_item returns string soname 'ha_connect'; create function jbin_set_item returns string soname 'ha_connect'; create function jbin_insert_item returns string soname 'ha_connect'; create function jbin_update_item returns string soname 'ha_connect'; create function jbin_file returns string soname 'ha_connect'; ``` On WIndows (from Connect 1.6): ``` create function jsonvalue returns string soname 'ha_connect'; create function json_make_array returns string soname 'ha_connect'; create function json_array_add_values returns string soname 'ha_connect'; create function json_array_add returns string soname 'ha_connect'; create function json_array_delete returns string soname 'ha_connect'; create function json_make_object returns string soname 'ha_connect'; create function json_object_nonull returns string soname 'ha_connect'; create function json_object_key returns string soname 'ha_connect'; create function json_object_add returns string soname 'ha_connect'; create function json_object_delete returns string soname 'ha_connect'; create function json_object_list returns string soname 'ha_connect'; create function jsonset_grp_size returns integer soname 'ha_connect'; create function jsonget_grp_size returns integer soname 'ha_connect'; create aggregate function json_array_grp returns string soname 'ha_connect'; create aggregate function json_object_grp returns string soname 'ha_connect'; create function jsonlocate returns string soname 'ha_connect'; create function json_locate_all returns string soname 'ha_connect'; create function jsoncontains returns integer soname 'ha_connect'; create function jsoncontains_path returns integer soname 'ha_connect'; create function json_item_merge returns string soname 'ha_connect'; create function json_get_item returns string soname 'ha_connect'; create function jsonget_string returns string soname 'ha_connect'; create function jsonget_int returns integer soname 'ha_connect'; create function jsonget_real returns real soname 'ha_connect'; create function json_set_item returns string soname 'ha_connect'; create function json_insert_item returns string soname 'ha_connect'; create function json_update_item returns string soname 'ha_connect'; create function json_file returns string soname 'ha_connect'; create function jfile_make returns string soname 'ha_connect'; create function json_serialize returns string soname 'ha_connect'; create function jbin_array returns string soname 'ha_connect'; create function jbin_array_add_values returns string soname 'ha_connect'; create function jbin_array_add returns string soname 'ha_connect'; create function jbin_array_delete returns string soname 'ha_connect'; create function jbin_object returns string soname 'ha_connect'; create function jbin_object_nonull returns string soname 'ha_connect'; create function jbin_object_key returns string soname 'ha_connect'; create function jbin_object_add returns string soname 'ha_connect'; create function jbin_object_delete returns string soname 'ha_connect'; create function jbin_object_list returns string soname 'ha_connect'; create function jbin_item_merge returns string soname 'ha_connect'; create function jbin_get_item returns string soname 'ha_connect'; create function jbin_set_item returns string soname 'ha_connect'; create function jbin_insert_item returns string soname 'ha_connect'; create function jbin_update_item returns string soname 'ha_connect'; create function jbin_file returns string soname 'ha_connect'; ``` On WIndows (until Connect 1.5): ``` create function jsonvalue returns string soname 'ha_connect'; create function json_array returns string soname 'ha_connect'; create function json_array_add_values returns string soname 'ha_connect'; create function json_array_add returns string soname 'ha_connect'; create function json_array_delete returns string soname 'ha_connect'; create function json_object returns string soname 'ha_connect'; create function json_object_nonull returns string soname 'ha_connect'; create function json_object_key returns string soname 'ha_connect'; create function json_object_add returns string soname 'ha_connect'; create function json_object_delete returns string soname 'ha_connect'; create function json_object_list returns string soname 'ha_connect'; create function jsonset_grp_size returns integer soname 'ha_connect'; create function jsonget_grp_size returns integer soname 'ha_connect'; create aggregate function json_array_grp returns string soname 'ha_connect'; create aggregate function json_object_grp returns string soname 'ha_connect'; create function jsonlocate returns string soname 'ha_connect'; create function json_locate_all returns string soname 'ha_connect'; create function jsoncontains returns integer soname 'ha_connect'; create function jsoncontains_path returns integer soname 'ha_connect'; create function json_item_merge returns string soname 'ha_connect'; create function json_get_item returns string soname 'ha_connect'; create function jsonget_string returns string soname 'ha_connect'; create function jsonget_int returns integer soname 'ha_connect'; create function jsonget_real returns real soname 'ha_connect'; create function json_set_item returns string soname 'ha_connect'; create function json_insert_item returns string soname 'ha_connect'; create function json_update_item returns string soname 'ha_connect'; create function json_file returns string soname 'ha_connect'; create function jfile_make returns string soname 'ha_connect'; create function json_serialize returns string soname 'ha_connect'; create function jbin_array returns string soname 'ha_connect'; create function jbin_array_add_values returns string soname 'ha_connect'; create function jbin_array_add returns string soname 'ha_connect'; create function jbin_array_delete returns string soname 'ha_connect'; create function jbin_object returns string soname 'ha_connect'; create function jbin_object_nonull returns string soname 'ha_connect'; create function jbin_object_key returns string soname 'ha_connect'; create function jbin_object_add returns string soname 'ha_connect'; create function jbin_object_delete returns string soname 'ha_connect'; create function jbin_object_list returns string soname 'ha_connect'; create function jbin_item_merge returns string soname 'ha_connect'; create function jbin_get_item returns string soname 'ha_connect'; create function jbin_set_item returns string soname 'ha_connect'; create function jbin_insert_item returns string soname 'ha_connect'; create function jbin_update_item returns string soname 'ha_connect'; create function jbin_file returns string soname 'ha_connect'; ``` ### Jfile\_Bjson **MariaDB starting with [10.2.36](https://mariadb.com/kb/en/mariadb-10236-release-notes/)**JFile\_Bjson was introduced in [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/), [MariaDB 10.4.18](https://mariadb.com/kb/en/mariadb-10418-release-notes/), [MariaDB 10.3.28](https://mariadb.com/kb/en/mariadb-10328-release-notes/) and [MariaDB 10.2.36](https://mariadb.com/kb/en/mariadb-10236-release-notes/). ``` Jfile_Bjson(in_file_name, out_file_name, lrecl) ``` Converts the first argument pretty=0 json file to Bjson file. B(inary)json is a pre-parsed json format. It is described below in the Performance chapter (available in next Connect versions). ### Jfile\_Convert **MariaDB starting with [10.2.36](https://mariadb.com/kb/en/mariadb-10236-release-notes/)**JFile\_Convert was introduced in [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/), [MariaDB 10.4.18](https://mariadb.com/kb/en/mariadb-10418-release-notes/), [MariaDB 10.3.28](https://mariadb.com/kb/en/mariadb-10328-release-notes/) and [MariaDB 10.2.36](https://mariadb.com/kb/en/mariadb-10236-release-notes/). ``` Jfile_Convert(in_file_name, out_file_name, lrecl) ``` Converts the first argument json file to another *pretty=0* json file. The third integer argument is the record length to use. This is often required to process huge json files that would be very slow if they were in *pretty=2* format. This is done without completely parsing the file, is very fast and requires no big memory. ### Jfile\_Make **MariaDB starting with [10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)**Jfile\_Make was added in CONNECT 1.4 (from [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)). ``` Jfile_Make(arg1, arg2, [arg3], …) ``` The first argument must be a json item (if it is just a string, Jfile\_Make will try its best to see if it is a json item or an input file name). The following arguments are a string file name and an integer pretty value (defaulting to 2) in any order. This function creates a json file containing the first argument item. The returned string value is the created file name. If not specified as an argument, the file name can in some cases be retrieved from the first argument; in such cases the file itself is modified. This function can be used to create or format a json file. For instance, supposing we want to format the file tb.json, this can be done with the query: ``` select Jfile_Make('tb.json' jfile_, 2); ``` The tb.json file will be changed to: ``` [ { "_id": 5, "type": "food", "ratings": [ 5, 8, 9 ] }, { "_id": 6, "type": "car", "ratings": [ 5, 9 ] } ] ``` ### Json\_Array\_Add ``` Json_Array_Add(arg1, arg2, [arg3][, arg4][, ...]) ``` Note: In CONNECT version 1.3 (before [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)), this function behaved like the new `Json_Array_Add_Values` function. The following describes this function for CONNECT version 1.4 (from [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)) only. The first argument must be a JSON array. The second argument is added as member of this array. For example: ``` select Json_Array_Add(Json_Array(56,3.1416,'machin',NULL), 'One more') Array; ``` | Array | | --- | | [56,3.141600,"machin",null,"One more"] | Note: The first array is not escaped, its (alias) name beginning with ‘json\_’. Now we can see how adding an author to the JSAMPLE2 table can alternatively be done: ``` update jsample2 set json_author = json_array_add(json_author, json_object('Charles' FIRSTNAME, 'Dickens' LASTNAME)) where isbn = '9782840825685'; ``` Note: Calling a column returning JSON a name prefixed by json\_ (like json\_author here) is good practice and removes the need to give it an alias to prevent escaping when used as an argument. Additional arguments: If a third integer argument is given, it specifies the position (zero based) of the added value: ``` select Json_Array_Add('[5,3,8,7,9]' json_, 4, 2) Array; ``` | Array | | --- | | [5,3,4,8,7,9] | If a string argument is added, it specifies the Json path to the array to be modified. For instance: ``` select Json_Array_Add('{"a":1,"b":2,"c":[3,4]}' json_, 5, 1, 'c'); ``` | Json\_Array\_Add('{"a":1,"b":2,"c":[3, 4]}' json\_, 5, 1, 'c') | | --- | | {"a":1,"b":2,"c":[3,5,4]} | ### Json\_Array\_Add\_Values Json\_Array\_Add\_Values added in CONNECT 1.4 replaces the function Json\_Array\_Add of CONNECT version 1.3 (before [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)). ``` Json_Array_Add_Values(arg, arglist) ``` The first argument must be a JSON array string. Then all other arguments are added as members of this array. For example: ``` select Json_Array_Add_Values (Json_Array(56, 3.1416, 'machin', NULL), 'One more', 'Two more') Array; ``` | Array | | --- | | [56,3.141600,"machin",null,"One more","Two more"] | ### Json\_Array\_Delete ``` Json_Array_Delete(arg1, arg2 [,arg3] [...]) ``` The first argument should be a JSON array. The second argument is an integer indicating the rank (0 based conforming to general json usage) of the element to delete. For example: ``` select Json_Array_Delete(Json_Array(56,3.1416,'foo',NULL),1) Array; ``` | Array | | --- | | [56,"foo",null] | Now we can see how to delete the second author from the JSAMPLE2 table: ``` update jsample2 set json_author = json_array_delete(json_author, 1) where isbn = '9782840825685'; ``` A Json path can be specified as a third string argument ### Json\_Array\_Grp ``` Json_Array_Grp(arg) ``` This is an aggregate function that makes an array filled from values coming from the rows retrieved by a query. Let us suppose we have the pet table: | name | race | number | | --- | --- | --- | | John | dog | 2 | | Bill | cat | 1 | | Mary | dog | 1 | | Mary | cat | 1 | | Lisbeth | rabbit | 2 | | Kevin | cat | 2 | | Kevin | bird | 6 | | Donald | dog | 1 | | Donald | fish | 3 | The query: ``` select name, json_array_grp(race) from pet group by name; ``` will return: | | | | --- | --- | | name | json\_array\_grp(race) | | Bill | ["cat"] | | Donald | ["dog","fish"] | | John | ["dog"] | | Kevin | ["cat","bird"] | | Lisbeth | ["rabbit"] | | Mary | ["dog","cat"] | One problem with the JSON aggregate functions is that they construct their result in memory and cannot know the needed amount of storage, not knowing the number of rows of the used table. Therefore, the number of values for each group is limited. This limit is the value of JsonGrpSize whose default value is 10 but can be set using the JsonSet\_Grp\_Size function. Nevertheless, working on a larger table is possible, but only after setting JsonGrpSize to the ceiling of the number of rows per group for the table. Try not to set it to a very large value to avoid memory exhaustion. ### JsonContains ``` JsonContains(json_doc, item [, int])< ``` This function can be used to check whether an item is contained in a document. Its arguments are the same than the ones of the JsonLocate function; only the return value changes. The integer returned value is 1 is the item is contained in the document or 0 otherwise. ### JsonContains\_Path ``` JsonContains_Path(json_doc, path) ``` This function can be used to check whether a Json path is contained in the document. The integer returned value is 1 is the path is contained in the document or 0 otherwise. ### Json\_File ``` Json_File(arg1, [arg2, [arg3]], …) ``` The first argument must be a file name. This function returns the text of the file that is supposed to be a json file. If only one argument is specified, the file text is returned without being parsed. Up to two additional arguments can be specified: A string argument is the path to the sub-item to be returned. An integer argument specifies the pretty format value of the file. This function is chiefly used to get the json item argument of other json functions from a json file. For instance, supposing the file tb.json is: ``` { "_id" : 5, "type" : "food", "ratings" : [ 5, 8, 9 ] } { "_id" : 6, "type" : "car", "ratings" : [ 5, 9 ] } ``` Extracting a value from it can be done with a query such as: ``` select JsonGet_String(Json_File('tb.json', 0), '[1]:type') "Type"; ``` or, from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/): ``` select JsonGet_String(Json_File('tb.json', 0), '$[1].type') "Type"; ``` This query returns: | Type | | --- | | car | However, we’ll see that, most of the time, it is better to use Jbin\_File or to directly specify the file name in queries. In particular this function should not be used for queries that must modify the json item because, even if the modified json is returned, the file itself would be unchanged. ### Json\_Get\_Item **MariaDB starting with [10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)**Json\_Get\_Item was added in CONNECT 1.4 (from [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)). ``` Json_Get_Item(arg1, arg2, …) ``` This function returns a subset of the json document passed as first argument. The second argument is the json path of the item to be returned and should be one returning a json item (terminated by a ‘\*’). If not, the function will try to make it right but this is not foolproof. For instance: ``` select Json_Get_Item(Json_Object('foo' as "first", Json_Array('a', 33) as "json_second"), 'second') as "item"; ``` The correct path should have been ‘second:\*’ (or from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/), ‘second.\*’), but in this simple case the function was able to make it right. The returned item: | item | | --- | | ["a",33] | Note: The array is aliased “json\_second” to indicate it is a json item and avoid escaping it. However, the “json\_” prefix is skipped when making the object and must not be added to the path. ### JsonGet\_Grp\_Size ``` JsonGet_Grp_Size(val) ``` This function returns the JsonGrpSize value. ### JsonGet\_String / JsonGet\_Int / JsonGet\_Real **MariaDB starting with [10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)**JsonGet\_String, JsonGet\_Int and JsonGet\_Real were added in CONNECT 1.4 (from [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/)). ``` JsonGet_String(arg1, arg2, [arg3] …) JsonGet_Int(arg1, arg2, [arg3] …) JsonGet_Real(arg1, arg2, [arg3] …) ``` The first argument should be a JSON item. If it is a string with no alias, it will be converted as a json item. The second argument is the path of the item to be located in the first argument and returned, eventually converted according to the used function. For example: ``` select JsonGet_String('{"qty":7,"price":29.50,"garanty":null}','price') "String", JsonGet_Int('{"qty":7,"price":29.50,"garanty":null}','price') "Int", JsonGet_Real('{"qty":7,"price":29.50,"garanty":null}','price') "Real"; ``` This query returns: | String | Int | Real | | --- | --- | --- | | 29.50 | 29 | 29.500000000000000 | The function *JsonGet\_Real* can be given a third argument to specify the number of decimal digits of the returned value. For instance: ``` select JsonGet_Real('{"qty":7,"price":29.50,"garanty":null}','price',4) "Real"; ``` This query returns: | String | | --- | | 29.50 | The given path can specify all operators for arrays except the “expand” [X] operator (or from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/), the“expand” [\*] operator). For instance: ``` select JsonGet_Int(Json_Array(45,28,36,45,89), '[4]') "Rank", JsonGet_Int(Json_Array(45,28,36,45,89), '[#]') "Number", JsonGet_String(Json_Array(45,28,36,45,89), '[","]') "Concat", JsonGet_Int(Json_Array(45,28,36,45,89), '[+]') "Sum", JsonGet_Real(Json_Array(45,28,36,45,89), '[!]', 2) "Avg"; ``` The result: | Rank | Number | Concat | Sum | Avg | | --- | --- | --- | --- | --- | | 89 | 5 | 45,28,36,45,89 | 243 | 48.60 | ### Json\_Item\_Merge ``` Json_Item_Merge(arg1, arg2, …) ``` This function merges two arrays or two objects. For arrays, this is done by adding to the first array all the values of the second array. For instance: ``` select Json_Item_Merge(Json_Array('a','b','c'), Json_Array('d','e','f')) as "Result"; ``` The function returns: | Result | | --- | | ["a","b","c","d","e","f"] | For objects, the pairs of the second object are added to the first object if the key does not yet exist in it; otherwise the pair of the first object is set with the value of the matching pair of the second object. For instance: ``` select Json_Item_Merge(Json_Object(1 "a", 2 "b", 3 "c"), Json_Object(4 "d",5 "b",6 "f")) as "Result"; ``` The function returns: | Result | | --- | | {"a":1,"b":5,"c":3,"d":4,"f":6} | ### JsonLocate ``` JsonLocate(arg1, arg2, [arg3], …): ``` The first argument must be a JSON tree. The second argument is the item to be located. The item to be located can be a constant or a json item. Constant values must be equal in type and value to be found. This is "shallow equality" – strings, integers and doubles won't match. This function returns the json path to the located item or null if it is not found. For example: ``` select JsonLocate('{"AUTHORS":[{"FN":"Jules", "LN":"Verne"}, {"FN":"Jack", "LN":"London"}]}' json_, 'Jack') Path; ``` This query returns: | Path | | --- | | AUTHORS:[1]:FN | or, from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/): | Path | | --- | | $.AUTHORS[1].FN | The path syntax is the same used in JSON CONNECT tables. By default, the path of the first occurrence of the item is returned. The third parameter can be used to specify the occurrence whose path is to be returned. For instance: ``` select JsonLocate('[45,28,[36,45],89]',45) first, JsonLocate('[45,28,[36,45],89]',45,2) second, JsonLocate('[45,28,[36,45],89]',45.0) `wrong type`, JsonLocate('[45,28,[36,45],89]','[36,45]' json_) json; ``` | first | second | wrong type | json | | --- | --- | --- | --- | | [0] | [2]:[1] | <null> | [2] | or, from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/): | first | second | wrong type | json | | --- | --- | --- | --- | | $[0] | $[2][1] | <null> | $[2] | For string items, the comparison is case sensitive by default. However, it is possible to specify a string to be compared case insensitively by giving it an alias beginning by “ci”: ``` select JsonLocate('{"AUTHORS":[{"FN":"Jules", "LN":"Verne"}, {"FN":"Jack", "LN":"London"}]}' json_, 'VERNE' ci) Path; ``` | Path | | --- | | AUTHORS:[0]:LN | or, from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/): | Path | | --- | | $.AUTHORS[0].LN | ### Json\_Locate\_All ``` Json_Locate_All(arg1, arg2, [arg3], …): ``` The first argument must be a JSON item. The second argument is the item to be located. This function returns the paths to all locations of the item as an array of strings. For example: ``` select Json_Locate_All('[[45,28],[[36,45],89]]',45); ``` This query returns: | All paths | | --- | | ["[0]:[0]","[1]:[0]:[1]"] | or, from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/): | All paths | | --- | ["$[0][0]","$[1][0][1]"] The returned array can be applied other functions. For instance, to get the number of occurrences of an item in a json tree, you can do: ``` select JsonGet_Int(Json_Locate_All('[[45,28],[[36,45],89]]',45), '[#]') "Nb of occurs"; ``` or, from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/): ``` select JsonGet_Int(Json_Locate_All('[[45,28],[[36,45],89]]',45), '$[#]') "Nb of occurs"; ``` The displayed result: | Nb of occurs | | --- | | 2 | If specified, the third integer argument set the depth to search in the document. This means the maximum items in the paths (until [MariaDB 10.2.7](https://mariadb.com/kb/en/mariadb-1027-release-notes/), the number of ‘:’ separator characters in them plus one). This value defaults to 10 but can be increased for complex documents or reduced to set the maximum wanted depth of the returned paths. ### Json\_Make\_Array ``` Json_Make_Array(val1, …, valn) ``` This function was named “Json\_Array” in previous versions of CONNECT. It was renamed because [MariaDB 10.2](../what-is-mariadb-102/index) features native JSON functions including a [Json\_Array](../json_array/index) function. The native function does almost the same as the UDF one, but does not accept CONNECT-specific arguments such as the result from JBIN functions. Json\_Make\_Array returns a string denoting a JSON array with all its arguments as members. For example: ``` select Json_Make_Array(56, 3.1416, 'My name is "Foo"', NULL); ``` | Json\_Make\_Array(56, 3.1416, 'My name is "Foo"',N ULL) | | --- | | [56,3.141600,"My name is \"Foo\"",null] | Note: The argument list can be void. If so, a void array is returned. This function was named “Json\_Array” in previous versions of CONNECT. It was renamed because [MariaDB 10.2](../what-is-mariadb-102/index) features native JSON functions including a “Json\_Array” function. The native function does almost the same as the UDF one but does not accept CONNECT specific arguments such as the result from JBIN functions. ### Json\_Make\_Object ``` Json_Make_Object(arg1, …, argn) ``` This function was named “Json\_Object” in previous versions of CONNECT. It was renamed because [MariaDB 10.2](../what-is-mariadb-102/index) features native JSON functions including a [Json\_Object](../json_object/index) function. The native function does what the UDF Json\_Object\_Key does. Json\_Make\_Object returns a string denoting a JSON object. For instance: ``` select Json_Make_Object(56, 3.1416, 'machin', NULL); ``` The object is filled with pairs corresponding to the given arguments. The key of each pair is made from the argument (default or specified) alias. | Json\_Make\_Object(56, 3.1416, 'machin', NULL) | | --- | | {"56":56,"3.1416":3.141600,"machin":"machin","NULL":null} | When needed, it is possible to specify the keys by giving an alias to the arguments: ``` select Json_Make_Object(56 qty, 3.1416 price, 'machin' truc, NULL garanty); ``` | Json\_Make\_Object(56 qty,3.1416 price,'machin' truc, NULL garanty) | | --- | | {"qty":56,"price":3.141600,"truc":"machin","garanty":null} | If the alias is prefixed by ‘json\_’ (to prevent escaping) the key name is stripped from that prefix. This function is chiefly useful when entering values retrieved from a table, the key being by default the column name: ``` select Json_Make_Object(matricule, nom, titre, salaire) from connect.employe where nom = 'PANTIER'; ``` | Json\_Make\_Object(matricule, nom, titre, salaire) | | --- | | {"matricule":40567,"nom":"PANTIER","titre":"DIRECTEUR","salaire":14000.000000} | This function was named “Json\_Object” in previous versions of CONNECT. It was renamed because [MariaDB 10.2](../what-is-mariadb-102/index) features native JSON functions including a “Json\_Object” function. The native function does what the UDF Json\_Object\_Key does. ### Json\_Object\_Add ``` Json_Object_Add(arg1, arg2, [arg3] …) ``` The first argument must be a JSON object. The second argument is added as a pair to this object. For example: ``` select Json_Object_Add ('{"item":"T-shirt","qty":27,"price":24.99}' json_old,'blue' color) newobj; ``` | newobj | | --- | | {"item":"T-shirt","qty":27,"price":24.990000,"color":"blue"} | Note: If the specified key already exists in the object, its value is replaced by the new one. The third string argument is a Json path to the target object. ### Json\_Object\_Delete ``` Json_Object_Delete(arg1, arg2, [arg3] …): ``` The first argument must be a JSON object. The second argument is the key of the pair to delete. For example: ``` select Json_Object_Delete('{"item":"T-shirt","qty":27,"price":24.99}' json_old, 'qty') newobj; ``` | newobj | | --- | | {"item":"T-shirt","price":24.99} | The third string argument is a Json path to the object to be the target of deletion. ### Json\_Object\_Grp ``` Json_Object_Grp(arg1,arg2) ``` This function works like Json\_Array\_Grp. It makes a JSON object filled with value pairs whose keys are passed from its first argument and values are passed from its second argument. This can be seen with the query: ``` select name, json_object_grp(number,race) from pet group by name; ``` This query returns: | name | json\_object\_grp(number,race) | | --- | --- | | Bill | {"cat":1} | | Donald | {"dog":1,"fish":3} | | John | {"dog":2} | | Kevin | {"cat":2,"bird":6} | | Lisbeth | {"rabbit":2} | | Mary | {"dog":1,"cat":1} | ### Json\_Object\_Key ``` Json_Object_Key([key1, val1 [, …, keyn, valn]]) ``` Return a string denoting a JSON object. For instance: ``` select Json_Object_Key('qty', 56, 'price', 3.1416, 'truc', 'machin', 'garanty', NULL); ``` The object is filled with pairs made from each key/value arguments. | Json\_Object\_Key('qty', 56, 'price', 3.1416, 'truc', 'machin', 'garanty', NULL) | | --- | | {"qty":56,"price":3.141600,"truc":"machin","garanty":null} | ### Json\_Object\_List ``` Json_Object_List(arg1, …): ``` The first argument must be a JSON object. This function returns an array containing the list of all keys existing in the object. For example: ``` select Json_Object_List(Json_Object(56 qty,3.1416 price,'machin' truc, NULL garanty)) "Key List"; ``` | Key List | | --- | | ["qty","price","truc","garanty"] | ### Json\_Object\_Nonull ``` Json_Object_Nonull(arg1, …, argn) ``` This function works like [Json\_Make\_Object](#json_make_object) but “null” arguments are ignored and not inserted in the object. Arguments are regarded as “null” if they are JSON null values, void arrays or objects, or arrays or objects containing only null members. It is mainly used to avoid constructing useless null items when converting tables (see later). ### Json\_Object\_Values ``` Json_Object_Values(json_object) ``` The first argument must be a JSON object. This function returns an array containing the list of all values existing in the object. For example: ``` select Json_Object_Values('{"One":1,"Two":2,"Three":3}') "Value List"; ``` | Value List | | --- | | [1,2,3] | ### JsonSet\_Grp\_Size ``` JsonSet_Grp_Size(val) ``` This function is used to set the JsonGrpSize value. This value is used by the following aggregate functions as a ceiling value of the number of items in each group. It returns the JsonGrpSize value that can be its default value when passed 0 as argument. ### Json\_Set\_Item / Json\_Insert\_Item / Json\_Update\_Item ``` Json_{Set | Insert | Update}_Item(json_doc, [item, path [, val, path …]]) ``` These functions insert or update data in a JSON document and return the result. The value/path pairs are evaluated left to right. The document produced by evaluating one pair becomes the new value against which the next pair is evaluated. * Json\_Set\_Item replaces existing values and adds non-existing values. * Json\_Insert\_Item inserts values without replacing existing values. * Json\_Update\_Item replaces only existing values. Example: ``` set @j = Json_Array(1, 2, 3, Json_Object_Key('quatre', 4)); select Json_Set_Item(@j, 'foo', '[1]', 5, '[3]:cinq') as "Set", Json_Insert_Item(@j, 'foo', '[1]', 5, '[3]:cinq') as "Insert", Json_Update_Item(@j, 'foo', '[1]', 5, '[3]:cinq') as "Update"; ``` or, from [MariaDB 10.2.8](https://mariadb.com/kb/en/mariadb-1028-release-notes/): ``` set @j = Json_Array(1, 2, 3, Json_Object_Key('quatre', 4)); select Json_Set_Item(@j, 'foo', '$[1]', 5, '$[3].cinq') as "Set", Json_Insert_Item(@j, 'foo', '$[1]', 5, '$[3].cinq') as "Insert", Json_Update_Item(@j, 'foo', '$[1]', 5, '$[3].cinq') as "Update"; ``` This query returns: | Set | Insert | Update | | --- | --- | --- | | [1,"foo",3,{"quatre":4,"cinq":5}] | [1,2,3,{"quatre":4,"cinq":5}] | [1,"foo",3,{"quatre":4}] | ### JsonValue ``` JsonValue (val) ``` Returns a JSON value as a string, for instance: ``` select JsonValue(3.1416); ``` | JsonValue(3.1416) | | --- | | 3.141600 | Before [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/), this function was called Json\_Value, but was renamed to avoid clashing with the [JSON\_VALUE](../json_value/index) function. The “JBIN” return type ---------------------- Almost all functions returning a json string - whose name begins with *Json\_* - have a counterpart with a name beginning with *Jbin\_*. This is both for performance (speed and memory) as well as for better control of what the functions should do. This is due to the way CONNECT UDFs work internally. The Json functions, when receiving json strings as parameters, parse them and construct a binary tree in memory. They work on this tree and before returning; serialize this tree to return a new json string. If the json document is large, this can take up a large amount of time and storage space. It is all right when one simple json function is called – it must be done anyway – but is a waste of time and memory when json functions are used as parameters to other json functions. To avoid multiple serializing and parsing, the Jbin functions should be used as parameters to other functions. Indeed, they do not serialize the memory document tree, but return a structure allowing the receiving function to have direct access to the memory tree. This saves the serialize-parse steps otherwise needed to pass the argument and removes the need to reallocate the memory of the binary tree, which by the way is 6 to 7 times the size of the json string. For instance: ``` select Json_Object(Jbin_Array_Add(Jbin_Array('a','b','c'), 'd') as "Jbin_foo") as "Result"; ``` This query returns: | Result | | --- | | {"foo":["a","b","c","d"]} | Here the binary json tree allocated by *Jbin\_Array* is completed by *Jbin\_Array\_Add* and *Json\_Object* and serialized only once to make the final result string. It would be serialized and parsed two more times if using “Json” functions. Note that Jbin results are recognized as such because they are aliased beginning with “Jbin\_”. This is why in the *Json\_Object* function the alias is specified as “Jbin\_foo”. What happens if it is not recognized as such? These functions are declared as returning a string and to take care of this, the returned structure begins with a zero-terminated string. For instance: ``` select Jbin_Array('a','b','c'); ``` This query replies: | Jbin\_Array('a','b','c') | | --- | | Binary Json array | Note: When testing, the tree returned by a “Jbin” function can be seen using the *Json\_Serialize* function whose unique parameter must be a “Jbin” result. For instance: ``` select Json_Serialize(Jbin_Array('a','b','c')); ``` This query returns: | Json\_Serialize(Jbin\_Array('a','b','c')) | | --- | | ["a","b","c"] | Note: For this simple example, this is equivalent to using the *Json\_Array* function. ### Using a file as json UDF first argument We have seen that many json UDFs can have an additional argument not yet described. This is in the case where the json item argument was referring to a file. Then the additional integer argument is the pretty value of the json file. It matters only when the first argument is just a file name (to make the UDF understand this argument is a file name, it should be aliased with a name beginning with jfile\_) or if the function modifies the file, in which case it will be rewritten with this pretty format. The json item is created by extracting the required part from the file. This can be the whole file but more often only some of it. There are two ways to specify the sub-item of the file to be used: 1. Specifying it in the *Json\_File* or *Jbin\_File* arguments. 2. Specifying it in the receiving function (not possible for all functions). It doesn’t make any difference when the *Jbin\_File* is used but it does with *Json\_File*. For instance: ``` select Jfile_Make('{"a":1, "b":[44, 55]}' json_, 'test.json'); select Json_Array_Add(Json_File('test.json', 'b'), 66); ``` The second query returns: | Json\_Array\_Add(Json\_File('test.json', 'b'), 66) | | --- | | [44,55,66] | It just returns the – modified -- subset returned by the Json\_File function, while the query: ``` select Json_Array_Add(Json_File('test.json'), 66, 'b'); ``` returns what was received from *Json\_File* with the modification made on the subset. | Json\_Array\_Add(Json\_File('test.json'), 66, 'b') | | --- | | {"a":1,"b":[44,55,66]} | Note that in both case the test.json file is not modified. This is because the *Json\_File* function returns a string representing all or part of the file text but no information about the file name. This is all right to check what would be the effect of the modification to the file. However, to have the file modified, use the *Jbin\_File* function or directly give the file name. *Jbin\_File* returns a structure containing the file name, a pointer to the file parsed tree and eventually a pointer to the subset when a path is given as a second argument: ``` select Json_Array_Add(Jbin_File('test.json', 'b'), 66); ``` This query returns: | Json\_Array\_Add(Jbin\_File('test.json', 'b'), 66) | | --- | | test.json | This time the file is modified. This can be checked with: ``` select Json_File('test.json', 3); ``` | Json\_File('test.json', 3) | | --- | | {"a":1,"b":[44,55,66]} | The reason why the first argument is returned by such a query is because of tables such as: ``` create table tb ( n int key, jfile_cols char(10) not null); insert into tb values(1,'test.json'); ``` In this table, the *jfile\_cols* column just contains a file name. If we update it by: ``` update tb set jfile_cols = select Json_Array_Add(Jbin_File('test.json', 'b'), 66) where n = 1; ``` This is the test.json file that must be modified, not the jfile\_cols column. This can be checked by: ``` select JsonGet_String(jfile_cols, '[1]:*') from tb; ``` | JsonGet\_String(jfile\_cols, '[1]:\*') | | --- | | {"a":1,"b":[44,55,66]} | Note: It was an important facility to name the second column of the table beginning by “jfile\_” so the json functions knew it was a file name without obliging to specify an alias in the queries. ### Using “Jbin” to control what the query execution does This is applying in particular when acting on json files. We have seen that a file was not modified when using the *Json\_File* function as an argument to a modifying function because the modifying function just received a copy of the json file. This is not true when using the *Jbin\_File* function that does not serialize the binary document and make it directly accessible. Also, as we have seen earlier, json functions that modify their first file parameter modify the file and return the file name. This is done by directly serializing the internal binary document as a file. However, the “Jbin” counterpart of these functions does not serialize the binary document and thus does not modify the json file. For example let us compare these two queries: /\* First query \*/ ``` select Json_Object(Jbin_Object_Add(Jbin_File('bt2.json'), 4 as "d") as "Jbin_bt1") as "Result"; ``` /\* Second query \*/ ``` select Json_Object(Json_Object_Add(Jbin_File('bt2.json'), 4 as "d") as "Jfile_bt1") as "Result"; ``` Both queries return: | Result | | --- | | {"bt1":{"a":1,"b":2,"c":3,"d":4}} | In the first query *Jbin\_Object\_Add* does not serialize the document (no “Jbin” functions do) and *Json\_Object* just returns a serialized modified tree. Consequently, the file bt2.json is not modified. This query is all right to copy a modified version of the json file without modifying it. However, in the second query *Json\_Object\_Add* does modify the json file and returns the file name. The *Json\_Object* function receives this file name, reads and parses the file, makes an object from it and returns the serialized result. This modification can be done willingly but can be an unwanted side effect of the query. Therefore, using “Jbin” argument functions, in addition to being faster and using less memory, are also safer when dealing with json files that should not be modified. Using JSON as Dynamic Columns ----------------------------- The JSON nosql language has all the features to be used as an alternative to dynamic columns. For instance, take the following example of dynamic columns: ``` create table assets ( item_name varchar(32) primary key, /* A common attribute for all items */ dynamic_cols blob /* Dynamic columns will be stored here */ ); INSERT INTO assets VALUES ('MariaDB T-shirt', COLUMN_CREATE('color', 'blue', 'size', 'XL')); INSERT INTO assets VALUES ('Thinkpad Laptop', COLUMN_CREATE('color', 'black', 'price', 500)); SELECT item_name, COLUMN_GET(dynamic_cols, 'color' as char) AS color FROM assets; +-----------------+-------+ | item_name | color | +-----------------+-------+ | MariaDB T-shirt | blue | | Thinkpad Laptop | black | +-----------------+-------+ ``` /\* Remove a column: \*/ ``` UPDATE assets SET dynamic_cols=COLUMN_DELETE(dynamic_cols, "price") WHERE COLUMN_GET(dynamic_cols, 'color' as char)='black'; ``` /\* Add a column: \*/ ``` UPDATE assets SET dynamic_cols=COLUMN_ADD(dynamic_cols, 'warranty', '3 years') WHERE item_name='Thinkpad Laptop'; ``` /\* You can also list all columns, or get them together with their values in JSON format: \*/ ``` SELECT item_name, column_list(dynamic_cols) FROM assets; +-----------------+---------------------------+ | item_name | column_list(dynamic_cols) | +-----------------+---------------------------+ | MariaDB T-shirt | `size`,`color` | | Thinkpad Laptop | `color`,`warranty` | +-----------------+---------------------------+ SELECT item_name, COLUMN_JSON(dynamic_cols) FROM assets; +-----------------+----------------------------------------+ | item_name | COLUMN_JSON(dynamic_cols) | +-----------------+----------------------------------------+ | MariaDB T-shirt | {"size":"XL","color":"blue"} | | Thinkpad Laptop | {"color":"black","warranty":"3 years"} | +-----------------+----------------------------------------+ ``` The same result can be obtained with json columns using the json UDF’s: /\* JSON equivalent \*/ ``` create table jassets ( item_name varchar(32) primary key, /* A common attribute for all items */ json_cols varchar(512) /* Jason columns will be stored here */ ); INSERT INTO jassets VALUES ('MariaDB T-shirt', Json_Object('blue' color, 'XL' size)); INSERT INTO jassets VALUES ('Thinkpad Laptop', Json_Object('black' color, 500 price)); SELECT item_name, JsonGet_String(json_cols, 'color') AS color FROM jassets; +-----------------+-------+ | item_name | color | +-----------------+-------+ | MariaDB T-shirt | blue | | Thinkpad Laptop | black | +-----------------+-------+ ``` /\* Remove a column: \*/ ``` UPDATE jassets SET json_cols=Json_Object_Delete(json_cols, 'price') WHERE JsonGet_String(json_cols, 'color')='black'; ``` /\* Add a column \*/ ``` UPDATE jassets SET json_cols=Json_Object_Add(json_cols, '3 years' warranty) WHERE item_name='Thinkpad Laptop'; ``` /\* You can also list all columns, or get them together with their values in JSON format: \*/ ``` SELECT item_name, Json_Object_List(json_cols) FROM jassets; +-----------------+-----------------------------+ | item_name | Json_Object_List(json_cols) | +-----------------+-----------------------------+ | MariaDB T-shirt | ["color","size"] | | Thinkpad Laptop | ["color","warranty"] | +-----------------+-----------------------------+ SELECT item_name, json_cols FROM jassets; +-----------------+----------------------------------------+ | item_name | json_cols | +-----------------+----------------------------------------+ | MariaDB T-shirt | {"color":"blue","size":"XL"} | | Thinkpad Laptop | {"color":"black","warranty":"3 years"} | +-----------------+----------------------------------------+ ``` However, using JSON brings features not existing in dynamic columns: * Use of a language used by many implementation and developers. * Full support of arrays, currently missing from dynamic columns. * Access of subpart of json by JPATH that can include calculations on arrays. * Possible references to json files. With more experience, additional UDFs can be easily written to support new needs. New Set of BSON Functions ------------------------- All these functions have been rewritten using the new JSON handling way and are temporarily available changing the J starting name to B. Then Json\_Make\_Array new style is called using Bson\_Make\_Array. Some, such as Bson\_Item\_Delete, are new and some fix bugs found in their Json counterpart. Converting Tables to JSON ------------------------- The JSON UDF’s and the direct Jpath “\*” facility are powerful tools to convert table and files to the JSON format. For instance, the file `biblio3.json` we used previously can be obtained by converting the `xsample.xml file`. This can be done like this: From Connect 1.07.0002 ``` create table xj1 (row varchar(500) jpath='*') engine=connect table_type=JSON file_name='biblio3.json' option_list='jmode=2'; ``` Before Connect 1.07.0002 ``` create table xj1 (row varchar(500) field_format='*') engine=connect table_type=JSON file_name='biblio3.json' option_list='jmode=2'; ``` And then : ``` insert into xj1 select json_object_nonull(ISBN, language LANG, SUBJECT, json_array_grp(json_object(authorfn FIRSTNAME, authorln LASTNAME)) json_AUTHOR, TITLE, json_object(translated PREFIX, json_object(tranfn FIRSTNAME, tranln LASTNAME) json_TRANSLATOR) json_TRANSLATED, json_object(publisher NAME, location PLACE) json_PUBLISHER, date DATEPUB) from xsampall2 group by isbn; ``` The xj1 table rows will directly receive the Json object made by the select statement used in the insert statement and the table file will be made as shown (xj1 is pretty=2 by default) Its mode is Jmode=2 because the values inserted are strings even if they denote json objects. Another way to do this is to create a table describing the file format we want before the `biblio3.json` file existed: From Connect 1.07.0002 ``` create table jsampall3 ( ISBN char(15), LANGUAGE char(2) jpath='LANG', SUBJECT char(32), AUTHORFN char(128) jpath='AUTHOR:[X]:FIRSTNAME', AUTHORLN char(128) jpath='AUTHOR:[X]:LASTNAME', TITLE char(32), TRANSLATED char(32) jpath='TRANSLATOR:PREFIX', TRANSLATORFN char(128) jpath='TRANSLATOR:FIRSTNAME', TRANSLATORLN char(128) jpath='TRANSLATOR:LASTNAME', PUBLISHER char(20) jpath='PUBLISHER:NAME', LOCATION char(20) jpath='PUBLISHER:PLACE', DATE int(4) jpath='DATEPUB') engine=CONNECT table_type=JSON file_name='biblio3.json'; ``` Before Connect 1.07.0002 ``` create table jsampall3 ( ISBN char(15), LANGUAGE char(2) field_format='LANG', SUBJECT char(32), AUTHORFN char(128) field_format='AUTHOR:[X]:FIRSTNAME', AUTHORLN char(128) field_format='AUTHOR:[X]:LASTNAME', TITLE char(32), TRANSLATED char(32) field_format='TRANSLATOR:PREFIX', TRANSLATORFN char(128) field_format='TRANSLATOR:FIRSTNAME', TRANSLATORLN char(128) field_format='TRANSLATOR:LASTNAME', PUBLISHER char(20) field_format='PUBLISHER:NAME', LOCATION char(20) field_format='PUBLISHER:PLACE', DATE int(4) field_format='DATEPUB') engine=CONNECT table_type=JSON file_name='biblio3.json'; ``` and to populate it by: ``` insert into jsampall3 select * from xsampall; ``` This is a simpler method. However, the issue is that this method cannot handle the multiple column values. This is why we inserted from `xsampall` not from `xsampall2`. How can we add the missing multiple authors in this table? Here again we must create a utility table able to handle JSON strings. From Connect 1.07.0002 ``` create table xj2 (ISBN char(15), author varchar(150) jpath='AUTHOR:*') engine=connect table_type=JSON file_name='biblio3.json' option_list='jmode=1'; ``` Before Connect 1.07.0002 ``` create table xj2 (ISBN char(15), author varchar(150) field_format='AUTHOR:*') engine=connect table_type=JSON file_name='biblio3.json' option_list='jmode=1'; ``` ``` update xj2 set author = (select json_array_grp(json_object(authorfn FIRSTNAME, authorln LASTNAME)) from xsampall2 where isbn = xj2.isbn); ``` Voilà ! Converting json files --------------------- We have seen that json files can be formatted differently depending on the pretty option. In particular, big data files should be formatted with pretty equal to 0 when used by a CONNECT json table. The best and simplest way to convert a file from one format to another is to use the *Jfile\_Make* function. Indeed this function makes a file of specified format using the syntax: ``` Jfile_Make(json_document, [file_name], [pretty]); ``` The file name is optional when the json document comes from a Jbin\_File function because the returned structure makes it available. For instance, to convert back the json file tb.json to pretty= 0, this can be simply done by: ``` select Jfile_Make(Jbin_File('tb.json'), 0); ``` Performance Consideration ------------------------- MySQL and PostgreSQL have a JSON data type that is not just text but an internal encoding of JSON data. This is to save parsing time when executing JSON functions. Of course, the parse must be done anyway when creating the data and serializing must be done to output the result. CONNECT directly works on character strings impersonating JSON values with the need of parsing them all the time but with the advantage of working easily on external data. Generally, this is not too penalizing because JSON data are often of some or reasonable size. The only case where it can be a serious problem is when working on a big JSON file. Then, the file should be formatted or converted to *pretty=0*. From Connect 1.7.002, this easily done using the Jfile\_Convert function, for instance: ``` select jfile_convert('bibdoc.json','bibdoc0.json',350); ``` Such a json file should not be used directly by JSON UDFs because they parse the whole file, even when only a subset is used. Instead, it should be used by a JSON table created on it. Indeed, JSON tables do not parse the whole document but just the item corresponding to the row they are working on. In addition, indexing can be used by the table as explained previously on this page. Generally speaking, the maximum flexibility offered by CONNECT is by using JSON tables and JSON UDFs together. Some things are better handled by tables, other by UDFs. The tools are there but it is up to you to discover the best way to resolve your problems. ### Bjson files Starting with Connect 1.7.002, *pretty=0* json files can be converted to a binary format that is a pre-parsed representation of json. This can be done with the Jfile\_Bjson UDF function, for instance: ``` select jfile_bjson('bigfile.json','binfile.json',3500); ``` Here the third argument, the record length, must 6 to 10 times larger than the lrecl of the initial json file because the parsed representation is bigger than the original json text representation. Tables using such Bjson files must specify ‘Pretty=-1’ in the option list. It is probably similar to the BSON used by MongoDB and PostgreSQL and permits to process queries up to 10 times faster than working on text json files. Indexing is also available for tables using this format making even more performance improvement. For instance, some queries on a json table of half a million rows, that were previously done in more than 10 seconds, took only 0.1 second when converted and indexed. Here again, this has been remade to use the new way Json is handled. The files made using the bfile\_bjson function are only from two to four times the size of the source files. This new representation is not compatible with the old one. Therefore, these files must be used with BSON tables only. Specifying a JSON table Encoding -------------------------------- An important feature of JSON is that strings should in UNICODE. As a matter of fact, all examples we have found on the Internet seemed to be just ASCII. This is because UNICODE is generally encoded in JSON files using UTF8 or UTF16 or UTF32. To specify the required encoding, just use the data\_charset CONNECT option or the native DEFAULT CHARSET option. Retrieving JSON data from MongoDB --------------------------------- Classified as a NoSQL database program, MongoDB uses JSON-like documents (BSON) grouped in collections. The simplest way, and only method available before Connect 1.6, to access MongoDB data was to export a collection to a JSON file. This produces a file having the pretty=0 format. Viewed as SQL, a collection is a table and documents are table rows. Since CONNECT version 1.6, it is now possible to directly access MongoDB collections via their MongoDB C Driver. This is the purpose of the MONGO table type described later. However, JSON tables can also do it in a somewhat different way (providing MONGO support is installed as described for MONGO tables). It is achieved by specifying the MongoDB connection URI while creating the table. For instance: From Connect 1.7.002 ``` create or replace table jinvent ( _id char(24) not null, item char(12) not null, instock varchar(300) not null jpath='instock.*') engine=connect table_type=JSON tabname='inventory' lrecl=512 connection='mongodb://localhost:27017'; ``` Before Connect 1.7.002 ``` create or replace table jinvent ( _id char(24) not null, item char(12) not null, instock varchar(300) not null field_format='instock.*') engine=connect table_type=JSON tabname='inventory' lrecl=512 connection='mongodb://localhost:27017'; ``` In this statement, the *file\_name* option was replaced by the *connection* option. It is the URI enabling to retrieve data from a local or remote MongoDB server. The *tabname* option is the name of the MongoDB collection that will be used and the *dbname* option could have been used to indicate the database containing the collection (it defaults to the current database). The way it works is that the documents retrieved from MongoDB are serialized and CONNECT uses them as if they were read from a file. This implies serializing by MongoDB and parsing by CONNECT and is not the best performance wise. CONNECT tries its best to reduce the data transfer when a query contains a reduced column list and/or a where clause. This way makes all the possibilities of the JSON table type available, such as calculated arrays. However, to work on large JSON collations, using the MONGO table type is generally the normal way. Note: JSON tables using the MongoDB access accept the specific MONGO options [colist](../connect-mongo-table-type/index#colist-option), [filter](../connect-mongo-table-type/index#filter-option) and [pipeline](../connect-mongo-table-type/index#pipeline-option). They are described in the MONGO table chapter. Summary of Options and Variables Used with Json Tables ------------------------------------------------------ Options and variables that can be used when creating Json tables are listed here: | Table Option | Type | Description | | --- | --- | --- | | ENGINE | String | Must be specified as CONNECT. | | TABLE\_TYPE | String | Must be JSON or BSON. | | FILE\_NAME | String | The optional file (path) name of the Json file. Can be absolute or relative to the current data directory. If not specified, it defaults to the table name and json file type. | | DATA\_CHARSET | String | Set it to ‘utf8’ for most Unicode Json documents. | | LRECL | Number | The file record size for pretty < 2 json files. | | HTTP | String | The HTTP of the server of REST queries. | | URI | String | THE URI of REST queries | | CONNECTION\* | String | Specifies a connection to `MONGODB`. | | ZIPPED | Boolean | True if the json file(s) is/are zipped in one or several zip files. | | MULTIPLE | Number | Used to specify a multiple file table. | | SEP\_CHAR | String | Set it to ‘:’ for old tables using the old json path syntax. | | CATFUNC | String | The catalog function (column) used when creating a catalog table. | | OPTION\_LIST | String | Used to specify all other options listed below. | (\*) For Json tables connected to MongoDB, Mongo specific options can also be used. Other options must be specified in the option list: | Table Option | Type | Description | | --- | --- | --- | | DEPTHLEVEL | Number | Specifies the depth in the document CONNECT looks when defining columns by discovery or in catalog tables | | PRETTY | Number | Specifies the format of the Json file (-1 for Bjson files) | | EXPAND | String | The name of the column to expand. | | OBJECT | String | The json path of the sub-document used for the table. | | BASE | Number | The numbering base for arrays: 0 (the default) or 1. | | LIMIT | Number | The maximum number of array values to use when concatenating, calculating or expanding arrays. Defaults to 50 (>= Connect 1.7.0003), 10 (<= Connect 1.7.0002). | | FULLARRAY | Boolean | Used when creating with Discovery. Make a column for each value of arrays (up to LIMIT). | | JMODE | Number | The Json mode (array of objects, array of arrays, or array of values) Only used when inserting new rows. | | ACCEPT | Boolean | Keep null columns (for discovery). | | AVGLEN | Number | An estimate average length of rows. This is used only when indexing and can be set if indexing fails by miscalculating the table max size. | | STRINGIFY | String | Ask discovery to make a column to return the Json representation of this object. | Column options: | Column Option | Type | Description | | --- | --- | --- | | JPATHFIELD\_FORMAT | String | Defaults to the column name. | | DATE\_FORMAT | String | Specifies the date format into the Json file when defining a DATE, DATETIME or TIME column. | Variables used with Json tables are: * [connect\_default\_depth](../connect-system-variables/index#connect_default_depth) * [connect\_json\_null](../connect-system-variables/index#connect_json_null) * [connect\_json\_all\_path](../connect-system-variables/index#connect_json_all_path) * [connect\_force\_bson](../connect-system-variables/index#connect_force_bson) Notes ----- 1. [↑](#_ref-0) The value n can be 0 based or 1 based depending on the base table option. The default is 0 to match what is the current usage in the Json world but it can be set to 1 for tables created in old versions. 2. [↑](#_ref-1) See for instance: [json-functions](../json-functions/index), <https://github.com/mysqludf/lib_mysqludf_json#readme> and <https://blogs.oracle.com/svetasmirnova/entry/json_udf_functions_version_04> 3. [↑](#_ref-2) This will not work when CONNECT is compiled embedded Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Spider Case Studies Spider Case Studies =================== A list of users or clients that are using Spider and agree to be referenced: * Tencent Games. They handle 100TB data on 396 Spider nodes and 2800 data nodes. They use this cluster for their online games. * Kadokawa Corporation * MicroAd, Inc. * Sansan, Inc. * teamLab Inc. * CCM Benchmark <http://www.slideshare.net/skysql/ccm-escape-case-study-skysql-paris-meetup-17122013> * Softlink <http://fr.slideshare.net/skysql/galaxy-big-data-with-mariadb> * Gavo <http://wiki.ivoa.net/internal/IVOA/InterOpMay2014NewTechnologies/Spider-MariaDB.pdf> * Blablacar Using for storing various logs * Believe Digital Using for back office analytics queries to aggregate multi billions tables in real time Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb GREATEST GREATEST ======== Syntax ------ ``` GREATEST(value1,value2,...) ``` Description ----------- With two or more arguments, returns the largest (maximum-valued) argument. The arguments are compared using the same rules as for [LEAST()](../least/index). Examples -------- ``` SELECT GREATEST(2,0); +---------------+ | GREATEST(2,0) | +---------------+ | 2 | +---------------+ ``` ``` SELECT GREATEST(34.0,3.0,5.0,767.0); +------------------------------+ | GREATEST(34.0,3.0,5.0,767.0) | +------------------------------+ | 767.0 | +------------------------------+ ``` ``` SELECT GREATEST('B','A','C'); +-----------------------+ | GREATEST('B','A','C') | +-----------------------+ | C | +-----------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Installing MariaDB on IBM Cloud Installing MariaDB on IBM Cloud =============================== Get MariaDB on IBM Cloud You should have an IBM Cloud account, otherwise you can [register here](https://cloud.ibm.com/registration). At the end of the tutorial you will have a cluster with MariaDB up and running. IBM Cloud uses Bitnami charts to deploy MariaDB on with helm 1. We will provision a new Kubernetes Cluster for you if, you already have one skip to step **2** 2. We will deploy the IBM Cloud Block Storage plug-in, if already have it skip to step **3** 3. MariaDB deployment Step 1 provision Kubernetes Cluster ----------------------------------- * Click the **Catalog** button on the top * Select **Service** from the catalog * Search for **Kubernetes Service** and click on it * You are now at the Kubernetes deployment page, you need to specify some details about the cluster * Choose a plan **standard** or **free**, the free plan only has one worker node and no subnet, to provision a standard cluster, you will need to upgrade you account to Pay-As-You-Go * To upgrade to a Pay-As-You-Go account, complete the following steps: * In the console, go to Manage > Account. * Select Account settings, and click Add credit card. * Enter your payment information, click Next, and submit your information * Choose **classic** or **VPC**, read the [docs](https://cloud.ibm.com/docs/containers?topic=containers-infrastructure_providers) and choose the most suitable type for yourself * Now choose your location settings, for more information please visit [Locations](https://cloud.ibm.com/docs/containers?topic=containers-regions-and-zones#zones) * Choose **Geography** (continent) * Choose **Single** or **Multizone**, in single zone your data is only kept in on datacenter, on the other hand with Multizone it is distributed to multiple zones, thus safer in an unforseen zone failure * Choose a **Worker Zone** if using Single zones or **Metro** if Multizone * If you wish to use Multizone please set up your account with [VRF](https://cloud.ibm.com/docs/dl?topic=dl-overview-of-virtual-routing-and-forwarding-vrf-on-ibm-cloud) or [enable Vlan spanning](https://cloud.ibm.com/docs/vlans?topic=vlans-vlan-spanning#vlan-spanning) * If at your current location selection, there is no available Virtual LAN, a new Vlan will be created for you * Choose a **Worker node setup** or use the preselected one, set **Worker node amount per zone** * Choose **Master Service Endpoint**, In VRF-enabled accounts, you can choose private-only to make your master accessible on the private network or via VPN tunnel. Choose public-only to make your master publicly accessible. When you have a VRF-enabled account, your cluster is set up by default to use both private and public endpoints. For more information visit [endpoints](https://cloud.ibm.com/docs/account?topic=account-service-endpoints-overview). * Give cluster a **name** * Give desired **tags** to your cluster, for more information visit [tags](https://cloud.ibm.com/docs/account?topic=account-tag) * Click **create** * Wait for you cluster to be provisioned * Your cluster is ready for usage Step 2 deploy IBM Cloud Block Storage plug-in --------------------------------------------- The Block Storage plug-in is a persistent, high-performance iSCSI storage that you can add to your apps by using Kubernetes Persistent Volumes (PVs). * Click the **Catalog** button on the top * Select **Software** from the catalog * Search for **IBM Cloud Block Storage plug-in** and click on it * On the application page Click in the dot next to the cluster, you wish to use * Click on **Enter or Select Namespace** and choose the default Namespace or use a custom one (if you get error please wait 30 minutes for the cluster to finalize) * Give a **name** to this workspace * Click **install** and wait for the deployment Step 3 deploy MariaDB --------------------- We will deploy MariaDB on our cluster * Click the **Catalog** button on the top * Select **Software** from the catalog * Search for **MariaDB** and click on it * Please select IBM Kubernetes Service * On the application page Click in the dot next to the cluster, you wish to use * Click on **Enter or Select Namespace** and choose the default Namespace or use a custom one * Give a unique **name** to workspace, which you can easily recognize * Select which resource group you want to use, it's for access controll and billing purposes. For more information please visit [resource groups](https://cloud.ibm.com/docs/account?topic=account-account_setup#bp_resourcegroups) * Give **tags** to your MariaDB, for more information visit [tags](https://cloud.ibm.com/docs/account?topic=account-tag) * Click on **Parameters with default values**, You can set deployment values or use the default ones * Please set the MariaDB root password in the parameters * After finishing everything, **tick** the box next to the agreements and click **install** * The MariaDB workspace will start installing, wait a couple of minutes * Your MariaDB workspace has been successfully deployed Verify MariaDB installation --------------------------- * Go to [Resources](http://cloud.ibm.com/resources) in your browser * Click on **Clusters** * Click on your Cluster * Now you are at you clusters overview, here Click on **Actions** and **Web terminal** from the dropdown menu * Click **install** - wait couple of minutes * Click on **Actions** * Click **Web terminal** --> a terminal will open up * **Type** in the terminal, please change NAMESPACE to the namespace you choose at the deployment setup: ``` $ kubectl get ns ``` ``` $ kubectl get pod -n NAMESPACE -o wide ``` ``` $ kubectl get service -n NAMESPACE ``` * Enter your pod with bash , please replace PODNAME with your mariadb pod's name ``` $ kubectl exec --stdin --tty PODNAME -n NAMESPACE -- /bin/bash ``` * After you are in your pod please enter enter Mariadb and enter your root password after the prompt ``` $ mysql -u root -p ``` You have succesfully deployed MariaDB IBM Cloud! Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CONNECT DBF Table Type CONNECT DBF Table Type ====================== Overview -------- A table of type `DBF` is physically a dBASE III or IV formatted file (used by many products like dBASE, Xbase, FoxPro etc.). This format is similar to the [FIX](../connect-dos-and-fix-table-types/index) type format with in addition a prefix giving the characteristics of the file, describing in particular all the fields (columns) of the table. Because `DBF` files have a header that contains Meta data about the file, in particular the column description, it is possible to create a table based on an existing `DBF` file without giving the column description, for instance: ``` create table cust engine=CONNECT table_type=DBF file_name='cust.dbf'; ``` To see what CONNECT has done, you can use the `DESCRIBE` or `SHOW CREATE TABLE` commands, and eventually modify some options with the `ALTER TABLE` command. The case of deleted lines is handled in a specific way for DBF tables. Deleted lines are not removed from the file but are "soft deleted" meaning they are marked as deleted. In particular, the number of lines contained in the file header does not take care of soft deleted lines. This is why if you execute these two commands applied to a DBF table named *tabdbf*: ``` select count(*) from tabdbf; select count(*) from tabdbf where 1; ``` They can give a different result, the (fast) first one giving the number of physical lines in the file and the second one giving the number of line that are not (soft) deleted. The commands UPDATE, INSERT, and DELETE can be used with DBF tables. The DELETE command marks the deleted lines as suppressed but keeps them in the file. The INSERT command, if it is used to populate a newly created table, constructs the file header before inserting new lines. **Note:** For DBF tables, column name length is limited to 11 characters and field length to 256 bytes. Conversion of dBASE Data Types ------------------------------ CONNECT handles only types that are stored as characters. | Symbol | DBF Type | CONNECT Type | Description | | --- | --- | --- | --- | | B | Binary (string) | TYPE\_STRING | 10 digits representing a .DBT block number. | | C | Character | TYPE\_STRING | All OEM code page characters - padded with blanks to the width of the field. | | D | Date | TYPE\_DATE | 8 bytes - date stored as a string in the format YYYYMMDD. | | N | Numeric | TYPE\_INT TYPE\_BIGINT TYPE\_DOUBLE | Number stored as a string, right justified, and padded with blanks to the width of the field. | | L | Logical | TYPE\_STRING | 1 byte - initialized to 0x20 otherwise T or F. | | M | Memo (string) | TYPE\_STRING | 10 digits representing a .DBT block number. | | @ | Timestamp | Not supported | 8 bytes - two longs, first for date, second for time. It is the number of days since 01/01/4713 BC. | | I | Long | Not supported | 4 bytes. Leftmost bit used to indicate sign, 0 negative. | | + | Autoincrement | Not supported | Same as a Long | | F | Float | TYPE\_DOUBLE | Number stored as a string, right justified, and padded with blanks to the width of the field. | | O | Double | Not supported | 8 bytes - no conversions, stored as a double. | | G | OLE | TYPE\_STRING | 10 digits representing a .DBT block number. | For the N numeric type, CONNECT converts it to TYPE\_DOUBLE if the decimals value is not 0, to TYPE\_BIGINT if the length value is greater than 10, else to TYPE\_INT. For M, B, and G types, CONNECT just returns the DBT number. Reading soft deleted lines of a DBF table ----------------------------------------- It is possible to read these lines by changing the read mode of the table. This is specified by an option `READMODE` that can take the values: | | | | --- | --- | | **0** | Standard mode. This is the default option. | | **1** | Read all lines including soft deleted ones. | | **2** | Read only the soft deleted lines. | For example, to read all lines of the tabdbf table, you can do: ``` alter table tabdbf option_list='Readmode=1'; ``` To come back to normal mode, specify READMODE=0. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Comment Syntax Comment Syntax ============== There are three supported comment styles in MariaDB: 1. From a '`#`' to the end of a line: ``` SELECT * FROM users; # This is a comment ``` 2. From a '`--` ' to the end of a line. The space after the two dashes is required (as in MySQL). ``` SELECT * FROM users; -- This is a comment ``` 3. C style comments from an opening '`/*`' to a closing '`*/`'. Comments of this form can span multiple lines: ``` SELECT * FROM users; /* This is a multi-line comment */ ``` Nested comments are possible in some situations, but they are not supported or recommended. Executable Comments ------------------- As an aid to portability between different databases, MariaDB supports executable comments. These special comments allow you to embed SQL code which will not execute when run on other databases, but will execute when run on MariaDB. MariaDB supports both MySQL's executable comment format, and a slightly modified version specific to MariaDB. This way, if you have SQL code that works on MySQL and MariaDB, but not other databases, you can wrap it in a MySQL executable comment, and if you have code that specifically takes advantage of features only available in MariaDB you can use the MariaDB specific format to hide the code from MySQL. ### Executable Comment Syntax MySQL and MariaDB executable comment syntax: ``` /*! MySQL or MariaDB-specific code */ ``` Code that should be executed only starting from a specific MySQL or MariaDB version: ``` /*!##### MySQL or MariaDB-specific code */ ``` The numbers, represented by '`######`' in the syntax examples above specify the specific the minimum versions of MySQL and MariaDB that should execute the comment. The first number is the major version, the second 2 numbers are the minor version and the last 2 is the patch level. For example, if you want to embed some code that should only execute on MySQL or MariaDB starting from 5.1.0, you would do the following: ``` /*!50100 MySQL and MariaDB 5.1.0 (and above) code goes here. */ ``` MariaDB-only executable comment syntax (starting from [MariaDB 5.3.1](https://mariadb.com/kb/en/mariadb-531-release-notes/)): ``` /*M! MariaDB-specific code */ /*M!###### MariaDB-specific code */ ``` MariaDB ignores MySQL-style executable comments that have a version number in the range `50700..99999`. This is needed to skip features introduced in MySQL-5.7 that are not ported to MariaDB 10.x yet. ``` /*!50701 MariaDB-10.x ignores MySQL-5.7 specific code */ ``` **Note:** comments which have a version number in the range `50700..99999` that use MariaDB-style executable comment syntax are still executed. ``` /*M!50701 MariaDB-10.x does not ignore this */ ``` Statement delimiters cannot be used within executable comments. Examples -------- In MySQL all the following will return 2: In MariaDB, the last 2 queries would return 3. ``` SELECT 2 /* +1 */; SELECT 1 /*! +1 */; SELECT 1 /*!50101 +1 */; SELECT 2 /*M! +1 */; SELECT 2 /*M!50301 +1 */; ``` The following executable statement will not work due to the delimiter inside the executable portion: ``` /*M!100100 select 1 ; */ ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1 ``` Instead, the delimiter should be placed outside the executable portion: ``` /*M!100100 select 1 */; +---+ | 1 | +---+ | 1 | +---+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Assignment Operator (:=) Assignment Operator (:=) ======================== Syntax ------ ``` var_name := expr ``` Description ----------- Assignment operator for assigning a value. The value on the right is assigned to the variable on left. Unlike the [= operator](../assignment-operators-assignment-operator/index), `:=` can always be used to assign a value to a variable. This operator works with both [user-defined variables](../user-defined-variables/index) and [local variables](../declare-variable/index). When assigning the same value to several variables, [LAST\_VALUE()](../last_value/index) can be useful. Examples -------- ``` SELECT @x := 10; +----------+ | @x := 10 | +----------+ | 10 | +----------+ SELECT @x, @y := @x; +------+----------+ | @x | @y := @x | +------+----------+ | 10 | 10 | +------+----------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema socket_instances Table Performance Schema socket\_instances Table ========================================== The `socket_instances` table lists active server connections, with each record being a Unix socket file or TCP/IP connection. The `socket_instances` table contains the following columns: | Column | Description | | --- | --- | | `EVENT_NAME` | `NAME` from the `setup_instruments` table, and the name of the `wait/io/socket/*` instrument that produced the event. | | `OBJECT_INSTANCE_BEGIN` | Memory address of the object. | | `THREAD_ID` | Thread identifier that the server assigns to each socket. | | `SOCKET_ID` | The socket's internal file handle. | | `IP` | Client IP address. Blank for Unix socket file, otherwise an IPv4 or IPv6 address. Together with the PORT identifies the connection. | | `PORT` | TCP/IP port number, from 0 to 65535. Together with the IP identifies the connection. | | `STATE` | Socket status, either `IDLE` if waiting to receive a request from a client, or `ACTIVE` | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb INTERSECT INTERSECT ========= **MariaDB starting with [10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/)**INTERSECT was introduced in [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/). The result of an intersect is the intersection of right and left `SELECT` results, i.e. only records that are present in both result sets will be included in the result of the operation. Syntax ------ ``` SELECT ... (INTERSECT [ALL | DISTINCT] | EXCEPT [ALL | DISTINCT] | UNION [ALL | DISTINCT]) SELECT ... [(INTERSECT [ALL | DISTINCT] | EXCEPT [ALL | DISTINCT] | UNION [ALL | DISTINCT]) SELECT ...] [ORDER BY [column [, column ...]]] [LIMIT {[offset,] row_count | row_count OFFSET offset}] ``` Description ----------- MariaDB has supported `INTERSECT` (as well as [EXCEPT](../except/index)) in addition to [UNION](../union/index) since [MariaDB 10.3](../what-is-mariadb-103/index). All behavior for naming columns, `ORDER BY` and `LIMIT` is the same as for [UNION](../union/index). `INTERSECT` implicitly supposes a `DISTINCT` operation. The result of an intersect is the intersection of right and left `SELECT` results, i.e. only records that are present in both result sets will be included in the result of the operation. `INTERSECT` has higher precedence than `UNION` and `EXCEPT` (unless running [running in Oracle mode](../sql_modeoracle/index), in which case all three have the same precedence). If possible it will be executed linearly but if not it will be translated to a subquery in the `FROM` clause: ``` (select a,b from t1) union (select c,d from t2) intersect (select e,f from t3) union (select 4,4); ``` will be translated to: ``` (select a,b from t1) union select c,d from ((select c,d from t2) intersect (select e,f from t3)) dummy_subselect union (select 4,4) ``` **MariaDB starting with [10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/)**### Parentheses From [MariaDB 10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/), parentheses can be used to specify precedence. Before this, a syntax error would be returned. **MariaDB starting with [10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)**### ALL/DISTINCT `INTERSECT ALL` and `INTERSECT DISTINCT` were introduced in [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/). The `ALL` operator leaves duplicates intact, while the `DISTINCT` operator removes duplicates. `DISTINCT` is the default behavior if neither operator is supplied, and the only behavior prior to [MariaDB 10.5](../what-is-mariadb-105/index). Examples -------- Show customers which are employees: ``` (SELECT e_name AS name, email FROM employees) INTERSECT (SELECT c_name AS name, email FROM customers); ``` Difference between [UNION](../union/index), [EXCEPT](../except/index) and INTERSECT. `INTERSECT ALL` and `EXCEPT ALL` are available from [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/). ``` CREATE TABLE seqs (i INT); INSERT INTO seqs VALUES (1),(2),(2),(3),(3),(4),(5),(6); SELECT i FROM seqs WHERE i <= 3 UNION SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | | 3 | | 4 | | 5 | | 6 | +------+ SELECT i FROM seqs WHERE i <= 3 UNION ALL SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | | 2 | | 3 | | 3 | | 3 | | 3 | | 4 | | 5 | | 6 | +------+ SELECT i FROM seqs WHERE i <= 3 EXCEPT SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | +------+ SELECT i FROM seqs WHERE i <= 3 EXCEPT ALL SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | | 2 | +------+ SELECT i FROM seqs WHERE i <= 3 INTERSECT SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 3 | +------+ SELECT i FROM seqs WHERE i <= 3 INTERSECT ALL SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 3 | | 3 | +------+ ``` Parentheses for specifying precedence, from [MariaDB 10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/) ``` CREATE OR REPLACE TABLE t1 (a INT); CREATE OR REPLACE TABLE t2 (b INT); CREATE OR REPLACE TABLE t3 (c INT); INSERT INTO t1 VALUES (1),(2),(3),(4); INSERT INTO t2 VALUES (5),(6); INSERT INTO t3 VALUES (1),(6); ((SELECT a FROM t1) UNION (SELECT b FROM t2)) INTERSECT (SELECT c FROM t3); +------+ | a | +------+ | 1 | | 6 | +------+ (SELECT a FROM t1) UNION ((SELECT b FROM t2) INTERSECT (SELECT c FROM t3)); +------+ | a | +------+ | 1 | | 2 | | 3 | | 4 | | 6 | +------+ ``` See Also -------- * [UNION](../union/index) * [EXCEPT](../except/index) * [Get Set for Set Theory: UNION, INTERSECT and EXCEPT in SQL](https://www.youtube.com/watch?v=UNi-fVSpRm0) (video tutorial) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Subtraction Operator (-) Subtraction Operator (-) ======================== Syntax ------ ``` - ``` Description ----------- Subtraction. The operator is also used as the unary minus for changing sign. If both operands are integers, the result is calculated with [BIGINT](../bigint/index) precision. If either integer is unsigned, the result is also an unsigned integer, unless the NO\_UNSIGNED\_SUBTRACTION [SQL\_MODE](../sql-mode/index) is enabled, in which case the result is always signed. For real or string operands, the operand with the highest precision determines the result precision. Examples -------- ``` SELECT 96-9; +------+ | 96-9 | +------+ | 87 | +------+ SELECT 15-17; +-------+ | 15-17 | +-------+ | -2 | +-------+ SELECT 3.66 + 1.333; +--------------+ | 3.66 + 1.333 | +--------------+ | 4.993 | +--------------+ ``` Unary minus: ``` SELECT - (3+5); +---------+ | - (3+5) | +---------+ | -8 | +---------+ ``` See Also -------- * [Type Conversion](../type-conversion/index) * [Addition Operator (+)](../addition-operator/index) * [Multiplication Operator (\*)](../multiplication-operator/index) * [Division Operator (/)](../division-operator/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb OPTIMIZE TABLE OPTIMIZE TABLE ============== Syntax ------ ``` OPTIMIZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE tbl_name [, tbl_name] ... [WAIT n | NOWAIT] ``` Description ----------- `OPTIMIZE TABLE` has two main functions. It can either be used to defragment tables, or to update the InnoDB fulltext index. **MariaDB starting with [10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/)**#### WAIT/NOWAIT Set the lock wait timeout. See [WAIT and NOWAIT](../wait-and-nowait/index). ### Defragmenting `OPTIMIZE TABLE` works for [InnoDB](../innodb/index) (before [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/), only if the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) server system variable is set), [Aria](../aria/index), [MyISAM](../myisam/index) and [ARCHIVE](../archive/index) tables, and should be used if you have deleted a large part of a table or if you have made many changes to a table with variable-length rows (tables that have [VARCHAR](../varchar/index), [VARBINARY](../varbinary/index), [BLOB](../blob/index), or [TEXT](../text/index) columns). Deleted rows are maintained in a linked list and subsequent `INSERT` operations reuse old row positions. This statement requires [SELECT and INSERT privileges](../grant/index) for the table. By default, `OPTIMIZE TABLE` statements are written to the [binary log](../binary-log/index) and will be [replicated](../replication/index). The `NO_WRITE_TO_BINLOG` keyword (`LOCAL` is an alias) will ensure the statement is not written to the binary log. From [MariaDB 10.3.19](https://mariadb.com/kb/en/mariadb-10319-release-notes/), `OPTIMIZE TABLE` statements are not logged to the binary log if [read\_only](../server-system-variables/index#read_only) is set. See also [Read-Only Replicas](../read-only-replicas/index). `OPTIMIZE TABLE` is also supported for partitioned tables. You can use `[ALTER TABLE](../alter-table/index) ... OPTIMIZE PARTITION` to optimize one or more partitions. You can use `OPTIMIZE TABLE` to reclaim the unused space and to defragment the data file. With other storage engines, `OPTIMIZE TABLE` does nothing by default, and returns this message: " The storage engine for the table doesn't support optimize". However, if the server has been started with the `--skip-new` option, `OPTIMIZE TABLE` is linked to [ALTER TABLE](../alter-table/index), and recreates the table. This operation frees the unused space and updates index statistics. The [Aria](../aria/index) storage engine supports [progress reporting](../progress-reporting/index) for this statement. If a [MyISAM](../myisam/index) table is fragmented, [concurrent inserts](../concurrent-inserts/index) will not be performed until an `OPTIMIZE TABLE` statement is executed on that table, unless the [concurrent\_insert](../server-system-variables/index#concurrent_insert) server system variable is set to `ALWAYS`. ### Updating an InnoDB fulltext index When rows are added or deleted to an InnoDB [fulltext index](../full-text-indexes/index), the index is not immediately re-organized, as this can be an expensive operation. Change statistics are stored in a separate location . The fulltext index is only fully re-organized when an `OPTIMIZE TABLE` statement is run. By default, an OPTIMIZE TABLE will defragment a table. In order to use it to update fulltext index statistics, the [innodb\_optimize\_fulltext\_only](../innodb-system-variables/index#innodb_optimize_fulltext_only) system variable must be set to `1`. This is intended to be a temporary setting, and should be reset to `0` once the fulltext index has been re-organized. Since fulltext re-organization can take a long time, the [innodb\_ft\_num\_word\_optimize](../innodb-system-variables/index#innodb_ft_num_word_optimize) variable limits the re-organization to a number of words (2000 by default). You can run multiple OPTIMIZE statements to fully re-organize the index. ### Defragmenting InnoDB tablespaces [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) merged the Facebook/Kakao defragmentation patch, allowing one to use `OPTIMIZE TABLE` to defragment InnoDB tablespaces. For this functionality to be enabled, the [innodb\_defragment](../innodb-system-variables/index#innodb_defragment) system variable must be enabled. No new tables are created and there is no need to copy data from old tables to new tables. Instead, this feature loads `n` pages (determined by [innodb-defragment-n-pages](../innodb-system-variables/index#innodb_defragment_n_pages)) and tries to move records so that pages would be full of records and then frees pages that are fully empty after the operation. Note that tablespace files (including ibdata1) will not shrink as the result of defragmentation, but one will get better memory utilization in the InnoDB buffer pool as there are fewer data pages in use. See [Defragmenting InnoDB Tablespaces](../defragmenting-innodb-tablespaces/index) for more details. See Also -------- * [Optimize Table in InnoDB with ALGORITHM set to INPLACE](../innodb-online-ddl-operations-with-the-inplace-alter-algorithm/index#optimize-table) * [Optimize Table in InnoDB with ALGORITHM set to NOCOPY](../innodb-online-ddl-operations-with-the-nocopy-alter-algorithm/index#optimize-table) * [Optimize Table in InnoDB with ALGORITHM set to INSTANT](../innodb-online-ddl-operations-with-the-instant-alter-algorithm/index#optimize-table) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema SPATIAL_REF_SYS Table Information Schema SPATIAL\_REF\_SYS Table ========================================== **MariaDB starting with [10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/)**The `SPATIAL_REF_SYS` table was introduced in [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) Description ----------- The [Information Schema](../information_schema/index) `SPATIAL_REF_SYS` table stores information on each spatial reference system used in the database. It contains the following columns: | Column | Type | Null | Description | | --- | --- | --- | --- | | `SRID` | `smallint(5)` | `NO` | An integer value that uniquely identifies each Spatial Reference System within a database. | | `AUTH_NAME` | `varchar(512)` | `NO` | The name of the standard or standards body that is being cited for this reference system. | | `AUTH_SRID` | `smallint(5)` | `NO` | The numeric ID of the coordinate system in the above authority's catalog. | | `SRTEXT` | `varchar(2048)` | `NO` | The [Well-known Text Representation](../wkt/index) of the Spatial Reference System. | Note: See [MDEV-7540](https://jira.mariadb.org/browse/MDEV-7540). See also -------- * `[information\_schema.GEOMETRY\_COLUMNS](../information-schema-geometry_status-table/index)` table. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb FLUSH FLUSH ===== Syntax ------ ``` FLUSH [NO_WRITE_TO_BINLOG | LOCAL] flush_option [, flush_option] ... ``` or when flushing tables: ``` FLUSH [NO_WRITE_TO_BINLOG | LOCAL] TABLES [table_list] [table_flush_option] ``` where `table_list` is a list of tables separated by `,` (comma). Description ----------- The `FLUSH` statement clears or reloads various internal caches used by MariaDB. To execute `FLUSH`, you must have the `RELOAD` privilege. See [GRANT](../grant/index). The `RESET` statement is similar to `FLUSH`. See [RESET](../reset/index). You cannot issue a FLUSH statement from within a [stored function](../stored-functions/index) or a [trigger](../triggers/index). Doing so within a stored procedure is permitted, as long as it is not called by a stored function or trigger. See [Stored Routine Limitations](../stored-routine-limitations/index), [Stored Function Limitations](../stored-function-limitations/index) and [Trigger Limitations](../trigger-limitations/index). If a listed table is a view, an error like the following will be produced: ``` ERROR 1347 (HY000): 'test.v' is not BASE TABLE ``` By default, `FLUSH` statements are written to the [binary log](../binary-log/index) and will be [replicated](../replication/index). The `NO_WRITE_TO_BINLOG` keyword (`LOCAL` is an alias) will ensure the statement is not written to the binary log. The different flush options are: | Option | Description | | --- | --- | | `CHANGED_PAGE_BITMAPS` | [XtraDB](../about-xtradb/index) only. Internal command used for backup purposes. See the [Information Schema CHANGED\_PAGE\_BITMAPS Table](../information-schema-changed_page_bitmaps-table/index). | | `CLIENT_STATISTICS` | Reset client statistics (see [SHOW CLIENT\_STATISTICS](../show-client-statistics/index)). | | `DES_KEY_FILE` | Reloads the DES key file (Specified with the [--des-key-file startup option](../mysqld-options-full-list/index)). | | `HOSTS` | Flush the hostname cache (used for converting ip to host names and for unblocking blocked hosts. See [max\_connect\_errors](../server-system-variables/index#max_connect_errors)) | | `INDEX_STATISTICS` | Reset index statistics (see [SHOW INDEX\_STATISTICS](../show-index-statistics/index)). | | ``[ERROR | ENGINE | GENERAL | SLOW | BINARY | RELAY] LOGS`` | Close and reopen the specified log type, or all log types if none are specified. `FLUSH RELAY LOGS [connection-name]` can be used to flush the relay logs for a specific connection. Only one connection can be specified per `FLUSH` command. See [Multi-source replication](../multi-source-replication/index). `FLUSH ENGINE LOGS` will delete all unneeded [Aria](../aria/index) redo logs. Since [MariaDB 10.1.30](https://mariadb.com/kb/en/mariadb-10130-release-notes/) and [MariaDB 10.2.11](https://mariadb.com/kb/en/mariadb-10211-release-notes/), `FLUSH BINARY LOGS DELETE_DOMAIN_ID=(list-of-domains)` can be used to discard obsolete [GTID](../gtid/index) domains from the server's [binary log](../binary-log/index) state. In order for this to be successful, no event group from the listed [GTID](../gtid/index) domains can be present in existing [binary log](../binary-log/index) files. If some still exist, then they must be purged prior to executing this command. If the command completes successfully, then it also rotates the [binary log](../binary-log/index). | | `MASTER` | Deprecated option, use [RESET MASTER](../reset/index) instead. | | `PRIVILEGES` | Reload all privileges from the privilege tables in the `mysql` database. If the server is started with `--skip-grant-table` option, this will activate the privilege tables again. | | [QUERY CACHE](../flush-query-cache/index) | Defragment the [query cache](../query-cache/index) to better utilize its memory. If you want to reset the query cache, you can do it with [RESET QUERY CACHE](../reset/index). | | `QUERY_RESPONSE_TIME` | See the [QUERY\_RESPONSE\_TIME](../query_response_time-plugin/index) plugin. | | `SLAVE` | Deprecated option, use [RESET REPLICA or RESET SLAVE](../reset-replica/index) instead. | | `SSL` | Used to dynamically reinitialize the server's [TLS](../data-in-transit-encryption/index) context by reloading the files defined by several [TLS system variables](../ssltls-system-variables/index). See [FLUSH SSL](#flush-ssl) for more information. This command was first added in [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/). | | `STATUS` | Resets all [server status variables](../server-status-variables/index) that can be reset to 0. Not all global status variables support this, so not all global values are reset. See [FLUSH STATUS](#flush-status) for more information. | | `TABLE` | Close tables given as options or all open tables if no table list was used. From [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/), using without any table list will only close tables not in use, and tables not locked by the FLUSH TABLES connection. If there are no locked tables, FLUSH TABLES will be instant and will not cause any waits, as it no longer waits for tables in use. When a table list is provided, from [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/), the server will wait for the end of any transactions that are using the tables. Previously, FLUSH TABLES only waited for the statements to complete. | | `TABLES` | Same as `FLUSH TABLE`. | | `[TABLES ... FOR EXPORT](../flush-tables-for-export/index)` | For InnoDB tables, flushes table changes to disk to permit binary table copies while the server is running. See [FLUSH TABLES ... FOR EXPORT](../flush-tables-for-export/index) for more. | | `TABLES WITH READ LOCK` | Closes all open tables. New tables are only allowed to be opened with read locks until an [UNLOCK TABLES](../transactions-unlock-tables/index) is given. | | `TABLES WITH READ LOCK AND DISABLE CHECKPOINT` | As `TABLES WITH READ LOCK` but also disable all checkpoint writes by transactional table engines. This is useful when doing a disk snapshot of all tables. | | `TABLE_STATISTICS` | Reset table statistics (see [SHOW TABLE\_STATISTICS](../show-table-statistics/index)). | | `USER_RESOURCES` | Resets all per hour [user resources](../grant/index#setting-per-account-resources-limits). This enables clients that have exhausted their resources to connect again. | | `USER_STATISTICS` | Reset user statistics (see [SHOW USER\_STATISTICS](../show-user-statistics/index)). | | `USER_VARIABLES` | Reset user variables (see [User-defined variables](../user-defined-variables/index)). | You can also use the [mysqladmin](../mysqladmin/index) client to flush things. Use `mysqladmin --help` to examine what flush commands it supports. `FLUSH RELAY LOGS` ------------------ ``` FLUSH RELAY LOGS 'connection_name'; ``` ### Compatibility with MySQL **MariaDB starting with [10.7.0](https://mariadb.com/kb/en/mariadb-1070-release-notes/)**The `FOR CHANNEL` keyword was added for MySQL compatibility. This is identical as using the channel\_name directly after the `FLUSH command`. For example, one can now use: ``` FLUSH RELAY LOGS FOR CHANNEL 'connection_name'; ``` `FLUSH STATUS` -------------- [Server status variables](../server-status-variables/index) can be reset by executing the following: ``` FLUSH STATUS; ``` ### Global Status Variables that Support `FLUSH STATUS` Not all global status variables support being reset by `FLUSH STATUS`. Currently, the following status variables are reset by `FLUSH STATUS`: * [Aborted\_clients](../server-status-variables/index#aborted_clients) * [Aborted\_connects](../server-status-variables/index#aborted_connects) * [Binlog\_cache\_disk\_use](../replication-and-binary-log-status-variables/index#binlog_cache_disk_use) * [Binlog\_cache\_use](../replication-and-binary-log-status-variables/index#binlog_cache_use) * [Binlog\_stmt\_cache\_disk\_use](../replication-and-binary-log-status-variables/index#binlog_stmt_cache_disk_use) * [Binlog\_stmt\_cache\_use](../replication-and-binary-log-status-variables/index#binlog_stmt_cache_use) * [Connection\_errors\_accept](../server-status-variables/index#connection_errors_accept) * [Connection\_errors\_internal](../server-status-variables/index#connection_errors_internal) * [Connection\_errors\_max\_connections](../server-status-variables/index#connection_errors_max_connections) * [Connection\_errors\_peer\_address](../server-status-variables/index#connection_errors_peer_address) * [Connection\_errors\_select](../server-status-variables/index#connection_errors_select) * [Connection\_errors\_tcpwrap](../server-status-variables/index#connection_errors_tcpwrap) * [Created\_tmp\_files](../server-status-variables/index#created_tmp_files) * [Delayed\_errors](../server-status-variables/index#delayed_errors) * [Delayed\_writes](../server-status-variables/index#delayed_writes) * [Feature\_check\_constraint](../server-status-variables/index#feature_check_constraint) * [Feature\_delay\_key\_write](../server-status-variables/index#feature_delay_key_write) * [Max\_used\_connections](../server-status-variables/index#max_used_connections) * [Opened\_plugin\_libraries](../server-status-variables/index#opened_plugin_libraries) * [Performance\_schema\_accounts\_lost](../performance-schema-status-variables/index#performance_schema_accounts_lost) * [Performance\_schema\_cond\_instances\_lost](../performance-schema-status-variables/index#performance_schema_cond_instances_lost) * [Performance\_schema\_digest\_lost](../performance-schema-status-variables/index#performance_schema_digest_lost) * [Performance\_schema\_file\_handles\_lost](../performance-schema-status-variables/index#performance_schema_file_handles_lost) * [Performance\_schema\_file\_instances\_lost](../performance-schema-status-variables/index#performance_schema_file_instances_lost) * [Performance\_schema\_hosts\_lost](../performance-schema-status-variables/index#performance_schema_hosts_lost) * [Performance\_schema\_locker\_lost](../performance-schema-status-variables/index#performance_schema_locker_lost) * [Performance\_schema\_mutex\_instances\_lost](../performance-schema-status-variables/index#performance_schema_mutex_instances_lost) * [Performance\_schema\_rwlock\_instances\_lost](../performance-schema-status-variables/index#performance_schema_rwlock_instances_lost) * [Performance\_schema\_session\_connect\_attrs\_lost](../performance-schema-status-variables/index#performance_schema_session_connect_attrs_lost) * [Performance\_schema\_socket\_instances\_lost](../performance-schema-status-variables/index#performance_schema_socket_instances_lost) * [Performance\_schema\_stage\_classes\_lost](../performance-schema-status-variables/index#performance_schema_stage_classes_lost) * [Performance\_schema\_statement\_classes\_lost](../performance-schema-status-variables/index#performance_schema_statement_classes_lost) * [Performance\_schema\_table\_handles\_lost](../performance-schema-status-variables/index#performance_schema_table_handles_lost) * [Performance\_schema\_table\_instances\_lost](../performance-schema-status-variables/index#performance_schema_table_instances_lost) * [Performance\_schema\_thread\_instances\_lost](../performance-schema-status-variables/index#performance_schema_thread_instances_lost) * [Performance\_schema\_users\_lost](../performance-schema-status-variables/index#performance_schema_users_lost) * [Qcache\_hits](../server-status-variables/index#qcache_hits) * [Qcache\_inserts](../server-status-variables/index#qcache_inserts) * [Qcache\_lowmem\_prunes](../server-status-variables/index#qcache_lowmem_prunes) * [Qcache\_not\_cached](../server-status-variables/index#qcache_not_cached) * [Rpl\_semi\_sync\_master\_no\_times](../semisynchronous-replication-plugin-status-variables/index#rpl_semi_sync_master_no_times) * [Rpl\_semi\_sync\_master\_no\_tx](../semisynchronous-replication-plugin-status-variables/index#rpl_semi_sync_master_no_tx) * [Rpl\_semi\_sync\_master\_timefunc\_failures](../semisynchronous-replication-plugin-status-variables/index#rpl_semi_sync_master_timefunc_failures) * [Rpl\_semi\_sync\_master\_wait\_pos\_backtraverse](../semisynchronous-replication-plugin-status-variables/index#rpl_semi_sync_master_wait_pos_backtraverse) * [Rpl\_semi\_sync\_master\_yes\_tx](../semisynchronous-replication-plugin-status-variables/index#rpl_semi_sync_master_yes_tx) * [Rpl\_transactions\_multi\_engine](../replication-and-binary-log-status-variables/index#rpl_transactions_multi_engine) * [Server\_audit\_writes\_failed](../mariadb-audit-plugin-status-variables/index#server_audit_writes_failed) * [Slave\_retried\_transactions](../replication-and-binary-log-status-variables/index#slave_retried_transactions) * [Slow\_launch\_threads](../server-status-variables/index#slow_launch_threads) * [Ssl\_accept\_renegotiates](../ssltls-status-variables/index#ssl_accept_renegotiates) * [Ssl\_accepts](../ssltls-status-variables/index#ssl_accepts) * [Ssl\_callback\_cache\_hits](../ssltls-status-variables/index#ssl_callback_cache_hits) * [Ssl\_client\_connects](../ssltls-status-variables/index#ssl_client_connects) * [Ssl\_connect\_renegotiates](../ssltls-status-variables/index#ssl_connect_renegotiates) * [Ssl\_ctx\_verify\_depth](../ssltls-status-variables/index#ssl_ctx_verify_depth) * [Ssl\_ctx\_verify\_mode](../ssltls-status-variables/index#ssl_ctx_verify_mode) * [Ssl\_finished\_accepts](../ssltls-status-variables/index#ssl_finished_accepts) * [Ssl\_finished\_connects](../ssltls-status-variables/index#ssl_finished_connects) * [Ssl\_session\_cache\_hits](../ssltls-status-variables/index#ssl_session_cache_hits) * [Ssl\_session\_cache\_misses](../ssltls-status-variables/index#ssl_session_cache_misses) * [Ssl\_session\_cache\_overflows](../ssltls-status-variables/index#ssl_session_cache_overflows) * [Ssl\_session\_cache\_size](../ssltls-status-variables/index#ssl_session_cache_size) * [Ssl\_session\_cache\_timeouts](../ssltls-status-variables/index#ssl_session_cache_timeouts) * [Ssl\_sessions\_reused](../ssltls-status-variables/index#ssl_sessions_reused) * [Ssl\_used\_session\_cache\_entries](../ssltls-status-variables/index#ssl_used_session_cache_entries) * [Subquery\_cache\_hit](../server-status-variables/index#subquery_cache_hit) * [Subquery\_cache\_miss](../server-status-variables/index#subquery_cache_miss) * [Table\_locks\_immediate](../server-status-variables/index#table_locks_immediate) * [Table\_locks\_waited](../server-status-variables/index#table_locks_waited) * [Tc\_log\_max\_pages\_used](../server-status-variables/index#tc_log_max_pages_used) * [Tc\_log\_page\_waits](../server-status-variables/index#tc_log_page_waits) * [Transactions\_gtid\_foreign\_engine](../replication-and-binary-log-status-variables/index#transactions_gtid_foreign_engine) * [Transactions\_multi\_engine](../replication-and-binary-log-status-variables/index#transactions_multi_engine) The different usage of `FLUSH TABLES` ------------------------------------- ### The purpose of `FLUSH TABLES` The purpose of `FLUSH TABLES` is to clean up the open table cache and table definition cache from not in use tables. This frees up memory and file descriptors. Normally this is not needed as the caches works on a FIFO bases, but can be useful if the server seams to use up to much memory for some reason. ### The purpose of `FLUSH TABLES WITH READ LOCK` `FLUSH TABLES WITH READ LOCK` is useful if you want to take a backup of some tables. When `FLUSH TABLES WITH READ LOCK` returns, all write access to tables are blocked and all tables are marked as 'properly closed' on disk. The tables can still be used for read operations. ### The purpose of `FLUSH TABLES table_list` `FLUSH TABLES` table\_list is useful if you want to copy a table object/files to or from the server. This command puts a lock that stops new users of the table and will wait until everyone has stopped using the table. The table is then removed from the table definition and table cache. Note that it's up to the user to ensure that no one is accessing the table between `FLUSH TABLES` and the table is copied to or from the server. This can be secured by using [LOCK TABLES](../lock-tables/index). If there are any tables locked by the connection that is using `FLUSH TABLES` all the locked tables will be closed as part of the flush and reopened and relocked before `FLUSH TABLES` returns. This allows one to copy the table after `FLUSH TABLES` returns without having any writes on the table. For now this works works with most tables, except InnoDB as InnoDB may do background purges on the table even while it's write locked. ### The purpose of `FLUSH TABLES table_list WITH READ LOCK` `FLUSH TABLES table_list WITH READ LOCK` should work as `FLUSH TABLES WITH READ LOCK`, but only those tables that are listed will be properly closed. However in practice this works exactly like `FLUSH TABLES WITH READ LOCK` as the `FLUSH` command has anyway to wait for all WRITE operations to end because we are depending on a global read lock for this code. In the future we should consider fixing this to instead use meta data locks. Implementation of `FLUSH TABLES` commands in [MariaDB 10.4.8](https://mariadb.com/kb/en/mariadb-1048-release-notes/) and above ------------------------------------------------------------------------------------------------------------------------------ ### Implementation of `FLUSH TABLES` * Free memory and file descriptors not in use ### Implementation of `FLUSH TABLES WITH READ LOCK` * Lock all tables read only for simple old style backup. * All background writes are suspended and tables are marked as closed. * No statement requiring table changes are allowed for any user until `UNLOCK TABLES`. Instead of using `FLUSH TABLE WITH READ LOCK` one should in most cases instead use [BACKUP STAGE BLOCK\_COMMIT](../backup-stage/index). ### Implementation of `FLUSH TABLES table_list` * Free memory and file descriptors for tables not in use from table list. * Lock given tables as read only. * Wait until all translations has ended that uses any of the given tables. * Wait until all background writes are suspended and tables are marked as closed. ### Implementation of `FLUSH TABLES table_list FOR EXPORT` * Free memory and file descriptors for tables not in use from table list * Lock given tables as read. * Wait until all background writes are suspended and tables are marked as closed. * Check that all tables supports `FOR EXPORT` * No changes to these tables allowed until `UNLOCK TABLES` This is basically the same behavior as in old MariaDB version if one first lock the tables, then do `FLUSH TABLES`. The tables will be copyable until `UNLOCK TABLES`. FLUSH SSL --------- **MariaDB starting with [10.4](../what-is-mariadb-104/index)**The `FLUSH SSL` command was first added in [MariaDB 10.4](../what-is-mariadb-104/index). In [MariaDB 10.4](../what-is-mariadb-104/index) and later, the `FLUSH SSL` command can be used to dynamically reinitialize the server's [TLS](../data-in-transit-encryption/index) context. This is most useful if you need to replace a certificate that is about to expire without restarting the server. This operation is performed by reloading the files defined by the following [TLS system variables](../ssltls-system-variables/index): * [ssl\_cert](../ssltls-system-variables/index#ssl_cert) * [ssl\_key](../ssltls-system-variables/index#ssl_key) * [ssl\_ca](../ssltls-system-variables/index#ssl_ca) * [ssl\_capath](../ssltls-system-variables/index#ssl_capath) * [ssl\_crl](../ssltls-system-variables/index#ssl_crl) * [ssl\_crlpath](../ssltls-system-variables/index#ssl_crlpath) These [TLS system variables](../ssltls-system-variables/index) are not dynamic, so their values can **not** be changed without restarting the server. If you want to dynamically reinitialize the server's [TLS](../data-in-transit-encryption/index) context, then you need to change the certificate and key files at the relevant paths defined by these [TLS system variables](../ssltls-system-variables/index), without actually changing the values of the variables. See [MDEV-19341](https://jira.mariadb.org/browse/MDEV-19341) for more information. Reducing Memory Usage --------------------- To flush some of the global caches that take up memory, you could execute the following command: ``` FLUSH LOCAL HOSTS, QUERY CACHE, TABLE_STATISTICS, INDEX_STATISTICS, USER_STATISTICS; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb User Variables Plugin User Variables Plugin ===================== **MariaDB starting with [10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/)**The `user_variables` plugin was first released in [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) The `user_variables` plugin creates the [USER\_VARIABLES](../information-schema-user_variables-table/index) table in the [INFORMATION\_SCHEMA](../information-schema/index) database. This table contains information about [user-defined variables](../user-defined-variables/index). Installing the Plugin --------------------- **MariaDB starting with [10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)**In [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) and later, the `user_variables` plugin is statically linked into the server by default, so it does not need to be installed. Prior to [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/), although the plugin's shared library is distributed with MariaDB by default, the plugin was not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB. The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing [INSTALL SONAME](../install-soname/index) or [INSTALL PLUGIN](../install-plugin/index). For example: ``` INSTALL SONAME 'user_variables'; ``` The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the [--plugin-load](../mysqld-options/index#-plugin-load) or the [--plugin-load-add](../mysqld-options/index#-plugin-load-add) options. This can be specified as a command-line argument to [mysqld](../mysqld-options/index) or it can be specified in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... plugin_load_add = user_variables ``` Uninstalling the Plugin ----------------------- You can uninstall the plugin dynamically by executing [UNINSTALL SONAME](../uninstall-soname/index) or [UNINSTALL PLUGIN](../uninstall-plugin/index). For example: ``` UNINSTALL SONAME 'user_variables'; ``` If you installed the plugin by providing the [--plugin-load](../mysqld-options/index#-plugin-load) or the [--plugin-load-add](../mysqld-options/index#-plugin-load-add) options in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), then those options should be removed to prevent the plugin from being loaded the next time the server is restarted. Examples -------- ``` SELECT * FROM information_schema.USER_VARIABLES ORDER BY VARIABLE_NAME; +---------------+----------------+---------------+--------------------+ | VARIABLE_NAME | VARIABLE_VALUE | VARIABLE_TYPE | CHARACTER_SET_NAME | +---------------+----------------+---------------+--------------------+ | var | 0 | INT | utf8 | | var2 | abc | VARCHAR | utf8 | +---------------+----------------+---------------+--------------------+ ``` ### Flushing User-Defined Variables User-defined variables are reset and the Information Schema table emptied with the [FLUSH USER\_VARIABLES](../flush/index) statement. ``` SET @str = CAST(123 AS CHAR(5)); SELECT * FROM information_schema.USER_VARIABLES ORDER BY VARIABLE_NAME; +---------------+----------------+---------------+--------------------+ | VARIABLE_NAME | VARIABLE_VALUE | VARIABLE_TYPE | CHARACTER_SET_NAME | +---------------+----------------+---------------+--------------------+ | str | 123 | VARCHAR | utf8mb3 | +---------------+----------------+---------------+--------------------+ FLUSH USER_VARIABLES; SELECT * FROM information_schema.USER_VARIABLES ORDER BY VARIABLE_NAME; Empty set (0.000 sec) ``` Versions -------- | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Stable | [MariaDB 10.3.13](https://mariadb.com/kb/en/mariadb-10313-release-notes/) | | 1.0 | Gamma | [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) | | 1.0 | Alpha | [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) | Options ------- ### `user_variables` * **Description:** Controls how the server should treat the plugin when the server starts up. + Valid values are: - `OFF` - Disables the plugin without removing it from the [mysql.plugins](../mysqlplugin-table/index) table. - `ON` - Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled. - `FORCE` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. - `FORCE_PLUS_PERMANENT` - Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with [UNINSTALL SONAME](../uninstall-soname/index) or [UNINSTALL PLUGIN](../uninstall-plugin/index) while the server is running. + See [Plugin Overview: Configuring Plugin Activation at Server Startup](../plugin-overview/index#configuring-plugin-activation-at-server-startup) for more information. * **Commandline:** `--user-variables=value` * **Data Type:** `enumerated` * **Default Value:** `ON` * **Valid Values:** `OFF`, `ON`, `FORCE`, `FORCE_PLUS_PERMANENT` --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Manual SST of Galera Cluster Node With Percona XtraBackup Manual SST of Galera Cluster Node With Percona XtraBackup ========================================================= Mariabackup should be used instead of XtraBackup on all supported releases. See [manual SST with Mariabackup](../manual-sst-of-galera-cluster-node-with-mariabackup/index). In [MariaDB 10.1](../what-is-mariadb-101/index) and later, [Mariabackup](../mariabackup/index) is the recommended backup method to use instead of Percona XtraBackup. In [MariaDB 10.3](../what-is-mariadb-103/index), Percona XtraBackup is **not supported**. See [Percona XtraBackup Overview: Compatibility with MariaDB](../percona-xtrabackup-overview/index#compatibility-with-mariadb) for more information. In [MariaDB 10.2](../what-is-mariadb-102/index) and [MariaDB 10.1](../what-is-mariadb-101/index), Percona XtraBackup is only **partially supported**. See [Percona XtraBackup Overview: Compatibility with MariaDB](../percona-xtrabackup-overview/index#compatibility-with-mariadb) for more information. Sometimes it can be helpful to perform a "manual SST" when Galera's [normal SSTs](../introduction-to-state-snapshot-transfers-ssts/index) fail. This can be especially useful when the cluster's `[datadir](../server-system-variables/index#datadir)` is very large, since a normal SST can take a long time to fail in that case. A manual SST essentially consists of taking a backup of the donor, loading the backup on the joiner, and then manually editing the cluster state on the joiner node. This page will show how to perform this process with [Percona XtraBackup](../backup-restore-and-import-clients-percona-xtrabackup/index). Process ------- * Check that the donor and joiner nodes have the same XtraBackup version. ``` innobackupex --version ``` * Create backup directory on donor. ``` MYSQL_BACKUP_DIR=/mysql_backup mkdir $MYSQL_BACKUP_DIR ``` * Take a [full backup](https://www.percona.com/doc/percona-xtrabackup/2.4/howtos/recipes_ibkx_local.html) the of the donor node with `innobackupex`. The `[--galera-info](https://www.percona.com/doc/percona-xtrabackup/2.4/innobackupex/innobackupex_option_reference.html#cmdoption-innobackupex-galera-info)` option should also be provided, so that the node's cluster state is also backed up. ``` DB_USER=sstuser DB_USER_PASS=password innobackupex --user=$DB_USER --password=$DB_USER_PASS --galera-info --no-timestamp $MYSQL_BACKUP_DIR ``` * Verify that the MariaDB Server process is stopped on the joiner node. This will depend on your [service manager](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index). For example, on [systemd](../systemd/index) systems, you can execute:: ``` systemctl status mariadb ``` * Create the backup directory on the joiner node. ``` MYSQL_BACKUP_DIR=/mysql_backup mkdir $MYSQL_BACKUP_DIR ``` * Copy the backup from the donor node to the joiner node. ``` OS_USER=dba JOINER_HOST=dbserver2.mariadb.com rsync -av $MYSQL_BACKUP_DIR/* ${OS_USER}@${JOINER_HOST}:${MYSQL_BACKUP_DIR} ``` * [Prepare the backup](https://www.percona.com/doc/percona-xtrabackup/2.4/howtos/recipes_ibkx_local.html#prepare-the-backup) on the joiner node. ``` innobackupex --apply-log $MYSQL_BACKUP_DIR ``` * Get the Galera Cluster version ID from the donor node's `grastate.dat` file. ``` MYSQL_DATADIR=/var/lib/mysql cat $MYSQL_DATADIR/grastate.dat | grep version ``` For example, a very common version number is "2.1". * Get the node's cluster state from the `[--xtrabackup\_galera\_info](https://www.percona.com/doc/percona-xtrabackup/2.4/innobackupex/innobackupex_option_reference.html#cmdoption-innobackupex-galera-info)` file in the backup that was copied to the joiner node. ``` cat $MYSQL_BACKUP_DIR/xtrabackup_galera_info ``` Example output: ``` d38587ce-246c-11e5-bcce-6bbd0831cc0f:1352215 ``` This output is in the format: ``` uuid:seqno ``` * Create a `grastate.dat` file in the backup directory of the joiner node. The Galera Cluster version ID, the cluster uuid, and the seqno from previous steps will be used to fill in the relevant fields. For example, with the example values from the last two steps, we could do: ``` sudo tee $MYSQL_BACKUP_DIR/grastate.dat <<EOF # GALERA saved state version: 2.1 uuid: d38587ce-246c-11e5-bcce-6bbd0831cc0f seqno: 1352215 safe_to_bootstrap: 0 EOF ``` * Remove the existing contents of the `[datadir](../server-system-variables/index#datadir)` on the joiner node. ``` MYSQL_DATADIR=/var/lib/mysql rm -Rf $MYSQL_DATADIR/* ``` * Copy the contents of the backup directory to the `[datadir](../server-system-variables/index#datadir)` the on joiner node. ``` cp -R $MYSQL_BACKUP_DIR/* $MYSQL_DATADIR/ ``` * Make sure the permissions of the `[datadir](../server-system-variables/index#datadir)` are correct on the joiner node. ``` chown -R mysql:mysql $MYSQL_DATADIR/ ``` * Start the MariaDB Server process on the joiner node. This will depend on your [service manager](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index). For example, on [systemd](../systemd/index) systems, you can execute:: ``` systemctl start mariadb ``` * Watch the MariaDB [error log](../error-log/index) on the joiner node and verify that the node does not need to perform a [normal SSTs](../introduction-to-state-snapshot-transfers-ssts/index) due to the manual SST. ``` tail -f /var/log/mysql/mysqld.log ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb RANDOM_BYTES RANDOM\_BYTES ============= **MariaDB starting with [10.10.0](https://mariadb.com/kb/en/mariadb-10100-release-notes/)**The RANDOM\_BYTES function generates a binary string of random bytes. It was added in [MariaDB 10.10.0](https://mariadb.com/kb/en/mariadb-10100-release-notes/). Syntax ------ ``` RANDOM_BYTES(length) ``` Description ----------- Given a *length* from 1 to 1024, generates a binary string of *length* consisting of random bytes generated by the SSL library's random number generator. See the RAND\_bytes() function documentation of your SSL library for information on the random number generator. In the case of [OpenSSL](https://www.openssl.org/docs/man1.1.1/man3/RAND_bytes.html), a cryptographically secure pseudo random generator (CSPRNG) is used. Statements containing the RANDOM\_BYTES function are [unsafe for replication](../unsafe-statements-for-statement-based-replication/index). An error occurs if *length* is outside the range 1 to 1024. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Operators Operators ========== Operators can be used for comparing values or for assigning values. There are several operators and they may be used in different SQL statements and clauses. Some can be used somewhat on their own, not within an SQL statement clause. For comparing values—string or numeric—you can use symbols such as the equal-sign (i.e., `=`) or the exclamation point and the equal-sign together (i.e., `!=`). You might use these in `WHERE` clauses or within a flow-control statement or function (e.g., [IF( )](../if-function/index)). You can also use basic regular expressions with the `LIKE` operator. For assigning values, you can also use the equal-sign or other arithmetic symbols (e.g. plus-sign). You might do this with the [SET](../set/index) statement or in a `SET` clause in an [UPDATE](../update/index) statement. | Title | Description | | --- | --- | ### [Arithmetic Operators](../arithmetic-operators/index) | Title | Description | | --- | --- | | [Addition Operator (+)](../addition-operator/index) | Addition. | | [DIV](../div/index) | Integer division. | | [Division Operator (/)](../division-operator/index) | Division. | | [MOD](../mod/index) | Modulo operation. Remainder of N divided by M. | | [Modulo Operator (%)](../modulo-operator/index) | Modulo operator. Returns the remainder of N divided by M. | | [Multiplication Operator (\*)](../multiplication-operator/index) | Multiplication. | | [Subtraction Operator (-)](../subtraction-operator-/index) | Subtraction and unary minus. | ### [Assignment Operators](../assignment-operators/index) | Title | Description | | --- | --- | | [Assignment Operator (:=)](../assignment-operator/index) | Assignment operator for assigning a value. | | [Assignment Operator (=)](../assignment-operators-assignment-operator/index) | The equal sign as an assignment operator. | ### [Bit Functions and Operators](../bit-functions-and-operators/index) | Title | Description | | --- | --- | | [Operator Precedence](../operator-precedence/index) | Precedence of SQL operators | | [&](../bitwise_and/index) | Bitwise AND | | [<<](../shift-left/index) | Left shift | | [>>](../shift-right/index) | Shift right | | [BIT\_COUNT](../bit_count/index) | Returns the number of set bits | | [^](../bitwise-xor/index) | Bitwise XOR | | [|](../bitwise-or/index) | Bitwise OR | | [~](../bitwise-not/index) | Bitwise NOT | | [Parentheses](../parentheses/index) | Parentheses modify the precedence of other operators in an expression | | [TRUE FALSE](../true-false/index) | TRUE and FALSE evaluate to 1 and 0 | ### [Comparison Operators](../comparison-operators/index) | Title | Description | | --- | --- | | [!=](../not-equal/index) | Not equal operator. | | [<](../less-than/index) | Less than operator. | | [<=](../less-than-or-equal/index) | Less than or equal operator. | | [<=>](../null-safe-equal/index) | NULL-safe equal operator. | | [=](../equal/index) | Equal operator. | | [>](../greater-than/index) | Greater than operator. | | [>=](../greater-than-or-equal/index) | Greater than or equal operator. | | [BETWEEN AND](../between-and/index) | True if expression between two values. | | [COALESCE](../coalesce/index) | Returns the first non-NULL parameter | | [GREATEST](../greatest/index) | Returns the largest argument. | | [IN](../in/index) | True if expression equals any of the values in the list. | | [INTERVAL](../interval/index) | Index of the argument that is less than the first argument | | [IS](../is/index) | Tests whether a boolean is TRUE, FALSE, or UNKNOWN. | | [IS NOT](../is-not/index) | Tests whether a boolean value is not TRUE, FALSE, or UNKNOWN | | [IS NOT NULL](../is-not-null/index) | Tests whether a value is not NULL | | [IS NULL](../is-null/index) | Tests whether a value is NULL | | [ISNULL](../isnull/index) | Checks if an expression is NULL | | [LEAST](../least/index) | Returns the smallest argument. | | [NOT BETWEEN](../not-between/index) | Same as NOT (expr BETWEEN min AND max) | | [NOT IN](../not-in/index) | Same as NOT (expr IN (value,...)) | ### [Logical Operators](../logical-operators/index) | Title | Description | | --- | --- | | [!](../not/index) | Logical NOT. | | [&&](../and/index) | Logical AND. | | [XOR](../xor/index) | Logical XOR. | | [||](../or/index) | Logical OR. | ### Other Operators Articles | Title | Description | | --- | --- | | [Operator Precedence](../operator-precedence/index) | Precedence of SQL operators | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_GeometryFromText ST\_GeometryFromText ==================== A synonym for [ST\_GeomFromText](../st_geomfromtext/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb QA Tools QA Tools ======== Tools used for quality assurance testing: * [Worklog Quality Checklist Template](../worklog-quality-checklist-template/index) a template for creating a checklist for testing individual features or WorkLogs * [MTR/mysqltest reference](http://dev.mysql.com/doc/mysqltest/2.0/en/mysqltest-reference.html) * [The Random Query Generator](http://github.com/RQG/RQG-Documentation/wiki/Category:RandomQueryGenerator) * [BuildBot Manual](http://buildbot.net/buildbot/docs/latest/) See also: --------- * [RQG Performance Comparisons](../rqg-performance-comparisons/index) * [RQG Extensions for MariaDB Features](../rqg-extensions-for-mariadb-features/index) * [Optimizer Quality](../optimizer-quality/index) * [QA Tools](index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Platform X3 MariaDB Platform X3 ==================== **MariaDB Platform X3** responds to business design challenges by integrating: * MariaDB Server, the leading enterprise open source database; * MariaDB ColumnStore, a columnar database for on-demand analytical processing; and * MariaDB MaxScale, the world's most advanced database proxy. MariaDB Server powers website and application workloads as a modern RDBMS. MariaDB Platform X3 extends MariaDB Server's capabilities to include: * Transactional workloads (OLTP); * Analytical workloads (OLAP); and * the combination of the two as Hybrid Transactional and Analytical Processing (HTAP) queries. | Title | Description | | --- | --- | | [Sample Platform X3 implementation for Transactional and Analytical Workloads](../sample-platform-x3-implementation-for-transactional-and-analytical-workloads/index) | MariaDB Platform X3 responds to business design challenges by integrating:... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Delimiters Delimiters ========== The default delimiter in the [mysql](../mysql-client/index) client (from [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), [also called mariadb](../mariadb-command-line-client/index)) is the semicolon. When creating [stored programs](../stored-programs-and-views/index) from the command-line, it is likely you will need to differentiate between the regular delimiter and a delimiter inside a [BEGIN END](../begin-end/index) block. To understand better, consider the following example: ``` CREATE FUNCTION FortyTwo() RETURNS TINYINT DETERMINISTIC BEGIN DECLARE x TINYINT; SET x = 42; RETURN x; END; ``` If you enter the above line by line, the mysql client will treat the first semicolon, at the end of the `DECLARE x TINYINT` line, as the end of the statement. Since that's only a partial definition, it will throw a syntax error, as follows: ``` CREATE FUNCTION FortyTwo() RETURNS TINYINT DETERMINISTIC BEGIN DECLARE x TINYINT; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 3 ``` The solution is to specify a distinct delimiter for the duration of the process, using the DELIMITER command. The delimiter can be any set of characters you choose, but it needs to be a distinctive set of characters that won't cause further confusion. `//` is a common choice, and used throughout the knowledgebase. Here's how the function could be successfully entered from the mysql client with the new delimiter. ``` DELIMITER // CREATE FUNCTION FortyTwo() RETURNS TINYINT DETERMINISTIC BEGIN DECLARE x TINYINT; SET x = 42; RETURN x; END // DELIMITER ; ``` At the end, the delimiter is restored to the default semicolon. The `\g` and `\G` delimiters can always be used, even when a custom delimiter is specified. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema FEEDBACK Table Information Schema FEEDBACK Table ================================= The [Information Schema](../information_schema/index) `FEEDBACK` table is created when the [Feedback Plugin](../feedback-plugin/index) is enabled, and contains the complete contents submitted by the plugin. It contains two columns: | Column | Description | | --- | --- | | `VARIABLE_NAME` | Name of the item of information being collected. | | `VARIABLE_VALUE` | Contents of the item of information being collected. | It is possible to disable automatic collection, by setting the `[feedback\_url](../feedback-plugin/index#feedback_url)` variable to an empty string, and to submit the contents manually, as follows: ``` $ mysql -e 'SELECT * FROM information_schema.FEEDBACK' > report.txt ``` Then you can send it by opening `<https://mariadb.org/feedback_plugin/post>` in your browser, and uploading your generated `report.txt`. Or you can do it from the command line with (for example): ``` $ curl -F [email protected] https://mariadb.org/feedback_plugin/post ``` Manual uploading allows you to be absolutely sure that we receive only the data shown in the `information_schema.FEEDBACK` table and that no private or sensitive information is being sent. Example ------- ``` SELECT * FROM information_schema.FEEDBACK\G ... *************************** 906. row *************************** VARIABLE_NAME: Uname_sysname VARIABLE_VALUE: Linux *************************** 907. row *************************** VARIABLE_NAME: Uname_release VARIABLE_VALUE: 3.13.0-53-generic *************************** 908. row *************************** VARIABLE_NAME: Uname_version VARIABLE_VALUE: #89-Ubuntu SMP Wed May 20 10:34:39 UTC 2015 *************************** 909. row *************************** VARIABLE_NAME: Uname_machine VARIABLE_VALUE: x86_64 *************************** 910. row *************************** VARIABLE_NAME: Uname_distribution VARIABLE_VALUE: lsb: Ubuntu 14.04.2 LTS *************************** 911. row *************************** VARIABLE_NAME: Collation used latin1_german1_ci VARIABLE_VALUE: 1 *************************** 912. row *************************** VARIABLE_NAME: Collation used latin1_swedish_ci VARIABLE_VALUE: 18 *************************** 913. row *************************** VARIABLE_NAME: Collation used utf8_general_ci VARIABLE_VALUE: 567 *************************** 914. row *************************** VARIABLE_NAME: Collation used latin1_bin VARIABLE_VALUE: 1 *************************** 915. row *************************** VARIABLE_NAME: Collation used binary VARIABLE_VALUE: 16 *************************** 916. row *************************** VARIABLE_NAME: Collation used utf8_bin VARIABLE_VALUE: 4044 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB 5.2 TODO MariaDB 5.2 TODO ================ **Note:** This page is obsolete. The information is old, outdated, or otherwise currently incorrect. We are keeping the page for historical reasons only. **Do not** rely on the information in this article. See the [Summary page](../what-is-mariadb-52/index), Release Notes and Changelog pages for details of what is in each 5.2 release: ### [MariaDB 5.2 Release Notes](../release-notes/index) This section includes a summary of all important features in [MariaDB 5.2](../what-is-mariadb-52/index). * [MariaDB 5.2.0-beta Release Notes](https://mariadb.com/kb/en/mariadb-520-release-notes/) (5.2.0-beta released 10 Apr 2010) * [MariaDB 5.2.1-beta Release Notes](https://mariadb.com/kb/en/mariadb-521-release-notes/) (5.2.1-beta released 18 Jun 2010) * [MariaDB 5.2.2](https://mariadb.com/kb/en/mariadb-522-release-notes/) Release Notes (in development) ### [MariaDB 5.2 Changelogs](../changelogs/index) * [MariaDB 5.2.0-beta Changelog](https://mariadb.com/kb/en/mariadb-520-changelog/) (5.2.0-beta released 10 Apr 2010) * [MariaDB 5.2.1-beta Changelog](https://mariadb.com/kb/en/mariadb-521-changelog/) (5.2.1-beta released 18 Jun 2010) * [MariaDB 5.2.2](https://mariadb.com/kb/en/mariadb-522-release-notes/) Changelog (in development) As stated above, all non-completed todo items have been moved to [MariaDB 5.3](../what-is-mariadb-53/index), see [MariaDB 5.3 TODO](../mariadb-53-todo/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Creating Mroonga User-Defined Functions Creating Mroonga User-Defined Functions ======================================= The [Mroonga storage engine](../mroonga/index) includes a number of [user-defined functions](../user-defined-functions/index) that need to be created before they can be used. If these are not created already during Mroonga setup, you will need to do so yourself. The full list of available functions and the statements to create them are found in `share/mroonga/install.sql`, for example, as of Mroonga 7.07 ([MariaDB 10.2.11](https://mariadb.com/kb/en/mariadb-10211-release-notes/) and [MariaDB 10.1.29](https://mariadb.com/kb/en/mariadb-10129-release-notes/)) running on Linux: ``` DROP FUNCTION IF EXISTS last_insert_grn_id; CREATE FUNCTION last_insert_grn_id RETURNS INTEGER SONAME 'ha_mroonga.so'; DROP FUNCTION IF EXISTS mroonga_snippet; CREATE FUNCTION mroonga_snippet RETURNS STRING SONAME 'ha_mroonga.so'; DROP FUNCTION IF EXISTS mroonga_command; CREATE FUNCTION mroonga_command RETURNS STRING SONAME 'ha_mroonga.so'; DROP FUNCTION IF EXISTS mroonga_escape; CREATE FUNCTION mroonga_escape RETURNS STRING SONAME 'ha_mroonga.so'; DROP FUNCTION IF EXISTS mroonga_snippet_html; CREATE FUNCTION mroonga_snippet_html RETURNS STRING SONAME 'ha_mroonga.so'; DROP FUNCTION IF EXISTS mroonga_normalize; CREATE FUNCTION mroonga_normalize RETURNS STRING SONAME 'ha_mroonga.so'; DROP FUNCTION IF EXISTS mroonga_highlight_html; CREATE FUNCTION mroonga_highlight_html RETURNS STRING SONAME 'ha_mroonga.so'; DROP FUNCTION IF EXISTS mroonga_query_expand; CREATE FUNCTION mroonga_query_expand RETURNS STRING SONAME 'ha_mroonga.so'; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Storage Engine FAQ Storage Engine FAQ ================== ### Are storage engines designed for MySQL compatible with MariaDB? In most cases, yes. MariaDB tries to keep API compatibility with MySQL, even across major versions. ### Will storage engines created for MariaDB work in MySQL? It will mostly work. It would need #ifdef's to adjust to MySQL-5.6 API, for example, for multi-read-range API, for table discovery API, etc. But most of the code will work as is, without any changes. ### Do storage engine binaries need to be recompiled for MariaDB? Yes. You will need to recompile the storage engine against the exact version of MySQL or MariaDB you intend to run it on. This is due to the version of the server being stored in the storage engine binary, and the server will refuse to load it if it was compiled for a different version. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Unicode Unicode ======= Unicode is a standard for encoding text across multiple writing systems. MariaDB supports a number of [character sets](../data-types-character-sets-and-collations/index) for storing Unicode data: | Character Set | Description | | --- | --- | | ucs2 | UCS-2, each character is represented by a 2-byte code with the most significant byte first. Fixed-length 16-bit encoding. | | utf8 | Until [MariaDB 10.5](../what-is-mariadb-105/index), this was a UTF-8 encoding using one to three bytes per character. Basic Latin letters, numbers and punctuation use one byte. European and Middle East letters mostly fit into 2 bytes. Korean, Chinese, and Japanese ideographs use 3-bytes. No supplementary characters are stored. From [MariaDB 10.6](../what-is-mariadb-106/index), `utf8` is an alias for `utf8mb3`, but this can changed to `ut8mb4` by changing the default value of the [old\_mode](../server-system-variables/index#old_mode) system variable. | | utf8mb3 | UTF-8 encoding using one to three bytes per character. Basic Latin letters, numbers and punctuation use one byte. European and Middle East letters mostly fit into 2 bytes. Korean, Chinese, and Japanese ideographs use 3-bytes. No supplementary characters are stored. Until [MariaDB 10.5](../what-is-mariadb-105/index), this was an alias for `utf8`. From [MariaDB 10.6](../what-is-mariadb-106/index), `utf8` is by default an alias for `utf8mb3`, but this can changed to `ut8mb4` by changing the default value of the [old\_mode](../server-system-variables/index#old_mode) system variable. | | utf8mb4 | UTF-8 encoding the same as `utf8mb3` but which stores supplementary characters in four bytes. | | utf16 | UTF-16, same as ucs2, but stores supplementary characters in 32 bits. 16 or 32-bits. | | utf32 | UTF-32, fixed-length 32-bit encoding. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb XA Transactions XA Transactions =============== Overview -------- The MariaDB XA implementation is based on the X/Open CAE document Distributed Transaction Processing: The XA Specification. This document is published by The Open Group and available at <http://www.opengroup.org/public/pubs/catalog/c193.htm>. XA transactions are designed to allow distributed transactions, where a transaction manager (the application) controls a transaction which involves multiple resources. Such resources are usually DBMSs, but could be resources of any type. The whole set of required transactional operations is called a global transaction. Each subset of operations which involve a single resource is called a local transaction. XA used a 2-phases commit (2PC). With the first commit, the transaction manager tells each resource to prepare an effective commit, and waits for a confirm message. The changes are not still made effective at this point. If any of the resources encountered an error, the transaction manager will rollback the global transaction. If all resources communicate that the first commit is successful, the transaction manager can require a second commit, which makes the changes effective. In MariaDB, XA transactions can only be used with storage engines that support them. At least [InnoDB](../innodb/index), [TokuDB](../tokudb/index), [SPIDER](../spider/index) and [MyRocks](../myrocks/index) support them. For InnoDB, until [MariaDB 10.2](../what-is-mariadb-102/index), XA transactions can be disabled by setting the [innodb\_support\_xa](../innodb-system-variables/index#innodb_support_xa) server system variable to 0. From [MariaDB 10.3](../what-is-mariadb-103/index), XA transactions are always supported. Like regular transactions, XA transactions create [metadata locks](../metadata-locking/index) on accessed tables. XA transactions require [REPEATABLE READ](../set-transaction/index#repeatable-read) as a minimum isolation level. However, distributed transactions should always use [SERIALIZABLE](../set-transaction/index#serializable). Trying to start more than one XA transaction at the same time produces a 1400 error ([SQLSTATE](../sqlstate/index) 'XAE09'). The same error is produced when attempting to start an XA transaction while a regular transaction is in effect. Trying to start a regular transaction while an XA transaction is in effect produces a 1399 error ([SQLSTATE](../sqlstate/index) 'XAE07'). The [statements that cause an implicit COMMIT](../sql-statements-that-cause-an-implicit-commit/index) for regular transactions produce a 1400 error ([SQLSTATE](../sqlstate/index) 'XAE09') if a XA transaction is in effect. Internal XA vs External XA -------------------------- XA transactions are an overloaded term in MariaDB. If a [storage engine](../storage-engines/index) is XA-capable, it can mean one or both of these: * It supports MariaDB's internal two-phase commit API. This is transparent to the user. Sometimes this is called "internal XA", since MariaDB's internal [transaction coordinator log](../transaction-coordinator-log/index) can handle coordinating these transactions. * It supports XA transactions, with the `XA START`, `XA PREPARE`, `XA COMMIT`, etc. statements. Sometimes this is called "external XA", since it requires the use of an external transaction coordinator to use this feature properly. Transaction Coordinator Log --------------------------- If you have two or more XA-capable storage engines enabled, then a transaction coordinator log must be available. There are currently two implementations of the transaction coordinator log: * Binary log-based transaction coordinator log * Memory-mapped file-based transaction coordinator log If the [binary log](../binary-log/index) is enabled on a server, then the server will use the binary log-based transaction coordinator log. Otherwise, it will use the memory-mapped file-based transaction coordinator log. See [Transaction Coordinator Log](../transaction-coordinator-log/index) for more information. Syntax ------ ``` XA {START|BEGIN} xid [JOIN|RESUME] XA END xid [SUSPEND [FOR MIGRATE]] XA PREPARE xid XA COMMIT xid [ONE PHASE] XA ROLLBACK xid XA RECOVER [FORMAT=['RAW'|'SQL']] xid: gtrid [, bqual [, formatID ]] ``` The interface to XA transactions is a set of SQL statements starting with `XA`. Each statement changes a transaction's state, determining which actions it can perform. A transaction which does not exist is in the `NON-EXISTING` state. `XA START` (or `BEGIN`) starts a transaction and defines its `xid` (a transaction identifier). The `JOIN` or `RESUME` keywords have no effect. The new transaction will be in `ACTIVE` state. The `xid` can have 3 components, though only the first one is mandatory. `gtrid` is a quoted string representing a global transaction identifier. `bqual` is a quoted string representing a local transaction identifier. `formatID` is an unsigned integer indicating the format used for the first two components; if not specified, defaults to 1. MariaDB does not interpret in any way these components, and only uses them to identify a transaction. `xid`s of transactions in effect must be unique. `XA END` declares that the specified `ACTIVE` transaction is finished and it changes its state to `IDLE`. `SUSPEND [FOR MIGRATE]` has no effect. `XA PREPARE` prepares an `IDLE` transaction for commit, changing its state to `PREPARED`. This is the first commit. `XA COMMIT` definitely commits and terminates a transaction which has already been `PREPARED`. If the `ONE PHASE` clause is specified, this statements performs a 1-phase commit on an `IDLE` transaction. `XA ROLLBACK` rolls back and terminates an `IDLE` or `PREPARED` transaction. `XA RECOVER` shows information about all `PREPARED` transactions. When trying to execute an operation which is not allowed for the transaction's current state, an error is produced: ``` XA COMMIT 'test' ONE PHASE; ERROR 1399 (XAE07): XAER_RMFAIL: The command cannot be executed when global transaction is in the ACTIVE state XA COMMIT 'test2'; ERROR 1399 (XAE07): XAER_RMFAIL: The command cannot be executed when global transaction is in the NON-EXISTING state ``` XA RECOVER ---------- The `XA RECOVER` statement shows information about all transactions which are in the `PREPARED` state. It does not matter which connection created the transaction: if it has been `PREPARED`, it appears. But this does not mean that a connection can commit or rollback a transaction which was started by another connection. Note that transactions using a 1-phase commit are never in the `PREPARED` state, so they cannot be shown by `XA RECOVER`. `XA RECOVER` produces four columns: ``` XA RECOVER; +----------+--------------+--------------+------+ | formatID | gtrid_length | bqual_length | data | +----------+--------------+--------------+------+ | 1 | 4 | 0 | test | +----------+--------------+--------------+------+ ``` **MariaDB starting with [10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)**You can use `XA RECOVER FORMAT='SQL'` to get the data in a human readable form that can be directly copy-pasted into `XA COMMIT` or `XA ROLLBACK`. This is particularly useful for binary `xid` generated by some transaction coordinators. `formatID` is the `formatID` part of `xid`. `data` are the `gtrid` and `bqual` parts of `xid`, concatenated. `gtrid_length` and `bqual_length` are the lengths of `gtrid` and `bqual`, respectevely. Examples -------- 2-phases commit: ``` XA START 'test'; INSERT INTO t VALUES (1,2); XA END 'test'; XA PREPARE 'test'; XA COMMIT 'test'; ``` 1-phase commit: ``` XA START 'test'; INSERT INTO t VALUES (1,2); XA END 'test'; XA COMMIT 'test' ONE PHASE; ``` Human-readable: ``` xa start '12\r34\t67\v78', 'abc\ndef', 3; insert t1 values (40); xa end '12\r34\t67\v78', 'abc\ndef', 3; xa prepare '12\r34\t67\v78', 'abc\ndef', 3; xa recover format='RAW'; +----------+--------------+--------------+--------------------+ | formatID | gtrid_length | bqual_length | data | +----------+--------------+--------------+--------------------+ 34 67v78abc 11 | 7 | 12 def | +----------+--------------+--------------+--------------------+ xa recover format='SQL'; +----------+--------------+--------------+-----------------------------------------------+ | formatID | gtrid_length | bqual_length | data | +----------+--------------+--------------+-----------------------------------------------+ | 3 | 11 | 7 | X'31320d3334093637763738',X'6162630a646566',3 | +----------+--------------+--------------+-----------------------------------------------+ xa rollback X'31320d3334093637763738',X'6162630a646566',3; ``` Known Issues ------------ ### MariaDB Galera Cluster [MariaDB Galera Cluster](../galera-cluster/index) does not support XA transactions. However, [MariaDB Galera Cluster](../galera-cluster/index) builds include a built-in plugin called `wsrep`. Prior to [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/), this plugin was internally considered an [XA-capable](index) [storage engine](../storage-engines/index). Consequently, these [MariaDB Galera Cluster](../galera-cluster/index) builds have multiple XA-capable storage engines by default, even if the only "real" storage engine that supports external [XA transactions](index) enabled on these builds by default is [InnoDB](../innodb/index). Therefore, when using one these builds MariaDB would be forced to use a [transaction coordinator log](../transaction-coordinator-log/index) by default, which could have performance implications. See [Transaction Coordinator Log Overview: MariaDB Galera Cluster](../transaction-coordinator-log-overview/index#mariadb-galera-cluster) for more information. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Setting Character Sets and Collations Setting Character Sets and Collations ===================================== In MariaDB, the default [character set](../data-types-character-sets-and-collations/index) is latin1, and the default collation is latin1\_swedish\_ci (however this may differ in some distros, see for example [Differences in MariaDB in Debian](../differences-in-mariadb-in-debian/index)). Both character sets and collations can be specified from the server right down to the column level, as well as for client-server connections. When changing a character set and not specifying a collation, the default collation for the new character set is always used. Character sets and collations always cascade down, so a column without a specified collation will look for the table default, the table for the database, and the database for the server. It's therefore possible to have extremely fine-grained control over all the character sets and collations used in your data. Default collations for each character set can be viewed with the [SHOW COLLATION](../show-collation/index) statement, for example, to find the default collation for the latin2 character set: ``` SHOW COLLATION LIKE 'latin2%'; +---------------------+---------+----+---------+----------+---------+ | Collation | Charset | Id | Default | Compiled | Sortlen | +---------------------+---------+----+---------+----------+---------+ | latin2_czech_cs | latin2 | 2 | | Yes | 4 | | latin2_general_ci | latin2 | 9 | Yes | Yes | 1 | | latin2_hungarian_ci | latin2 | 21 | | Yes | 1 | | latin2_croatian_ci | latin2 | 27 | | Yes | 1 | | latin2_bin | latin2 | 77 | | Yes | 1 | +---------------------+---------+----+---------+----------+---------+ ``` Server Level ------------ The [character\_set\_server](../server-system-variables/index#character_set_server) system variable can be used to change the default server character set. It can be set both on startup or dynamically, with the [SET](../set/index) command: ``` SET character_set_server = 'latin2'; ``` Similarly, the [collation\_server](../server-system-variables/index#collation_server) variable is used for setting the default server collation. ``` SET collation_server = 'latin2_czech_cs'; ``` Database Level -------------- The [CREATE DATABASE](../create-database/index) and [ALTER DATABASE](../alter-database/index) statements have optional character set and collation clauses. If these are left out, the server defaults are used. ``` CREATE DATABASE czech_slovak_names CHARACTER SET = 'keybcs2' COLLATE = 'keybcs2_bin'; ``` ``` ALTER DATABASE czech_slovak_names COLLATE = 'keybcs2_general_ci'; ``` To determine the default character set used by a database, use: ``` SHOW CREATE DATABASE czech_slovak_names; +--------------------+--------------------------------------------------------------------------------+ | Database | Create Database | +--------------------+--------------------------------------------------------------------------------+ | czech_slovak_names | CREATE DATABASE `czech_slovak_names` /*!40100 DEFAULT CHARACTER SET keybcs2 */ | +--------------------+--------------------------------------------------------------------------------+ ``` or alternatively, for the character set and collation: ``` SELECT * FROM INFORMATION_SCHEMA.SCHEMATA; +--------------+--------------------+----------------------------+------------------------+----------+ | CATALOG_NAME | SCHEMA_NAME | DEFAULT_CHARACTER_SET_NAME | DEFAULT_COLLATION_NAME | SQL_PATH | +--------------+--------------------+----------------------------+------------------------+----------+ | def | czech_slovak_names | keybcs2 | keybcs2_general_ci | NULL | | def | information_schema | utf8 | utf8_general_ci | NULL | | def | mysql | latin1 | latin1_swedish_ci | NULL | | def | performance_schema | utf8 | utf8_general_ci | NULL | | def | test | latin1 | latin1_swedish_ci | NULL | +--------------+--------------------+----------------------------+------------------------+----------+ ``` It is also possible to specify only the collation, and, since each collation only applies to one character set, the associated character set will automatically be specified. ``` CREATE DATABASE danish_names COLLATE 'utf8_danish_ci'; SHOW CREATE DATABASE danish_names; +--------------+----------------------------------------------------------------------------------------------+ | Database | Create Database | +--------------+----------------------------------------------------------------------------------------------+ | danish_names | CREATE DATABASE `danish_names` /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_danish_ci */ | +--------------+----------------------------------------------------------------------------------------------+ ``` Although there are [character\_set\_database](../server-system-variables/index#character_set_database) and [collation\_database](../server-system-variables/index#collation_database) system variables which can be set dynamically, these are used for determining the character set and collation for the default database, and should only be set by the server. Table Level ----------- The [CREATE TABLE](../create-table/index) and [ALTER TABLE](../alter-table/index) statements support optional character set and collation clauses, a MariaDB and MySQL extension to standard SQL. ``` CREATE TABLE english_names (id INT, name VARCHAR(40)) CHARACTER SET 'utf8' COLLATE 'utf8_icelandic_ci'; ``` If neither character set nor collation is provided, the database default will be used. If only the character set is provided, the default collation for that character set will be used . If only the collation is provided, the associated character set will be used. See [Supported Character Sets and Collations](../supported-character-sets-and-collations/index). ``` ALTER TABLE table_name CONVERT TO CHARACTER SET charset_name [COLLATE collation_name]; ``` If no collation is provided, the collation will be set to the default collation for that character set. See [Supported Character Sets and Collations](../supported-character-sets-and-collations/index). For [VARCHAR](../varchar/index) or [TEXT](../text/index) columns, CONVERT TO CHARACTER SET changes the data type if needed to ensure the new column is long enough to store as many characters as the original column. For example, an ascii TEXT column requires a single byte per character, so the column can hold up to 65,535 characters. If the column is converted to utf8, 3 bytes can be required for each character, so the column will be converted to [MEDIUMTEXT](../mediumtext/index) to be able to hold the same number of characters. `CONVERT TO CHARACTER SET binary` will convert [CHAR](../char/index), [VARCHAR](../varchar/index) and [TEXT](../text/index) columns to [BINARY](../binary/index), [VARBINARY](../varbinary/index) and [BLOB](../blob/index) respectively, and from that point will no longer have a character set, or be affected by future `CONVERT TO CHARACTER SET` statements. To avoid data type changes resulting from `CONVERT TO CHARACTER SET`, use `MODIFY` on the individual columns instead. For example: ``` ALTER TABLE table_name MODIFY ascii_text_column TEXT CHARACTER SET utf8; ALTER TABLE table_name MODIFY ascii_varchar_column VARCHAR(M) CHARACTER SET utf8; ``` Column Level ------------ Character sets and collations can also be specified for columns that are character types CHAR, TEXT or VARCHAR. The [CREATE TABLE](../create-table/index) and [ALTER TABLE](../alter-table/index) statements support optional character set and collation clauses for this purpose - unlike those at the table level, the column level definitions are standard SQL. ``` CREATE TABLE european_names ( croatian_names VARCHAR(40) COLLATE 'cp1250_croatian_ci', greek_names VARCHAR(40) CHARACTER SET 'greek'); ``` If neither collation nor character set is provided, the table default is used. If only the character set is specified, that character set's default collation is used, while if only the collation is specified, the associated character set is used. When using [ALTER TABLE](../alter-table/index) to change a column's character set, you need to ensure the character sets are compatible with your data. MariaDB will map the data as best it can, but it's possible to lose data if care is not taken. The [SHOW CREATE TABLE](../show-create-table/index) statement or INFORMATION SCHEMA database can be used to determine column character sets and collations. ``` SHOW CREATE TABLE european_names\G *************************** 1. row *************************** Table: european_names Create Table: CREATE TABLE `european_names` ( `croatian_names` varchar(40) CHARACTER SET cp1250 COLLATE cp1250_croatian_ci DEFAULT NULL, `greek_names` varchar(40) CHARACTER SET greek DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_danish_ci ``` ``` SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME LIKE 'european%'\G *************************** 1. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: danish_names TABLE_NAME: european_names COLUMN_NAME: croatian_names ORDINAL_POSITION: 1 COLUMN_DEFAULT: NULL IS_NULLABLE: YES DATA_TYPE: varchar CHARACTER_MAXIMUM_LENGTH: 40 CHARACTER_OCTET_LENGTH: 40 NUMERIC_PRECISION: NULL NUMERIC_SCALE: NULL DATETIME_PRECISION: NULL CHARACTER_SET_NAME: cp1250 COLLATION_NAME: cp1250_croatian_ci COLUMN_TYPE: varchar(40) COLUMN_KEY: EXTRA: PRIVILEGES: select,insert,update,references COLUMN_COMMENT: *************************** 2. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: danish_names TABLE_NAME: european_names COLUMN_NAME: greek_names ORDINAL_POSITION: 2 COLUMN_DEFAULT: NULL IS_NULLABLE: YES DATA_TYPE: varchar CHARACTER_MAXIMUM_LENGTH: 40 CHARACTER_OCTET_LENGTH: 40 NUMERIC_PRECISION: NULL NUMERIC_SCALE: NULL DATETIME_PRECISION: NULL CHARACTER_SET_NAME: greek COLLATION_NAME: greek_general_ci COLUMN_TYPE: varchar(40) COLUMN_KEY: EXTRA: PRIVILEGES: select,insert,update,references COLUMN_COMMENT: ``` Filenames --------- Since [MariaDB 5.1](../what-is-mariadb-51/index), the [character\_set\_filesystem](../server-system-variables/index#character_set_filesystem) system variable has controlled interpretation of file names that are given as literal strings. This affects the following statements and functions: * [SELECT INTO DUMPFILE](../select-into-dumpfile/index) * SELECT INTO OUTFILE * [LOAD DATA INFILE](../load-data-infile/index) * [LOAD XML](../load-xml/index) * [LOAD\_FILE()](../load_file/index) Literals -------- By default, the character set and collation used for literals is determined by the [character\_set\_connection](../server-system-variables/index#character_set_connection) and [collation\_connection](../server-system-variables/index#collation_connection) system variables. However, they can also be specified explicitly: ``` [_charset_name]'string' [COLLATE collation_name] ``` The character set of string literals that do not have a character set introducer is determined by the [character\_set\_connection](../server-system-variables/index#character_set_connection) system variable. This query: ``` SELECT CHARSET('a'), @@character_set_connection; ``` always returns the same character set name in both columns. [character\_set\_client](../server-system-variables/index#character_set_client) and [character\_set\_connection](../server-system-variables/index#character_set_connection) are normally (e.g. during handshake, or after a SET NAMES query) are set to equal values. However, it's possible to set to different values. ### Examples Examples when setting @@character\_set\_client and @@character\_set\_connection to different values can be useful: Example 1: Suppose, we have a utf8 database with this table: ``` CREATE TABLE t1 (a VARCHAR(10)) CHARACTER SET utf8 COLLATE utf8_general_ci; INSERT INTO t1 VALUES ('oe'),('ö'); ``` Now we connect to it using "mysql.exe", which uses the DOS character set (cp850 on a West European machine), and want to fetch all records that are equal to 'ö' according to the German phonebook rules. It's possible with the following: ``` SET @@character_set_client=cp850, @@character_set_connection=utf8; SELECT a FROM t1 WHERE a='ö' COLLATE utf8_german2_ci; ``` This will return: ``` +------+ | a | +------+ | oe | | ö | +------+ ``` It works as follows: 1. The client sends the query using cp850. 2. The server, when parsing the query, creates a utf8 string literal by converting 'ö' from @@character\_set\_client (cp850) to @@character\_set\_connection (utf8) 3. The server applies the collation "utf8\_german2\_ci" to this string literal. 4. The server uses utf8\_german2\_ci for comparison. Note, if we rewrite the script like this: ``` SET NAMES cp850; SELECT a FROM t1 WHERE a='ö' COLLATE utf8_german2_ci; ``` we'll get an error: ``` ERROR 1253 (42000): COLLATION 'utf8_german2_ci' is not valid for CHARACTER SET 'cp850' ``` because: * on step #2, the literal is not converted to utf8 any more and is created using cp850. * on step #3, the server fails to apply utf8\_german2\_ci to an cp850 string literal. Example 2: Suppose we have a utf8 database and use "mysql.exe" from a West European machine again. We can do this: ``` SET @@character_set_client=cp850, @@character_set_connection=utf8; CREATE TABLE t2 AS SELECT 'ö'; ``` It will create a table with a column of the type `VARCHAR(1) CHARACTER SET utf8`. Note, if we rewrite the query like this: ``` SET NAMES cp850; CREATE TABLE t2 AS SELECT 'ö'; ``` It will create a table with a column of the type `VARCHAR(1) CHARACTER SET cp850`, which is probably not a good idea. ### N Also, `N` or `n` can be used as prefix to convert a literal into the National Character set (which in MariaDB is always utf8). For example: ``` SELECT _latin2 'Müller'; +-----------+ | MĂźller | +-----------+ | MĂźller | +-----------+ ``` ``` SELECT CHARSET(N'a string'); +----------------------+ | CHARSET(N'a string') | +----------------------+ | utf8 | +----------------------+ ``` ``` SELECT 'Mueller' = 'Müller' COLLATE 'latin1_german2_ci'; +---------------------------------------------------+ | 'Mueller' = 'Müller' COLLATE 'latin1_german2_ci' | +---------------------------------------------------+ | 1 | +---------------------------------------------------+ ``` Stored Programs and Views ------------------------- The literals which occur in stored programs and views, by default, use the character set and collation which was specified by the [character\_set\_connection](../server-system-variables/index#character_set_connection) and [collation\_connection](../server-system-variables/index#collation_connection) system variables when the stored program was created. These values can be seen using the SHOW CREATE statements. To change the character sets used for literals in an existing stored program, it is necessary to drop and recreate the stored program. For stored routines parameters and return values, a character set and a collation can be specified via the CHARACTER SET and COLLATE clauses. Before 5.5, specifying a collation was not supported. The following example shows that the character set and collation are determined at the time of creation: ``` SET @@local.character_set_connection='latin1'; DELIMITER || CREATE PROCEDURE `test`.`x`() BEGIN SELECT CHARSET('x'); END; || Query OK, 0 rows affected (0.00 sec) DELIMITER ; SET @@local.character_set_connection='utf8'; CALL `test`.`x`(); +--------------+ | CHARSET('x') | +--------------+ | latin1 | +--------------+ ``` The following example shows how to specify a function parameters character set and collation: ``` CREATE FUNCTION `test`.`y`(`str` TEXT CHARACTER SET utf8 COLLATE utf8_bin) RETURNS TEXT CHARACTER SET latin1 COLLATE latin1_bin BEGIN SET @param_coll = COLLATION(`str`); RETURN `str`; END; -- return value's collation: SELECT COLLATION(`test`.`y`('Hello, planet!')); +-----------------------------------------+ | COLLATION(`test`.`y`('Hello, planet!')) | +-----------------------------------------+ | latin1_bin | +-----------------------------------------+ -- parameter's collation: SELECT @param_coll; +-------------+ | @param_coll | +-------------+ | utf8_bin | +-------------+ ``` ### Illegal Collation Mix **MariaDB [10.1.28](https://mariadb.com/kb/en/mariadb-10128-release-notes/) - [10.1.29](https://mariadb.com/kb/en/mariadb-10129-release-notes/)**In [MariaDB 10.1.28](https://mariadb.com/kb/en/mariadb-10128-release-notes/), you may encounter Error 1267 when performing comparison operations in views on tables that use binary constants. For instance, ``` CREATE TABLE test.t1 ( a TEXT CHARACTER SET gbk ) ENGINE=InnoDB CHARSET=latin1 COLLATE=latin1_general_cs; INSERT INTO t1 VALUES ('user_a'); CREATE VIEW v1 AS SELECT a <> 0xEE5D FROM t1; SELECT * FROM v1; Error 1267 (HY000): Illegal mix of collations (gbk_chinese_ci, IMPLICIT) and (latin_swedish_ci, COERCIBLE) for operation ``` When the view query is written to file, MariaDB converts the binary character into a string literal, which causes it to be misinterpreted when you execute the `[SELECT](../select/index)` statement. If you encounter this issue, set the character set in the view to force it to the value you want. MariaDB throws this error due to a bug that was fixed in [MariaDB 10.1.29](https://mariadb.com/kb/en/mariadb-10129-release-notes/). Later releases do not throw errors in this situation. Example: Changing the Default Character Set To UTF-8 ---------------------------------------------------- To change the default character set from latin1 to UTF-8, the following settings should be specified in the my.cnf configuration file. ``` [mysql] ... default-character-set=utf8mb4 ... [mysqld] ... collation-server = utf8mb4_unicode_ci init-connect='SET NAMES utf8mb4' character-set-server = utf8mb4 ... ``` Note that the `default-character-set` option is a client option, not a server option. See Also -------- * [String literals](../string-literals/index) * [CAST()](../cast/index) * [CONVERT()](../convert/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Joining Tables with JOIN Clauses Joining Tables with JOIN Clauses ================================ In the absence of a more tutorial-level document, here is a simple example of three basic JOIN types, which you can experiment with in order to see what the different joins accomplish: ``` CREATE TABLE t1 ( a INT ); CREATE TABLE t2 ( b INT ); INSERT INTO t1 VALUES (1), (2), (3); INSERT INTO t2 VALUES (2), (4); SELECT * FROM t1 INNER JOIN t2 ON t1.a = t2.b; SELECT * FROM t1 CROSS JOIN t2; SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.b; SELECT * FROM t2 LEFT JOIN t1 ON t1.a = t2.b; ``` The first two SELECTs are (unfortunately) commonly written with an older form: ``` SELECT * FROM t1, t2 WHERE t1.a = t2.b; SELECT * FROM t1, t2; ``` What you can see from this is that an **INNER JOIN** produces a result set containing only rows that have a match, in both tables (t1 and t2), for the specified join condition(s). A **CROSS JOIN** produces a result set in which every row in each table is joined to every row in the other table; this is also called a **cartesian product**. In MariaDB the CROSS keyword can be omitted, as it does nothing. Any JOIN without an ON clause is a CROSS JOIN. The **LEFT JOIN** is an **outer join**, which produces a result set with all rows from the table on the "left" (t1); the values for the columns in the other table (t2) depend on whether or not a match was found. If no match is found, all columns from that table are set to NULL for that row. The **RIGHT JOIN** is similar to the LEFT JOIN, though its resultset contains all rows from the right table, and the left table's columns will be filled with NULLs when needed. JOINs can be concatenated to read results from three or more tables. Here is the output of the various SELECT statements listed above: ``` SELECT * FROM t1 INNER JOIN t2 ON t1.a = t2.b; ------ ------ | a | b | ------ ------ | 2 | 2 | ------ ------ 1 row in set (0.00 sec) SELECT * FROM t1 CROSS JOIN t2; ------ ------ | a | b | ------ ------ | 1 | 2 | | 2 | 2 | | 3 | 2 | | 1 | 4 | | 2 | 4 | | 3 | 4 | ------ ------ 6 rows in set (0.00 sec) SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.b; ------ ------ | a | b | ------ ------ | 1 | NULL | | 2 | 2 | | 3 | NULL | ------ ------ 3 rows in set (0.00 sec) SELECT * FROM t2 LEFT JOIN t1 ON t1.a = t2.b; ------ ------ | b | a | ------ ------ | 2 | 2 | | 4 | NULL | ------ ------ 2 rows in set (0.00 sec) ``` That should give you a bit more understanding of how JOINS work! Other References ---------------- * [JOINs Tutorial with Examples](https://blog.devart.com/mysql-joins-tutorial-with-examples.html) * [How to write complex queries](https://blog.devart.com/how-to-write-complex-mysql-queries.html) See Also -------- * [More Advanced JOINs](../more-advanced-joins/index) * [Comma vs JOIN](../comma-vs-join/index) * <http://www.keithjbrown.co.uk/vworks/mysql/mysql_p5.shtml> - Nice tutorial. Part 5 covers joins. *The initial version of this article was copied, with permission, from <http://hashmysql.org/wiki/Introduction_to_Joins> on 2012-10-05.* Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb INSERT IGNORE INSERT IGNORE ============= Ignoring Errors --------------- Normally [INSERT](../insert/index) stops and rolls back when it encounters an error. By using the [IGNORE](../ignore/index) keyword all errors are converted to warnings, which will not stop inserts of additional rows. The IGNORE and DELAYED options are ignored when you use [ON DUPLICATE KEY UPDATE](../insert-on-duplicate-key-update/index). Prior to MySQL and [MariaDB 5.5.28](https://mariadb.com/kb/en/mariadb-5528-release-notes/), no warnings were issued for duplicate key errors when using `IGNORE`. You can get the old behavior if you set [OLD\_MODE](../old_mode/index) to `NO_DUP_KEY_WARNINGS_WITH_IGNORE`. Examples -------- ``` CREATE TABLE t1 (x INT UNIQUE); INSERT INTO t1 VALUES(1),(2); INSERT INTO t1 VALUES(2),(3); ERROR 1062 (23000): Duplicate entry '2' for key 'x' SELECT * FROM t1; +------+ | x | +------+ | 1 | | 2 | +------+ 2 rows in set (0.00 sec) INSERT IGNORE INTO t1 VALUES(2),(3); Query OK, 1 row affected, 1 warning (0.04 sec) SHOW WARNINGS; +---------+------+---------------------------------+ | Level | Code | Message | +---------+------+---------------------------------+ | Warning | 1062 | Duplicate entry '2' for key 'x' | +---------+------+---------------------------------+ SELECT * FROM t1; +------+ | x | +------+ | 1 | | 2 | | 3 | +------+ ``` See [INSERT ON DUPLICATE KEY UPDATE](../insert-on-duplicate-key-update/index) for further examples using that syntax. See Also -------- * [INSERT](../insert/index) * [INSERT DELAYED](../insert-delayed/index) * [INSERT SELECT](../insert-select/index) * [HIGH\_PRIORITY and LOW\_PRIORITY](../high_priority-and-low_priority/index) * [Concurrent Inserts](../concurrent-inserts/index) * [INSERT - Default & Duplicate Values](../insert-default-duplicate-values/index) * [INSERT IGNORE](index) * [INSERT ON DUPLICATE KEY UPDATE](../insert-on-duplicate-key-update/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Data Type Storage Requirements Data Type Storage Requirements ============================== The following tables indicate the approximate data storage requirements for each data type. Numeric Data Types ------------------ | Data Type | Storage Requirement | | --- | --- | | [TINYINT](../tinyint/index) | 1 byte | | [SMALLINT](../smallint/index) | 2 bytes | | [MEDIUMINT](../mediumint/index) | 3 bytes | | [INT](../int/index) | 4 bytes | | [BIGINT](../bigint/index) | 8 bytes | | [FLOAT](../float/index)(p) | 4 bytes if p <= 24, otherwise 8 bytes | | [DOUBLE](../double/index) | 8 bytes | | [DECIMAL](../decimal/index) | See table below | | [BIT](../bit/index)(M) | (M+7)/8 bytes | Note that MEDIUMINT columns will require 4 bytes in memory (for example, in InnoDB buffer pool). ### Decimal [Decimals](../decimal/index) are stored using a binary format, with the integer and the fraction stored separately. Each nine-digit multiple requires 4 bytes, followed by a number of bytes for whatever remains, as follows: | Remaining digits | Storage Requirement | | --- | --- | | 0 | 0 bytes | | 1 | 1 byte | | 2 | 1 byte | | 3 | 2 bytes | | 4 | 2 bytes | | 5 | 3 bytes | | 6 | 3 bytes | | 7 | 4 bytes | | 8 | 4 bytes | String Data Types ----------------- In the descriptions below, `M` is the declared column length (in characters or in bytes), while `len` is the actual length in bytes of the value. | Data Type | Storage Requirement | | --- | --- | | [ENUM](../enum/index) | 1 byte for up to 255 enum values, 2 bytes for 256 to 65,535 enum values | | [CHAR(M)](../char/index) | M × w bytes, where w is the number of bytes required for the maximum-length character in the character set | | [BINARY(M)](../binary/index) | M bytes | | [VARCHAR(M)](../varchar/index), [VARBINARY(M)](../varbinary/index) | len + 1 bytes if column is 0 – 255 bytes, len + 2 bytes if column may require more than 255 bytes | | [TINYBLOB](../tinyblob/index), [TINYTEXT](../tinytext/index) | len + 1 bytes | | [BLOB](../blob/index), [TEXT](../text/index) | len + 2 bytes | | [MEDIUMBLOB](../mediumblob/index), [MEDIUMTEXT](../mediumtext/index) | len + 3 bytes | | [LONGBLOB](../longblob/index), [LONGTEXT](../longtext/index) | len + 4 bytes | | [SET](../set/index) | Given M members of the set, (M+7)/8 bytes, rounded up to 1, 2, 3, 4, or 8 bytes | | [INET6](../inet6/index) | 16 bytes | | [UUID](uuid_datatype) | 16 bytes | In some [character sets](../data-types-character-sets-and-collations/index), not all characters use the same number of bytes. utf8 encodes characters with one to three bytes per character, while utf8mb4 requires one to four bytes per character. When using field the COMPRESSED attribute, 1 byte is reserved for metadata. For example, VARCHAR(255) will use +2 bytes instead of +1. ### Examples Assuming a single-byte character-set: | | | | | | | --- | --- | --- | --- | --- | | Value | CHAR(2) | Storage Required | VARCHAR(2) | Storage Required | | '' | ' ' | 2 bytes | '' | 1 byte | | '1' | '1 ' | 2 bytes | '1' | 2 bytes | | '12' | '12' | 2 bytes | '12' | 3 bytes | Date and Time Data Types ------------------------ | Data Type | Storage Requirement | | --- | --- | | [DATE](../date/index) | 3 bytes | | [TIME](../time/index) | 3 bytes | | [DATETIME](../datetime/index) | 8 bytes | | [TIMESTAMP](../timestamp/index) | 4 bytes | | [YEAR](../year-data-type/index) | 1 byte | ### Microseconds [MariaDB 5.3](../what-is-mariadb-53/index) and MySQL 5.6 introduced [microseconds](../microseconds-in-mariadb/index). The underlying storage implementations were different, but from [MariaDB 10.1](../what-is-mariadb-101/index), MariaDB defaults to the MySQL format (by means of the [mysql56\_temporal\_format](../server-system-variables/index#mysql56_temporal_format) variable). Microseconds have the following additional storage requirements: #### MySQL 5.6+ and [MariaDB 10.1](../what-is-mariadb-101/index)+ | Precision | Storage Requirement | | --- | --- | | 0 | 0 bytes | | 1,2 | 1 byte | | 3,4 | 2 bytes | | 5,6 | 3 bytes | #### [MariaDB 5.3](../what-is-mariadb-53/index) - [MariaDB 10.0](../what-is-mariadb-100/index) | Precision | Storage Requirement | | --- | --- | | 0 | 0 bytes | | 1,2 | 1 byte | | 3,4,5 | 2 bytes | | 6 | 3 bytes | NULLs ----- For the InnoDB [COMPACT](../innodb-compact-row-format/index), [DYNAMIC](../innodb-dynamic-row-format/index) and [COMPRESSED](../innodb-compressed-row-format/index) row formats, a number of bytes will be allocated in the record header for the nullable fields. If there are between 1 and 8 nullable fields, 1 such byte will be allocated. In the record payload area, no space will be reserved for values that are NULL. For the [InnoDB REDUNDANT row format](../innodb-redundant-row-format/index), the overhead is 1 bit in the record header (as a part of the 1-byte or 2-byte "end of field" pointer). In that format, a NULL fixed-length field will consume the same amount of space as any NOT NULL value in the record payload area. The motivation is that it is possible to update in place between NOT NULL and NULL values. In other formats, NULL values usually require 1 bit in the data file, 1 byte in the index file. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Entity-Attribute-Value Implementation Entity-Attribute-Value Implementation ===================================== The desires ----------- * Open-ended set of "attributes" (key=value) for each "entity". That is, the list of attributes is not known at development time, and will grow in the future. (This makes one column per attribute impractical.) * "ad hoc" queries testing attributes. * Attribute values come in different types (numbers, strings, dates, etc.) * Scale to lots of entities, yet perform well. It goes by various names * EAV -- Entity - Attribute - Value * key-value * RDF -- This is a flavor of EAV * MariaDB has dynamic columns that look something like the solution below, with the added advantage of being able to index the columns otherwise hidden in the blob. (There are caveats.) * MySQL 5.7 Has JSON datatype, plus functions to access parts * MongoDB, CouchDB -- and others -- Not SQL-based. Bad solution ------------ * Table with 3 columns: entity\_id, key, value * The "value" is a string, or maybe multiple columns depending on datatype or other kludges. * a JOIN b ON a.entity=b.entity AND b.key='x' JOIN c ON ... WHERE a.value=... AND b.value=... The problems ------------ * The SELECTs get messy -- multiple JOINs * Datatype issues -- It's clumsy to be putting numbers into strings * Numbers stored in [VARCHAR](../varchar/index) do not compare 'correctly', especially for range tests. * Bulky. * Dedupping the values is clumsy. A solution ---------- Decide which columns need to be searched/sorted by SQL queries. No, you don't need all the columns to be searchable or sortable. Certain columns are frequently used for selection; identify these. You probably won't use all of them in all queries, but you will use some of them in every query. The solution uses one table for all the EAV stuff. The columns include the searchable fields plus one [BLOB](../blob/index). Searchable fields are declared appropriately ([INT](../int/index), [TIMESTAMP](../timestamp/index), etc). The BLOB contains JSON-encoding of all the extra fields. The table should be [InnoDB](../innodb/index), hence it should have a PRIMARY KEY. The entitity\_id is the 'natural' PK. Add a small number of other indexes (often 'composite') on the searchable fields. [PARTITIONing](../managing-mariadb-partitioning/index) is unlikely to be of any use, unless the Entities should purged after some time. (Example: News Articles) But what about the ad hoc queries? ---------------------------------- You have included the most important fields to search on -- date, category, etc. These should filter the data down significantly. When you also need to filter on something more obscure, that will be handled differently. The application code will look at the BLOB for that; more on this later. Why it works ------------ * You are not really going to search on more than a few fields. * The disk footprint is smaller; Smaller --> More cacheable --> Faster * It needs no JOINs * The indexes are useful * The one table has one row per entity, and can grow as needed. (EAV needs many rows per entity.) * Performance is as good as the indexes you have on the 'searchable fields'. * Optionally, you can duplicate the indexed fields in the BLOB. * Values missing from 'searchable fields' would need to be NULL (or whatever), and the code would need to deal with such. Details on the BLOB/JSON ------------------------ * Build the extra (or all) key-value pairs in a hash (associative array) in your application. Encode it. COMPRESS it. Insert that string into the [BLOB](../blob/index). * JSON is recommended, but not mandatory; it is simpler than XML. Other serializations (eg, YAML) could be used. * COMPRESS the JSON and put it into a [BLOB](../blob/index) (or [MEDIUMBLOB](../mediumblob/index)) instead of a [TEXT](../text/index) field. Compression gives about 3x shrinkage. * When SELECTing, UNCOMPRESS the blob. Decode the string into a hash. You are now ready to interrogate/display any of the extra fields. * If you choose to use the JSON features of MariaDB or 5.7, you will have to forgo the compression feature described. * MySQL 5.7.8's JSON native JSON datatype uses a binary format for more efficient access. Conclusions ----------- * Schema is reasonably compact (compression, real datatypes, less redundancy, etc, than EAV) * Queries are fast (since you have picked 'good' indexes) * Expandable (JSON is happy to have new fields) * Compatible (No 3rd party products, just supported products) * Range tests work (unlike storing [INTs](../int/index) in [VARCHARs](../varchar/index)) * (Drawback) Cannot use the non-indexed attributes in WHERE or ORDER BY clauses, must deal with that in the app. (MySQL 5.7 partially alleviates this.) Postlog ------- Posted Jan, 2014; Refreshed Feb, 2016. * MariaDB's [Dynamic Columns](../dynamic-columns/index) * [MySQL 5.7's JSON](https://dev.mysql.com/doc/refman/5.7/en/json.html) This looks very promising; I will need to do more research to see how much of this article is obviated by it: [Using MySQL as a Document Store in 5.7](http://dev.mysql.com/doc/refman/5.7/en/document-store.html), [more DocStore discussion](http://mysqlserverteam.com/mysql-5-7-12-part-6-mysql-document-store-a-new-chapter-in-the-mysql-story/) If you insist on EAV, set [optimizer\_search\_depth=1](../server-system-variables/index#optimizer_search_depth). See also -------- Rick James graciously allowed us to use this article in the Knowledge Base. [Rick James' site](http://mysql.rjweb.org/) has other useful tips, how-tos, optimizations, and debugging tips. Original source: <http://mysql.rjweb.org/doc.php/eav> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Data Warehousing High Speed Ingestion Data Warehousing High Speed Ingestion ===================================== The problem ----------- You are ingesting lots of data. Performance is bottlenecked in the INSERT area. This will be couched in terms of Data Warehousing, with a huge `Fact` table and Summary (aggregation) tables. Overview of solution -------------------- * Have a separate staging table. * Inserts go into `Staging`. * Normalization and Summarization reads Staging, not Fact. * After normalizing, the data is copied from Staging to Fact. `Staging` is one (or more) tables in which the data lives only long enough to be handed off to Normalization, Summary, and the Fact tables. Since we are probably talking about a billion-row table, shrinking the width of the Fact table by normalizing (as mentioned here). Changing an [INT](../int/index) to a [MEDIUMINT](../mediumint/index) will save a GB. Replacing a string by an id (normalizing) saves many GB. This helps disk space and cacheability, hence speed. Injection speed --------------- Some variations: * Big dump of data once an hour, versus continual stream of records. * The input stream could be single-threaded or multi-threaded. * You might have 3rd party software tying your hands. Generally the fastest injection rate can be achieved by "staging" the INSERTs in some way, then batch processing the staged records. This blog discusses various techniques for staging and batch processing. Normalization ------------- Let's say your Input has a [VARCHAR](../varchar/index) `host\_name` column, but you need to turn that into a smaller [MEDIUMINT](../mediumint/index) `host\_id` in the Fact table. The "Normalization" table, as I call it, looks something like ``` CREATE TABLE Hosts ( host_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT, host_name VARCHAR(99) NOT NULL, PRIMARY KEY (host_id), -- for mapping one direction INDEX(host_name, host_id) -- for mapping the other direction ) ENGINE=InnoDB; -- InnoDB works best for Many:Many mapping table ``` Here's how you can use `Staging` as an efficient way achieve the swap from name to id. Staging has two fields (for this normalization example): ``` host_name VARCHAR(99) NOT NULL, -- Comes from the insertion proces host_id MEDIUMINT UNSIGNED NULL, -- NULL to start with; see code below ``` Meawhile, the Fact table has: ``` host_id MEDIUMINT UNSIGNED NOT NULL, ``` SQL #1 (of 2): ``` # This should not be in the main transaction, and it should be done with autocommit = ON # In fact, it could lead to strange errors if this were part # of the main transaction and it ROLLBACKed. INSERT IGNORE INTO Hosts (host_name) SELECT DISTINCT s.host_name FROM Staging AS s LEFT JOIN Hosts AS n ON n.host_name = s.host_name WHERE n.host_id IS NULL; ``` By isolating this as its own transaction, we get it finished in a hurry, thereby minimizing blocking. By saying IGNORE, we don't care if other threads are 'simultaneously' inserting the same host\_names. There is a subtle reason for the LEFT JOIN. If, instead, it were INSERT IGNORE..SELECT DISTINCT, then the INSERT would preallocate auto\_increment ids for as many rows as the SELECT provides. This is very likely to "burn" a lot of ids, thereby leading to overflowing MEDIUMINT unnecessarily. The LEFT JOIN leads to finding just the new ids that are needed (except for the rare possibility of a 'simultaneous' insert by another thread). More rationale: [Mapping table](../building-the-best-index-for-a-given-select/index) SQL #2: ``` # Also not in the main transaction, and it should be with autocommit = ON # This multi-table UPDATE sets the ids in Staging: UPDATE Hosts AS n JOIN Staging AS s ON s.host_name = n host_name SET s.host_id = n.host_id ``` This gets the IDs, whether already existing, set by another thread, or set by SQL #1. If the size of `Staging` changes depending on the busy versus idle times of the day, this pair of SQL statements has another comforting feature. The more rows in `Staging`, the more efficient the SQL runs, thereby helping compensate for the "busy" times. The companion [Data Warehouse article](../data-warehousing-techniques/index) folds SQL #2 into the INSERT INTO Fact. But you may need host\_id for further normalization steps and/or Summarization steps, so this explicit UPDATE shown here is often better. Flip-flop staging ----------------- The simple way to stage is to ingest for a while, then batch-process what is in `Staging`. But that leads to new records piling up waiting to be staged. To avoid that issue, have 2 processes: * one process (or set of processes) for INSERTing into `Staging`; * one process (or set of processes) to do the batch processing (normalization, summarization). To keep the processes from stepping on each other, we have a pair of staging tables: * `Staging` is being INSERTed into; * `StageProcess` is one being processed for normalization, summarization, and moving to the Fact table. A separate process does the processing, then swaps the tables: ``` DROP TABLE StageProcess; CREATE TABLE StageProcess LIKE Staging; RENAME TABLE Staging TO tmp, StageProcess TO Staging, tmp TO StageProcess; ``` This may not seem like the shortest way to do it, but has these features: * The DROP + CREATE might be faster than TRUNCATE, which is the desired effect. * The RENAME is atomic, so the INSERT process(es) never find that `Staging` is missing. A variant on the 2-table flip-flop is to have a separate `Staging` table for each Insertion process. The Processing process would run around to each Staging in turn. A variant on that would be to have a separate processing process for each Insertion process. The choice depends on which is faster (insertion or processing). There are tradeoffs; a single processing thread avoids some locks, but lacks some parallelism. Engine choice ------------- `Fact` table -- [InnoDB](../innodb/index), if for no other reason than that a system crash would not need a REPAIR TABLE. (REPAIRing a billion-row [MyISAM](../myisam/index) table can take hours or days.) Normalization tables -- InnoDB, primarily because it can be done efficiently with 2 indexes, whereas, MyISAM would need 4 to achieve the same efficiency. `Staging` -- Lots of options here. * If you have multiple Inserters and a single Staging table, InnoDB is desirable due to row-level, not table-level, locking. * MEMORY may be the fastest and it avoids I/O. This is good for a single staging table. * For multiple Inserters, a separate Staging table for each Inserter is desired. * For multiple Inserters into a single Staging table, InnoDB may be faster. (MEMORY does table-level locking.) * With one non-InnoDB Staging table per Inserter, using an explicit LOCK TABLE avoids repeated implicit locks on each INSERT. * But, if you are doing LOCK TABLE and the Processing thread is separate, an UNLOCK is necessary periodically to let the RENAME grab the table. * "Batch INSERTs" (100-1000 rows per SQL) eliminates much of the issues of the above bullet items. Confused? Lost? There are enough variations in applications that make it impractical to predict what is best. Or, simply good enough. Your ingestion rate may be low enough that you don't hit the brick walls that I am helping you avoid. Should you do "CREATE TEMPORARY TABLE"? Probably not. Consider `Staging` as part of the data flow, not to be DROPped. Summarization ------------- This is mostly covered here: [Summary Tables](../data-warehousing-summary-tables/index) Summarize from the Staging table instead of the Fact table. Replication Issues ------------------ Row Based Replication (RBR) is probably the best option. The following allows you to keep more of the Ingestion process in the Master, thereby not bogging down the Slave(s) with writes to the Staging table. * RBR * `Staging` is in a separate database * That database is not replicated (binlog-ignore-db on Master) * In the Processing steps, USE that database, reach into the main db via syntax like "MainDb.Hosts". (Otherwise, the binlog-ignore-db does the wrong thing.) That way * Writes to `Staging` are not replicated. * Normalization sends only the few updates to the normalization tables. * Summarization sends only the updates to the summary tables. * Flip-flop does not replicate the DROP, CREATE or RENAME. Sharding -------- You could possibly spread the data you are trying ingest across multiple machines in a predictable way (sharding on hash, range, etc). Running "reports" on a sharded Fact table is a challenge unto itself. On the other hand, Summary Tables rarely get too big to manage on a single machine. For now, Sharding is beyond the scope of this blog. Push me vs pull me ------------------ I have implicitly assumed the data is being pushed into the database. If, instead, you are "pulling" data from some source(s), then there are some different considerations. Case 1: An hourly upload; run via cron 1. Grab the upload, parse it 2. Put it into the Staging table 3. Normalize -- each SQL in its own transaction (autocommit) 4. BEGIN 5. Summarize 6. Copy from Staging to Fact. 7. COMMIT If you need parallelism in Summarization, you will have to sacrifice the transactional integrity of steps 4-7. Caution: If these steps add up to more than an hour, you are in deep dodo. Case 2: You are polling for the data It is probably reasonable to have multiple processes doing this, so it will be detailed about locking. 0. Create a Staging table for this polling processor. Loop: 1. With some locked mechanism, decide which 'thing' to poll. 2. Poll for the data, pull it in, parse it. (Potentially polling and parsing are significantly costly) 3. Put it into the process-specific Staging table 4. Normalize -- each SQL in its own transaction (autocommit) 5. BEGIN 6. Summarize 7. Copy from Staging to Fact. 8. COMMIT 9. Declare that you are finished with this 'thing' (see step 1) EndLoop. iblog\_file\_size should be larger than the change in the STATUS "Innodb\_os\_log\_written" across the BEGIN...COMMIT transaction (for either Case). See also -------- * [companion Data Warehouse blog](../mariadb/data-warehousing-techniques/index) * [companion Summary Table blog](../mariadb/data-warehousing-summary-tables/index) * [a forum thread that prodded me into writing this blog](http://forums.mysql.com/read.php?106,623744) * [StackExchange discussion](http://dba.stackexchange.com/a/108726/1876) Rick James graciously allowed us to use this article in the Knowledge Base. [Rick James' site](http://mysql.rjweb.org/) has other useful tips, how-tos, optimizations, and debugging tips. Original source: <http://mysql.rjweb.org/doc.php/staging_table> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Starting and Stopping MariaDB Starting and Stopping MariaDB ============================== | Title | Description | | --- | --- | | [Starting and Stopping MariaDB Server](../starting-and-stopping-mariadb-automatically/index) | Starting MariaDB, including details on service managers. | | [Configuring MariaDB with Option Files](../configuring-mariadb-with-option-files/index) | Configuring MariaDB with my.cnf and other option files. | | [mysqld Configuration Files and Groups](../mysqld-configuration-files-and-groups/index) | Which configuration files and groups mysqld reads. | | [mysqld Options](../mysqld-options/index) | Lists of all the options for mysqld. | | [What to Do if MariaDB Doesn't Start](../what-to-do-if-mariadb-doesnt-start/index) | Troubleshooting MariaDB when it fails to start. | | [Running MariaDB from the Build Directory](../running-mariadb-from-the-build-directory/index) | Running mariadbd (mysqld) directly from the source directory without make install. | | [mysql.server](../mysqlserver/index) | Startup script included in MariaDB distributions on Unix | | [mysqld\_safe](../mysqld_safe/index) | Recommended way to start a mysqld server on a non-systemd Unix. | | [mysqladmin](../mysqladmin/index) | Admin tool for monitoring, creating/dropping databases, stopping mysqld etc. | | [Switching Between Different Installed MariaDB Versions](../switching-between-different-installed-mariadb-versions/index) | Managing different installed MariaDB versions and running them one at a time | | [Running Multiple MariaDB Server Processes](../running-multiple-mariadb-server-processes/index) | Running multiple MariaDB Server processes on the same server. | | [Specifying Permissions for Schema (Data) Directories and Tables](../specifying-permissions-for-schema-data-directories-and-tables/index) | MariaDB uses the following modes for creating directories and files | | [mysqld\_multi](../mysqld_multi/index) | Manage several mysqld processes. | | [launchd](../launchd/index) | launchd is the startup service used in MacOS X. | | [systemd](../systemd/index) | How systemd is configured on MariaDB packages and how to alter its configuration. | | [sysVinit](../sysvinit/index) | sysVinit is one of the most common service managers for Linux and Unix. | | [mariadb-admin](../mariadb-admin/index) | Symlink or new name for mysqladmin. | | [mariadbd](../mariadbd/index) | Symlink or new name for mysqld. | | [mariadbd-multi](../mariadbd-multi/index) | Symlink or new name for mysqld\_multi. | | [mariadbd-safe](../mariadbd-safe/index) | Symlink or new name for mysqld\_safe. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Docker and MariaDB Docker and MariaDB =================== Docker is an open source container manager that can be used to quickly create ephemeral containers running specific software. Docker containers can be used for production, development or testing, though it is not the preferred choice to run MariaDB in production. | Title | Description | | --- | --- | | [Benefits of Managing Docker Containers with Orchestration Software](../benefits-of-managing-docker-containers-with-orchestration-software/index) | Benefits of managing Docker with Automation Software. | | [Installing and Using MariaDB via Docker](../installing-and-using-mariadb-via-docker/index) | Creating and managing a MariaDB Docker container. | | [Running MariaDB ColumnStore Docker containers on Linux, Windows and MacOS](../running-mariadb-columnstore-docker-containers-on-linux-windows-and-macos/index) | Docker allows for a simple setup of a ColumnStore single server instance for evaluation purposes | | [Creating a Custom Docker Image](../creating-a-custom-docker-image/index) | How to write a Dockerfile to create custom Docker images. | | [Setting Up a LAMP Stack with Docker Compose](../setting-up-a-lamp-stack-with-docker-compose/index) | How to use Docker Compose to set up containers running a LAMP stack. | | [Docker Security Concerns](../docker-security-concerns/index) | Security matters related to Docker containers. | | [MariaDB Container Cheat Sheet](../mariadb-container-cheat-sheet/index) | Get the images Images can be found on MariaDB Docker Hub. To get the list o... | | [MariaDB Docker Environment Variables](../mariadb-docker-environment-variables/index) | Environment variables can be passed on the docker run command line. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DELETE DELETE ====== Syntax ------ Single-table syntax: ``` DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name [PARTITION (partition_list)] [FOR PORTION OF period FROM expr1 TO expr2] [WHERE where_condition] [ORDER BY ...] [LIMIT row_count] [RETURNING select_expr [, select_expr ...]] ``` Multiple-table syntax: ``` DELETE [LOW_PRIORITY] [QUICK] [IGNORE] tbl_name[.*] [, tbl_name[.*]] ... FROM table_references [WHERE where_condition] ``` Or: ``` DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name[.*] [, tbl_name[.*]] ... USING table_references [WHERE where_condition] ``` Trimming history: ``` DELETE HISTORY FROM tbl_name [PARTITION (partition_list)] [BEFORE SYSTEM_TIME [TIMESTAMP|TRANSACTION] expression] ``` Description ----------- | Option | Description | | --- | --- | | LOW\_PRIORITY | Wait until all SELECT's are done before starting the statement. Used with storage engines that uses table locking (MyISAM, Aria etc). See [HIGH\_PRIORITY and LOW\_PRIORITY clauses](../high_priority-and-low_priority-clauses/index) for details. | | QUICK | Signal the storage engine that it should expect that a lot of rows are deleted. The storage engine engine can do things to speed up the DELETE like ignoring merging of data blocks until all rows are deleted from the block (instead of when a block is half full). This speeds up things at the expanse of lost space in data blocks. At least [MyISAM](../myisam/index) and [Aria](../aria/index) support this feature. | | IGNORE | Don't stop the query even if a not-critical error occurs (like data overflow). See [How IGNORE works](../ignore/index) for a full description. | For the single-table syntax, the `DELETE` statement deletes rows from tbl\_name and returns a count of the number of deleted rows. This count can be obtained by calling the [ROW\_COUNT()](../row-count/index) function. The `WHERE` clause, if given, specifies the conditions that identify which rows to delete. With no `WHERE` clause, all rows are deleted. If the [ORDER BY](../order-by/index) clause is specified, the rows are deleted in the order that is specified. The [LIMIT](../limit/index) clause places a limit on the number of rows that can be deleted. For the multiple-table syntax, `DELETE` deletes from each `tbl_name` the rows that satisfy the conditions. In this case, [ORDER BY](../order-by/index) and [LIMIT](../limit/index)> cannot be used. A `DELETE` can also reference tables which are located in different databases; see [Identifier Qualifiers](../identifier-qualifiers/index) for the syntax. `where_condition` is an expression that evaluates to true for each row to be deleted. It is specified as described in [SELECT](../select/index). Currently, you cannot delete from a table and select from the same table in a subquery. You need the `DELETE` privilege on a table to delete rows from it. You need only the `SELECT` privilege for any columns that are only read, such as those named in the `WHERE` clause. See [GRANT](../grant/index). As stated, a `DELETE` statement with no `WHERE` clause deletes all rows. A faster way to do this, when you do not need to know the number of deleted rows, is to use `TRUNCATE TABLE`. However, within a transaction or if you have a lock on the table, `TRUNCATE TABLE` cannot be used whereas `DELETE` can. See [TRUNCATE TABLE](../truncate-table/index), and [LOCK](../lock/index). ### PARTITION See [Partition Pruning and Selection](../partition-pruning-and-selection/index) for details. ### FOR PORTION OF **MariaDB starting with [10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/)**See [Application Time Periods - Deletion by Portion](../application-time-periods/index#deletion-by-portion). ### RETURNING It is possible to return a resultset of the deleted rows for a single table to the client by using the syntax `DELETE ... RETURNING select_expr [, select_expr2 ...]]` Any of SQL expression that can be calculated from a single row fields is allowed. Subqueries are allowed. The AS keyword is allowed, so it is possible to use aliases. The use of aggregate functions is not allowed. RETURNING cannot be used in multi-table DELETEs. **MariaDB starting with [10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/)**### Same Source and Target Table Until [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), deleting from a table with the same source and target was not possible. From [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), this is now possible. For example: ``` DELETE FROM t1 WHERE c1 IN (SELECT b.c1 FROM t1 b WHERE b.c2=0); ``` **MariaDB starting with [10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/)**### DELETE HISTORY One can use `DELETE HISTORY` to delete historical information from [System-versioned tables](../system-versioned-tables/index). Examples -------- How to use the [ORDER BY](../order-by/index) and [LIMIT](../limit/index) clauses: ``` DELETE FROM page_hit ORDER BY timestamp LIMIT 1000000; ``` How to use the RETURNING clause: ``` DELETE FROM t RETURNING f1; +------+ | f1 | +------+ | 5 | | 50 | | 500 | +------+ ``` The following statement joins two tables: one is only used to satisfy a WHERE condition, but no row is deleted from it; rows from the other table are deleted, instead. ``` DELETE post FROM blog INNER JOIN post WHERE blog.id = post.blog_id; ``` ### Deleting from the Same Source and Target ``` CREATE TABLE t1 (c1 INT, c2 INT); DELETE FROM t1 WHERE c1 IN (SELECT b.c1 FROM t1 b WHERE b.c2=0); ``` Until [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), this returned: ``` ERROR 1093 (HY000): Table 't1' is specified twice, both as a target for 'DELETE' and as a separate source for ``` From [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/): ``` Query OK, 0 rows affected (0.00 sec) ``` See Also -------- * [How IGNORE works](../ignore/index) * [SELECT](../select/index) * [ORDER BY](../order-by/index) * [LIMIT](../limit/index) * [REPLACE ... RETURNING](../replacereturning/index) * [INSERT ... RETURNING](../insertreturning/index) * [Returning clause](https://www.youtube.com/watch?v=n-LTdEBeAT4) (video) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Converting Tables from MyISAM to InnoDB Converting Tables from MyISAM to InnoDB ======================================= The task -------- You have decided to change one or more tables from [MyISAM](../myisam/index) to [InnoDB](../innodb/index). That should be as simple as `ALTER TABLE foo ENGINE=InnoDB`. But you have heard that there might be some subtle issues. This describes possible issues that may arise and what to do about them. *Recommendation.* One way to assist in searching for issues in is to do (at least in \*nix) ``` mysqldump --no-data --all-databases >schemas egrep 'CREATE|PRIMARY' schemas # Focusing on PRIMARY KEYs egrep 'CREATE|FULLTEXT' schemas # Looking for FULLTEXT indexes egrep 'CREATE|KEY' schemas # Looking for various combinations of indexes ``` Understanding how the indexes work will help you better understand what might run faster or slower in InnoDB. INDEX Issues ------------ *(Most of these Recommendations and some of these Facts have exceptions.)* *Fact.* Every InnoDB table has a PRIMARY KEY. If you do not provide one, then the first non-NULL UNIQUE key is used. If that can't be done, then a 6-byte, hidden, integer is provided. *Recommendation.* Look for tables without a PRIMARY KEY. Explicitly specify a PRIMARY KEY, even if it's an artificial AUTO\_INCREMENT. This is not an absolute requirement, but it is a stronger admonishment for InnoDB than for MyISAM. Some day you may need to walk through the table; without an explicit PK, you can't do it. *Fact.* The fields of the PRIMARY KEY are included in each Secondary key. * Check for redundant indexes with this in mind. ``` PRIMARY KEY(id), INDEX(b), -- effectively the same as INDEX(b, id) INDEX(b, id) -- effectively the same as INDEX(b) ``` * (Keep one of the INDEXes, not both) * Note subtle things like ``` PRIMARY KEY(id), UNIQUE(b), -- keep for uniqueness constraint INDEX(b, id) -- DROP this one ``` * Also, since the PK and the data coexist: ``` PRIMARY KEY(id), INDEX(id, b) -- DROP this one; it adds almost nothing ``` *Contrast.* This feature of MyISAM is not available in InnoDB; the value of 'id' will start over at 1 for each different value of 'abc': ``` id INT UNSIGNED NOT NULL AUTO_INCREMENT, PRIMARY KEY (abc, id) ``` A way to simulate the MyISAM 'feature' might be something like: What you want is this, but it won't work because it is referencing the table twice: ``` INSERT INTO foo (other, id, ...) VALUES (123, (SELECT MAX(id)+1 FROM foo WHERE other = 123), ...); ``` Instead, you need some variant on this. (You may already have a BEGIN...COMMIT.) ``` BEGIN; SELECT @id := MAX(id)+1 FROM foo WHERE other = 123 FOR UPDATE; INSERT INTO foo (other, id, ...) VALUES (123, @id, ...); COMMIT; ``` Having a transaction is mandatory to prevent another thread from grabbing the same id. *Recommendation.* Look for such PRIMARY KEYs. If you find such, ponder how to change the design. There is no straightforward workaround. However, the following may be ok. (Be sure that the datatype for id is big enough since it won't start over.): ``` id INT UNSIGNED NOT NULL AUTO_INCREMENT, PRIMARY KEY (abc, id), UNIQUE(id) ``` *Recommendation.* Keep the PRIMARY KEY short. If you have Secondary keys, remember that they include the fields of the PK. A long PK would make the Secondary keys bulky. Well, maybe not — if the is a lot of overlap in fields. Example: `PRIMARY KEY(a,b,c), INDEX(c,b,a)` — no extra bulk. *Recommendation.* Check AUTO\_INCREMENT sizes. * BIGINT is almost never needed. It wastes at least 4 bytes per row (versus INT). * Always use UNSIGNED and NOT NULL. * MEDIUMINT UNSIGNED (16M max) might suffice instead of INT * Be sure to be pessimistic — it is painful to ALTER. *Contrast.* "Vertical Partitioning". This is where you artificially split a table to move bulky columns (eg, a BLOB) into another, parallel, table. It is beneficial in MyISAM to avoid stepping over the blob when you don't need to read it. InnoDB stores BLOB and TEXT differently — 767 bytes are in the record, the rest is in some other block. So, it may (or may not) be worth putting the tables back together. Caution: An InnoDB row is limited to 8KB, and the 767 counts against that. *Fact.* FULLTEXT (prior to [MariaDB 10.0.5](https://mariadb.com/kb/en/mariadb-1005-release-notes/)) and SPATIAL indexes are not available in InnoDB. Note that MyISAM and InnoDB [FULLTEXT indexes](../full-text-indexes/index) use different <stopword> lists and different system variables. *Recommendation.* Search for such indexes. Keep such tables in MyISAM. Better yet, do Vertical Partitioning (see above) to split out the minimum number of columns from InnoDB. *Fact.* The maximum length of an INDEX is different between the Engines. (This change is not likely to hit you, but watch out.) MyISAM allows 1000 bytes; InnoDB allows 767 bytes, just big enough for a ``` VARCHAR(255) CHARACTER SET utf8. ERROR 1071 (42000): Specified key was too long; max key length is 767 bytes ``` *Fact.* The PRIMARY KEY is included in the data. Hence, SHOW TABLE STATUS will show and `Index_length` of 0 bytes (or 16KB) for a table with no secondary indexes. Otherwise, `Index_length` is the total size for the secondary keys. *Fact.* The PRIMARY KEY is included in the data. Hence, exact match by PK may be a little faster with InnoDB. And, "range" scans by PK are likely to be faster. *Fact.* A lookup by Secondary Key traverses the secondary key's BTree, grabs the PRIMARY KEY, then traverses the PK's BTree. Hence, secondary key lookups are a little more cumbersome in InnoDB. *Contrast.* The fields of the PRIMARY KEY are included in each Secondary key. This may lead to "Using index" (in the EXPLAIN plan) for InnoDB for cases where it did not happen in MyISAM. (This is a slight performance boost, and counteracts the double-lookup otherwise needed.) However, when "Using index" would be useful on the PRIMARY KEY, MyISAM would do an "index scan", yet InnoDB effectively has to do a "table scan". *Same as MyISAM.* Almost always ``` INDEX(a) -- DROP this one because the other one handles it. INDEX(a,b) ``` *Contrast.* The data is stored in PK order. This means that "recent" records are 'clustered' together at the end. This may give you better 'locality of reference' than in MyISAM. *Same as MyISAM.* The optimizer almost never uses two indexes in a single SELECT. (5.1 will occasionally do "index merge".) SELECT in subqueries and UNIONs can independently pick indexes. *Subtle issue.* When you DELETE a row, the AUTO\_INCREMENT id will be burned. Ditto for REPLACE, which is a DELETE plus an INSERT. *Very subtle issue.* Replication occurs on COMMIT. If you have multiple threads using transactions, the AUTO\_INCREMENTs can arrive at a slave out of order. One transaction BEGINs, grabs an id. Then another transaction grabs an id but COMMITs before the first finishes. *Same as MyISAM.* "Prefix" indexing is usually bad in both InnoDB and MyISAM. Example: `INDEX(foo(30))` Non-INDEX Issues ---------------- Disk space for InnoDB is likely to be 2-3 times as much as for MyISAM. MyISAM and InnoDB use RAM radically differently. If you change all your tables, you should make significant adjustments: * [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) — small but non-zero; say, 10M; * [innodb\_buffer\_pool\_size](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_size) — 70% of available RAM InnoDB has essentially no need for CHECK, OPTIMIZE, or ANALYZE. Remove them from your maintenance scripts. (No real harm if you keep them.) Backup scripts may need checking. A MyISAM table can be backed up by copying three files. With InnoDB this is only possible if [innodb\_file\_per\_table](../xtradbinnodb-server-system-variables/index#innodb_file_per_table) is set to 1. Before [MariaDB 10.0](../what-is-mariadb-100/index), capturing a table or database for copying from production to a development environment was not possible. Change to [mysqldump](../mysqldump/index). Since [MariaDB 10.0](../what-is-mariadb-100/index) a hot copy can be created - see [Backup and restore overview](../backup-and-restore-overview/index). Before [MariaDB 5.5](../what-is-mariadb-55/index), the DATA DIRECTORY [table option](../create-table/index#table-options) was not supported for InnoDB. Since [MariaDB 5.5](../what-is-mariadb-55/index) it is supported, but only in CREATE TABLE. INDEX DIRECTORY has no effect, since InnoDB does not use separate files for indexes. To better balance the workload through several disks, the paths of some InnoDB log files can also be changed. Understand autocommit and BEGIN/COMMIT. * (default) autocommit = 1: In the absence of any BEGIN or COMMIT statements, every statement is a transaction by itself. This is close to the MyISAM behavior, but is not really the best. * autocommit = 0: COMMIT will close a transaction and start another one. To me, this is kludgy. * (recommended) BEGIN...COMMIT gives you control over what sequence of operation(s) are to be considered a transaction and "atomic". Include the ROLLBACK statement if you need to undo stuff back to the BEGIN. Perl's DBIx::DWIW and Java's JDBC have API calls to do BEGIN and COMMIT. These are probably better than 'executing' BEGIN and COMMIT. Test for errors everywhere! Because InnoDB uses row-level locking, it can stumble into deadlocks that you are not expecting. The engine will automatically ROLLBACK to the BEGIN. The normal recovery is to redo, beginning at the BEGIN. Note that this is a strong reason to have BEGINs. LOCK/UNLOCK TABLES — remove them. Replace them (sort of) with BEGIN ... COMMIT. (LOCK will work if [innodb\_table\_locks](../xtradbinnodb-server-system-variables/index#innodb_table_locks) is set to 1, but it is less efficient, and may have subtle issues.) In 5.1, ALTER ONLINE TABLE can speed up some operations significantly. (Normally ALTER TABLE copies the table over and rebuilds the indexes.) The "limits" on virtually everything are different between MyISAM and InnoDB. Unless you have huge tables, wide rows, lots of indexes, etc, you are unlikely to stumble into a different limit. Mixture of MyISAM and InnoDB? This is OK. But there are caveats. * RAM settings should be adjusted to accordingly. * JOINing tables of different Engines works. * A transaction that affects tables of both types can ROLLBACK InnoDB changes, but will leave MyISAM changes intact. * Replication: MyISAM statements are replicated when finished; InnoDB statements are held until the COMMIT. FIXED (vs DYNAMIC) is meaningless in InnoDB. PARTITION — You can partition MyISAM and InnoDB tables. Remember the screwball rule: You must either * have no UNIQUE (or PRIMARY) keys, or * have the value you are "partitioning on" in every UNIQUE key. The former is not advised for InnoDB. The latter is messy if you want an AUTO\_INCREMENT. PRIMARY KEY in PARTITION — Since every key must include the field on which you are PARTITIONing, how can AUTO\_INCREMENT work? Well, there seems to be a convenient special case: * This works: PRIMARY KEY(autoinc, partition\_key) * This does not work for InnoDB: PRIMARY KEY(partition\_key, autoinc) That is, an AUTO\_INCREMENT will correctly increment, and be unique across all PARTITINOs, when it is the first field of the PRIMARY KEY, but not otherwise. See Also -------- Rick James graciously allowed us to use this article in the Knowledge Base. [Rick James' site](http://mysql.rjweb.org/) has other useful tips, how-tos, optimizations, and debugging tips. Original source: <http://mysql.rjweb.org/doc.php/myisam2innodb> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb LASTVAL LASTVAL ======= `LASTVAL` is a synonym for [PREVIOUS VALUE for sequence\_name](../previous-value-for-sequence_name/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_GeomCollFromWKB ST\_GeomCollFromWKB =================== Syntax ------ ``` ST_GeomCollFromWKB(wkb[,srid]) ST_GeometryCollectionFromWKB(wkb[,srid]) GeomCollFromWKB(wkb[,srid]) GeometryCollectionFromWKB(wkb[,srid]) ``` Description ----------- Constructs a GEOMETRYCOLLECTION value using its [WKB](../well-known-binary-wkb-format/index) representation and SRID. `ST_GeomCollFromWKB()`, `ST_GeometryCollectionFromWKB()`, `GeomCollFromWKB()` and `GeometryCollectionFromWKB()` are synonyms. Examples -------- ``` SET @g = ST_AsBinary(ST_GeomFromText('GEOMETRYCOLLECTION( POLYGON((5 5,10 5,10 10,5 5)),POINT(10 10))')); SELECT ST_AsText(ST_GeomCollFromWKB(@g)); +----------------------------------------------------------------+ | ST_AsText(ST_GeomCollFromWKB(@g)) | +----------------------------------------------------------------+ | GEOMETRYCOLLECTION(POLYGON((5 5,10 5,10 10,5 5)),POINT(10 10)) | +----------------------------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb LIMIT LIMIT ===== Description ----------- Use the `LIMIT` clause to restrict the number of returned rows. When you use a single integer *n* with `LIMIT`, the first *n* rows will be returned. Use the [ORDER BY](../order-by/index) clause to control which rows come first. You can also select a number of rows after an offset using either of the following: ``` LIMIT offset, row_count LIMIT row_count OFFSET offset ``` When you provide an offset *m* with a limit *n*, the first *m* rows will be ignored, and the following *n* rows will be returned. Executing an [UPDATE](../update/index) with the `LIMIT` clause is not safe for replication. `LIMIT 0` is an exception to this rule (see [MDEV-6170](https://jira.mariadb.org/browse/MDEV-6170)). There is a [LIMIT ROWS EXAMINED](../limit-rows-examined/index) optimization which provides the means to terminate the execution of [SELECT](../select/index) statements which examine too many rows, and thus use too many resources. See [LIMIT ROWS EXAMINED](../limit-rows-examined/index). ### Multi-Table Updates **MariaDB starting with [10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/)**Until [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/), it was not possible to use `LIMIT` (or [ORDER BY](../order-by/index)) in a multi-table [UPDATE](../update/index) statement. This restriction was lifted in [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/). ### GROUP\_CONCAT **MariaDB starting with [10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/)**Starting from [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/), it is possible to use `LIMIT` with [GROUP\_CONCAT()](../group_concat/index). Examples -------- ``` CREATE TABLE members (name VARCHAR(20)); INSERT INTO members VALUES('Jagdish'),('Kenny'),('Rokurou'),('Immaculada'); SELECT * FROM members; +------------+ | name | +------------+ | Jagdish | | Kenny | | Rokurou | | Immaculada | +------------+ ``` Select the first two names (no ordering specified): ``` SELECT * FROM members LIMIT 2; +---------+ | name | +---------+ | Jagdish | | Kenny | +---------+ ``` All the names in alphabetical order: ``` SELECT * FROM members ORDER BY name; +------------+ | name | +------------+ | Immaculada | | Jagdish | | Kenny | | Rokurou | +------------+ ``` The first two names, ordered alphabetically: ``` SELECT * FROM members ORDER BY name LIMIT 2; +------------+ | name | +------------+ | Immaculada | | Jagdish | +------------+ ``` The third name, ordered alphabetically (the first name would be offset zero, so the third is offset two): ``` SELECT * FROM members ORDER BY name LIMIT 2,1; +-------+ | name | +-------+ | Kenny | +-------+ ``` From [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/), `LIMIT` can be used in a multi-table update: ``` CREATE TABLE warehouse (product_id INT, qty INT); INSERT INTO warehouse VALUES (1,100),(2,100),(3,100),(4,100); CREATE TABLE store (product_id INT, qty INT); INSERT INTO store VALUES (1,5),(2,5),(3,5),(4,5); UPDATE warehouse,store SET warehouse.qty = warehouse.qty-2, store.qty = store.qty+2 WHERE (warehouse.product_id = store.product_id AND store.product_id >= 1) ORDER BY store.product_id DESC LIMIT 2; SELECT * FROM warehouse; +------------+------+ | product_id | qty | +------------+------+ | 1 | 100 | | 2 | 100 | | 3 | 98 | | 4 | 98 | +------------+------+ SELECT * FROM store; +------------+------+ | product_id | qty | +------------+------+ | 1 | 5 | | 2 | 5 | | 3 | 7 | | 4 | 7 | +------------+------+ ``` From [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/), `LIMIT` can be used with [GROUP\_CONCAT](../group_concat/index), so, for example, given the following table: ``` CREATE TABLE d (dd DATE, cc INT); INSERT INTO d VALUES ('2017-01-01',1); INSERT INTO d VALUES ('2017-01-02',2); INSERT INTO d VALUES ('2017-01-04',3); ``` the following query: ``` SELECT SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(":",dd,cc) ORDER BY cc DESC),",",1) FROM d; +----------------------------------------------------------------------------+ | SUBSTRING_INDEX(GROUP_CONCAT(CONCAT_WS(":",dd,cc) ORDER BY cc DESC),",",1) | +----------------------------------------------------------------------------+ | 2017-01-04:3 | +----------------------------------------------------------------------------+ ``` can be more simply rewritten as: ``` SELECT GROUP_CONCAT(CONCAT_WS(":",dd,cc) ORDER BY cc DESC LIMIT 1) FROM d; +-------------------------------------------------------------+ | GROUP_CONCAT(CONCAT_WS(":",dd,cc) ORDER BY cc DESC LIMIT 1) | +-------------------------------------------------------------+ | 2017-01-04:3 | +-------------------------------------------------------------+ ``` See Also -------- * [ROWNUM() function](../rownum/index) * [SELECT](../select/index) * [UPDATE](../update/index) * [DELETE](../delete/index) * [Joins and Subqueries](../joins-subqueries/index) * [ORDER BY](../order-by/index) * [GROUP BY](../group-by/index) * [Common Table Expressions](../common-table-expressions/index) * [SELECT WITH ROLLUP](../select-with-rollup/index) * [SELECT INTO OUTFILE](../select-into-outfile/index) * [SELECT INTO DUMPFILE](../select-into-dumpfile/index) * [FOR UPDATE](../for-update/index) * [LOCK IN SHARE MODE](../lock-in-share-mode/index) * [Optimizer Hints](../optimizer-hints/index) * [SELECT ... OFFSET ... FETCH](../select-offset-fetch/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Well-Known Binary (WKB) Format Well-Known Binary (WKB) Format ============================== WKB stands for Well-Known Binary, a format for representing geographical and geometrical data. WKB uses 1-byte unsigned integers, 4-byte unsigned integers, and 8-byte double-precision numbers. * The first byte indicates the byte order. 00 for big endian, or 01 for little endian. * The next 4 bytes indicate the geometry type. Values from 1 to 7 indicate whether the type is Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, or GeometryCollection respectively. * The 8-byte floats represent the co-ordinates. Take the following example, a sequence of 21 bytes each represented by two hex digits: ``` 000000000140000000000000004010000000000000 ``` * It's big endian + 00**0000000140000000000000004010000000000000** * It's a POINT + 00**00000001**40000000000000004010000000000000 * The X co-ordinate is 2.0 + 0000000001**4000000000000000**4010000000000000 * The Y-co-ordinate is 4.0 + 00000000014000000000000000**4010000000000000** Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CONNECT INI Table Type CONNECT INI Table Type ====================== Overview -------- The INI type is one of the configuration or initialization files often found on Windows machines. For instance, let us suppose you have the following contact file *contact.ini*: ``` [BER] name=Bertrand forename=Olivier address=21 rue Ferdinand Buisson city=Issy-les-Mlx zipcode=92130 tel=09.54.36.29.60 cell=06.70.06.04.16 [WEL] name=Schmitt forename=Bernard hired=19/02/1985 address=64 tiergarten strasse city=Berlin zipcode=95013 tel=03.43.377.360 [UK1] name=Smith forename=Henry hired=08/11/2003 address=143 Blum Rd. city=London zipcode=NW1 2BP ``` CONNECT lets you view it as a table in two different ways. Column layout ------------- The first way is to regard it as a table having one line per section, the columns being the keys you want to display. In this case, the CREATE statement could be: ``` create table contact ( contact char(16) flag=1, name char(20), forename char(32), hired date date_format='DD/MM/YYYY', address char(64), city char(20), zipcode char(8), tel char(16)) engine=CONNECT table_type=INI file_name='contact.ini'; ``` The column that will contain the section name can have any name but must specify `flag=1`. All other columns must have the names of the keys we want to display (case insensitive). The type can be character or numeric depending on the key value type, and the length is the maximum expected length for the key value. Once done, the statement: ``` select contact, name, hired, city, tel from contact; ``` This statement will display the file in tabular format. | contact | name | hired | city | tel | | --- | --- | --- | --- | --- | | BER | Bertrand | 1970-01-01 | Issy-les-Mlx | 09.54.36.29.60 | | WEL | Schmitt | 1985-02-19 | Berlin | 03.43.377.360 | | UK1 | Smith | 2003-11-08 | London | NULL | Only the keys defined in the create statements are visible; keys that do not exist in a section are displayed as null or pseudo null (blank for character, 1/1/70 for dates, and 0 for numeric) for columns declared NOT NULL. All relational operations can be applied to this table. The table (and the file) can be updated, inserted and conditionally deleted. The only constraint is that when inserting values, the section name must be the first in the list of values. **Note 1:** When inserting, if a section already exists, no new section will be created but the new values will be added or replace those of the existing section. Thus, the following two commands are equivalent: ``` update contact set forename = 'Harry' where contact = 'UK1'; insert into contact (contact,forename) values('UK1','Harry'); ``` **Note 2:** Because sections represent one line, a DELETE statement on a section key will delete the whole section. Row layout ---------- To be a good candidate for tabular representation, an INI file should have often the same keys in all sections. In practice, many files commonly found on computers, such as the *win.ini* file of the Windows directory or the *my.ini* file cannot be viewed that way because each section has different keys. In this case, a second way is to regard the file as a table having one row per section key and whose columns can be the section name, the key name, and the key value. For instance, let us define the table: ``` create table xcont ( section char(16) flag=1, keyname char(16) flag=2, value char(32)) engine=CONNECT table_type=INI file_name='contact.ini' option_list='Layout=Row'; ``` In this statement, the "Layout" option sets the display format, Column by default or anything else not beginning by 'C' for row layout display. The names of the three columns can be freely chosen. The Flag option gives the meaning of the column. Specify `flag=1` for the section name and `flag=2` for the key name. Otherwise, the column will contain the key value. Once done, the command: ``` select * from xcont; ``` Will display the following result: | section | keyname | value | | --- | --- | --- | | BER | name | Bertrand | | BER | forename | Olivier | | BER | address | 21 rue Ferdinand Buisson | | BER | city | Issy-les-Mlx | | BER | zipcode | 92130 | | BER | tel | 09.54.36.29.60 | | BER | cell | 06.70.06.04.16 | | WEL | name | Schmitt | | WEL | forename | Bernard | | WEL | hired | 19/02/1985 | | WEL | address | 64 tiergarten strasse | | WEL | city | Berlin | | WEL | zipcode | 95013 | | WEL | tel | 03.43.377.360 | | UK1 | name | Smith | | UK1 | forename | Henry | | UK1 | hired | 08/11/2003 | | UK1 | address | 143 Blum Rd. | | UK1 | city | London | | UK1 | zipcode | NW1 2BP | **Note:** When processing an INI table, all section names are retrieved in a buffer of 8K bytes (2048 bytes before 10.0.17). For a big file having many sections, this size can be increased using for example: ``` option_list='seclen=16K'; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Plans for MariaDB 10.5 Plans for MariaDB 10.5 ====================== [MariaDB 10.5](../what-is-mariadb-105/index) is stable, so no new features will be added. See [Plans for MariaDB 10.6](../plans-for-mariadb-106/index) instead. JIRA ---- We manage our development plans in JIRA, so the definitive list will be there. [This search](https://jira.mariadb.org/issues/?jql=project+%3D+MDEV+AND+issuetype+%3D+Task+AND+fixVersion+in+%2810.5%29+ORDER+BY+priority+DESC) shows what we **currently** plan for 10.5. It shows all tasks with the **Fix-Version** being 10.5. Not all these tasks will really end up in 10.5, but tasks with the "red" priorities have a much higher chance of being done in time for 10.5. Practically, you can think of these tasks as "features that **will** be in 10.5". Tasks with the "green" priorities probably won't be in 10.5. Think of them as "bonus features that would be **nice to have** in 10.5". Contributing ------------ If you want to be part of developing any of these features, see [Contributing to the MariaDB Project](../contributing-to-the-mariadb-project/index). You can also add new features to this list or to [JIRA](../jira-project-planning-and-tracking/index). See Also -------- * [Current tasks for 10.5](https://jira.mariadb.org/issues/?jql=project%20%3D%20MDEV%20AND%20issuetype%20%3D%20Task%20AND%20fixVersion%20in%20(10.5)%20ORDER%20BY%20priority%20DESC) * [10.5 Features/fixes by vote](https://jira.mariadb.org/issues/?jql=project%20%3D%20MDEV%20AND%20issuetype%20%3D%20Task%20AND%20fixVersion%20in%20(10.5)%20ORDER%20BY%20votes%20DESC%2C%20priority%20DESC) * [What is MariaDB 10.5?](../what-is-mariadb-105/index) * [What is MariaDB 10.4?](../what-is-mariadb-104/index) * [What is MariaDB 10.3?](../what-is-mariadb-103/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mariadb-conv mariadb-conv ============ **MariaDB starting with [10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)**`mariadb-conv` is a character set conversion utility for MariaDB and was added in [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/). Usage ----- ``` mariadb-conv [OPTION...] [FILE...] ``` Options ------- `mariadb-conv` supports the following options: | Option | Description | | --- | --- | | -f, --from=name | Specifies the encoding of the input. | | -t, --to=name | Specifies the encoding of the output. | | -c, --continue | Silently ignore conversion errors. | | --delimiter=name | Treat the specified characters as delimiters. | By default, `mariadb-conv` exits whenever it encounters any conversion problems, for example: * the input byte sequence is not valid in the source character set * the character cannot be converted to the target character set The `-c` option makes `mariadb-conv` ignore such errors and use the question mark '?' to replace bytes in bad input sequences, or unconvertable characters. The `--delimiter=...` option makes `mariadb-conv` treat the specified characters as delimiters rather than data to convert, so the input is treated as a combination of: * data chunks, which are converted according to the `-f` and `-t` options. * delimiters, which are not converted and are copied from the input to the output as is. Examples -------- Converts the file `file.latin1.txt` from `latin1` to `utf8`. ``` mariadb-conv -f latin1 -t utf8 file.latin1.txt ``` Convert the file `file.latin1.txt` from `latin1` to `utf8`, reading the input data from stdin. ``` mariadb-conv -f latin1 -t utf8 < file.latin1.txt ``` Using mariadb-conv in a pipe: ``` echo test | ./mariadb-conv -f utf8 -t ucs2 >file.ucs2.txt ``` As a side effect, mariadb-conv can be used to list MariaDB data directories in a human readable form. Suppose you create the following tables: ``` SET NAMES utf8; CREATE OR REPLACE TABLE t1 (a INT); CREATE OR REPLACE TABLE ß (a INT); CREATE OR REPLACE TABLE абв (a INT); CREATE OR REPLACE TABLE 桌子 (a INT); ``` The above makes the server create the following files in the MariaDB data directory: ``` @1j.frm @1j.ibd @[email protected] @[email protected] @g0@[email protected] @g0@[email protected] t1.frm t1.ibd ``` It's not precisely clear which file stores which table, because MariaDB uses a special table-name-to-file-name encoding. This command on Linux (assuming an utf-8 console) can print the table list in a readable way:: ``` ls | mariadb-conv -f filename -t utf8 --delimiter=".\n" ß.frm ß.ibd 桌子.frm 桌子.ibd абв.frm абв.ibd t1.frm t1.ibd ``` Note, the `--delimiter=".\n"` option is needed to make `mariadb-conv` treat the dot character (delimiting the encoded table name from the file extension) and the new line character (delimiting separate lines) as delimiters rather than as the data to convert (otherwise the conversion would fail). Windows users can use the following command to list the data directory in the ANSI text console: ``` dir /b | mariadb-conv -c -f filename -t cp850 --delimiter=".\r\n" ``` Note: * The `-t` options assume a Western machine. * The `-c` option is needed to ignore conversion errors for Cyrillic and CJK characters. * `--delimiter=` additionally needs the carriage return character \r Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb BIN BIN === Syntax ------ ``` BIN(N) ``` Description ----------- Returns a string representation of the binary value of the given longlong (that is, `[BIGINT](../bigint/index)`) number. This is equivalent to `[CONV(N,10,2)](../conv/index)`. The argument should be positive. If it is a `FLOAT`, it will be truncated. Returns `NULL` if the argument is `NULL`. Examples -------- ``` SELECT BIN(12); +---------+ | BIN(12) | +---------+ | 1100 | +---------+ ``` See Also -------- * [Binary literals](../binary-literals/index) * [CONV()](../conv/index) * [OCT()](../oct/index) * [HEX()](../hex/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb INT2 INT2 ==== `INT2` is a synonym for [SMALLINT](../smallint/index). ``` CREATE TABLE t1 (x INT2); DESC t1; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | x | smallint(6) | YES | | NULL | | +-------+-------------+------+-----+---------+-------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CONNECT Table Types - Special "Virtual" Tables CONNECT Table Types - Special "Virtual" Tables ============================================== The special table types supported by CONNECT are the Virtual table type ([VIR](../connect-table-types-vir/index) - introduced in [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/)), Directory Listing table type (DIR), the Windows Management Instrumentation Table Type (WMI), and the “Mac Address” type (MAC). These tables are “virtual tables”, meaning they have no physical data but rather produce result data using specific algorithms. Note that this is close to what Views are, so they could be regarded as special views. DIR Type -------- A table of type DIR returns a list of file name and description as a result set. To create a DIR table, use a Create Table statement such as: ``` create table source ( DRIVE char(2) NOT NULL, PATH varchar(256) NOT NULL, FNAME varchar(256) NOT NULL, FTYPE char(4) NOT NULL, SIZE double(12,0) NOT NULL flag=5, MODIFIED datetime NOT NULL) engine=CONNECT table_type=DIR file_name='..\\*.cc'; ``` When used in a query, the table returns the same file information listing than the system "DIR `*.cc`" statement would return if executed in the same current directory (here supposedly ..\) For instance, the query: ``` select fname, size, modified from source where fname like '%handler%'; ``` Displays: | fname | size | modified | | --- | --- | --- | | handler | 152177 | 2011-06-13 18:08:29 | | sql\_handler | 25321 | 2011-06-13 18:08:31 | **Note:** the important item in this table is the flag option value (set sequentially from 0 by default) because it determines which particular information item is returned in the column: | Flag value | Information | | --- | --- | | 0 | The disk drive (Windows) | | 1 | The file path | | 2 | The file name | | 3 | The file type | | 4 | The file attribute | | 5 | The file size | | 6 | The last write access date | | 7 | The last read access date | | 8 | The file creation date | ### The Subdir option When specified in the create table statement, the subdir option indicates to list, in addition to the files contained in the specified directory, all the files verifying the filename pattern that are contained in sub-directories of the specified directory. For instance, using: ``` create table data ( PATH varchar(256) NOT NULL flag=1, FNAME varchar(256) NOT NULL, FTYPE char(4) NOT NULL, SIZE double(12,0) NOT NULL flag=5) engine=CONNECT table_type=DIR file_name='*.frm' option_list='subdir=1'; select path, count(*), sum(size) from data group by path; ``` You will get the following result set showing how many tables are created in the MariaDB databases and what is the total length of the FRM files: | path | count(\*) | sum(size) | | --- | --- | --- | | \CommonSource\mariadb-5.2.7\sql\data\connect\ | 30 | 264469 | | \CommonSource\mariadb-5.2.7\sql\data\mysql\ | 23 | 207168 | | \CommonSource\mariadb-5.2.7\sql\data\test\ | 22 | 196882 | ### The Nodir option (Windows) The Boolean Nodir option can be set to false (0 or no) to add directories that match the file name pattern from the listed files (it is true by default). This is an addition to CONNECT version 1.6. Previously, directory names matching pattern were listed on Windows. Directories were and are never listed on Linux. Note: The way file names are retrieved makes positional access to them impossible. Therefore, DIR tables cannot be indexed or sorted when it is done using positions. Be aware, in particular when using the subdir option, that queries on DIR tables are slow and can last almost forever if made on a directory that contains a great number of files in it and its sub-directories. dir tables can be used to populate a list of files used to create a multiple=2 table. However, this is not as useful as it was when the multiple 3 did not exist. Windows Management Instrumentation Table Type “WMI” --------------------------------------------------- **Note:** This table type is available on Windows only. WMI provides an operating system interface through which instrumented components provide information. Some Microsoft tools to retrieve information through WMI are the WMIC console command and the WMI CMI Studio application. The CONNECT WMI table type enables administrators and operators not capable of scripting or programming on top of WMI to enjoy the benefit of WMI without even learning about it. It permits to present this information as tables that can be queried, transformed, copied in documents or other tables. To create a WMI table displaying information coming from a WMI provider, you must provide the namespace and the class name that characterize the information you want to retrieve. The best way to find them is to use the WMI CIM Studio that have tools to browse namespaces and classes and that can display the names of the properties of that class. The column names of the tables must be the names (case insensitive) of the properties you want to retrieve. For instance: ``` create table alias ( friendlyname char(32) not null, target char(50) not null) engine=CONNECT table_type='WMI' option_list='Namespace=root\\cli,Class=Msft_CliAlias'; ``` WMI tables returns one row for each instance of the related information. The above example is handy to get the class equivalent of the alias of the WMIC command and also to have a list of many classes commonly used. Because most of the useful classes belong to the 'root\cimv2' namespace, this is the default value for WMI tables when the namespace is not specified. Some classes have many properties whose name and type may not be known when creating the table. To find them, you can use the WMI CMI Studio application but his will be rarely required because CONNECT is able to retrieve them. Actually, the class specification also has default values for some namespaces. For the ‘root\cli’ namespace the class name defaults to ‘Msft\_CliAlias’ and for the ‘root\_cimv2’ namespace the class default value is ‘Win32\_ComputerSystemProduct’. Because many class names begin with ‘Win32\_’ it is not necessary to say it and specifying the class as ‘Product’ will effectively use class ‘Win32\_Product’. For example if you define a table as: ``` create table CSPROD engine=CONNECT table_type='WMI'; ``` It will return the information on the current machine, using the class ComputerSystemProduct of the CIMV2 namespace. For instance: ``` select * from csprod; ``` Will return a result such as: | Column | Row 1 | | --- | --- | | Caption | Computer system product | | Description | Computer system product | | IdentifyingNumber | LXAP50X32982327A922300 | | Name | Aspire 8920 | | SKUNumber | | | UUID | 00FC523D-B8F7-DC12-A70E-00B0D1A46136 | | Vendor | Acer | | Version | Aspire 8920 | **Note:** This is a transposed display that can be obtained with some GUI. ### Getting column information An issue, when creating a WMI table, is to make its column definition. Indeed, even when you know the namespace and the class for the wanted information, it is not easy to find what are the names and types of its properties. However, because CONNECT can retrieve this information from the WMI provider, you can simply omit defining columns and CONNECT will do the job. Alternatively, you can get this information using a catalog table (see below). ### Performance Consideration Some WMI providers can be very slow to answer. This is not an issue for those that return few object instances, such as the ones returning computer, motherboard, or Bios information. They generally return only one row (instance). However, some can return many rows, in particular the "CIM\_DataFile" class. This is why care must be taken about them. Firstly, it is possible to limit the allocated result size by using the ‘Estimate’ create table option. To avoid result truncation, CONNECT allocates a result of 100 rows that is enough for almost all tables.The 'Estimate' option permits to reduce this size for all classes that return only a few rows, and in some rare case to increase it to avoid truncation. However, it is not possible to limit the time taken by some WMI providers to answer, in particular the CIM\_DATAFILE class. Indeed the Microsoft documentation says about it: "Avoid enumerating or querying for all instances of CIM\_DataFile on a computer because the volume of data is likely to either affect performance or cause the computer to stop responding." Sure enough, even a simple query such as: ``` select count(*) from cim where drive = 'D:' and path like '\\MariaDB\\%'; ``` is prone to last almost forever (probably due to the LIKE clause). This is why, when not asking for some specific items, you should consider using the DIR table type instead. ### Syntax of WMI queries Queries to WMI providers are done using the WQL language, not the SQL language. CONNECT does the job of making the WQL query. However, because of the restriction of the WQL syntax, the WHERE clause will be generated only when respecting the following restrictions: 1. No function. 2. No comparison between two columns. 3. No expression (currently a CONNECT restriction) 4. No BETWEEN and IN predicates. Filtering with WHERE clauses not respecting these conditions will still be done by MariaDB only, except in the case of CIM\_Datafile class for the reason given above. However, there is one point that is not covered yet, the syntax used to specify dates in queries. WQL does not recognize dates as number items but translates them to its internal format dates specified as text. Many formats are recognized as described in the Microsoft documentation but only one is useful because common to WQL and MariaDB SQL. Here is an example of a query on a table named "cim" created by: ``` create table cim ( Name varchar(255) not null, LastModified datetime not null) engine=CONNECT table_type='WMI' option_list='class=CIM_DataFile,estimate=5000'; ``` The date must be specified with the format in which CIM DATETIME values are stored (WMI uses the date and time formats defined by the Distributed Management Task Force). ``` select * from cim where drive = 'D:' and path = '\\PlugDB\\Bin\\' and lastmodified > '20120415000000.000000+120'; ``` This syntax must be strictly respected. The text has the format: ``` yyyymmddHHMMSS.mmmmmmsUUU ``` It is: year, month, day, hour, minute, second, millisecond, and signed minute deviation from [UTC](../coordinated-universal-time/index). This format is locale-independent so you can write a query that runs on any machine. **Note 1:** The WMI table type is available only in Windows versions of CONNECT. **Note 2:** WMI tables are read only. **Note 3:** WMI tables are not indexable. **Note 4:** WMI consider all strings as case insensitive. MAC Address Table Type “MAC” ---------------------------- **Note:** This table type is available on Windows only. This type is used to display various general information about the computer and, in particular, about its network cards. To create such a table, the syntax to use is: ``` create table tabname (column definition) engine=CONNECT table_type=MAC; ``` Column names can be freely chosen because their signification, i.e. the values they will display, comes from the specified Flag option. The valid values for Flag are: | Flag | Valeur | Type | | --- | --- | --- | | 1 | Host name | varchar(132) | | 2 | Domain | varchar(132) | | 3 | DNS address | varchar(24) | | 4 | Node type | int(1) | | 5 | Scope ID | varchar(256) | | 6 | Routing | int(1) | | 7 | Proxy | int(1) | | 8 | DNS | int(1) | | 10 | Name | varchar(260) | | 11 | Description | varchar(132) | | 12 | MAC address | char(24) | | 13 | Type | int(3) | | 14 | DHCP | int(1) | | 15 | IP address | char(16) | | 16 | SUBNET mask | char(16) | | 17 | GATEWAY | char(16) | | 18 | DHCP server | char(16) | | 19 | Have WINS | int(1) | | 20 | Primary WINS | char(16) | | 21 | Secondary WINS | char(16) | | 22 | Lease obtained | datetime | | 23 | Lease expires | datetime | **Note:** The information of columns having a Flag value less than 10 are unique for the computer, the other ones are specific to the network cards of the computer. For instance, you can define the table *macaddr* as: ``` create table macaddr ( Host varchar(132) flag=1, Card varchar(132) flag=11, Address char(24) flag=12, IP char(16) flag=15, Gateway char(16) flag=17, Lease datetime flag=23) engine=CONNECT table_type=MAC; ``` If you execute the query: ``` select host, address, ip, gateway, lease from macaddr; ``` It will return, for example: | Host | Address | IP | Gateway | Lease | | --- | --- | --- | --- | --- | | OLIVIER | 00-A0-D1-A4-61-36 | 0.0.0.0 | 0.0.0.0 | 1970-01-01 00:00:00 | | OLIVIER | 00-1D-E0-9B-90-0B | 192.168.0.10 | 192.168.0.254 | 2011-09-18 10:28:5 | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DO DO == Syntax ------ ``` DO expr [, expr] ... ``` Description ----------- `DO` executes the expressions but does not return any results. In most respects, `DO` is shorthand for `SELECT expr, ...,` but has the advantage that it is slightly faster when you do not care about the result. `DO` is useful primarily with functions that have side effects, such as `[RELEASE\_LOCK()](../release_lock/index)`. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Multiple User Module Guide ColumnStore Multiple User Module Guide ====================================== Introduction ------------ This Document describes the setup and the functionality of the MariaDB ColumnStore User Module in a Multiple Node configuration. It will detail the different ways to configure how queries are processed with the Multiple Nodes and how the MariaDB ColumnStore Replication works. ColumnStore user module ----------------------- The ColumnStore User Module manages and controls the operation of end-user queries. For additional details on this can be found here: [https://mariadb.com/kb/en/mariadb/columnstore-user-module/](../mariadb/columnstore-user-module/index) ColumnStore user module configuration ------------------------------------- A MariaDB ColumnStore system will have at least 1 User Module. It might reside on the same server as the MariaDB ColumnStore Performance Module or can reside on a separate server. A MariaDB ColumnStore system can also be configured to have more than 1 User Modules. The advantages of having Multiple User Modules: * Higher concurrency queries execution by distributing the queries across all User Modules * Higher Query Performance * Provides User Modules High Availability into the system * Provides support of MariaDB ColumnStore User Module Replication A MariaDB ColumnStore system can be configured with Multiple User Modules either during the install installation phase when running the configuration script postConfigure. More details can be found here: [https://mariadb.com/kb/en/mariadb/installing-and-configuring-a-multi-server-columnstore-system/](../mariadb/installing-and-configuring-a-multi-server-columnstore-system/index) An existing MariaDB ColumnStore system can be scaled out by adding addition User Modules. More Details can be found here on adding addition modules to a system: ColumnStore user module status ------------------------------ Use the 'mcsadmin getSystemInfo' to display the Module Status along with the current Master User Module, which is called "Primary Front-End MariaDB ColumnStore Module" Here is an example: ``` # mcsadmin getSystemInfo getsysteminfo Tue Jun 12 13:45:21 2018 System 1.1.4 System and Module statuses Component Status Last Status Change ------------ -------------------------- ------------------------ System ACTIVE Tue Jun 12 13:41:25 2018 Module um1 ACTIVE Tue Jun 12 13:41:14 2018 Module um2 ACTIVE Tue Jun 12 13:41:00 2018 Module pm1 ACTIVE Tue Jun 12 13:40:49 2018 Active Parent OAM Performance Module is 'pm1' Primary Front-End MariaDB ColumnStore Module is 'um1' MariaDB ColumnStore Replication Feature is enabled MariaDB ColumnStore Process statuses Process Module Status Last Status Change Process ID ------------------ ------ --------------- ------------------------ ---------- ProcessMonitor um1 ACTIVE Tue Jun 12 13:40:34 2018 2231 ServerMonitor um1 ACTIVE Tue Jun 12 13:40:52 2018 2560 DBRMWorkerNode um1 ACTIVE Tue Jun 12 13:40:51 2018 2573 ExeMgr um1 ACTIVE Tue Jun 12 13:41:05 2018 3548 DDLProc um1 ACTIVE Tue Jun 12 13:41:12 2018 4522 DMLProc um1 ACTIVE Tue Jun 12 13:41:24 2018 5098 mysqld um1 ACTIVE Tue Jun 12 13:41:15 2018 2519 ProcessMonitor um2 ACTIVE Tue Jun 12 13:40:37 2018 2220 ServerMonitor um2 ACTIVE Tue Jun 12 13:40:56 2018 2569 DBRMWorkerNode um2 ACTIVE Tue Jun 12 13:41:01 2018 2582 ExeMgr um2 ACTIVE Tue Jun 12 13:41:03 2018 2779 DDLProc um2 COLD_STANDBY Tue Jun 12 13:41:00 2018 DMLProc um2 COLD_STANDBY Tue Jun 12 13:41:00 2018 mysqld um2 ACTIVE Tue Jun 12 13:40:59 2018 2528 ProcessMonitor pm1 ACTIVE Tue Jun 12 13:39:53 2018 1833 ProcessManager pm1 ACTIVE Tue Jun 12 13:39:59 2018 1892 DBRMControllerNode pm1 ACTIVE Tue Jun 12 13:40:42 2018 2702 ServerMonitor pm1 ACTIVE Tue Jun 12 13:40:46 2018 2716 DBRMWorkerNode pm1 ACTIVE Tue Jun 12 13:40:45 2018 2731 DecomSvr pm1 ACTIVE Tue Jun 12 13:40:47 2018 2828 PrimProc pm1 ACTIVE Tue Jun 12 13:40:55 2018 2906 WriteEngineServer pm1 ACTIVE Tue Jun 12 13:40:57 2018 2953 Active Alarm Counts: Critical = 0, Major = 0, Minor = 0, Warning = 0, Info = 0 ``` [https://mariadb.com/kb/en/mariadb/managing-columnstore-module-configurations/](../mariadb/managing-columnstore-module-configurations/index) ColumnStore multiple user module query execution ------------------------------------------------ Each of the User Modules have a MariaDB server process (mysqld) that that receive a query request from the MariaDB console or from remote applications via the MariaDB Port interface (defaulted is 3306). The MariaDB server process will send that request to the MariaDB ColumnStore process ExeMgr for processing. More details about how this is processed can be found here: [https://mariadb.com/kb/en/mariadb/columnstore-user-module/](../mariadb/columnstore-user-module/index) ColumnStore cross engine joins ------------------------------ MariaDB ColumnStore allows columnstore tables to be joined with non-columnstore tables (e.g. InnoDB tables) within a query. The standard configuration is to process these on the local User Module where the request was made. So the Automatic Query Round-Robin Distribution functionality doesn't apply to this type of queries. More information on ColumnStore Cross Engine Joins can be found here: [https://mariadb.com/kb/en/mariadb/configuring-columnstore-cross-engine-joins/](../mariadb/configuring-columnstore-cross-engine-joins/index) ### Automatic query round-robin distribution In a standard Multi-Node configuration install with more than 1 User Module, the query request are scaled-out across all User Modules using an automatic round-robin distribution functionality. This means that the MariaDB server process will distribute the query requests to all User Modules (ExeMgrs) in the MariaDB ColumnStore system. The ExeMgr will handle the processing of the query request and pass back the resulting data to the initial MariaDB server process, which will in turn provide that result set to the calling client. This round-robin distribution is handled on a session by sessions basis. ### Localized query distribution It is also possible to override the default round-robin logic and route queries only to the ExeMgr on the same host as the MariaDB server. With large result sets this may be more optimal as it avoids remote data transfers when the ExeMgr is not local. So what this means that when a Query comes into the MariaDB server process on UM1, it will send it to the ExeMgr on UM1 only for process. And the same would apply to the other User Modules. UM2 MariaDB Server process will send to UM2 ExeMgr. So if the user has a reason to want to keep all or a certain group of queries being process on 1 node, like UM1 and then use UM2 for backup only or maybe to handle special queries, then would be a reason for this type of configuration. To do this, the ExeMgr(s) port addresses in the MariaDB Columnstore configuration file (Columnstore.xml) would need to be updated after the install to contain the loop back address of 127.0.0.1. Here is the steps to achieve that. Note this examples shows update a 2 User Module system with 2 ExeMgrs. If you had 3 or more, than you would run the setConfig command the additional times. Here is the steps, run from PM1: (reminder, all changes to the config file need to be made on PM1) ``` # mcsadmin stopSystem y # /usr/local/mariadb/columnstore/bin/setConfig ExeMgr1 IPAddr 127.0.0.1 # /usr/local/mariadb/columnstore/bin/setConfig ExeMgr2 IPAddr 127.0.0.1 # mcsadmin startsystem ``` NOTE: The steps are assuming a root install directory, change for an non-root install where the directory is different. NOTE: To go from a Localized query distribution back to a query round-robin distribution, you would either need to run the same commands above, but replacing the 127.0.0.1 with the real IP Addresses of the 2 servers. Or do a shutdown and run postConfigure again from pm1. ColumnStore local performance module query ------------------------------------------ MariaDB ColumnStore support Local Performance Module Query where a query can be run locally on a Performance Module when a system is configured to have the User Module and the Performance Module on different servers. In this case, the Performance Module will have the User Module process running like the MariaDB Server Process and ExeMgr. But they are only there to process local queries. There will not process queries as part of the Automatic Query Round-Robin Distribution. More information on ColumnStore Local Performance Module Query can be found here: [https://mariadb.com/kb/en/mariadb/configuring-columnstore-local-pm-query-mode/](../mariadb/configuring-columnstore-local-pm-query-mode/index) ColumnStore user module replication ----------------------------------- MariaDB Columnstore supports User Module Replication. This will synchronize the the User Module data, which consist of the MariaDB Columnstore Database Schemas and the non-columnstore engine schemas and data. When enabled, it will synchronize the data from the Master Data Replication module, default is User Module 1, to all of the other User Modules including the Local Performance Modules. It uses the standard MySQL Data replication functionality to do this from the MariaDB Server Process. Which the setup to distribute from the Master User Module, any DDL and non-columnstore table creation and population must be done from the Master User Module. This will keep all of the User Module Databases in-sync. MariaDB ColumnStore utilizing the same Standard Replication that is used in the MariaDB Server application though the use of binlogs. The Master User Module will be assigned in the my.cnf file with SERVER-ID of 1. User Module #1 is the default Master at system startup. In the case of a failover where UM1 goes offline and another User Modules takes over as the Master, that User Module will be updated as SERVER-ID of 1. When User Module #1 recovers, it will be assigned a non 1 ID. Default User for Replication is idbrep and will be created from the scripts master-rep-columnstore.sh and slave-rep-columnstore.sh ``` https://github.com/mariadb-corporation/mariadb-columnstore-engine/blob/develop-1.2/oam/install_scripts/master-rep-columnstore.sh https://github.com/mariadb-corporation/mariadb-columnstore-engine/blob/develop-1.2/oam/install_scripts/slave-rep-columnstore.sh ``` ### Enabling replication The ColumnStore User Module Replication functionality can be enabled a couple of different ways: * During the initial configuration setup in postConfigure * Using the MariaDB ColumnStore Admin console ``` # mcsadmin enableMySQLReplication ``` ### Disabling replication The ColumnStore User Module Replication functionality can be disabled a couple of different ways: * During the initial configuration setup in postConfigure * Using the MariaDB ColumnStore Admin console ``` # mcsadmin disableMySQLReplication ``` The option to disable the MariaDB ColumnStore User Module Replication is available since there are additional third party tools that can be used to do the Data Replication. ### MariaDB Database password If you set a root password within the MariaDB Database, you will need to create a .my.cnf file as shown here and it will need to reside on all servers that have a User Module MariaDB running. [https://mariadb.com/kb/en/library/mariadb-columnstore-system-usage/#mysql-root-user-password](../library/mariadb-columnstore-system-usage/index#mysql-root-user-password) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb DBT3 Example Preparation Time DBT3 Example Preparation Time ============================= This page contains database preparation and creation times that were discovered while working on the [DBT3 Automation Scripts](../dbt3-automation-scripts/index). Database creation times ----------------------- | Setup | Time | Size on Disk | | --- | --- | --- | | Postgre s30 on pitbull | 758 min = 12 h 38 min. | 75 GB | | MariaDB + MyISAM s10 on 4CPU 4GB RAM developer machine | 96 m 22s = 1h 36m 22s | 17 GB | | MariaDB + MyISAM s100 on facebook-maria2: | 424m 4s = 7h 4m 4s. | 162 GB | | MariaDB + InnoDB s100 on facebook-maria2: | 577m 42s = 9h 37m 42s. | | | [MariaDB 5.3.2](https://mariadb.com/kb/en/mariadb-532-release-notes/) + InnoDB s30 on facebook-maria1 | 122m39.753s = 2h 2m 40s. | 71 GB | | [MariaDB 5.5.18](https://mariadb.com/kb/en/mariadb-5518-release-notes/) + InnoDB s30 on facebook-maria1 | 150m46.218s = 2h 30m 46s. | 71 GB | | MySQL 5.6.4 + InnoDB s30 on facebook-maria1: | 140m18.272s = 2h 20m 18s. | 71 GB | | MariaDB + MyISAM s30 on pitbull with pre\_create\_PK | > 3h 30m (with limited RAM to 11 GB) | | | MariaDB + MyISAM s30 on facebook-maria1: | 99m 8s = 1h 39m 8s. | 49 GB | | MySQL 5.6.4 + MyISAM s30 on facebook-maria1 | 114m 17s. | 49 GB | Dataload creation time ---------------------- | Setup | Time | Size on Disk | | --- | --- | --- | | Scale 10 on 4CPU 4GB RAM developer machine | 8 min 44 sec. | 10.4 GB | | Scale 30 on pitbull.askmonty.org | 20 min 28 sec. | 32 GB (with limited RAM to 11 GB) | | Scale 100 on facebook-maria2 | 78 min 27.601s. | 106 GB | | Scale 30 on facebook-maria1 | 23 min 40 sec. | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Quality Quality ======== This section collects articles related to MariaDB quality assurance efforts. | Title | Description | | --- | --- | | [mysql-test](../mysqltest/index) | Testing utility | | [Code Coverage](../code-coverage/index) | Getting more MariaDB source code covered by the MTR test suite | | [Code Coverage with dgcov](../dgcov/index) | The dgcov tool helps you check the coverage for new code. | | [QA Tests](../qa-tests/index) | Various tests used for QA | | [QA Metrics](../qa-metrics/index) | Code Coverage and Bugs | | [QA Datasets](../qa-datasets/index) | Realistic datasets are essential for proper testing. | | [QA Tools](../qa-tools/index) | Tools used for quality assurance testing. | | [Optimizer Quality](../optimizer-quality/index) | Generating queries, validating results, and so on. | | [QA - Aria Recovery](../qa-aria-recovery/index) | General principles and tests used to ensure Aria recovery is solid. | | [Benchmarks and Long Running Tests](../benchmarks-and-long-running-tests/index) | Here you will find details about our automated benchmark runs and long runn... | | [Worklog Quality Checklist Template](../worklog-quality-checklist-template/index) | The purpose of this template is to produce individual checklists for testi... | | [InnoDB Upgrade Tests](../innodb-upgrade-tests/index) | RQG-based upgrade tests with focus on InnoDB data live upgrade | | [Random Query Generator Tests](../random-query-generator-tests/index) | Automatic tests using the Random Query Generator. | | [RQG Extensions for MariaDB](../rqg-extensions-for-mariadb/index) | Extensions added to the random query generator for MariaDB testing. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB ColumnStore software upgrade 1.2.x GA to 1.2.4 GA MariaDB ColumnStore software upgrade 1.2.x GA to 1.2.4 GA ========================================================= MariaDB ColumnStore software upgrade 1.2.x GA to 1.2.4 GA --------------------------------------------------------- ### Changes in 1.2.1 and later #### libjemalloc dependency ColumnStore 1.2.3 onward requires libjemalloc to be installed. For Ubuntu & Debian based distributions this is installed using the package "libjemalloc1" in the standard repositories. For CentOS the package is in RedHat's EPEL repository: ``` sudo yum -y install epel-release sudo yum install jemalloc ``` #### Non-distributed is the default distribution mode in postConfigure The default distribution mode has changed from 'distributed' to 'non-distributed'. During an upgrade, however, the default is to use the distribution mode used in the original installation. The options '-d' and '-n' can always be used to override the default. #### Non-root user sudo setup Root-level permissions are no longer required to install or upgrade ColumnStore for some types of installations. Installations requiring some level of sudo access, and the instructions, are listed here: [https://mariadb.com/kb/en/library/preparing-for-columnstore-installation-121/#update-sudo-configuration-if-needed-by-root-user](../library/preparing-for-columnstore-installation-121/index#update-sudo-configuration-if-needed-by-root-user) #### Running the mysql\_upgrade script As part of the upgrade process to 1.2.4, the user is might be required to run the mysql\_upgrade script on all of the following nodes. 1. If the system was upgraded to 1.1.x to 1.2.x. And now it being upgrade to 1.2.4, the mysql\_upgrade script will need to be run. 2. If the system was initially installed with 1.2.x and now its being upgraded to 1.2.4, the mysql\_upgrade script doesnt need to be run. So this section can be skipped. * All User Modules on a system configured with separate User and Performance Modules * All Performance Modules on a system configured with separate User and Performance Modules and Local Query Feature is enabled * All Performance Modules on a system configured with combined User and Performance Modules mysql\_upgrade should be run once the upgrade has been completed. This is an example of how it run on a root user install: ``` /usr/local/mariadb/columnstore/mysql/bin/mysql_upgrade --defaults-file=/usr/local/mariadb/columnstore/mysql/my.cnf --force ``` This is an example of how it run on a non-root user install, assuming ColumnStore is installed under the user's home directory: ``` $HOME/mariadb/columnstore/mysql/bin/mysql_upgrade --defaults-file=$HOME/mariadb/columnstore/mysql/my.cnf --force ``` In addition you should run the upgrade stored procedure below for a major version upgrade. #### Executing the upgrade stored procedure 1. If the system was upgraded to 1.1.x to 1.2.x. And now it being upgrade to 1.2.4, the upgrade stored procedure will need to be run. 2. If the system was initially installed with 1.2.x and now its being upgraded to 1.2.4, the upgrade stored procedure doesnt need to be run. So this section can be skipped. This updates the MariaDB FRM files by altering every ColumnStore table with a blank table comment. This will not affect options set using table comments but will erase any table comment the user has manually set. You only need to execute this as part of a major version upgrade. It is executed using the following query which should be executed by a user which has access to alter every ColumnStore table: ``` call columnstore_info.columnstore_upgrade(); ``` ### Setup In this section, we will refer to the directory ColumnStore is installed in as <CSROOT>. If you installed the RPM or DEB package, then your <CSROOT> will be /usr/local. If you installed it from the tarball, <CSROOT> will be where you unpacked it. #### Columnstore.xml / my.cnf Configuration changes made manually are not automatically carried forward during the upgrade. These modifications will need to be made again manually after the upgrade is complete. After the upgrade process the configuration files will be saved at: * <CSROOT>/mariadb/columnstore/etc/Columnstore.xml.rpmsave * <CSROOT>/mariadb/columnstore/mysql/my.cnf.rpmsave #### MariaDB root user database password If you have specified a root user database password (which is good practice), then you must configure a .my.cnf file with user credentials for the upgrade process to use. Create a .my.cnf file in the user home directory with 600 file permissions with the following content (updating PASSWORD as appropriate): ``` [mysqladmin] user = root password = PASSWORD ``` ### Choosing the type of upgrade Note, softlinks may cause a problem during the upgrade if you use the RPM or DEB packages. If you have linked a directory above /usr/local/mariadb/columnstore, the softlinks will be deleted and the upgrade will fail. In that case you will need to upgrade using the binary tarball instead. If you have only linked the data directories (ie /usr/local/MariaDB/columnstore/data\*), the RPM/DEB package upgrade will work. #### Root User Installs ##### Upgrading MariaDB ColumnStore using the tarball of RPMs (distributed mode) Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Download the package mariadb-columnstore-1.2.4-1-centos#.x86\_64.rpm.tar.gz to the PM1 server where you are installing MariaDB ColumnStore.** **Shutdown the MariaDB ColumnStore system:** ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate a set of RPMs that will reside in the /root/ directory. ``` # tar -zxf mariadb-columnstore-1.2.4-1-centos#.x86_64.rpm.tar.gz ``` * Uninstall the old packages, then install the new packages. The MariaDB ColumnStore software will be installed in /usr/local/. ``` # rpm -e --nodeps $(rpm -qa | grep '^mariadb-columnstore') # rpm -ivh mariadb-columnstore-*1.2.4*rpm ``` * Run postConfigure using the upgrade option ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` * Run the mysql\_upgrade script on the nodes documented above for a root user install [https://mariadb.com/kb/en/library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/#running-the-mysql\_upgrade-script](../library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/index#running-the-mysql_upgrade-script) ##### Upgrading MariaDB ColumnStore using RPM Package Repositories (non-distributed mode) The system can be upgraded when it was previously installed from the Package Repositories. This will need to be run on each module in the system. Additional information can be found in this document on how to setup and install using the 'yum' package repo command: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Shutdown the MariaDB ColumnStore system:** ``` # mcsadmin shutdownsystem y ``` * Uninstall MariaDB ColumnStore Packages ``` # yum remove mariadb-columnstore* ``` * Install MariaDB ColumnStore Packages ``` # yum --enablerepo=mariadb-columnstore clean metadata # yum install mariadb-columnstore* ``` NOTE: On all modules except for PM1, start the columnstore service ``` # /usr/local/mariadb/columnstore/bin/columnstore start ``` * Run postConfigure using the upgrade and non-distributed options ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u -n ``` * Run the mysql\_upgrade script on the nodes documented above for a root user install [https://mariadb.com/kb/en/library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/#running-the-mysql\_upgrade-script](../library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/index#running-the-mysql_upgrade-script) ##### Upgrading MariaDB ColumnStore using the binary tarball (distributed mode) Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /usr/local directory mariadb-columnstore-1.2.4-1.x86\_64.bin.tar.gz * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Run pre-uninstall script ``` # /usr/local/mariadb/columnstore/bin/pre-uninstall ``` * Unpack the tarball in the /usr/local/ directory. ``` # tar -zxvf mariadb-columnstore-1.2.4-1.x86_64.bin.tar.gz ``` * Run post-install scripts ``` # /usr/local/mariadb/columnstore/bin/post-install ``` * Run postConfigure using the upgrade option ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` * Run the mysql\_upgrade script on the nodes documented above for a root user install [https://mariadb.com/kb/en/library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/#running-the-mysql\_upgrade-script](../library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/index#running-the-mysql_upgrade-script) ##### Upgrading MariaDB ColumnStore using the DEB tarball (distributed mode) Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /root directory mariadb-columnstore-1.2.4-1.amd64.deb.tar.gz * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which contains DEBs. ``` # tar -zxf mariadb-columnstore-1.2.4-1.amd64.deb.tar.gz ``` * Remove and install all MariaDB ColumnStore debs ``` # cd /root/ # dpkg -r $(dpkg --list | grep 'mariadb-columnstore' | awk '{print $2}') # dpkg --install mariadb-columnstore-*1.2.4-1*deb ``` * Run postConfigure using the upgrade option ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` * Run the mysql\_upgrade script on the nodes documented above for a root user install [https://mariadb.com/kb/en/library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/#running-the-mysql\_upgrade-script](../library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/index#running-the-mysql_upgrade-script) ##### Upgrading MariaDB ColumnStore using DEB Package Repositories (non-distributed mode) The system can be upgraded when it was previously installed from the Package Repositories. This will need to be run on each module in the system Additional information can be found in this document on how to setup and install using the 'apt-get' package repo command: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Shutdown the MariaDB ColumnStore system:** ``` # mcsadmin shutdownsystem y ``` * Uninstall MariaDB ColumnStore Packages ``` # apt-get remove mariadb-columnstore* ``` * Install MariaDB ColumnStore Packages ``` # apt-get update # sudo apt-get install mariadb-columnstore* ``` NOTE: On all modules except for PM1, start the columnstore service ``` # /usr/local/mariadb/columnstore/bin/columnstore start ``` * Run postConfigure using the upgrade and non-distributed options ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u -n ``` * Run the mysql\_upgrade script on the nodes documented above for a root user install [https://mariadb.com/kb/en/library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/#running-the-mysql\_upgrade-script](../library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/index#running-the-mysql_upgrade-script) #### Non-Root User Installs ##### Upgrade MariaDB ColumnStore from the binary tarball without sudo access (non-distributed mode) This upgrade method applies when root/sudo access is not an option. The uninstall script for 1.2.x requires root access to perform some operations. These operations are the following: * removing /etc/profile.d/columnstore{Alias,Env}.sh to remove aliases and environment variables from all users. * running '<CSROOT>/mysql/columnstore/bin/syslogSetup.sh uninstall' to remove ColumnStore from the logging system * removing the columnstore startup script * remove /etc/ld.so.conf.d/columnstore.conf to ColumnStore directories from the ld library search path Because you are upgrading ColumnStore and not uninstalling it, they are not necessary. If at some point you wish to uninstall it, you (or your sysadmin) will have to perform those operations by hand. The upgrade instructions: * Download the binary tarball to the current installation location on all nodes. See <https://downloads.mariadb.com/ColumnStore/> * Shutdown the MariaDB ColumnStore system: ``` $ mcsadmin shutdownsystem y ``` * Copy Columnstore.xml to Columnstore.xml.rpmsave, and my.cnf to my.cnf.rpmsave ``` $ cp <CSROOT>/mariadb/columnstore/etc/Columnstore{.xml,.xml.rpmsave} $ cp <CSROOT>/mariadb/columnstore/mysql/my{.cnf,.cnf.rpmsave} ``` * On all nodes, untar the new files in the same location as the old ones ``` $ tar zxf columnstore-1.2.4-1.x86_64.bin.tar.gz ``` * On all nodes, run post-install, specifying where ColumnStore is installed ``` $ <CSROOT>/mariadb/columnstore/bin/post-install --installdir=<CSROOT>/mariadb/columnstore ``` * On all nodes except for PM1, start the columnstore service ``` $ <CSROOT>/mariadb/columnstore/bin/columnstore start ``` * On PM1 only, run postConfigure, specifying the upgrade, non-distributed installation mode, and the location of the installation ``` $ <CSROOT>/mariadb/columnstore/bin/postConfigure -u -n -i <CSROOT>/mariadb/columnstore ``` * Run the mysql\_upgrade script on the nodes documented above for a non-root user install [https://mariadb.com/kb/en/library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/#running-the-mysql\_upgrade-script](../library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/index#running-the-mysql_upgrade-script) ##### Upgrade MariaDB ColumnStore from the binary tarball (distributed mode) Upgrade MariaDB ColumnStore as user USER on the server designated as PM1: * Download the package into the user's home directory mariadb-columnstore-1.2.4-1.x86\_64.bin.tar.gz * Shutdown the MariaDB ColumnStore system: ``` $ mcsadmin shutdownsystem y ``` * Run the pre-uninstall script; this will require sudo access as you are running a script from 1.2.x. ``` $ <CSROOT>/mariadb/columnstore/bin/pre-uninstall --installdir=<CSROOT>/mariadb/columnstore ``` * Make the sudo changes as noted at the beginning of this document * Unpack the tarball in the same place as the original installation ``` $ tar -zxvf mariadb-columnstore-1.2.4-1.x86_64.bin.tar.gz ``` * Run post-install scripts ``` $ <CSROOT>/mariadb/columnstore/bin/post-install --installdir=<CSROOT>/mariadb/columnstore ``` * Run postConfigure using the upgrade option ``` $ <CSROOT>/mariadb/columnstore/bin/postConfigure -u -i <CSROOT>/mariadb/columnstore ``` * Run the mysql\_upgrade script on the nodes documented above for a non-root user install [https://mariadb.com/kb/en/library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/#running-the-mysql\_upgrade-script](../library/mariadb-columnstore-software-upgrade-117-ga-to-124-ga/index#running-the-mysql_upgrade-script) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Partitioning Limitations with MariaDB Partitioning Limitations with MariaDB ===================================== The following limitations apply to partitioning in MariaDB: * Each table can contain a maximum of 8192 partitions (from [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/)). In [MariaDB 5.5](../what-is-mariadb-55/index) and until 10.0.3, the limit was 1024. * Currently, queries are never parallelized, even when they involve multiple partitions. * A table can only be partitioned if the storage engine supports partitioning. * All partitions must use the same storage engine. For a workaround, see [Using CONNECT - Partitioning and Sharding](../using-connect-partitioning-and-sharding/index). * A partitioned table cannot contain, or be referenced by, [foreign keys](../foreign-keys/index). * The [query cache](../query-cache/index) is not aware of partitioning and partition pruning. Modifying a partition will invalidate the entries related to the whole table. * Updates can run more slowly when binlog\_format=ROW and a partitioned table is updated than an equivalent update of a non-partitioned table. * All columns used in the partitioning expression for a partitioned table must be part of every unique key that the table may have. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb About MariaDB ColumnStore About MariaDB ColumnStore ========================= MariaDB ColumnStore is a columnar storage engine that utilizes a massively parallel distributed data architecture. It's a columnar storage system built by porting InfiniDB 4.6.7 to MariaDB, and released under the GPL license. From [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/), it is available as a storage engine for MariaDB Server. Before then, it is only available as a separate download. Documentation for the latest release of Columnstore is not available on the Knowledge Base. Instead, see: * [Release Notes](https://mariadb.com/docs/release-notes/mariadb-columnstore-1-5-2-release-notes/) * [Deployment Instructions](https://mariadb.com/docs/deploy/community-single-columnstore/) It is designed for big data scaling to process petabytes of data, linear scalability and exceptional performance with real-time response to analytical queries. It leverages the I/O benefits of columnar storage, compression, just-in-time projection, and horizontal and vertical partitioning to deliver tremendous performance when analyzing large data sets. Links: * [MariaDB Columnstore Blogs](https://mariadb.com/resources/blog/tag/columnstore/). * A Google Group exists for MariaDB ColumnStore that can be used to discuss ideas, issues and communicate with the community: Send email to [email protected] or use the [forum interface](https://groups.google.com/forum/#!forum/mariadb-columnstore) * Bugs can be reported in MariaDB Jira: <https://jira.mariadb.org> (see [Reporting Bugs](../reporting-bugs/index)). Please file bugs under the MCOL project and include the output from the [support utility](../system-troubleshooting-mariadb-columnstore/index) if possible. MariaDB ColumnStore is released under the GPL license. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Mroonga Mroonga ======== Mroonga (formerly named Groonga Storage Engine) is a storage engine that provides fast CJK-ready full text searching using column store. | Title | Description | | --- | --- | | [About Mroonga](../about-mroonga/index) | Mroonga full text search storage engine. | | [Mroonga Overview](../mroonga-overview/index) | Basic Mroonga usage. | | [Mroonga Status Variables](../mroonga-status-variables/index) | Mroonga-related status variables. | | [Mroonga System Variables](../mroonga-system-variables/index) | Mroonga-related system variables. | | [Mroonga User-Defined Functions](../mroonga-user-defined-functions/index) | Mroonga user-defined functions (UDFs). | | [Information Schema MROONGA\_STATS Table](../information-schema-mroonga_stats-table/index) | Mroonga activities statistics. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.spider_table_position_for_recovery Table mysql.spider\_table\_position\_for\_recovery Table ================================================== The `mysql.spider_table_position_for_recovery` table is installed by the [Spider storage engine](../spider/index). **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this table uses the [Aria](../aria/index) storage engine. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. It contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | db\_name | char(64) | NO | PRI | | | | table\_name | char(199) | NO | PRI | | | | failed\_link\_id | int(11) | NO | PRI | 0 | | | source\_link\_id | int(11) | NO | PRI | 0 | | | file | text | YES | | NULL | | | position | text | YES | | NULL | | | gtid | text | YES | | NULL | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Aria System Variables Aria System Variables ===================== This page documents system variables related to the [Aria storage engine](../aria/index). For options that are not system variables, see [Aria Options](../mysqld-options/index#aria-storage-engine-options). See [Server System Variables](../server-system-variables/index) for a complete list of system variables and instructions on setting system variables. Also see the [Full list of MariaDB options, system and status variables](../full-list-of-mariadb-options-system-and-status-variables/index). #### `aria_block_size` * **Description:** Block size to be used for Aria index pages. Changing this requires dumping, deleting old tables and deleting all log files, and then restoring your Aria tables. If key lookups take too long (and one has to search roughly 8192/2 by default to find each key), can be made smaller, e.g. `4096`. * **Commandline:** `--aria-block-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `8192` * **Range:** + >= [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/): `4096` to `32768` in increments of `1024` + <= [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/): `1024` to `32768` in increments of `1024` --- #### `aria_checkpoint_interval` * **Description:** Interval in seconds between automatic checkpoints. 0 means 'no automatic checkpoints' which makes sense only for testing. * **Commandline:** `--aria-checkpoint-interval=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `30` * **Range:** `0` to `4294967295` --- #### `aria_checkpoint_log_activity` * **Description:** Number of bytes that the transaction log has to grow between checkpoints before a new checkpoint is written to the log. * **Commandline:** `aria-checkpoint-log-activity=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1048576` * **Range** `0` to `4294967295` --- #### `aria_encrypt_tables` * **Description:** Enables automatic encryption of all user-created Aria tables that have the `[ROW\_FORMAT](../create-table/index#row_format)` table option set to `[PAGE](../aria-storage-formats/index#page)`. See [Data at Rest Encryption](../data-at-rest-encryption/index) and [Enabling Encryption for User-created Tables](../encrypting-data-for-aria/index#enabling-encryption-for-user-created-tables). * **Commandline:** `aria-encrypt-tables={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `aria_force_start_after_recovery_failures` * **Description:** Number of consecutive log recovery failures after which logs will be automatically deleted to cure the problem; 0 (the default) disables the feature. * **Commandline:** `--aria-force-start-after-recovery-failures=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `0` --- #### `aria_group_commit` * **Description:** Specifies Aria [group commit mode](../aria-group-commit/index). * **Commandline:** `--aria_group_commit="value"` * **Alias:** `maria_group_commit` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Valid values:** + `none` - *Group commit is disabled.* + `hard` - *Wait the number of microseconds specified by aria\_group\_commit\_interval before actually doing the commit. If the interval is 0 then just check if any other threads have requested a commit during the time this commit was preparing (just before sync() file) and send their data to disk also before sync().* + `soft` - *The service thread will wait the specified time and then sync() to the log. If the interval is 0 then it won't wait for any commits (this is dangerous and should generally not be used in production)* * **Default Value:** `none` --- #### `aria_group_commit_interval` * **Description:** Interval between [Aria group commits](../aria-group-commit/index) in microseconds (1/1000000 second) for other threads to come and do a commit in "hard" mode and sync()/commit at all in "soft" mode. Option only has effect if [aria\_group\_commit](#aria_group_commit) is used. * **Commandline:** `--aria_group_commit_interval=#` * **Alias:** `maria_group_commit_interval` * **Scope:** Global * **Dynamic:** No * **Type:** numeric * **Valid Values:** + **Default Value:** `0` *(no waiting)* + **Range:** `0-4294967295` --- #### `aria_log_file_size` * **Description:** Limit for Aria transaction log size * **Commandline:** `--aria-log-file-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1073741824` --- #### `aria_log_purge_type` * **Description:** Specifies how the Aria transactional log will be purged. Set to `at_flush` to keep a copy of the transaction logs (good as an extra backup). The logs will stay until the next [FLUSH LOGS](../flush/index); * **Commandline:** `--aria-log-purge-type=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `immediate` * **Valid Values:** `immediate`, `external`, `at_flush` --- #### `aria_max_sort_file_size` * **Description:** Don't use the fast sort index method to created index if the temporary file would get bigger than this. * **Commandline:** `--aria-max-sort-file-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `9223372036853727232` * **Range:** `0` to `9223372036854775807` --- #### `aria_page_checksum` * **Description:** Determines whether index and data should use page checksums for extra safety. Can be overridden per table with PAGE\_CHECKSUM clause in [CREATE TABLE](../create-table/index). * **Commandline:** `--aria-page-checksum=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `aria_pagecache_age_threshold` * **Description:** This characterizes the number of hits a hot block has to be untouched until it is considered aged enough to be downgraded to a warm block. This specifies the percentage ratio of that number of hits to the total number of blocks in the page cache. * **Commandline:** `--aria-pagecache-age-threshold=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `300` * **Range:** `100` to `9999900` --- #### `aria_pagecache_buffer_size` * **Description:** The size of the buffer used for index and data blocks for Aria tables. This can include explicit Aria tables, system tables, and temporary tables. Increase this to get better handling and measure by looking at [aria-status-variables/#aria\_pagecache\_reads](../aria-status-variables/index#aria_pagecache_reads) (should be small) vs [aria-status-variables/#aria\_pagecache\_read\_requests](../aria-status-variables/index#aria_pagecache_read_requests). * **Commandline:** `--aria-pagecache-buffer-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `134217720` (128MB) * **Range:** `131072` (128KB) upwards --- #### `aria_pagecache_division_limit` * **Description:** The minimum percentage of warm blocks in the key cache. * **Commandline:** `--aria-pagecache-division-limit=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `100` * **Range:** `1` to `100` --- #### `aria_pagecache_file_hash_size` * **Description:** Number of hash buckets for open and changed files. If you have many Aria files open you should increase this for faster flushing of changes. A good value is probably 1/10th of the number of possible open Aria files. * **Commandline:** `--aria-pagecache-file-hash-size=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `512` * **Range:** `128` to `16384` --- #### `aria_recover` * **Description:** `aria_recover` has been renamed to `aria_recover_options` in [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/). See [aria\_recover\_options](#aria_recover_options) for the description. --- #### `aria_recover_options` * **Description:** Specifies how corrupted tables should be automatically repaired. More than one option can be specified, for example `FORCE,BACKUP`. + `NORMAL`: Normal automatic repair, the default until [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) + `OFF`: Autorecovery is disabled, the equivalent of not using the option + `QUICK`: Does not check rows in the table if there are no delete blocks. + `FORCE`: Runs the recovery even if it determines that more than one row from the data file will be lost. + `BACKUP`: Keeps a backup of the data files. * **Commandline:** `--aria-recover-options[=#]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** + `BACKUP,QUICK` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)) + `NORMAL` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) * **Valid Values:** `NORMAL`, `BACKUP`, `FORCE`, `QUICK`, `OFF` * **Introduced:** [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) --- #### `aria_repair_threads` * **Description:** Number of threads to use when repairing Aria tables. The value of 1 disables parallel repair. Increasing from the default will usually result in faster repair, but will use more CPU and memory. * **Commandline:** `--aria-repair-threads=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` --- #### `aria_sort_buffer_size` * **Description:** The buffer that is allocated when sorting the index when doing a [REPAIR](../repair-table/index) or when creating indexes with [CREATE INDEX](../create-index/index) or [ALTER TABLE](../alter-table/index). * **Commandline:** `--aria-sort-buffer-size=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `268434432` --- #### `aria_stats_method` * **Description:** Determines how NULLs are treated for Aria index statistics purposes. If set to `nulls_equal`, all NULL index values are treated as a single group. This is usually fine, but if you have large numbers of NULLs the average group size is slanted higher, and the optimizer may miss using the index for ref accesses when it would be useful. If set to `nulls_unequal`, the default, the opposite approach is taken, with each NULL forming its own group of one. Conversely, the average group size is slanted lower, and the optimizer may use the index for ref accesses when not suitable. Setting to `nulls_ignored` ignores NULLs altogether from index group calculations. Statistics need to be recalculated after this method is changed. See also [Index Statistics](../index-statistics/index), [myisam\_stats\_method](../myisam-server-system-variables/index#myisam_stats_method) and [innodb\_stats\_method](../xtradbinnodb-server-system-variables/index#innodb_stats_method). * **Commandline:** `--aria-stats-method=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `nulls_unequal` * **Valid Values:** `nulls_equal`, `nulls_unequal`, `nulls_ignored` --- #### `aria_sync_log_dir` * **Description:** Controls syncing directory after log file growth and new file creation. * **Commandline:** `--aria-sync-log-dir=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `NEWFILE` * **Valid Values:** `NEWFILE`, `NEVER`, `ALWAYS` --- #### `aria_used_for_temp_tables` * **Description:** Readonly variable indicating whether the [Aria](../aria/index) storage engine is used for temporary tables. If set to `ON`, the default, the Aria storage engine is used. If set to `OFF`, MariaDB reverts to using [MyISAM](../myisam/index) for on-disk temporary tables. The [MEMORY](../memory-storage-engine/index) storage engine is used for temporary tables regardless of this variable's setting where appropriate. The default can be changed by not using the `--with-aria-tmp-tables` option when building MariaDB. * **Commandline:** No * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `deadlock_search_depth_long` * **Description:** Long search depth for the [two-step deadlock detection](../aria-two-step-deadlock-detection/index). Only used by the [Aria](../aria/index) storage engine. * **Commandline:** `--deadlock-search-depth-long=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `15` * **Range:** `0` to `33` --- #### `deadlock_search_depth_short` * **Description:** Short search depth for the [two-step deadlock detection](../aria-two-step-deadlock-detection/index). Only used by the [Aria](../aria/index) storage engine. * **Commandline:** `--deadlock-search-depth-short=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `4` * **Range:** `0` to `32` --- #### `deadlock_timeout_long` * **Description:** Long timeout in microseconds for the [two-step deadlock detection](../aria-two-step-deadlock-detection/index). Only used by the [Aria](../aria/index) storage engine. * **Commandline:** `--deadlock-timeout-long=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `50000000` * **Range:** `0` to `4294967295` --- #### `deadlock_timeout_short` * **Description:** Short timeout in microseconds for the [two-step deadlock detection](../aria-two-step-deadlock-detection/index). Only used by the [Aria](../aria/index) storage engine. * **Commandline:** `--deadlock-timeout-short=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `10000` * **Range:** `0` to `4294967295` --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Automating Upgrades with MariaDB.Org Downloads REST API Automating Upgrades with MariaDB.Org Downloads REST API ======================================================= The MariaDB Foundation maintains a Downloads REST API. See the [Downloads API documentation](https://mariadb.org/downloads-rest-api/) to find out all the tasks that you can accomplish with this API. Generally speaking, we can say that it provides information about MariaDB products and available versions. This allows to easily automate upgrades for MariaDB and related products. The Downloads API exposes HTTPS endpoints that return information in JSON format. HTTP and JSON are extremely common standards that can be easily used with any programming language. All the information provided by the API is public, so no authentication is required. How to Use the API with a Unix Shell ------------------------------------ Linux shells are great for writing simple scripts. They are compatible to each other to some extent, so simple scripts can be run on almost any Unix/Linux system. In the following examples we'll use Bash. On Linux, some programs you'll generally need to work with any REST API are: * [curl](https://curl.se/), to call HTTP URLs and get their output. * [js](https://stedolan.github.io/jq/), to extract or transform information from a JSON document. ### Example: Check When a New Version Becomes GA A trivial use case is to write a script that checks the list of MariaDB GA major versions and, when something changes, send us an email. So we can test the newest GA version and eventually install it. The script in this example will be extremely simple. We'll do it this way: * Retrieve the JSON object describing all MariaDB versions. * For each element of the array, only show the `release_id` and `release_status` properties, and concatenate them. * Apply a filter, so we only select the rows containing 'stable' but not 'old' (so we exclude 'Old Stable'). * From the remaining rows, only show the first column (the version number). * If the results we obtained are different from the previously written file (see last point) send an email. * Save the results into a file. This is something that we can easily do with a Unix shell: ``` #!/bin/bash current_ga_versions=$( curl https://downloads.mariadb.org/rest-api/mariadb/ | \ jq -r '.major_releases[] | .release_id + " " + .release_status' | \ grep -i 'stable' | grep -vi 'old' | \ cut -d ' ' -f 1 ) # create file if it doesn't exist, then compare version lists touch ga_versions previous_ga_versions=$( cat ga_versions ) echo "$current_ga_versions" > ga_versions if [ "$current_ga_versions" != "$previous_ga_versions" ]; then mail -s 'NOTE: New MariaDB GA Versions' [email protected] <<< 'There seems to be a new MariaDB GA version! Yay!' fi ``` The only non-standard command here is jq. It is a great way to manipulate JSON documents, so if you don't know it you may want to take a look at [jq documentation](https://stedolan.github.io/jq/manual/). How to Use the API with a Python Script --------------------------------------- To use the API with Python, we need a module that is able to send HTTP requests and parse a JSON output. The `requests` module has both these features. It can be installed as follows: ``` pip install requests ``` The following script prints stable versions to the standard output: ``` #!/usr/bin/env python import requests response = requests.get('https://downloads.mariadb.org/rest-api/mariadb/').json() for x in response['major_releases']: if x['release_status'] == 'Stable': print(x['release_id']) ``` `requests.get()` makes an HTTP call of type GET, and `requests.json()` returns a dictionary representing the previously obtained JSON document. --- Content initially contributed by [Vettabase Ltd](https://vettabase.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb InnoDB Upgrade Tests InnoDB Upgrade Tests ===================== RQG-based upgrade tests with focus on InnoDB data live upgrade. | Title | Description | | --- | --- | | [10.3.10 Release Upgrade Tests](../10310-release-upgrade-tests/index) | Failed with known bug MDEV-13094 | | [10.3.9 Release Upgrade Tests](../1039-release-upgrade-tests/index) | Failed with known bug MDEV-13094 | | [10.3.6-gamma Release Upgrade Tests](../1036-gamma-release-upgrade-tests/index) | Failed with bugs MDEV-15912, MDEV-13103, MDEV-13094 | | [10.3.5-gamma Release Upgrade Tests](../1035-gamma-release-upgrade-tests/index) | Failed with known bugs MDEV-13103, MDEV-13094 | | [10.3.4-beta Release Upgrade Tests](../1034-beta-release-upgrade-tests/index) | Numerous tests failed with MDEV-14990. Also known bugs MDEV-13103, MDEV-13094 | | [10.3.3-beta Release Upgrade Tests](../1033-beta-release-upgrade-tests/index) | 20 tests failed (crash upgrade from 10.3.2 is not supported) | | [10.2.18 Release Upgrade Tests](../10218-release-upgrade-tests/index) | PASSED (several unrelated failures) | | [10.2.17 Release Upgrade Tests](../10217-release-upgrade-tests/index) | Failed with known bug MDEV-13094 | | [10.2.14 Release Upgrade Tests](../10214-release-upgrade-tests/index) | Failed with known bugs MDEV-13103, MDEV-13094 | | [10.2.13 Release Upgrade Tests](../10213-release-upgrade-tests/index) | Failed with known bugs MDEV-13103, MDEV-13094 | | [10.2.12 Release Upgrade Tests](../10212-release-upgrade-tests/index) | Failed with known bugs MDEV-13103, MDEV-13094. | | [10.2.7 Release Upgrade Tests](../1027-release-upgrade-tests/index) | FAILED: Upgrade from 10.2, crash recovery; PASSED: Upgrade from 10.0, 10.1, MySQL 5.6, MySQL 5.7 | | [10.2.5 Pre-release Upgrade Tests](../1025-pre-release-upgrade-tests/index) | FAILED: Upgrade from 10.1; PASSED: Upgrade from 10.0, MySQL 5.6, MySQL 5.7 | | [10.1.36 Release Upgrade Tests](../10136-release-upgrade-tests/index) | PASSED | | [10.1.32 Release Upgrade Tests](../10132-release-upgrade-tests/index) | Failed with a known bug MDEV-13112 | | [10.1.30 Release Upgrade Tests](../10130-release-upgrade-tests/index) | 1 test failed (one-time failure upon undo upgrade from 10.1.10) | | [10.1.26 Release Upgrade Tests](../10126-release-upgrade-tests/index) | FAILED: Upgrade from 10.1, crash recovery; PASSED: Upgrade from 10.0, MySQL 5.6 | | [10.1.25 Release Upgrade Tests](../10125-release-upgrade-tests/index) | FAILED: Upgrade from 10.1, crash recovery; PASSED: Upgrade from 10.0, MySQL 5.6 | | [10.1.22 Pre-release Upgrade Tests](../10122-pre-release-upgrade-tests/index) | FAILED: Upgrade from 10.1; PASSED: Upgrade from 10.0, MySQL 5.6 | | [10.0.36 Release Upgrade Tests](../10036-release-upgrade-tests/index) | PASSED (two failures are unrelated) | | [10.0.34 Release Upgrade Tests](../10034-release-upgrade-tests/index) | PASSED | | [10.0.32 Release Upgrade Tests](../10032-release-upgrade-tests/index) | PASSED | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb my_print_defaults my\_print\_defaults =================== `my_print_defaults` displays the options from option groups of option files. It is useful to see which options a particular tool will use. Output is one option per line, displayed in the form in which they would be specified on the command line. Usage ----- ``` my_print_defaults [OPTIONS] [groups] ``` Options ------- | Option | Description | | --- | --- | | `-c`, `--config-file=name` | Deprecated, please use --defaults-file instead. Name of config file to read; if no extension is given, default extension (e.g., .ini or .cnf) will be added. | | `-#` ,`--debug[=#]` | In debug versions, write a debugging log. A typical debug\_options string is `d:t:o,file_name`. The default is `d:t:o,/tmp/my_print_defaults.trace`. | | `-c, --defaults-file=name` | Like --config-file, except: if first option, then read this file only, do not read global or per-user config files; should be the first option. Removed in [MariaDB 10.8.0](https://mariadb.com/kb/en/mariadb-1080-release-notes/). | | `-e`, `--defaults-extra-file=name` | Read this file after the global config file and before the config file in the users home directory; should be the first option. Removed in [MariaDB 10.8.0](https://mariadb.com/kb/en/mariadb-1080-release-notes/). | | `-g`, `--defaults-group-suffix=name` | In addition to the given groups, read also groups with this suffix. Removed in [MariaDB 10.8.0](https://mariadb.com/kb/en/mariadb-1080-release-notes/). | | `-e`, `--extra-file=name` | Deprecated. Synonym for --defaults-extra-file. | | `--mysqld` | Read the same set of groups that the mysqld binary does. | | `-n`, `--no-defaults` | Return an empty string (useful for scripts). | | `?`, `--help` | Display this help message and exit. | | `-v`, `--verbose` | Increase the output level. | | `-V`, `--version` | Output version information and exit. | Examples -------- ``` my_print_defaults --defaults-file=example.cnf client client-server mysql ``` [mysqlcheck](../mysqlcheck/index) reads from the [mysqlcheck] and [client] sections, so the following would display the mysqlcheck options. ``` my_print_defaults mysqlcheck client ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Profiling with Linux perf tool Profiling with Linux perf tool ============================== Linux `perf` tool can be used to do non-intrusive profiling. Frequency Based Sampling ------------------------ This mechanism can be used to answer the question, what is MariaDB doing on my CPU. ### Recording a sample Perf records at a high frequency, so only a short recording is sufficient to answer the question. If this is too short adjust the frequency at which perf does its recordings. ``` sudo perf record -p ${pidof mysqld} -g -o sample.perf -- sleep 5 ``` The `-g` option here records the calling stack. Because seeing time in a mutex function isn't particularly interesting without knowing which mutex it is. ### Viewing a sample To view a recording, you need the debug symbols for your executable. See [this page](../how-to-produce-a-full-stack-trace-for-mysqld/index#obtaining-debugging-symbols-for-your-mysqld-binary) on getting the debug symbols available. Changing the ownership of the recording means you can run perf report without sudo. This shows where in the process MariaDB is spending most of its time at the top level. MariaDB uses threads per user connection so this will usually show a significant time in a `handle\_connection` function. There are background threads that also run, so this can quickly show if its connection related time or a background thread. ``` sudo chown $USER: sample.perf perf report -i sample.perf -g ``` To see which low level functions are consuming the most time, `--no-children` means that each function listed include only the time that is being spend it this function and excluding the other functions it calls. ``` perf report -i sample.perf -g --no-children ``` Expanding out the function shows the complete call stack again. Multiple functions may have called the function you are looking at so there may be a different frequency breakdown. A more complete example of performance analysis using perf is on this [Percona community blog article](https://www.percona.com/community-blog/2020/02/05/finding-mysql-scaling-problems-using-perf/). Dynamic Tracepoints ------------------- ### Adding dynamic tracepoints One can add tracepoints at function entry/exit (and other locations too): ``` sudo perf probe -x /path/to/ha_rocksdb.so --add rocksdb_prepare sudo perf probe -x /path/to/ha_rocksdb.so --add rocksdb_prepare%return ``` ### Viewing the tracepoints ``` sudo perf probe -l ``` ### Running the profiler Something like: ``` perf record -e 'probe_ha_rocksdb:*' -a -- sleep 60 ``` Note: `-a` means system-wide. There's also `-p $PID` option ``` perf record -e 'probe_ha_rocksdb:*' -p $(pidof mysqld) -- sleep 60 ``` ### Examining the trace ``` perf script ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb InnoDB Row Formats Overview InnoDB Row Formats Overview =========================== The [InnoDB](../innodb/index) storage engine supports four different row formats: * [REDUNDANT](#redundant-row-format) * [COMPACT](#compact-row-format) * [DYNAMIC](#dynamic-row-format) * [COMPRESSED](#compressed-row-format) In [MariaDB 10.1](../what-is-mariadb-101/index) and before, the latter two row formats are only supported if the [InnoDB file format](../xtradbinnodb-file-format/index) is `Barracuda`. Therefore, the [innodb\_file\_format](../innodb-system-variables/index#innodb_file_format) system variable must be set to `Barracuda` to use these row formats in those versions. In [MariaDB 10.1](../what-is-mariadb-101/index) and before, the latter two row formats are also only supported if the table is in a [file per-table](../innodb-file-per-table-tablespaces/index) tablespace. Therefore, the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable must be set to `ON` to use these row formats in those versions. Default Row Format ------------------ **MariaDB starting with [10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)**In [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) and later, the [innodb\_default\_row\_format](../innodb-system-variables/index#innodb_default_row_format) system variable can be used to set the default row format for InnoDB tables. The possible values are: * `redundant` * `compact` * `dynamic` This system variable's default value is `dynamic`, which means that the default row format is `DYNAMIC`. This system variable cannot be set to `compressed`, which means that the default row format cannot be `COMPRESSED`. For example, the following statements would create a table with the `DYNAMIC` row format: ``` SET SESSION innodb_strict_mode=ON; SET GLOBAL innodb_default_row_format='dynamic'; CREATE TABLE tab ( id int, str varchar(50) ) ENGINE=InnoDB; ``` **MariaDB until [10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)**In [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) and before, the default row format is `COMPACT`. For example, the following statements would create a table with the `COMPACT` row format: ``` SET SESSION innodb_strict_mode=ON; CREATE TABLE tab ( id int, str varchar(50) ) ENGINE=InnoDB; ``` Setting a Table's Row Format ---------------------------- One way to specify an InnoDB table's row format is by setting the [ROW\_FORMAT](../create-table/index#row_format) table option to the relevant row format in a [CREATE TABLE](../create-table/index) or [ALTER TABLE](../alter-table/index) statement. For example: ``` SET SESSION innodb_strict_mode=ON; SET GLOBAL innodb_file_per_table=ON; SET GLOBAL innodb_file_format='Barracuda'; CREATE TABLE tab ( id int, str varchar(50) ) ENGINE=InnoDB ROW_FORMAT=DYNAMIC; ``` In [MariaDB 10.1](../what-is-mariadb-101/index) and before, InnoDB can silently ignore and override some row format choices if you do not have the [innodb\_file\_format](../innodb-system-variables/index#innodb_file_format) system variable set to `Barracuda` and the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable set to `ON`. Checking a Table's Row Format ----------------------------- The [SHOW TABLE STATUS](../show-table-status/index) statement can be used to see the row format used by a table. For example: ``` SHOW TABLE STATUS FROM db1 WHERE Name='tab'\G *************************** 1. row *************************** Name: tab Engine: InnoDB Version: 10 Row_format: Dynamic Rows: 0 Avg_row_length: 0 Data_length: 16384 Max_data_length: 0 Index_length: 0 Data_free: 0 Auto_increment: NULL Create_time: 2019-04-18 20:24:04 Update_time: NULL Check_time: NULL Collation: latin1_swedish_ci Checksum: NULL Create_options: row_format=DYNAMIC Comment: ``` The [information\_schema.INNODB\_SYS\_TABLES](../information-schema-innodb_sys_tables-table/index) table can also be queried to see the row format used by a table. For example: ``` SELECT * FROM information_schema.INNODB_SYS_TABLES WHERE name='db1/tab'\G *************************** 1. row *************************** TABLE_ID: 42 NAME: db1/tab FLAG: 33 N_COLS: 4 SPACE: 27 FILE_FORMAT: Barracuda ROW_FORMAT: Dynamic ZIP_PAGE_SIZE: 0 SPACE_TYPE: Single ``` A table's tablespace is tagged with the lowest InnoDB file format that supports the table's row format. So, even if the `Barracuda` file format is enabled, tables that use the `COMPACT` or `REDUNDANT` row formats will be tagged with the `Antelope` file format in the [information\_schema.INNODB\_SYS\_TABLES](../information-schema-innodb_sys_tables-table/index) table. Row Formats ----------- ### `REDUNDANT` Row Format The `REDUNDANT` row format is the original non-compacted row format. The `REDUNDANT` row format was the only available row format before MySQL 5.0.3. In that release, this row format was retroactively named the `REDUNDANT` row format. In the same release, the `COMPACT` row format was introduced as the new default row format. See [InnoDB REDUNDANT Row Format](../innodb-redundant-row-format/index) for more information. ### `COMPACT` Row Format **MariaDB until [10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)**In [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) and before, the default row format is `COMPACT`. The `COMPACT` row format is similar to the `REDUNDANT` row format, but it stores data in a more compact manner that requires about 20% less storage. This row format was originally introduced in MySQL 5.0.3. See [InnoDB COMPACT Row Format](../innodb-compact-row-format/index) for more information. ### `DYNAMIC` Row Format **MariaDB starting with [10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)**In [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) and later, the default row format is `DYNAMIC`. The `DYNAMIC` row format is similar to the `COMPACT` row format, but tables using the `DYNAMIC` row format can store even more data on overflow pages than tables using the `COMPACT` row format. This results in more efficient data storage than tables using the `COMPACT` row format, especially for tables containing columns using the [VARBINARY](../varbinary/index), [VARCHAR](../varchar/index), [BLOB](../blob/index) and [TEXT](../text/index) data types. However, InnoDB tables using the `COMPRESSED` row format are more efficient. See [InnoDB DYNAMIC Row Format](../innodb-dynamic-row-format/index) for more information. ### `COMPRESSED` Row Format An alternative way to compress InnoDB tables is by using [InnoDB Page Compression](../innodb-page-compression/index). The `COMPRESSED` row format is similar to the `COMPACT` row format, but tables using the `COMPRESSED` row format can store even more data on overflow pages than tables using the `COMPACT` row format. This results in more efficient data storage than tables using the `COMPACT` row format, especially for tables containing columns using the [VARBINARY](../varbinary/index), [VARCHAR](../varchar/index), [BLOB](../blob/index) and [TEXT](../text/index) data types. The `COMPRESSED` row format also supports compression of all data and index pages. See [InnoDB COMPRESSED Row Format](../innodb-compressed-row-format/index) for more information. Maximum Row Size ---------------- Several factors help determine the maximum row size of an InnoDB table. First, MariaDB enforces a 65,535 byte limit on a table's maximum row size. The total size of a table's [BLOB](../blob/index) and [TEXT](../text/index) columns do not count towards this limit. Only the pointers for a table's [BLOB](../blob/index) and [TEXT](../text/index) columns count towards this limit. MariaDB enforces this limit for all storage engines, so this limit also applies to InnoDB tables. Therefore, this limit is the absolute maximum row size for an InnoDB table. If you try to create a table that exceeds MariaDB's global limit on a table's maximum row size, then you will see an error like this: ``` ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs ``` However, InnoDB also has its own limits on the maximum row size, so an InnoDB table's maximum row size could be smaller than MariaDB's global limit. Second, the maximum amount of data that an InnoDB table can store in a row's main data page depends on the value of the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) system variable. At most, the data that a single row can consume on the row's main data page is half of the value of the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) system variable. With the default value of `16k`, that would mean that a single row can consume at most around 8 KB on the row's main data page. However, the limit on the row's main data page is not the absolute limit on the row's size. Third, all InnoDB row formats can store certain kinds of data in overflow pages, so the maximum row size of an InnoDB table can be larger than the maximum amount of data that can be stored in the row's main data page. Some row formats can store more data in overflow pages than others. For example, the `DYNAMIC` and `COMPRESSED` row formats can store the most data in overflow pages. To see how to determine the how the various InnoDB row formats can use overflow pages, see the following sections: * [InnoDB REDUNDANT Row Format: Overflow Pages with the REDUNDANT Row Format](../innodb-redundant-row-format/index#overflow-pages-with-the-redundant-row-format) * [InnoDB COMPACT Row Format: Overflow Pages with the COMPACT Row Format](../innodb-compact-row-format/index#overflow-pages-with-the-compact-row-format) * [InnoDB DYNAMIC Row Format: Overflow Pages with the DYNAMIC Row Format](../innodb-dynamic-row-format/index#overflow-pages-with-the-dynamic-row-format) * [InnoDB COMPRESSED Row Format: Overflow Pages with the COMPRESSED Row Format](../innodb-compressed-row-format/index#overflow-pages-with-the-compressed-row-format) If a table's definition can allow rows that the table's InnoDB row format can't actually store, then InnoDB will raise errors or warnings in certain scenarios. If the table were using the `REDUNDANT` or `COMPACT` row formats, then the error or warning would be the following: ``` ERROR 1118 (42000): Row size too large (> 8126). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, BLOB prefix of 768 bytes is stored inline. ``` And if the table were using the `DYNAMIC` or `COMPRESSED` row formats, then the error or warning would be the following: ``` ERROR 1118 (42000): Row size too large (> 8126). Changing some columns to TEXT or BLOB may help. In current row format, BLOB prefix of 0 bytes is stored inline. ``` These messages are raised in the following cases: * If [InnoDB strict mode](../innodb-strict-mode/index) is **enabled** and if a [DDL](../data-definition/index) statement is executed that touches the table, such as [CREATE TABLE](../create-table/index) or [ALTER TABLE](../alter-table/index), then InnoDB will raise an **error** with this message * If [InnoDB strict mode](../innodb-strict-mode/index) is **disabled** and if a [DDL](../data-definition/index) statement is executed that touches the table, such as [CREATE TABLE](../create-table/index) `or [ALTER TABLE](../alter-table/index)`, then InnoDB will raise a **warning** with this message. * Regardless of whether [InnoDB strict mode](../innodb-strict-mode/index) is enabled, if a [DML](../data-manipulation/index) statement is executed that attempts to write a row that the table's InnoDB row format can't store, then InnoDB will raise an **error** with this message. For information on how to solve the problem, see [Troubleshooting Row Size Too Large Errors with InnoDB](../troubleshooting-row-size-too-large-errors-with-innodb/index). Known Issues ------------ ### Upgrading Causes Row Size Too Large Errors Prior to [MariaDB 10.2.26](https://mariadb.com/kb/en/mariadb-10226-release-notes/), [MariaDB 10.3.17](https://mariadb.com/kb/en/mariadb-10317-release-notes/), and [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/), MariaDB doesn't properly calculate the row sizes while executing DDL. In these versions, *unsafe* tables can be created, even if [InnoDB strict mode](../innodb-strict-mode/index) is enabled. The calculations were fixed by [MDEV-19292](https://jira.mariadb.org/browse/MDEV-19292) in [MariaDB 10.2.26](https://mariadb.com/kb/en/mariadb-10226-release-notes/), [MariaDB 10.3.17](https://mariadb.com/kb/en/mariadb-10317-release-notes/), and [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/). As a side effect, some tables that could be created or altered in previous versions may get rejected with the following error in these releases and any later releases. ``` ERROR 1118 (42000): Row size too large (> 8126). Changing some columns to TEXT or BLOB may help. In current row format, BLOB prefix of 0 bytes is stored inline. ``` And users could also see the following message as an error or warning in the [error log](../error-log/index): ``` [Warning] InnoDB: Cannot add field col in table db1.tab because after adding it, the row size is 8478 which is greater than maximum allowed size (8126) for a record on index leaf page. ``` InnoDB used the wrong calculations to determine row sizes for quite a long time, so a lot of users may unknowingly have *unsafe* tables that the InnoDB row format can't actually store. InnoDB does not currently have an easy way to check which existing tables have this problem. See [MDEV-20400](https://jira.mariadb.org/browse/MDEV-20400) for more information. For information on how to solve the problem, see [Troubleshooting Row Size Too Large Errors with InnoDB](../troubleshooting-row-size-too-large-errors-with-innodb/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Precedence Control in Table Operations Precedence Control in Table Operations ====================================== **MariaDB starting with [10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/)**Beginning in [MariaDB 10.4](../what-is-mariadb-104/index), you can control the ordering of execution on table operations using parentheses. Syntax ------ ``` ( expression ) [ORDER BY [column[, column...]]] [LIMIT {[offset,] row_count | row_count OFFSET offset}] ``` Description ----------- Using parentheses in your SQL allows you to control the order of execution for `[SELECT](../select/index)` statements and [Table Value Constructor](../table-value-constructors/index), including `[UNION](../union/index)`, `[EXCEPT](../except/index)`, and `[INTERSECT](../intersect/index)` operations. MariaDB executes the parenthetical expression before the rest of the statement. You can then use `[ORDER BY](../order-by/index)` and `[LIMIT](../limit/index)` clauses the further organize the result-set. **Note**: In practice, the Optimizer may rearrange the exact order in which MariaDB executes different parts of the statement. When it calculates the result-set, however, it returns values as though the parenthetical expression were executed first. Example ------- ``` CREATE TABLE test.t1 (num INT); INSERT INTO test.t1 VALUES (1),(2),(3); (SELECT * FROM test.t1 UNION VALUES (10)) INTERSECT VALUES (1),(3),(10),(11); +------+ | num | +------+ | 1 | | 3 | | 10 | +------+ ((SELECT * FROM test.t1 UNION VALUES (10)) INTERSECT VALUES (1),(3),(10),(11)) ORDER BY 1 DESC; +------+ | num | +------+ | 10 | | 3 | | 1 | +------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_BUFFER_POOL_PAGES Table Information Schema INNODB\_BUFFER\_POOL\_PAGES Table ==================================================== The [Information Schema](../information_schema/index) `INNODB_BUFFER_POOL_PAGES` table is a Percona enhancement, and is only available for XtraDB, not InnoDB (see [XtraDB and InnoDB](../xtradb-and-innodb/index)). It contains a record for each page in the [buffer pool](../xtradbinnodb-memory-buffer/index). It has the following columns: | Column | Description | | --- | --- | | `PAGE_TYPE` | Type of page; one of `index`, `undo_log`, `inode`, `ibuf_free_list`, `allocated, bitmap`, `sys`, `trx_sys`, `fsp_hdr`, `xdes`, `blob`, `zblob`, `zblob2` and `unknown`. | | `SPACE_ID` | Tablespace ID. | | `PAGE_NO` | Page offset within tablespace. | | `LRU_POSITION` | Page position in the LRU (least-recently-used) list. | | `FIX_COUNT` | Page reference count, incremented each time the page is accessed. `0` if the page is not currently being accessed. | | `FLUSH_TYPE` | Flush type of the most recent flush.`0` (LRU), `2` (flush\_list) | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Database Normalization: Boyce-Codd Normal Form Database Normalization: Boyce-Codd Normal Form ============================================== This article follows on from [Database Normalization: 3rd Normal Form](../database-normalization-3rd-normal-form/index) E.F. Codd and R.F. Boyce, two of the people instrumental in the development of the database model, have been honored by the name of this normal form. E.F. Codd developed and expanded the relational model, and also developed normalization for relational models in 1970, while R.F. Boyce was one of the creators of Structured Query Language (then called SEQUEL). In spite of some resources stating the contrary, Boyce-Codd normal form is not the same as 4th normal form. Let's look at an example of data anomalies, which are presented in 3rd normal form and solved by transforming into Boyce-Codd normal form, before defining it. ### Table containing data about the student, course, and instructor relationship | Student Course Instructor table | | --- | | Student | | Course | | Instructor | Assume that the following is true for the table above: * Each instructor takes only one course * Each course can have one or more instructors * Each student only has one instructor per course * Each student can take one or more courses What would the key be? None of the fields on their own would be sufficient to uniquely identify a records, so you have to use two fields. Which two should you use? Perhaps *student* and *instructor* seem like the best choice, as that would allow you to determine the *course*. Or you could use *student* and *course*, which would determine the *instructor*. For now, let's use *student* and *course* as the key: ### Using student and course as the key | Student Course Instructor table | | --- | | *Student* | | *Course* | | Instructor | What normal form is this table in? It's in [1st normal form](../database-normalization-1st-normal-form/index), as it has a key and no repeating groups. It's also in [2nd normal form](../database-normalization-2nd-normal-form/index), as the instructor is dependent on both other fields (students have many courses, and therefore instructors, and courses have many instructors). Finally, it's also in [3rd normal form](../database-normalization-3rd-normal-form/index), as there is only one non-key attribute. But there are still some data anomalies. Look at the data sample below: ### More data anomalies | Student | Course | Instructor | | --- | --- | --- | | Conrad Pienaar | Biology | Nkosizana Asmal | | Dingaan Fortune | Mathematics | Kader Dlamini | | Gerrie Jantjies | Science | Helen Ginwala | | Mark Thobela | Biology | Nkosizana Asmal | | Conrad Pienaar | Science | Peter Leon | | Alicia Ncita | Science | Peter Leon | | Quinton Andrews | Mathematics | Kader Dlamini | The fact that Peter Leon teaches science is stored redundantly, as are Kader Dlamini with mathematics and Nkosizana Asmal with biology. The problem is that the *instructor* determines the *course*. Or put another, *course* is determined by *instructor*. The table conforms to [3rd normal form](../database-normalization-3rd-normal-form/index) rules because no non-key attribute is dependent upon a non-key attribute! Again, you use the familiar method of removing this field and placing it into another table, along with its key: ### Student Instructor table after removing Course | Student Course Instructor table | | --- | | *Student* | | *Instructor* | After removing the *course* field, the primary key needs to include both remaining fields to uniquely identify a record. ### Resulting Instructor table | Student Course Instructor table | | --- | | *Instructor* | | Course | Although we had chosen course as part of the primary key in the original table, the instructor determines the course, which is why we make it the primary key in this table. As you can see, the redundancy problem has been solved. Thus, a table is in Boyce-Codd normal form if: * it is in 3rd normal form * each determinant is a candidate key That sounds scary! For most people new to database design, these are new terms. If you followed along with the example above, however, the terms will soon become clear: * a *determinant* is an attribute that determines the value of another attribute. * a *candidate key* is either the key or an alternate key (in other words, the attribute could be a key for that table) In the initial table, *instructor* is not a candidate key (alone it cannot uniquely identify the record), yet it determines the course, so the table is not in Boyce-Codd normal form. Let's look at the example again, and see what happens if you chose student and instructor as the key. What normal form is the table in this time? ### Using student and instructor as the key | Student Course Instructor table | | --- | | *Student* | | *Instructor* | | Course | Once again it's in 1st normal form because there is a primary key and there are no repeating groups. This time, though, it's not in 2nd normal form because *course* is determined by only part of the key: the instructor. By removing *course* and its key, instructor, you get the structure shown below: ### Removing course | Student Instructor table | | --- | | *Student* | | *Instructor* | ### Creating a new table with course | Student Course Instructor table | | --- | | *Instructor* | | Course | Either way you do it, by making sure the tables are normalized into Boyce-Codd normal form, you get the same two resulting tables. It's usually the case that when there are alternate fields to choose as a key, it doesn't matter which ones you choose initially because after normalizing you get the same results either way. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_PolyFromText ST\_PolyFromText ================ Syntax ------ ``` ST_PolyFromText(wkt[,srid]) ST_PolygonFromText(wkt[,srid]) PolyFromText(wkt[,srid]) PolygonFromText(wkt[,srid]) ``` Description ----------- Constructs a [POLYGON](../polygon/index) value using its [WKT](../wkt-definition/index) representation and [SRID](../srid/index). `ST_PolyFromText()`, `ST_PolygonFromText()`, `PolyFromText()` and `ST_PolygonFromText()` are all synonyms. Examples -------- ``` CREATE TABLE gis_polygon (g POLYGON); INSERT INTO gis_polygon VALUES (PolygonFromText('POLYGON((10 10,20 10,20 20,10 20,10 10))')), (PolyFromText('POLYGON((0 0,50 0,50 50,0 50,0 0), (10 10,20 10,20 20,10 20,10 10))')); ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CURRENT_USER CURRENT\_USER ============= Syntax ------ ``` CURRENT_USER, CURRENT_USER() ``` Description ----------- Returns the user name and host name combination for the MariaDB account that the server used to authenticate the current client. This account determines your access privileges. The return value is a string in the utf8 [character set](../data-types-character-sets-and-collations/index). The value of `CURRENT_USER()` can differ from the value of [USER()](../user/index). [CURRENT\_ROLE()](../current_role/index) returns the current active role. Examples -------- ``` shell> mysql --user="anonymous" select user(),current_user(); +---------------------+----------------+ | user() | current_user() | +---------------------+----------------+ | anonymous@localhost | @localhost | +---------------------+----------------+ ``` When calling `CURRENT_USER()` in a stored procedure, it returns the owner of the stored procedure, as defined with `DEFINER`. See Also -------- * [USER()](../user/index) * [CREATE PROCEDURE](../create-procedure/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Mroonga Overview Mroonga Overview ================ Once Mroonga has been installed (see [About Mroonga](../about-mroonga/index)), its basic usage is similar to that of a [regular fulltext index](../full-text-indexes/index). For example: ``` CREATE TABLE ft_mroonga(copy TEXT,FULLTEXT(copy)) ENGINE=Mroonga; INSERT INTO ft_mroonga(copy) VALUES ('Once upon a time'), ('There was a wicked witch'), ('Who ate everybody up'); SELECT * FROM ft_mroonga WHERE MATCH(copy) AGAINST('wicked'); +--------------------------+ | copy | +--------------------------+ | There was a wicked witch | +--------------------------+ ``` Score ----- Mroonga can also order by weighting. For example, first add another record: ``` INSERT INTO ft_mroonga(copy) VALUES ('She met a wicked, wicked witch'); ``` Records can be returned by weighting, for example, the newly added record has two occurences of the word 'wicked' and a higher weighting: ``` SELECT *, MATCH(copy) AGAINST('wicked') AS score FROM ft_mroonga WHERE MATCH(copy) AGAINST('wicked') ORDER BY score DESC; +--------------------------------+--------+ | copy | score | +--------------------------------+--------+ | She met a wicked, wicked witch | 299594 | | There was a wicked witch | 149797 | +--------------------------------+--------+ ``` Parser ------ Mroonga permits you to set a different parser for searching by specifying the parser in the `CREATE TABLE` statement as a comment or, in older versions, changing the value of the [mroonga\_default\_parser](../mroonga-system-variables/index#mroonga_default_parser) system variable. For example: ``` CREATE TABLE ft_mroonga(copy TEXT,FULLTEXT(copy) COMMENT 'parser "TokenDelimitNull"') ENGINE=Mroonga;, ``` or ``` SET GLOBAL mroonga_default_parser = 'TokenBigramSplitSymbol'; ``` The following parser settings are available: | Setting | Description | | --- | --- | | off | No tokenizing is performed. | | TokenBigram | Default value. Continuous alphabetical characters, numbers or symbols are treated as a token. | | TokenBigramIgnoreBlank | Same as `TokenBigram` except that white spaces are ignored. | | TokenBigramIgnoreBlankSplitSymbol | Same as `TokenBigramSplitSymbol`. except that white spaces are ignore. | | TokenBigramIgnoreBlankSplitSymbolAlpha | Same as `TokenBigramSplitSymbolAlpha` except that white spaces are ignored. | | TokenBigramIgnoreBlankSplitSymbolAlphaDigit | Same as `TokenBigramSplitSymbolAlphaDigit` except that white spaces are ignored. | | TokenBigramSplitSymbol | Same as `TokenBigram` except that continuous symbols are not treated as a token, but tokenised in bigram. | | TokenBigramSplitSymbolAlpha | Same as `TokenBigram` except that continuous alphabetical characters are not treated as a token, but tokenised in bigram. | | TokenDelimit | Tokenises by splitting on white spaces. | | TokenDelimitNull | Tokenises by splitting on null characters (\0). | | TokenMecab | Tokenise using MeCab. Required Groonga to be buillt with MeCab support. | | TokenTrigram | Tokenises in trigrams but continuous alphabetical characters, numbers or symbols are treated as a token. | | TokenUnigram | Tokenises in unigrams but continuous alphabetical characters, numbers or symbols are treated as a token. | ### Examples #### TokenBigram vs TokenBigramSplitSymbol `TokenBigram` failing to match partial symbols which `TokenBigramSplitSymbol` matches, since `TokenBigramSplitSymbol` does not treat continuous symbols as a token. ``` DROP TABLE ft_mroonga; CREATE TABLE ft_mroonga(copy TEXT,FULLTEXT(copy) COMMENT 'parser "TokenBigram"') ENGINE=Mroonga; INSERT INTO ft_mroonga(copy) VALUES ('Once upon a time'), ('There was a wicked witch'), ('Who ate everybody up'), ('She met a wicked, wicked witch'), ('A really wicked, wicked witch!!?!'); SELECT * FROM ft_mroonga WHERE MATCH(copy) AGAINST('!?'); Empty set (0.00 sec) DROP TABLE ft_mroonga; CREATE TABLE ft_mroonga(copy TEXT,FULLTEXT(copy) COMMENT 'parser "TokenBigramSplitSymbol"') ENGINE=Mroonga; INSERT INTO ft_mroonga(copy) VALUES ('Once upon a time'), ('There was a wicked witch'), ('Who ate everybody up'), ('She met a wicked, wicked witch'), ('A really wicked, wicked witch!!?!'); SELECT * FROM ft_mroonga WHERE MATCH(copy) AGAINST('!?'); +-----------------------------------+ | copy | +-----------------------------------+ | A really wicked, wicked witch!!?! | +-----------------------------------+ ``` #### TokenBigram vs TokenBigramSplitSymbolAlpha ``` DROP TABLE ft_mroonga; CREATE TABLE ft_mroonga(copy TEXT,FULLTEXT(copy) COMMENT 'parser "TokenBigram"') ENGINE=Mroonga; INSERT INTO ft_mroonga(copy) VALUES ('Once upon a time'), ('There was a wicked witch'), ('Who ate everybody up'), ('She met a wicked, wicked witch'), ('A really wicked, wicked witch!!?!'); SELECT * FROM ft_mroonga WHERE MATCH(copy) AGAINST('ick'); Empty set (0.00 sec) DROP TABLE ft_mroonga; CREATE TABLE ft_mroonga(copy TEXT,FULLTEXT(copy) COMMENT 'parser "TokenBigramSplitSymbolAlpha"') ENGINE=Mroonga; INSERT INTO ft_mroonga(copy) VALUES ('Once upon a time'), ('There was a wicked witch'), ('Who ate everybody up'), ('She met a wicked, wicked witch'), ('A really wicked, wicked witch!!?!'); SELECT * FROM ft_mroonga WHERE MATCH(copy) AGAINST('ick'); +-----------------------------------+ | copy | +-----------------------------------+ | There was a wicked witch | | She met a wicked, wicked witch | | A really wicked, wicked witch!!?! | +-----------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_AREA ST\_AREA ======== Syntax ------ ``` ST_Area(poly) Area(poly) ``` Description ----------- Returns as a double-precision number the area of the Polygon value `poly`, as measured in its spatial reference system. `ST_Area()` and `Area()` are synonyms. Examples -------- ``` SET @poly = 'Polygon((0 0,0 3,3 0,0 0),(1 1,1 2,2 1,1 1))'; SELECT Area(GeomFromText(@poly)); +---------------------------+ | Area(GeomFromText(@poly)) | +---------------------------+ | 4 | +---------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHOW CONTRIBUTORS SHOW CONTRIBUTORS ================= Syntax ------ ``` SHOW CONTRIBUTORS ``` Description ----------- The `SHOW CONTRIBUTORS` statement displays information about the companies and people who financially contribute to MariaDB. For each contributor, it displays `Name`, `Location`, and `Comment` values. All columns are encoded as `latin1`. It displays all [members and sponsors of the MariaDB Foundation](https://mariadb.org/en/supporters) as well as other financial contributors. Example ------- ``` SHOW CONTRIBUTORS; +---------------------+-------------------------------+-------------------------------------------------------------+ | Name | Location | Comment | +---------------------+-------------------------------+-------------------------------------------------------------+ | Booking.com | https://www.booking.com | Founding member, Platinum Sponsor of the MariaDB Foundation | | Alibaba Cloud | https://www.alibabacloud.com/ | Platinum Sponsor of the MariaDB Foundation | | Tencent Cloud | https://cloud.tencent.com | Platinum Sponsor of the MariaDB Foundation | | Microsoft | https://microsoft.com/ | Platinum Sponsor of the MariaDB Foundation | | MariaDB Corporation | https://mariadb.com | Founding member, Platinum Sponsor of the MariaDB Foundation | | Visma | https://visma.com | Gold Sponsor of the MariaDB Foundation | | DBS | https://dbs.com | Gold Sponsor of the MariaDB Foundation | | IBM | https://www.ibm.com | Gold Sponsor of the MariaDB Foundation | | Tencent Games | http://game.qq.com/ | Gold Sponsor of the MariaDB Foundation | | Nexedi | https://www.nexedi.com | Silver Sponsor of the MariaDB Foundation | | Acronis | https://www.acronis.com | Silver Sponsor of the MariaDB Foundation | | Verkkokauppa.com | https://www.verkkokauppa.com | Bronze Sponsor of the MariaDB Foundation | | Virtuozzo | https://virtuozzo.com | Bronze Sponsor of the MariaDB Foundation | | Tencent Game DBA | http://tencentdba.com/about | Bronze Sponsor of the MariaDB Foundation | | Tencent TDSQL | http://tdsql.org | Bronze Sponsor of the MariaDB Foundation | | Percona | https://www.percona.com/ | Bronze Sponsor of the MariaDB Foundation | | Google | USA | Sponsoring encryption, parallel replication and GTID | | Facebook | USA | Sponsoring non-blocking API, LIMIT ROWS EXAMINED etc | | Ronald Bradford | Brisbane, Australia | EFF contribution for UC2006 Auction | | Sheeri Kritzer | Boston, Mass. USA | EFF contribution for UC2006 Auction | | Mark Shuttleworth | London, UK. | EFF contribution for UC2006 Auction | +---------------------+-------------------------------+-------------------------------------------------------------+ ``` See Also -------- * [Log of MariaDB contributors](../log-of-mariadb-contributions/index). * [SHOW AUTHORS](../show-authors/index) list the authors of MariaDB (including documentation, QA etc). * [MariaDB Foundation page on contributing financially](https://mariadb.org/donate/) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Buildbot Setup for Virtual Machines - Ubuntu Buildbot Setup for Virtual Machines - Ubuntu ============================================= | Title | Description | | --- | --- | | [Buildbot Setup for Virtual Machines - Ubuntu 14.04 "trusty"](../buildbot-setup-for-virtual-machines-ubuntu-1404-trusty/index) | Base install qemu-img create -f qcow2 /kvm/vms/vm-trusty-amd64-seri | | [Buildbot Setup for Virtual Machines - Ubuntu 13.10 "saucy"](../buildbot-setup-for-virtual-machines-ubuntu-1310-saucy/index) | Base install qemu-img create -f qcow2 /kvm/vms/vm-saucy-amd64-seria | | [Buildbot Setup for Virtual Machines - Ubuntu 13.04 "raring"](../buildbot-setup-for-virtual-machines-ubuntu-1304-raring/index) | Base install qemu-img create -f qcow2 /kvm/vms/vm-raring-amd64-seri | | [Buildbot Setup for Virtual Machines - Ubuntu 12.10 "quantal"](../buildbot-setup-for-virtual-machines-ubuntu-1210-quantal/index) | Base install qemu-img create -f qcow2 /kvm/vms/vm-quantal-amd64-ser | | [Buildbot Setup for Virtual Machines - Ubuntu 12.04 "precise"](../buildbot-setup-for-virtual-machines-ubuntu-1204-precise/index) | Base install qemu-img create -f qcow2 /kvm/vms/vm-precise-amd64-ser | | [Buildbot Setup for Virtual Machines - Ubuntu 11.10 "oneiric"](../buildbot-setup-for-virtual-machines-ubuntu-1110-oneiric/index) | Base install qemu-img create -f qcow2 /kvm/vms/vm-oneiric-amd64-ser | | [Buildbot Setup for Virtual Machines - Ubuntu 11.04 "natty"](../buildbot-setup-for-virtual-machines-ubuntu-1104-natty/index) | Base install qemu-img create -f qcow2 vm-natty-amd64-serial.qcow2 8G | | [Buildbot Setup for Virtual Machines - Ubuntu 10.10 "maverick"](../buildbot-setup-for-virtual-machines-ubuntu-1010-maverick/index) | Base install qemu-img create -f qcow2 vm-maverick-amd64-serial.qcow2 | | [Buildbot Setup for Virtual Machines - Ubuntu 10.04 (alpha), i386 and amd64](../buildbot-setup-for-virtual-machines-ubuntu-1004-alpha-i386-and-amd64/index) | Base install qemu-img create -f qcow2 vm-lucid-amd64-serial.qcow2 8G | | [Buildbot Setup for Virtual Machines - Ubuntu 9.04 i386](../buildbot-setup-for-virtual-machines-ubuntu-904-i386/index) | This vm is used to build source tarball and for Ubuntu 9.04 32-bit .deb. Fi... | | [Buildbot Setup for Virtual Machines - Ubuntu 9.04 amd64](../buildbot-setup-for-virtual-machines-ubuntu-904-amd64/index) | Base install qemu-img create -f qcow2 vm-jaunty-amd64-serial.qcow2 8 | | [Buildbot Setup for Virtual Machines - Ubuntu 8.04, 8.10, and 9.10](../buildbot-setup-for-virtual-machines-ubuntu-804-810-and-910/index) | These 6 platforms were installed together (i386 and amd64). Base installs U... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb resolve_stack_dump resolve\_stack\_dump ==================== resolve\_stack\_dump is a tool that resolves numeric stack strace dumps into symbols. Usage ----- ``` resolve_stack_dump [OPTIONS] symbols-file [numeric-dump-file] ``` The symbols-file should include the output from: `nm --numeric-sort mysqld`. The numeric-dump-file should contain a numeric stack trace from mysqld. If the numeric-dump-file is not given, the stack trace is read from stdin. Options ------- | Option | Description | | --- | --- | | `-h`, `--help` | Display this help and exit. | | `-V`, `--version` | Output version information and exit. | | `-s`, `--symbols-file=name` | Use specified symbols file. | | `-n`, `--numeric-dump-file=name` | Read the dump from specified file. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Backup and Restore Overview Backup and Restore Overview =========================== This article briefly discusses the main ways to backup MariaDB. For detailed descriptions and syntax, see the individual pages. More detail is in the process of being added. Logical vs Physical Backups --------------------------- Logical backups consist of the SQL statements necessary to restore the data, such as [CREATE DATABASE](../create-database/index), [CREATE TABLE](../create-table/index) and [INSERT](../insert/index). Physical backups are performed by copying the individual data files or directories. The main differences are as follows: * logical backups are more flexible, as the data can be restored on other hardware configurations, MariaDB versions or even on another DBMS, while physical backups cannot be imported on significantly different hardware, a different DBMS, or potentially even a different MariaDB version. * logical backups can be performed at the level of database and table, while physical databases are the level of directories and files. In the [MyISAM](../myisam/index) and [InnoDB](../innodb/index) storage engines, each table has an equivalent set of files. (In versions prior to [MariaDB 5.5](../what-is-mariadb-55/index), by default a number of InnoDB tables are stored in the same file, in which case it is not possible to backup by table. See [innodb\_file\_per\_table](../xtradbinnodb-server-system-variables/index#innodb_file_per_table).) * logical backups are larger in size than the equivalent physical backup. * logical backups takes more time to both backup and restore than the equivalent physical backup. * log files and configuration files are not part of a logical backup Backup Tools ------------ ### Mariabackup [Mariabackup](../mariadb-backup/index) is a fork of [Percona XtraBackup](../backup-restore-and-import-xtrabackup/index) with added support for [MariaDB 10.1](../what-is-mariadb-101/index) [compression](innodb_compression) and [data-at-rest encryption](../data-at-rest-encryption/index). It is included with [MariaDB 10.1.23](https://mariadb.com/kb/en/mariadb-10123-release-notes/) and later. ### mysqldump [mysqldump](../mysqldump/index) performs a logical backup. It is the most flexible way to perform a backup and restore, and a good choice when the data size is relatively small. For large datasets, the backup file can be large, and the restore time lengthy. mysqldump dumps the data into SQL format (it can also dump into other formats, such as CSV or XML) which can then easily be imported into another database. The data can be imported into other versions of MariaDB, MySQL, or even another DBMS entirely, assuming there are no version or DBMS-specific statements in the dump. mysqldump dumps triggers along with tables, as these are part of the table definition. However, [stored procedures](../stored-procedures/index), [views](../views/index), and [events](../events/index) are not, and need extra parameters to be recreated explicitly (for example, `--routines` and `--events`). [Procedures](../stored-procedures/index) and <functions> are however also part of the system tables (for example [mysql.proc](../mysqlproc-table/index)). #### InnoDB Logical Backups InnoDB uses the [buffer pool](../xtradbinnodb-buffer-pool/index), which stores data and indexes from its tables in memory. This buffer is very important for performance. If InnoDB data doesn't fit the memory, it is important that the buffer contains the most frequently accessed data. However, last accessed data is candidate for insertion into the buffer pool. If not properly configured, when a table scan happens, InnoDB may copy the whole contents of a table into the buffer pool. The problem with logical backups is that they always imply full table scans. An easy way to avoid this is by increasing the value of the [innodb\_old\_blocks\_time](../xtradbinnodb-server-system-variables/index#innodb_old_blocks_time) system variable. It represents the number of milliseconds that must pass before a recently accessed page can be put into the "new" sublist in the buffer pool. Data which is accessed only once should remain in the "old" sublist. This means that they will soon be evicted from the buffer pool. Since during the backup process the "old" sublist is likely to store data that is not useful, one could also consider resizing it by changing the value of the [innodb\_old\_blocks\_pct](../xtradbinnodb-server-system-variables/index#innodb_old_blocks_pct) system variable. It is also possible to explicitly dump the buffer pool on disk before starting a logical backup, and restore it after the process. This will undo any negative change to the buffer pool which happens during the backup. To dump the buffer pool, the [innodb\_buffer\_pool\_dump\_now](../innodb-system-variables/index#innodb_buffer_pool_dump_now) system variable can be set to ON. To restore it, the [innodb\_buffer\_pool\_load\_now](../innodb-system-variables/index#innodb_buffer_pool_load_now) system variable can be set to ON. #### Examples Backing up a single database ``` shell> mysqldump db_name > backup-file.sql ``` Restoring or loading the database ``` shell> mysql db_name < backup-file.sql ``` See the [mysqldump](../mysqldump/index) page for detailed syntax and examples. ### mysqlhotcopy mysqlhotcopy is currently deprecated. [mysqlhotcopy](../mysqlhotcopy/index) performs a physical backup, and works only for backing up [MyISAM](../myisam/index) and [ARCHIVE](../archive/index) tables. It can only be run on the same machine as the location of the database directories. #### Examples ``` shell> mysqlhotcopy db_name [/path/to/new_directory] shell> mysqlhotcopy db_name_1 ... db_name_n /path/to/new_directory ``` ### Percona XtraBackup In [MariaDB 10.1](../what-is-mariadb-101/index) and later, [Mariabackup](../mariabackup/index) is the recommended backup method to use instead of Percona XtraBackup. In [MariaDB 10.3](../what-is-mariadb-103/index), Percona XtraBackup is **not supported**. See [Percona XtraBackup Overview: Compatibility with MariaDB](../percona-xtrabackup-overview/index#compatibility-with-mariadb) for more information. In [MariaDB 10.2](../what-is-mariadb-102/index) and [MariaDB 10.1](../what-is-mariadb-101/index), Percona XtraBackup is only **partially supported**. See [Percona XtraBackup Overview: Compatibility with MariaDB](../percona-xtrabackup-overview/index#compatibility-with-mariadb) for more information. [Percona XtraBackup](../backup-restore-and-import-xtrabackup/index) is a tool for performing fast, hot backups. It was designed specifically for [XtraDB/InnoDB](../innodb/index) databases, but can be used with any storage engine (although not with [MariaDB 10.1](../what-is-mariadb-101/index) [encryption](../encryption/index) and [compression](../compression/index)). It is not included by default with MariaDB. ### Filesystem Snapshots Some filesystems, like Veritas, support snapshots. During the snapshot, the table must be locked. The proper steps to obtain a snapshot are: * From the mysql client, execute [FLUSH TABLES WITH READ LOCK](../flush/index). The client must remain open. * From a shell, execute `mount vxfs snapshot` * The client can execute [UNLOCK TABLES](../transactions-lock/index). * Copy the snapshot files. * From a shell, unmount the snapshot with `umount snapshot`. ### LVM Widely-used physical backup method, using a Perl script as a wrapper. See <http://www.lenzg.net/mylvmbackup/>. ### Percona TokuBackup For details, see: * [TokuDB Hot Backup – Part 1](https://www.percona.com/blog/2013/09/12/tokudb-hot-backup-part-1/) * [TokuDB Hot Backup – Part 2](https://www.percona.com/blog/2013/09/19/tokudb-hot-backup-part-2/) * [TokuDB Hot Backup Now a MySQL Plugin](https://www.percona.com/blog/2015/02/05/tokudb-hot-backup-now-mysql-plugin/) See Also -------- * [Streaming MariaDB backups in the cloud](https://mariadb.com/blog/streaming-mariadb-backups-cloud) (mariadb.com blog) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_RELATE ST\_RELATE ========== **MariaDB starting with [10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/)**The ST\_RELATE() function was introduced in [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) Syntax ------ ``` ST_Relate(g1, g2, i) ``` Description ----------- Returns true if Geometry `g1` is spatially related to Geometry`g2` by testing for intersections between the interior, boundary and exterior of the two geometries as specified by the values in intersection matrix pattern `i`. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CREATE TABLE CREATE TABLE ============ Syntax ------ ``` CREATE [OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name (create_definition,...) [table_options ]... [partition_options] CREATE [OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name [(create_definition,...)] [table_options ]... [partition_options] select_statement CREATE [OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name { LIKE old_table_name | (LIKE old_table_name) } select_statement: [IGNORE | REPLACE] [AS] SELECT ... (Some legal select statement) ``` Description ----------- Use the `CREATE TABLE` statement to create a table with the given name. In its most basic form, the `CREATE TABLE` statement provides a table name followed by a list of columns, indexes, and constraints. By default, the table is created in the default database. Specify a database with `*db\_name*.*tbl\_name*`. If you quote the table name, you must quote the database name and table name separately as ``*db\_name*`.`*tbl\_name*``. This is particularly useful for [CREATE TABLE ... SELECT](#create-table-select), because it allows to create a table into a database, which contains data from other databases. See [Identifier Qualifiers](../identifier-qualifiers/index). If a table with the same name exists, error 1050 results. Use [IF NOT EXISTS](#create-table-if-not-exists) to suppress this error and issue a note instead. Use [SHOW WARNINGS](../show-warnings/index) to see notes. The `CREATE TABLE` statement automatically commits the current transaction, except when using the [TEMPORARY](#create-temporary-table) keyword. For valid identifiers to use as table names, see [Identifier Names](../identifier-names/index). **Note:** if the default\_storage\_engine is set to ColumnStore then it needs setting on all UMs. Otherwise when the tables using the default engine are replicated across UMs they will use the wrong engine. You should therefore not use this option as a session variable with ColumnStore. [Microsecond precision](../microseconds-in-mariadb/index) can be between 0-6. If no precision is specified it is assumed to be 0, for backward compatibility reasons. Privileges ---------- Executing the `CREATE TABLE` statement requires the [CREATE](../grant/index#table-privileges) privilege for the table or the database. CREATE OR REPLACE ----------------- If the `OR REPLACE` clause is used and the table already exists, then instead of returning an error, the server will drop the existing table and replace it with the newly defined table. This syntax was originally added to make [replication](../replication/index) more robust if it has to rollback and repeat statements such as `CREATE ... SELECT` on replicas. ``` CREATE OR REPLACE TABLE table_name (a int); ``` is basically the same as: ``` DROP TABLE IF EXISTS table_name; CREATE TABLE table_name (a int); ``` with the following exceptions: * If `table_name` was locked with [LOCK TABLES](../lock-tables-and-unlock-tables/index) it will continue to be locked after the statement. * Temporary tables are only dropped if the `TEMPORARY` keyword was used. (With [DROP TABLE](../drop-table/index), temporary tables are preferred to be dropped before normal tables). ### Things to be Aware of With CREATE OR REPLACE * The table is dropped first (if it existed), after that the `CREATE` is done. Because of this, if the `CREATE` fails, then the table will not exist anymore after the statement. If the table was used with `LOCK TABLES` it will be unlocked. * One can't use `OR REPLACE` together with `IF EXISTS`. * Slaves in replication will by default use `CREATE OR REPLACE` when replicating `CREATE` statements that don''t use `IF EXISTS`. This can be changed by setting the variable [slave-ddl-exec-mode](../replication-and-binary-log-server-system-variables/index#slave_ddl_exec_mode) to `STRICT`. CREATE TABLE IF NOT EXISTS -------------------------- If the `IF NOT EXISTS` clause is used, then the table will only be created if a table with the same name does not already exist. If the table already exists, then a warning will be triggered by default. CREATE TEMPORARY TABLE ---------------------- Use the `TEMPORARY` keyword to create a temporary table that is only available to the current session. Temporary tables are dropped when the session ends. Temporary table names are specific to the session. They will not conflict with other temporary tables from other sessions even if they share the same name. They will shadow names of non-temporary tables or views, if they are identical. A temporary table can have the same name as a non-temporary table which is located in the same database. In that case, their name will reference the temporary table when used in SQL statements. You must have the [CREATE TEMPORARY TABLES](../grant/index#database-privileges) privilege on the database to create temporary tables. If no storage engine is specified, the [default\_tmp\_storage\_engine](../server-system-variables/index#default_tmp_storage_engine) setting will determine the engine. [ROCKSDB](../myrocks/index) temporary tables cannot be created by setting the [default\_tmp\_storage\_engine](../server-system-variables/index#default_tmp_storage_engine) system variable, or using `CREATE TEMPORARY TABLE LIKE`. Before [MariaDB 10.7](../what-is-mariadb-107/index), they could be specified, but would silently fail, and a MyISAM table would be created instead. From [MariaDB 10.7](../what-is-mariadb-107/index) an error is returned. Explicitly creating a temporary table with `ENGINE=ROCKSDB` has never been permitted. CREATE TABLE ... LIKE --------------------- Use the `LIKE` clause instead of a full table definition to create a table with the same definition as another table, including columns, indexes, and table options. Foreign key definitions, as well as any DATA DIRECTORY or INDEX DIRECTORY table options specified on the original table, will not be created. CREATE TABLE ... SELECT ----------------------- You can create a table containing data from other tables using the `CREATE ... SELECT` statement. Columns will be created in the table for each field returned by the `SELECT` query. You can also define some columns normally and add other columns from a `SELECT`. You can also create columns in the normal way and assign them some values using the query, this is done to force a certain type or other field characteristics. The columns that are not named in the query will be placed before the others. For example: ``` CREATE TABLE test (a INT NOT NULL, b CHAR(10)) ENGINE=MyISAM SELECT 5 AS b, c, d FROM another_table; ``` Remember that the query just returns data. If you want to use the same indexes, or the same columns attributes (`[NOT] NULL`, `DEFAULT`, `AUTO_INCREMENT`) in the new table, you need to specify them manually. Types and sizes are not automatically preserved if no data returned by the `SELECT` requires the full size, and `VARCHAR` could be converted into `CHAR`. The [CAST()](../cast/index) function can be used to forcee the new table to use certain types. Aliases (`AS`) are taken into account, and they should always be used when you `SELECT` an expression (function, arithmetical operation, etc). If an error occurs during the query, the table will not be created at all. If the new table has a primary key or `UNIQUE` indexes, you can use the [IGNORE](../ignore/index) or `REPLACE` keywords to handle duplicate key errors during the query. `IGNORE` means that the newer values must not be inserted an identical value exists in the index. `REPLACE` means that older values must be overwritten. If the columns in the new table are more than the rows returned by the query, the columns populated by the query will be placed after other columns. Note that if the strict `SQL_MODE` is on, and the columns that are not names in the query do not have a `DEFAULT` value, an error will raise and no rows will be copied. [Concurrent inserts](../concurrent-inserts/index) are not used during the execution of a `CREATE ... SELECT`. If the table already exists, an error similar to the following will be returned: ``` ERROR 1050 (42S01): Table 't' already exists ``` If the `IF NOT EXISTS` clause is used and the table exists, a note will be produced instead of an error. To insert rows from a query into an existing table, [INSERT ... SELECT](../insert-select/index) can be used. Column Definitions ------------------ ``` create_definition: { col_name column_definition | index_definition | period_definition | CHECK (expr) } column_definition: data_type [NOT NULL | NULL] [DEFAULT default_value | (expression)] [ON UPDATE [NOW | CURRENT_TIMESTAMP] [(precision)]] [AUTO_INCREMENT] [ZEROFILL] [UNIQUE [KEY] | [PRIMARY] KEY] [INVISIBLE] [{WITH|WITHOUT} SYSTEM VERSIONING] [COMMENT 'string'] [REF_SYSTEM_ID = value] [reference_definition] | data_type [GENERATED ALWAYS] AS { { ROW {START|END} } | { (expression) [VIRTUAL | PERSISTENT | STORED] } } [UNIQUE [KEY]] [COMMENT 'string'] constraint_definition: CONSTRAINT [constraint_name] CHECK (expression) ``` **Note:** Until [MariaDB 10.4](../what-is-mariadb-104/index), MariaDB accepts the shortcut format with a REFERENCES clause only in ALTER TABLE and CREATE TABLE statements, but that syntax does nothing. For example: ``` CREATE TABLE b(for_key INT REFERENCES a(not_key)); ``` MariaDB simply parses it without returning any error or warning, for compatibility with other DBMS's. Before [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) this was also true for `CHECK` constraints. However, only the syntax described below creates foreign keys. From [MariaDB 10.5](../what-is-mariadb-105/index), MariaDB will attempt to apply the constraint. See [Foreign Keys examples](../foreign-keys/index#references). Each definition either creates a column in the table or specifies and index or constraint on one or more columns. See [Indexes](#indexes) below for details on creating indexes. Create a column by specifying a column name and a data type, optionally followed by column options. See [Data Types](../data-types/index) for a full list of data types allowed in MariaDB. ### NULL and NOT NULL Use the `NULL` or `NOT NULL` options to specify that values in the column may or may not be `NULL`, respectively. By default, values may be `NULL`. See also [NULL Values in MariaDB](../null-values-in-mariadb/index). ### DEFAULT Column Option **MariaDB starting with [10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)**The `DEFAULT` clause was enhanced in [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). Some enhancements include * [BLOB](../blob/index) and [TEXT](../text/index) columns now support `DEFAULT`. * The `DEFAULT` clause can now be used with an expression or function. Specify a default value using the `DEFAULT` clause. If you don't specify `DEFAULT` then the following rules apply: * If the column is not defined with `NOT NULL`, `AUTO_INCREMENT` or `TIMESTAMP`, an explicit `DEFAULT NULL` will be added. Note that in MySQL and in MariaDB before 10.1.6, you may get an explicit `DEFAULT` for primary key parts, if not specified with NOT NULL. The default value will be used if you [INSERT](../insert/index) a row without specifying a value for that column, or if you specify [DEFAULT](../default/index) for that column. Before [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) you couldn't usually provide an expression or function to evaluate at insertion time. You had to provide a constant default value instead. The one exception is that you may use [CURRENT\_TIMESTAMP](../now/index) as the default value for a [TIMESTAMP](../timestamp/index) column to use the current timestamp at insertion time. [CURRENT\_TIMESTAMP](../now/index) may also be used as the default value for a [DATETIME](../datetime/index) From [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) you can use most functions in `DEFAULT`. Expressions should have parentheses around them. If you use a non deterministic function in `DEFAULT` then all inserts to the table will be [replicated](../replication/index) in [row mode](../binary-log-formats/index#row-based). You can even refer to earlier columns in the `DEFAULT` expression (excluding `AUTO_INCREMENT` columns): ``` CREATE TABLE t1 (a int DEFAULT (1+1), b int DEFAULT (a+1)); CREATE TABLE t2 (a bigint primary key DEFAULT UUID_SHORT()); ``` The `DEFAULT` clause cannot contain any [stored functions](../stored-functions/index) or [subqueries](../subqueries/index), and a column used in the clause must already have been defined earlier in the statement. Since [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/), it is possible to assign [BLOB](../blob/index) or [TEXT](../text/index) columns a `DEFAULT` value. In earlier versions, assigning a default to these columns was not possible. **MariaDB starting with [10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)**Starting from 10.3.3 you can also use DEFAULT ([NEXT VALUE FOR sequence](../next-value-for-sequence_name/index)) ### AUTO\_INCREMENT Column Option Use [AUTO\_INCREMENT](../auto_increment/index) to create a column whose value can can be set automatically from a simple counter. You can only use `AUTO_INCREMENT` on a column with an integer type. The column must be a key, and there can only be one `AUTO_INCREMENT` column in a table. If you insert a row without specifying a value for that column (or if you specify `0`, `NULL`, or [DEFAULT](../default/index) as the value), the actual value will be taken from the counter, with each insertion incrementing the counter by one. You can still insert a value explicitly. If you insert a value that is greater than the current counter value, the counter is set based on the new value. An `AUTO_INCREMENT` column is implicitly `NOT NULL`. Use [LAST\_INSERT\_ID](../last_insert_id/index) to get the [AUTO\_INCREMENT](../auto_increment/index) value most recently used by an [INSERT](../insert/index) statement. ### ZEROFILL Column Option If the `ZEROFILL` column option is specified for a column using a [numeric](../numeric-data-type-overview/index) data type, then the column will be set to `UNSIGNED` and the spaces used by default to pad the field are replaced with zeros. `ZEROFILL` is ignored in expressions or as part of a [UNION](../union/index). `ZEROFILL` is a non-standard MySQL and MariaDB enhancement. ### PRIMARY KEY Column Option Use `PRIMARY KEY` to make a column a primary key. A primary key is a special type of a unique key. There can be at most one primary key per table, and it is implicitly `NOT NULL`. Specifying a column as a unique key creates a unique index on that column. See the [Index Definitions](#index-definitions) section below for more information. ### UNIQUE KEY Column Option Use `UNIQUE KEY` (or just `UNIQUE`) to specify that all values in the column must be distinct from each other. Unless the column is `NOT NULL`, there may be multiple rows with `NULL` in the column. Specifying a column as a unique key creates a unique index on that column. See the [Index Definitions](#index-definitions) section below for more information. ### COMMENT Column Option You can provide a comment for each column using the `COMMENT` clause. The maximum length is 1024 characters. Use the [SHOW FULL COLUMNS](../show-columns/index) statement to see column comments. ### REF\_SYSTEM\_ID `REF_SYSTEM_ID` can be used to specify Spatial Reference System IDs for spatial data type columns. ### Generated Columns A generated column is a column in a table that cannot explicitly be set to a specific value in a [DML query](../data-manipulation/index). Instead, its value is automatically generated based on an expression. This expression might generate the value based on the values of other columns in the table, or it might generate the value by calling [built-in functions](../built-in-functions/index) or [user-defined functions (UDFs)](../user-defined-functions/index). There are two types of generated columns: * `PERSISTENT` or `STORED`: This type's value is actually stored in the table. * `VIRTUAL`: This type's value is not stored at all. Instead, the value is generated dynamically when the table is queried. This type is the default. Generated columns are also sometimes called computed columns or virtual columns. For a complete description about generated columns and their limitations, see [Generated (Virtual and Persistent/Stored) Columns](../generated-columns/index). ### COMPRESSED **MariaDB starting with [10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)**Certain columns may be compressed. See [Storage-Engine Independent Column Compression](../storage-engine-independent-column-compression/index). ### INVISIBLE **MariaDB starting with [10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)**Columns may be made invisible, and hidden in certain contexts. See [Invisible Columns](../invisible-columns/index). ### WITH SYSTEM VERSIONING Column Option **MariaDB starting with [10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/)**Columns may be explicitly marked as included from system versioning. See [System-versioned tables](../system-versioned-tables/index) for details. ### WITHOUT SYSTEM VERSIONING Column Option **MariaDB starting with [10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/)**Columns may be explicitly marked as excluded from system versioning. See [System-versioned tables](../system-versioned-tables/index) for details. Index Definitions ----------------- ``` index_definition: {INDEX|KEY} [index_name] [index_type] (index_col_name,...) [index_option] ... {{{|}}} {FULLTEXT|SPATIAL} [INDEX|KEY] [index_name] (index_col_name,...) [index_option] ... {{{|}}} [CONSTRAINT [symbol]] PRIMARY KEY [index_type] (index_col_name,...) [index_option] ... {{{|}}} [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY] [index_name] [index_type] (index_col_name,...) [index_option] ... {{{|}}} [CONSTRAINT [symbol]] FOREIGN KEY [index_name] (index_col_name,...) reference_definition index_col_name: col_name [(length)] [ASC | DESC] index_type: USING {BTREE | HASH | RTREE} index_option: [ KEY_BLOCK_SIZE [=] value {{{|}}} index_type {{{|}}} WITH PARSER parser_name {{{|}}} COMMENT 'string' {{{|}}} CLUSTERING={YES| NO} ] [ IGNORED | NOT IGNORED ] reference_definition: REFERENCES tbl_name (index_col_name,...) [MATCH FULL | MATCH PARTIAL | MATCH SIMPLE] [ON DELETE reference_option] [ON UPDATE reference_option] reference_option: RESTRICT | CASCADE | SET NULL | NO ACTION ``` `INDEX` and `KEY` are synonyms. Index names are optional, if not specified an automatic name will be assigned. Index name are needed to drop indexes and appear in error messages when a constraint is violated. ### Index Categories #### Plain Indexes Plain indexes are regular indexes that are not unique, and are not acting as a primary key or a foreign key. They are also not the "specialized" `FULLTEXT` or `SPATIAL` indexes. See [Getting Started with Indexes: Plain Indexes](../getting-started-with-indexes/index#plain-indexes) for more information. #### PRIMARY KEY For `PRIMARY KEY` indexes, you can specify a name for the index, but it is ignored, and the name of the index is always `PRIMARY`. From [MariaDB 10.3.18](https://mariadb.com/kb/en/mariadb-10318-release-notes/) and [MariaDB 10.4.8](https://mariadb.com/kb/en/mariadb-1048-release-notes/), a warning is explicitly issued if a name is specified. Before then, the name was silently ignored. See [Getting Started with Indexes: Primary Key](../getting-started-with-indexes/index#primary-key) for more information. #### UNIQUE The `UNIQUE` keyword means that the index will not accept duplicated values, except for NULLs. An error will raise if you try to insert duplicate values in a UNIQUE index. For `UNIQUE` indexes, you can specify a name for the constraint, using the `CONSTRAINT` keyword. That name will be used in error messages. See [Getting Started with Indexes: Unique Index](../getting-started-with-indexes/index#unique-index) for more information. #### FOREIGN KEY For `FOREIGN KEY` indexes, a reference definition must be provided. For `FOREIGN KEY` indexes, you can specify a name for the constraint, using the `CONSTRAINT` keyword. That name will be used in error messages. First, you have to specify the name of the target (parent) table and a column or a column list which must be indexed and whose values must match to the foreign key's values. The `MATCH` clause is accepted to improve the compatibility with other DBMS's, but has no meaning in MariaDB. The `ON DELETE` and `ON UPDATE` clauses specify what must be done when a `DELETE` (or a `REPLACE`) statements attempts to delete a referenced row from the parent table, and when an `UPDATE` statement attempts to modify the referenced foreign key columns in a parent table row, respectively. The following options are allowed: * `RESTRICT`: The delete/update operation is not performed. The statement terminates with a 1451 error (SQLSTATE '2300'). * `NO ACTION`: Synonym for `RESTRICT`. * `CASCADE`: The delete/update operation is performed in both tables. * `SET NULL`: The update or delete goes ahead in the parent table, and the corresponding foreign key fields in the child table are set to `NULL`. (They must not be defined as `NOT NULL` for this to succeed). * `SET DEFAULT`: This option is currently implemented only for the PBXT storage engine, which is disabled by default and no longer maintained. It sets the child table's foreign key fields to their `DEFAULT` values when the referenced parent table key entries are updated or deleted. If either clause is omitted, the default behavior for the omitted clause is `RESTRICT`. See [Foreign Keys](../foreign-keys/index) for more information. #### FULLTEXT Use the `FULLTEXT` keyword to create full-text indexes. See [Full-Text Indexes](../full-text-indexes/index) for more information. #### SPATIAL Use the `SPATIAL` keyword to create geometric indexes. See [SPATIAL INDEX](../spatial-index/index) for more information. ### Index Options #### KEY\_BLOCK\_SIZE Index Option The `KEY_BLOCK_SIZE` index option is similar to the [KEY\_BLOCK\_SIZE](#key_block_size) table option. With the [InnoDB](../innodb/index) storage engine, if you specify a non-zero value for the `KEY_BLOCK_SIZE` table option for the whole table, then the table will implicitly be created with the [ROW\_FORMAT](#row_format) table option set to `COMPRESSED`. However, this does not happen if you just set the `KEY_BLOCK_SIZE` index option for one or more indexes in the table. The [InnoDB](../innodb/index) storage engine ignores the `KEY_BLOCK_SIZE` index option. However, the [SHOW CREATE TABLE](../show-create-table/index) statement may still report it for the index. For information about the `KEY_BLOCK_SIZE` index option, see the [KEY\_BLOCK\_SIZE](#key_block_size) table option below. #### Index Types Each storage engine supports some or all index types. See [Storage Engine Index Types](../storage-engine-index-types/index) for details on permitted index types for each storage engine. Different index types are optimized for different kind of operations: * `BTREE` is the default type, and normally is the best choice. It is supported by all storage engines. It can be used to compare a column's value with a value using the =, >, >=, <, <=, `BETWEEN`, and `LIKE` operators. `BTREE` can also be used to find `NULL` values. Searches against an index prefix are possible. * `HASH` is only supported by the MEMORY storage engine. `HASH` indexes can only be used for =, <=, and >= comparisons. It can not be used for the `ORDER BY` clause. Searches against an index prefix are not possible. * `RTREE` is the default for [SPATIAL](../spatial/index) indexes, but if the storage engine does not support it `BTREE` can be used. Index columns names are listed between parenthesis. After each column, a prefix length can be specified. If no length is specified, the whole column will be indexed. `ASC` and `DESC` can be specified for compatibility with are DBMS's, but have no meaning in MariaDB. #### WITH PARSER Index Option The `WITH PARSER` index option only applies to [FULLTEXT](../full-text-indexes/index) indexes and contains the fulltext parser name. The fulltext parser must be an installed plugin. #### COMMENT Index Option A comment of up to 1024 characters is permitted with the `COMMENT` index option. The `COMMENT` index option allows you to specify a comment with user-readable text describing what the index is for. This information is not used by the server itself. #### CLUSTERING Index Option The `CLUSTERING` index option is only valid for tables using the [TokuDB](../tokudb/index) storage engine. #### IGNORED / NOT IGNORED **MariaDB starting with [10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/)**From [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/), indexes can be specified to be ignored by the optimizer. See [Ignored Indexes](../ignored-indexes/index). Periods ------- **MariaDB starting with [10.3.4](https://mariadb.com/kb/en/mariadb-1034-release-notes/)** ``` period_definition: PERIOD FOR SYSTEM_TIME (start_column_name, end_column_name) ``` MariaDB supports a subset of the standard syntax for periods. At the moment it's only used for creating [System-versioned tables](../system-versioned-tables/index). Both columns must be created, must be either of a `TIMESTAMP(6)` or `BIGINT UNSIGNED` type, and be generated as `ROW START` and `ROW END` accordingly. See [System-versioned tables](../system-versioned-tables/index) for details. The table must also have the `WITH SYSTEM VERSIONING` clause. Constraint Expressions ---------------------- **MariaDB starting with [10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)**[MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) introduced new ways to define a constraint. Note: Before [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/), constraint expressions were accepted in the syntax but ignored. [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) introduced two ways to define a constraint: * `CHECK(expression)` given as part of a column definition. * `CONSTRAINT [constraint_name] CHECK (expression)` Before a row is inserted or updated, all constraints are evaluated in the order they are defined. If any constraints fails, then the row will not be updated. One can use most deterministic functions in a constraint, including [UDFs](../user-defined-functions/index). ``` create table t1 (a int check(a>0) ,b int check (b> 0), constraint abc check (a>b)); ``` If you use the second format and you don't give a name to the constraint, then the constraint will get a auto generated name. This is done so that you can later delete the constraint with [ALTER TABLE DROP constraint\_name](../alter-table/index). One can disable all constraint expression checks by setting the variable `check_constraint_checks` to `OFF`. This is useful for example when loading a table that violates some constraints that you want to later find and fix in SQL. See [CONSTRAINT](../constraint/index) for more information. Table Options ------------- For each individual table you create (or alter), you can set some table options. The general syntax for setting options is: <OPTION\_NAME> = <option\_value>, [<OPTION\_NAME> = <option\_value> ...] The equal sign is optional. Some options are supported by the server and can be used for all tables, no matter what storage engine they use; other options can be specified for all storage engines, but have a meaning only for some engines. Also, engines can [extend `CREATE TABLE` with new options](../extending-create-table/index). If the `IGNORE_BAD_TABLE_OPTIONS` [SQL\_MODE](../sql-mode/index) is enabled, wrong table options generate a warning; otherwise, they generate an error. ``` table_option: [STORAGE] ENGINE [=] engine_name | AUTO_INCREMENT [=] value | AVG_ROW_LENGTH [=] value | [DEFAULT] CHARACTER SET [=] charset_name | CHECKSUM [=] {0 | 1} | [DEFAULT] COLLATE [=] collation_name | COMMENT [=] 'string' | CONNECTION [=] 'connect_string' | DATA DIRECTORY [=] 'absolute path to directory' | DELAY_KEY_WRITE [=] {0 | 1} | ENCRYPTED [=] {YES | NO} | ENCRYPTION_KEY_ID [=] value | IETF_QUOTES [=] {YES | NO} | INDEX DIRECTORY [=] 'absolute path to directory' | INSERT_METHOD [=] { NO | FIRST | LAST } | KEY_BLOCK_SIZE [=] value | MAX_ROWS [=] value | MIN_ROWS [=] value | PACK_KEYS [=] {0 | 1 | DEFAULT} | PAGE_CHECKSUM [=] {0 | 1} | PAGE_COMPRESSED [=] {0 | 1} | PAGE_COMPRESSION_LEVEL [=] {0 .. 9} | PASSWORD [=] 'string' | ROW_FORMAT [=] {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT|PAGE} | SEQUENCE [=] {0|1} | STATS_AUTO_RECALC [=] {DEFAULT|0|1} | STATS_PERSISTENT [=] {DEFAULT|0|1} | STATS_SAMPLE_PAGES [=] {DEFAULT|value} | TABLESPACE tablespace_name | TRANSACTIONAL [=] {0 | 1} | UNION [=] (tbl_name[,tbl_name]...) | WITH SYSTEM VERSIONING ``` ### [STORAGE] ENGINE `[STORAGE] ENGINE` specifies a [storage engine](../mariadb-storage-engines/index) for the table. If this option is not used, the default storage engine is used instead. That is, the [default\_storage\_engine](../server-system-variables/index#default_storage_engine) session option value if it is set, or the value specified for the `--default-storage-engine` [mysqld startup option](../mysqld-options-full-list/index), or the default storage engine, [InnoDB](../innodb/index). If the specified storage engine is not installed and active, the default value will be used, unless the `NO_ENGINE_SUBSTITUTION` [SQL MODE](../sql-mode/index) is set (default). This is only true for `CREATE TABLE`, not for `ALTER TABLE`. For a list of storage engines that are present in your server, issue a [SHOW ENGINES](../show-engines/index). ### AUTO\_INCREMENT `AUTO_INCREMENT` specifies the initial value for the [AUTO\_INCREMENT](../auto_increment/index) primary key. This works for MyISAM, Aria, InnoDB, MEMORY, and ARCHIVE tables. You can change this option with `ALTER TABLE`, but in that case the new value must be higher than the highest value which is present in the `AUTO_INCREMENT` column. If the storage engine does not support this option, you can insert (and then delete) a row having the wanted value - 1 in the `AUTO_INCREMENT` column. ### AVG\_ROW\_LENGTH `AVG_ROW_LENGTH` is the average rows size. It only applies to tables using [MyISAM](../myisam/index) and [Aria](../aria-storage-engine/index) storage engines that have the [ROW\_FORMAT](#row_format) table option set to `FIXED` format. MyISAM uses `MAX_ROWS` and `AVG_ROW_LENGTH` to decide the maximum size of a table (default: 256TB, or the maximum file size allowed by the system). ### [DEFAULT] CHARACTER SET/CHARSET `[DEFAULT] CHARACTER SET` (or `[DEFAULT] CHARSET`) is used to set a default character set for the table. This is the character set used for all columns where an explicit character set is not specified. If this option is omitted or `DEFAULT` is specified, database's default character set will be used. See [Setting Character Sets and Collations](../setting-character-sets-and-collations/index) for details on setting the [character sets](../data-types-character-sets-and-collations/index). ### CHECKSUM/TABLE\_CHECKSUM `CHECKSUM` (or `TABLE_CHECKSUM`) can be set to 1 to maintain a live checksum for all table's rows. This makes write operations slower, but [CHECKSUM TABLE](../checksum-table/index) will be very fast. This option is only supported for [MyISAM](../myisam/index) and [Aria tables](../aria-storage-engine/index). ### [DEFAULT] COLLATE `[DEFAULT] COLLATE` is used to set a default collation for the table. This is the collation used for all columns where an explicit character set is not specified. If this option is omitted or `DEFAULT` is specified, database's default option will be used. See [Setting Character Sets and Collations](../setting-character-sets-and-collations/index) for details on setting the [collations](../data-types-character-sets-and-collations/index) ### COMMENT `COMMENT` is a comment for the table. The maximum length is 2048 characters. Also used to define table parameters when creating a [Spider](../spider/index) table. ### CONNECTION `CONNECTION` is used to specify a server name or a connection string for a [Spider](../spider/index), [CONNECT](../connect/index), [Federated or FederatedX table](../about-federatedx/index). ### DATA DIRECTORY/INDEX DIRECTORY `DATA DIRECTORY` and `INDEX DIRECTORY` are supported for MyISAM and Aria, and DATA DIRECTORY is also supported by InnoDB if the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) server system variable is enabled, but only in CREATE TABLE, not in [ALTER TABLE](../alter-table/index). So, carefully choose a path for InnoDB tables at creation time, because it cannot be changed without dropping and re-creating the table. These options specify the paths for data files and index files, respectively. If these options are omitted, the database's directory will be used to store data files and index files. Note that these table options do not work for [partitioned](../managing-mariadb-partitioning/index) tables (use the partition options instead), or if the server has been invoked with the [--skip-symbolic-links startup option](../mysqld-options-full-list/index). To avoid the overwriting of old files with the same name that could be present in the directories, you can use [the `--keep_files_on_create` option](../mysqld-options-full-list/index) (an error will be issued if files already exist). These options are ignored if the `NO_DIR_IN_CREATE` [SQL\_MODE](../sql-mode/index) is enabled (useful for replication slaves). Also note that symbolic links cannot be used for InnoDB tables. `DATA DIRECTORY` works by creating symlinks from where the table would normally have been (inside the [datadir](../server-system-variables/index#datadir)) to where the option specifies. For security reasons, to avoid bypassing the privilege system, the server does not permit symlinks inside the datadir. Therefore, `DATA DIRECTORY` cannot be used to specify a location inside the datadir. An attempt to do so will result in an error `1210 (HY000) Incorrect arguments to DATA DIRECTORY`. ### DELAY\_KEY\_WRITE `DELAY_KEY_WRITE` is supported by MyISAM and Aria, and can be set to 1 to speed up write operations. In that case, when data are modified, the indexes are not updated until the table is closed. Writing the changes to the index file altogether can be much faster. However, note that this option is applied only if the `delay_key_write` server variable is set to 'ON'. If it is 'OFF' the delayed index writes are always disabled, and if it is 'ALL' the delayed index writes are always used, disregarding the value of `DELAY_KEY_WRITE`. ### ENCRYPTED The `ENCRYPTED` table option can be used to manually set the encryption status of an [InnoDB](../innodb/index) table. See [InnoDB Encryption](../innodb-encryption/index) for more information. Aria does not support the `ENCRYPTED` table option. See [MDEV-18049](https://jira.mariadb.org/browse/MDEV-18049). See [Data-at-Rest Encryption](../securing-mariadb-data-at-rest-encryption/index) for more information. ### ENCRYPTION\_KEY\_ID The `ENCRYPTION_KEY_ID` table option can be used to manually set the encryption key of an [InnoDB](../innodb/index) table. See [InnoDB Encryption](../innodb-encryption/index) for more information. Aria does not support the `ENCRYPTION_KEY_ID` table option. See [MDEV-18049](https://jira.mariadb.org/browse/MDEV-18049). See [Data-at-Rest Encryption](../securing-mariadb-data-at-rest-encryption/index) for more information. ### IETF\_QUOTES For the [CSV](../csv/index) storage engine, the `IETF_QUOTES` option, when set to `YES`, enables IETF-compatible parsing of embedded quote and comma characters. Enabling this option for a table improves compatibility with other tools that use CSV, but is not compatible with MySQL CSV tables, or MariaDB CSV tables created without this option. Disabled by default. ### INSERT\_METHOD `INSERT_METHOD` is only used with [MERGE](../merge/index) tables. This option determines in which underlying table the new rows should be inserted. If you set it to 'NO' (which is the default) no new rows can be added to the table (but you will still be able to perform `INSERT`s directly against the underlying tables). `FIRST` means that the rows are inserted into the first table, and `LAST` means that thet are inserted into the last table. ### KEY\_BLOCK\_SIZE `KEY_BLOCK_SIZE` is used to determine the size of key blocks, in bytes or kilobytes. However, this value is just a hint, and the storage engine could modify or ignore it. If `KEY_BLOCK_SIZE` is set to 0, the storage engine's default value will be used. With the [InnoDB](../innodb/index) storage engine, if you specify a non-zero value for the `KEY_BLOCK_SIZE` table option for the whole table, then the table will implicitly be created with the [ROW\_FORMAT](#row_format) table option set to `COMPRESSED`. ### MIN\_ROWS/MAX\_ROWS `MIN_ROWS` and `MAX_ROWS` let the storage engine know how many rows you are planning to store as a minimum and as a maximum. These values will not be used as real limits, but they help the storage engine to optimize the table. `MIN_ROWS` is only used by MEMORY storage engine to decide the minimum memory that is always allocated. `MAX_ROWS` is used to decide the minimum size for indexes. ### PACK\_KEYS `PACK_KEYS` can be used to determine whether the indexes will be compressed. Set it to 1 to compress all keys. With a value of 0, compression will not be used. With the `DEFAULT` value, only long strings will be compressed. Uncompressed keys are faster. ### PAGE\_CHECKSUM `PAGE_CHECKSUM` is only applicable to [Aria](../aria/index) tables, and determines whether indexes and data should use page checksums for extra safety. ### PAGE\_COMPRESSED `PAGE_COMPRESSED` is used to enable [InnoDB page compression](../compression/index) for [InnoDB](../innodb/index) tables. ### PAGE\_COMPRESSION\_LEVEL `PAGE_COMPRESSION_LEVEL` is used to set the compression level for [InnoDB page compression](../compression/index) for [InnoDB](../innodb/index) tables. The table must also have the [PAGE\_COMPRESSED](#page_compressed) table option set to `1`. Valid values for `PAGE_COMPRESSION_LEVEL` are 1 (the best speed) through 9 (the best compression), . ### PASSWORD `PASSWORD` is unused. ### RAID\_TYPE `RAID_TYPE` is an obsolete option, as the raid support has been disabled since MySQL 5.0. ### ROW\_FORMAT The `ROW_FORMAT` table option specifies the row format for the data file. Possible values are engine-dependent. #### Supported MyISAM Row Formats For [MyISAM](../myisam/index), the supported row formats are: * `FIXED` * `DYNAMIC` * `COMPRESSED` The `COMPRESSED` row format can only be set by the [myisampack](../myisampack/index) command line tool. See [MyISAM Storage Formats](../myisam-storage-formats/index) for more information. #### Supported Aria Row Formats For [Aria](../aria-storage-engine/index), the supported row formats are: * `PAGE` * `FIXED` * `DYNAMIC`. See [Aria Storage Formats](../aria-storage-formats/index) for more information. #### Supported InnoDB Row Formats For [InnoDB](../innodb/index), the supported row formats are: * `COMPACT` * `REDUNDANT` * `COMPRESSED` * `DYNAMIC`. If the `ROW_FORMAT` table option is set to `FIXED` for an InnoDB table, then the server will either return an error or a warning depending on the value of the [innodb\_strict\_mode](../innodb-system-variables/index#innodb_strict_mode) system variable. If the [innodb\_strict\_mode](../innodb-system-variables/index#innodb_strict_mode) system variable is set to `OFF`, then a warning is issued, and MariaDB will create the table using the default row format for the specific MariaDB server version. If the [innodb\_strict\_mode](../innodb-system-variables/index#innodb_strict_mode) system variable is set to `ON`, then an error will be raised. See [InnoDB Storage Formats](../innodb-storage-formats/index) for more information. #### Other Storage Engines and ROW\_FORMAT Other storage engines do not support the `ROW_FORMAT` table option. ### SEQUENCE **MariaDB starting with [10.3](../what-is-mariadb-103/index)**If the table is a [sequence](../sequences/index), then it will have the `SEQUENCE` set to `1`. ### STATS\_AUTO\_RECALC `STATS_AUTO_RECALC` indicates whether to automatically recalculate persistent statistics (see `STATS_PERSISTENT`, below) for an InnoDB table. If set to `1`, statistics will be recalculated when more than 10% of the data has changed. When set to `0`, stats will be recalculated only when an [ANALYZE TABLE](../analyze-table/index) is run. If set to `DEFAULT`, or left out, the value set by the [innodb\_stats\_auto\_recalc](../innodb-system-variables/index#innodb_stats_auto_recalc) system variable applies. See [InnoDB Persistent Statistics](../innodb-persistent-statistics/index). ### STATS\_PERSISTENT `STATS_PERSISTENT` indicates whether the InnoDB statistics created by [ANALYZE TABLE](../analyze-table/index) will remain on disk or not. It can be set to `1` (on disk), `0` (not on disk, the pre-MariaDB 10 behavior), or `DEFAULT` (the same as leaving out the option), in which case the value set by the [innodb\_stats\_persistent](../innodb-system-variables/index#innodb_stats_persistent) system variable will apply. Persistent statistics stored on disk allow the statistics to survive server restarts, and provide better query plan stability. See [InnoDB Persistent Statistics](../innodb-persistent-statistics/index). ### STATS\_SAMPLE\_PAGES `STATS_SAMPLE_PAGES` indicates how many pages are used to sample index statistics. If 0 or DEFAULT, the default value, the [innodb\_stats\_sample\_pages](../innodb-system-variables/index#innodb_stats_sample_pages) value is used. See [InnoDB Persistent Statistics](../innodb-persistent-statistics/index). ### TRANSACTIONAL `TRANSACTIONAL` is only applicable for Aria tables. In future Aria tables created with this option will be fully transactional, but currently this provides a form of crash protection. See [Aria Storage Engine](../aria-storage-engine/index) for more details. ### UNION `UNION` must be specified when you create a MERGE table. This option contains a comma-separated list of MyISAM tables which are accessed by the new table. The list is enclosed between parenthesis. Example: `UNION = (t1,t2)` ### WITH SYSTEM VERSIONING `WITH SYSTEM VERSIONING` is used for creating [System-versioned tables](../system-versioned-tables/index). Partitions ---------- ``` partition_options: PARTITION BY { [LINEAR] HASH(expr) | [LINEAR] KEY(column_list) | RANGE(expr) | LIST(expr) | SYSTEM_TIME [INTERVAL time_quantity time_unit] [LIMIT num] } [PARTITIONS num] [SUBPARTITION BY { [LINEAR] HASH(expr) | [LINEAR] KEY(column_list) } [SUBPARTITIONS num] ] [(partition_definition [, partition_definition] ...)] partition_definition: PARTITION partition_name [VALUES {LESS THAN {(expr) | MAXVALUE} | IN (value_list)}] [[STORAGE] ENGINE [=] engine_name] [COMMENT [=] 'comment_text' ] [DATA DIRECTORY [=] 'data_dir'] [INDEX DIRECTORY [=] 'index_dir'] [MAX_ROWS [=] max_number_of_rows] [MIN_ROWS [=] min_number_of_rows] [TABLESPACE [=] tablespace_name] [NODEGROUP [=] node_group_id] [(subpartition_definition [, subpartition_definition] ...)] subpartition_definition: SUBPARTITION logical_name [[STORAGE] ENGINE [=] engine_name] [COMMENT [=] 'comment_text' ] [DATA DIRECTORY [=] 'data_dir'] [INDEX DIRECTORY [=] 'index_dir'] [MAX_ROWS [=] max_number_of_rows] [MIN_ROWS [=] min_number_of_rows] [TABLESPACE [=] tablespace_name] [NODEGROUP [=] node_group_id] ``` If the `PARTITION BY` clause is used, the table will be [partitioned](../managing-mariadb-partitioning/index). A partition method must be explicitly indicated for partitions and subpartitions. Partition methods are: * `[LINEAR] HASH` creates a hash key which will be used to read and write rows. The partition function can be any valid SQL expression which returns an `INTEGER` number. Thus, it is possible to use the `HASH` method on an integer column, or on functions which accept integer columns as an argument. However, `VALUES LESS THAN` and `VALUES IN` clauses can not be used with `HASH`. An example: ``` CREATE TABLE t1 (a INT, b CHAR(5), c DATETIME) PARTITION BY HASH ( YEAR(c) ); ``` `[LINEAR] HASH` can be used for subpartitions, too. * `[LINEAR] KEY` is similar to `HASH`, but the index has an even distribution of data. Also, the expression can only be a column or a list of columns. `VALUES LESS THAN` and `VALUES IN` clauses can not be used with `KEY`. * [RANGE](../range-partitioning-type/index) partitions the rows using on a range of values, using the `VALUES LESS THAN` operator. `VALUES IN` is not allowed with `RANGE`. The partition function can be any valid SQL expression which returns a single value. * [LIST](../list-partitioning/index) assigns partitions based on a table's column with a restricted set of possible values. It is similar to `RANGE`, but `VALUES IN` must be used for at least 1 columns, and `VALUES LESS THAN` is disallowed. * `SYSTEM_TIME` partitioning is used for [System-versioned tables](../system-versioned-tables/index) to store historical data separately from current data. Only `HASH` and `KEY` can be used for subpartitions, and they can be `[LINEAR]`. It is possible to define up to 1024 partitions and subpartitions. The number of defined partitions can be optionally specified as `PARTITION count`. This can be done to avoid specifying all partitions individually. But you can also declare each individual partition and, additionally, specify a `PARTITIONS count` clause; in the case, the number of `PARTITION`s must equal count. Also see [Partitioning Types Overview](../partitioning-types-overview/index). Sequences --------- **MariaDB starting with [10.3](../what-is-mariadb-103/index)**`CREATE TABLE` can also be used to create a [SEQUENCE](../sequences/index). See [CREATE SEQUENCE](../create-sequence/index) and [Sequence Overview](../sequence-overview/index). Atomic DDL ---------- **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**[MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/) supports [Atomic DDL](../atomic-ddl/index). `CREATE TABLE` is atomic, except for `CREATE OR REPLACE`, which is only crash safe. Examples -------- ``` create table if not exists test ( a bigint auto_increment primary key, name varchar(128) charset utf8, key name (name(32)) ) engine=InnoDB default charset latin1; ``` This example shows a couple of things: * Usage of `IF NOT EXISTS`; If the table already existed, it will not be created. There will not be any error for the client, just a warning. * How to create a `PRIMARY KEY` that is [automatically generated](../auto_increment/index). * How to specify a table-specific [character set](../data-types-character-sets-and-collations/index) and another for a column. * How to create an index (`name`) that is only partly indexed (to save space). The following clauses will work from [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) only. ``` CREATE TABLE t1( a int DEFAULT (1+1), b int DEFAULT (a+1), expires DATETIME DEFAULT(NOW() + INTERVAL 1 YEAR), x BLOB DEFAULT USER() ); ``` See Also -------- * [Identifier Names](../identifier-names/index) * [ALTER TABLE](../alter-table/index) * [DROP TABLE](../drop-table/index) * [Character Sets and Collations](../character-sets-and-collations/index) * [SHOW CREATE TABLE](../show-create-table/index) * Storage engines can add their own [attributes for columns, indexes and tables](../engine-defined-new-tablefieldindex-attributes/index). * Variable [slave-ddl-exec-mode](../replication-and-binary-log-server-system-variables/index#slave_ddl_exec_mode). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb MIN/MAX optimization MIN/MAX optimization ==================== Min/Max optimization without GROUP BY ------------------------------------- MariaDB and MySQL can optimize the [MIN()](../min/index) and [MAX()](../max/index) functions to be a single row lookup in the following cases: * There is only one table used in the `SELECT`. * You only have constants, `MIN()` and `MAX()` in the `SELECT` part. * The argument to `MIN()` and `MAX()` is a simple column reference that is part of a key. * There is no `WHERE` clause or the `WHERE` is used with a constant for all prefix parts of the key before the argument to `MIN()`/`MAX()`. * If the argument is used in the `WHERE` clause, it can be be compared to a constant with `<` or `<=` in case of `MAX()` and with `>` or `>=` in case of `MIN()`. Here are some examples to clarify this. In this case we assume there is an index on columns `(a,b,c)` ``` SELECT MIN(a),MAX(a) from t1 SELECT MIN(b) FROM t1 WHERE a=const SELECT MIN(b),MAX(b) FROM t1 WHERE a=const SELECT MAX(c) FROM t1 WHERE a=const AND b=const SELECT MAX(b) FROM t1 WHERE a=const AND b<const SELECT MIN(b) FROM t1 WHERE a=const AND b>const SELECT MIN(b) FROM t1 WHERE a=const AND b BETWEEN const AND const SELECT MAX(b) FROM t1 WHERE a=const AND b BETWEEN const AND const ``` * Instead of `a=const` the condition `a IS NULL` can be used. The above optimization also works for [subqueries](../subqueries/index): ``` SELECT x from t2 where y= (SELECT MIN(b) FROM t1 WHERE a=const) ``` Cross joins, where there is no join condition for a table, can also be optimized to a few key lookups: ``` select min(t1.key_part_1), max(t2.key_part_1) from t1, t2 ``` Min/Max optimization with GROUP BY ---------------------------------- MariaDB and MySQL support loose index scan, which can speed up certain `GROUP BY` queries. The basic idea is that when scanning a `BTREE` index (the most common index type for the MariaDB storage engines) we can jump over identical values for any prefix of a key and thus speed up the scan significantly. Loose scan is possible in the following cases: * The query uses only one table. * The `GROUP BY` part only uses indexed columns in the same order as in the index. * The only aggregated functions in the `SELECT` part are `MIN()` and `MAX()` functions and all of them using the same column which is the next index part after the used `GROUP BY` columns. * Partial indexed columns cannot be used (like only indexing 10 characters of a `VARCHAR(20)` column). Loose scan will apply for your query if [`EXPLAIN`](../explain/index) shows `Using index for group-by` in the `Extra` column. In this case the optimizer will do only one extra row fetch to calculate the value for `MIN()` or `MAX()` for every unique key prefix. The following examples assume that the table `t1` has an index on `(a,b,c)`. ``` SELECT a, b, MIN(c),MAX(c) FROM t1 GROUP BY a,b ``` See also -------- * [MIN()](../min/index) * [MAX()](../max/index) * [MySQL manual on loose index scans](http://dev.mysql.com/doc/refman/5.7/en/group-by-optimization.html) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DECLARE CURSOR DECLARE CURSOR ============== Syntax ------ <= [MariaDB 10.2](../what-is-mariadb-102/index) ``` DECLARE cursor_name CURSOR FOR select_statement ``` From [MariaDB 10.3](../what-is-mariadb-103/index) ``` DECLARE cursor_name CURSOR [(cursor_formal_parameter[,...])] FOR select_statement cursor_formal_parameter: name type [collate clause] ``` From [MariaDB 10.8](../what-is-mariadb-108/index) ``` DECLARE cursor_name CURSOR [(cursor_formal_parameter[,...])] FOR select_statement cursor_formal_parameter: [IN] name type [collate clause] ``` Description ----------- This statement declares a [cursor](../programmatic-and-compound-statements-cursors/index). Multiple cursors may be declared in a [stored program](../stored-programs-and-views/index), but each cursor in a given block must have a unique name. `select_statement` is not executed until the [OPEN](../open/index) statement is executed. It is important to remember this if the query produces an error, or calls functions which have side effects. A `SELECT` associated to a cursor can use variables, but the query itself cannot be a variable, and cannot be dynamically composed. The `SELECT` statement cannot have an `INTO` clause. Cursors must be declared before [HANDLERs](../declare-handler/index), but after local variables and [CONDITIONs](../declare-condition/index). ### Parameters **MariaDB starting with [10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/)**From [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/), cursors can have parameters. This is a non-standard SQL extension. Cursor parameters can appear in any part of the DECLARE CURSOR select\_statement where a stored procedure variable is allowed (select list, WHERE, HAVING, LIMIT etc). ### IN **MariaDB starting with [10.8.0](https://mariadb.com/kb/en/mariadb-1080-release-notes/)**From [MariaDB 10.8.0](https://mariadb.com/kb/en/mariadb-1080-release-notes/) preview release, the `IN` qualifier is supported in the `cursor_format_parameter` part of the syntax. See [Cursor Overview](../cursor-overview/index) for an example. See Also -------- * [Cursor Overview](../cursor-overview/index) * [OPEN cursor\_name](../open/index) * [FETCH cursor\_name](../fetch/index) * [CLOSE cursor\_name](../close/index) * [Cursors in Oracle mode](../sql_modeoracle-from-mariadb-103/index#cursors) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Security Vulnerabilities Fixed in MariaDB Security Vulnerabilities Fixed in MariaDB ========================================= This page is about security vulnerabilities fixed in MariaDB. If you are looking for information on securing your MariaDB installation, see [Securing MariaDB](../securing-mariadb/index). Sensitive security issues can be reported on <https://hackerone.com/mariadb> or sent directly to the persons responsible for MariaDB security: security [AT] mariadb (dot) org. About CVEs ---------- CVE® stands for *"**C**ommon **V**ulnerabilities and **E**xposures"*. It is a publicly available and free to use database of known software vulnerabilities maintained at <https://cve.mitre.org/> On this page is the master list of CVEs fixed across all versions of MariaDB. Follow the links to more information on a particular CVE or specific version of MariaDB. Some CVEs apply to MySQL but are not present in MariaDB, these are listed on the [Security Vulnerabilities fixed in Oracle MySQL that did not exist in MariaDB](../security-vulnerabilities-in-oracle-mysql-that-did-not-exist-in-mariadb/index) page. Separate lists of CVEs fixed in specific MariaDB series are maintained on their individual "What is MariaDB x.x?" pages: * [What is MariaDB 10.9?](../what-is-mariadb-109/index) * [What is MariaDB 10.8?](../what-is-mariadb-108/index) * [What is MariaDB 10.7?](../what-is-mariadb-107/index) * [What is MariaDB 10.6?](../what-is-mariadb-106/index) * [What is MariaDB 10.5?](../what-is-mariadb-105/index) * [What is MariaDB 10.4?](../what-is-mariadb-104/index) * [What is MariaDB 10.3?](../what-is-mariadb-103/index) * [What is MariaDB 10.2?](../what-is-mariadb-102/index) * [What is MariaDB 10.1?](../what-is-mariadb-101/index) * [What is MariaDB 10.0?](../what-is-mariadb-100/index) * [What is MariaDB 5.5?](../what-is-mariadb-55/index) * [What is MariaDB 5.3?](../what-is-mariadb-53/index) * [What is MariaDB 5.2?](../what-is-mariadb-52/index) * [What is MariaDB 5.1?](../what-is-mariadb-51/index) Full List of CVEs fixed in MariaDB ---------------------------------- * [CVE-2022-32091](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32091): [MariaDB 10.9.2](../mdb-1092-rn/index), [MariaDB 10.8.4](../mdb-1084-rn/index), [MariaDB 10.7.5](../mdb-1075-rn/index), [MariaDB 10.6.9](../mdb-1069-rn/index), [MariaDB 10.5.17](../mdb-10517-rn/index), [MariaDB 10.4.26](../mdb-10426-rn/index), [MariaDB 10.3.36](../mdb-10336-rn/index) * [CVE-2022-32089](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32089): [MariaDB 10.9.2](../mdb-1092-rn/index), [MariaDB 10.8.4](../mdb-1084-rn/index), [MariaDB 10.7.5](../mdb-1075-rn/index), [MariaDB 10.6.9](../mdb-1069-rn/index), [MariaDB 10.5.17](../mdb-10517-rn/index), [MariaDB 10.4.26](../mdb-10426-rn/index) * [CVE-2022-32088](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32088): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-32087](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32087): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-32086](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32086): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index) * [CVE-2022-32085](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32085): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-32084](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32084): [MariaDB 10.9.2](../mdb-1092-rn/index), [MariaDB 10.8.4](../mdb-1084-rn/index), [MariaDB 10.7.5](../mdb-1075-rn/index), [MariaDB 10.6.9](../mdb-1069-rn/index), [MariaDB 10.5.17](../mdb-10517-rn/index), [MariaDB 10.4.26](../mdb-10426-rn/index), [MariaDB 10.3.36](../mdb-10336-rn/index) * [CVE-2022-32083](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32083): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-32082](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32082): [MariaDB 10.9.2](../mdb-1092-rn/index), [MariaDB 10.8.4](../mdb-1084-rn/index), [MariaDB 10.7.5](../mdb-1075-rn/index), [MariaDB 10.6.9](../mdb-1069-rn/index), [MariaDB 10.5.17](../mdb-10517-rn/index) * [CVE-2022-32081](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32081): [MariaDB 10.9.2](../mdb-1092-rn/index), [MariaDB 10.8.4](../mdb-1084-rn/index), [MariaDB 10.7.5](../mdb-1075-rn/index), [MariaDB 10.6.9](../mdb-1069-rn/index), [MariaDB 10.5.17](../mdb-10517-rn/index), [MariaDB 10.4.26](../mdb-10426-rn/index) * [CVE-2022-31624](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-31624): [MariaDB 10.6.5](../mdb-1065-rn/index), [MariaDB 10.5.13](../mdb-10513-rn/index), [MariaDB 10.4.22](../mdb-10422-rn/index), [MariaDB 10.3.32](../mdb-10332-rn/index), [MariaDB 10.2.41](../mdb-10241-rn/index) * [CVE-2022-27458](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27458): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-27457](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27457): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index) * [CVE-2022-27456](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27456): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-27455](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27455): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index) * [CVE-2022-27452](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27452): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-27451](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27451): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index) * [CVE-2022-27449](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27449): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-27448](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27448): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-27447](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27447): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-27446](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27446): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index) * [CVE-2022-27445](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27445): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27444](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27444): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index) * [CVE-2022-27387](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27387): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27386](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27386): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27385](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27385): [MariaDB 10.6.5](../mdb-1065-rn/index), [MariaDB 10.5.13](../mdb-10513-rn/index), [MariaDB 10.4.22](../mdb-10422-rn/index), [MariaDB 10.3.32](../mdb-10332-rn/index) * [CVE-2022-27384](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27384): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27383](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27383): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27382](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27382): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index) * [CVE-2022-27381](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27381): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27380](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27380): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27379](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27379): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-27378](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27378): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27377](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27377): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-27376](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-27376): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index) * [CVE-2022-24052](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-24052): [MariaDB 10.8.1](../mdb-1081-rn/index), [MariaDB 10.7.2](../mdb-1072-rn/index), [MariaDB 10.6.6](../mdb-1066-rn/index), [MariaDB 10.5.14](../mdb-10514-rn/index), [MariaDB 10.4.23](../mdb-10423-rn/index), [MariaDB 10.3.33](../mdb-10333-rn/index), [MariaDB 10.2.42](../mdb-10242-rn/index) * [CVE-2022-24051](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-24051): [MariaDB 10.8.1](../mdb-1081-rn/index), [MariaDB 10.7.2](../mdb-1072-rn/index), [MariaDB 10.6.6](../mdb-1066-rn/index), [MariaDB 10.5.14](../mdb-10514-rn/index), [MariaDB 10.4.23](../mdb-10423-rn/index), [MariaDB 10.3.33](../mdb-10333-rn/index), [MariaDB 10.2.42](../mdb-10242-rn/index) * [CVE-2022-24050](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-24050): [MariaDB 10.8.1](../mdb-1081-rn/index), [MariaDB 10.7.2](../mdb-1072-rn/index), [MariaDB 10.6.6](../mdb-1066-rn/index), [MariaDB 10.5.14](../mdb-10514-rn/index), [MariaDB 10.4.23](../mdb-10423-rn/index), [MariaDB 10.3.33](../mdb-10333-rn/index), [MariaDB 10.2.42](../mdb-10242-rn/index) * [CVE-2022-24048](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-24048): [MariaDB 10.8.1](../mdb-1081-rn/index), [MariaDB 10.7.2](../mdb-1072-rn/index), [MariaDB 10.6.6](../mdb-1066-rn/index), [MariaDB 10.5.14](../mdb-10514-rn/index), [MariaDB 10.4.23](../mdb-10423-rn/index), [MariaDB 10.3.33](../mdb-10333-rn/index), [MariaDB 10.2.42](../mdb-10242-rn/index) * [CVE-2022-21451](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-21451): [MariaDB 10.5.10](../mdb-10510-rn/index), [MariaDB 10.4.19](../mdb-10419-rn/index), [MariaDB 10.3.29](../mdb-10329-rn/index), [MariaDB 10.2.38](../mdb-10238-rn/index) * [CVE-2022-21427](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-21427): [MariaDB 10.5.7](../mdb-1057-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2022-0778](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-0778): [MariaDB 10.7.2](../mdb-1072-rn/index), [MariaDB 10.6.6](../mdb-1066-rn/index), [MariaDB 10.5.14](../mdb-10514-rn/index), [MariaDB 10.4.23](../mdb-10423-rn/index), [MariaDB 10.3.33](../mdb-10333-rn/index), [MariaDB 10.2.42](../mdb-10242-rn/index) * [CVE-2021-46669](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46669): [MariaDB 10.7.4](../mdb-1074-rn/index), [MariaDB 10.6.8](../mdb-1068-rn/index), [MariaDB 10.5.16](../mdb-10516-rn/index), [MariaDB 10.4.25](../mdb-10425-rn/index), [MariaDB 10.3.35](../mdb-10335-rn/index), [MariaDB 10.2.44](../mdb-10244-rn/index) * [CVE-2021-46668](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46668): [MariaDB 10.7.3](../mdb-1073-rn/index), [MariaDB 10.6.7](../mdb-1067-rn/index), [MariaDB 10.5.15](../mdb-10515-rn/index), [MariaDB 10.4.24](../mdb-10424-rn/index), [MariaDB 10.3.34](../mdb-10334-rn/index), [MariaDB 10.2.43](../mdb-10243-rn/index) * [CVE-2021-46667](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46667): [MariaDB 10.6.5](../mdb-1065-rn/index), [MariaDB 10.5.13](../mdb-10513-rn/index), [MariaDB 10.4.22](../mdb-10422-rn/index), [MariaDB 10.3.32](../mdb-10332-rn/index), [MariaDB 10.2.41](../mdb-10241-rn/index) * [CVE-2021-46666](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46666): [MariaDB 10.5.11](../mdb-10511-rn/index), [MariaDB 10.4.20](../mdb-10420-rn/index), [MariaDB 10.3.30](../mdb-10330-rn/index), [MariaDB 10.2.39](../mdb-10239-rn/index) * [CVE-2021-46665](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46665): [MariaDB 10.7.3](../mdb-1073-rn/index), [MariaDB 10.6.7](../mdb-1067-rn/index), [MariaDB 10.5.15](../mdb-10515-rn/index), [MariaDB 10.4.24](../mdb-10424-rn/index), [MariaDB 10.3.34](../mdb-10334-rn/index), [MariaDB 10.2.43](../mdb-10243-rn/index) * [CVE-2021-46664](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46664): [MariaDB 10.7.3](../mdb-1073-rn/index), [MariaDB 10.6.7](../mdb-1067-rn/index), [MariaDB 10.5.15](../mdb-10515-rn/index), [MariaDB 10.4.24](../mdb-10424-rn/index), [MariaDB 10.3.34](../mdb-10334-rn/index), [MariaDB 10.2.43](../mdb-10243-rn/index) * [CVE-2021-46663](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46663): [MariaDB 10.7.3](../mdb-1073-rn/index), [MariaDB 10.6.7](../mdb-1067-rn/index), [MariaDB 10.5.15](../mdb-10515-rn/index), [MariaDB 10.4.24](../mdb-10424-rn/index), [MariaDB 10.3.34](../mdb-10334-rn/index), [MariaDB 10.2.43](../mdb-10243-rn/index) * [CVE-2021-46662](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46662): [MariaDB 10.6.5](../mdb-1065-rn/index), [MariaDB 10.5.13](../mdb-10513-rn/index), [MariaDB 10.4.22](../mdb-10422-rn/index), [MariaDB 10.3.32](../mdb-10332-rn/index) * [CVE-2021-46661](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46661): [MariaDB 10.7.3](../mdb-1073-rn/index), [MariaDB 10.6.7](../mdb-1067-rn/index), [MariaDB 10.5.15](../mdb-10515-rn/index), [MariaDB 10.4.24](../mdb-10424-rn/index), [MariaDB 10.3.34](../mdb-10334-rn/index), [MariaDB 10.2.43](../mdb-10243-rn/index) * [CVE-2021-46659](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46659): [MariaDB 10.8.1](../mdb-1081-rn/index), [MariaDB 10.7.2](../mdb-1072-rn/index), [MariaDB 10.6.6](../mdb-1066-rn/index), [MariaDB 10.5.14](../mdb-10514-rn/index), [MariaDB 10.4.23](../mdb-10423-rn/index), [MariaDB 10.3.33](../mdb-10333-rn/index), [MariaDB 10.2.42](../mdb-10242-rn/index) * [CVE-2021-46658](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46658): [MariaDB 10.6.3](../mdb-1063-rn/index), [MariaDB 10.5.12](../mdb-10512-rn/index), [MariaDB 10.4.21](../mdb-10421-rn/index), [MariaDB 10.3.31](../mdb-10331-rn/index), [MariaDB 10.2.40](../mdb-10240-rn/index) * [CVE-2021-46657](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-46657): [MariaDB 10.5.11](../mdb-10511-rn/index), [MariaDB 10.4.20](../mdb-10420-rn/index), [MariaDB 10.3.30](../mdb-10330-rn/index), [MariaDB 10.2.39](../mdb-10239-rn/index) * [CVE-2021-35604](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-35604): [MariaDB 10.6.3](../mdb-1063-rn/index), [MariaDB 10.5.13](../mdb-10513-rn/index), [MariaDB 10.4.22](../mdb-10422-rn/index), [MariaDB 10.3.32](../mdb-10332-rn/index), [MariaDB 10.2.41](../mdb-10241-rn/index) * [CVE-2021-27928](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27928): [MariaDB 10.5.9](../mdb-1059-rn/index), [MariaDB 10.4.18](../mdb-10418-rn/index), [MariaDB 10.3.28](../mdb-10328-rn/index), [MariaDB 10.2.37](../mdb-10237-rn/index) * [CVE-2021-2389](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2389): [MariaDB 10.6.4](https://mariadb.com/kb/es/mariadb-1064-release-notes/) [[2](../mdb-1064-rn/index)], [MariaDB 10.5.12](../mdb-10512-rn/index), [MariaDB 10.4.21](../mdb-10421-rn/index), [MariaDB 10.3.31](../mdb-10331-rn/index), [MariaDB 10.2.40](../mdb-10240-rn/index) * [CVE-2021-2372](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2372): [MariaDB 10.6.4](https://mariadb.com/kb/es/mariadb-1064-release-notes/) [[2](../mdb-1064-rn/index)], [MariaDB 10.5.12](../mdb-10512-rn/index), [MariaDB 10.4.21](../mdb-10421-rn/index), [MariaDB 10.3.31](../mdb-10331-rn/index), [MariaDB 10.2.40](../mdb-10240-rn/index) * [CVE-2021-2194](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2194): [MariaDB 10.5.7](../mdb-1057-rn/index), [MariaDB 10.4.16](../mdb-10416-rn/index), [MariaDB 10.3.26](../mdb-10326-rn/index), [MariaDB 10.2.35](../mdb-10235-rn/index) * [CVE-2021-2180](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2180): [MariaDB 10.2.38](../mdb-10238-rn/index) * [CVE-2021-2174](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2174): [MariaDB 10.2.18](../mdb-10218-rn/index) * [CVE-2021-2166](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2166): [MariaDB 10.5.10](../mdb-10510-rn/index), [MariaDB 10.4.19](../mdb-10419-rn/index), [MariaDB 10.3.29](../mdb-10329-rn/index), [MariaDB 10.2.38](../mdb-10238-rn/index) * [CVE-2021-2154](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2154): [MariaDB 10.5.10](../mdb-10510-rn/index), [MariaDB 10.4.19](../mdb-10419-rn/index), [MariaDB 10.3.29](../mdb-10329-rn/index), [MariaDB 10.2.38](../mdb-10238-rn/index) * [CVE-2021-2144](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2144): [MariaDB 5.5.66](../mdb-5566-rn/index), [MariaDB 10.4.9](../mdb-1049-rn/index), [MariaDB 10.3.19](../mdb-10319-rn/index), [MariaDB 10.2.28](../mdb-10228-rn/index), [MariaDB 10.1.42](../mdb-10142-rn/index) * [CVE-2021-2032](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2032): [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) * [CVE-2021-2022](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2022): [MariaDB 10.5.5](../mdb-1055-rn/index), [MariaDB 10.4.14](../mdb-10414-rn/index), [MariaDB 10.3.24](../mdb-10324-rn/index), [MariaDB 10.2.33](../mdb-10233-rn/index), [MariaDB 10.1.46](../mdb-10146-rn/index) * [CVE-2021-2011](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2011): [MariaDB Connector/C 3.0.5](../mcc-305-rn/index), [MariaDB 5.5.61](../mdb-5561-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2021-2007](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-2007): [MariaDB Connector/C 3.1.3](../mcc-313-rn/index), [MariaDB 5.5.65](../mdb-5565-rn/index), [MariaDB 10.4.7](../mdb-1047-rn/index), [MariaDB 10.3.17](../mdb-10317-rn/index), [MariaDB 10.2.26](../mdb-10226-rn/index), [MariaDB 10.1.41](../mdb-10141-rn/index) * [CVE-2020-7221](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-7221): [MariaDB 10.4.12](../mdb-10412-rn/index) * [CVE-2020-2922](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-2922): [MariaDB Connector/C 3.1.3](../mcc-313-rn/index), [MariaDB 5.5.65](../mdb-5565-rn/index), [MariaDB 10.4.7](../mdb-1047-rn/index), [MariaDB 10.3.17](../mdb-10317-rn/index), [MariaDB 10.2.26](../mdb-10226-rn/index), [MariaDB 10.1.41](../mdb-10141-rn/index) * [CVE-2020-28912](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-28912): [MariaDB 10.5.7](../mdb-1057-rn/index), [MariaDB 10.4.16](../mdb-10416-rn/index), [MariaDB 10.3.26](../mdb-10326-rn/index), [MariaDB 10.2.35](../mdb-10235-rn/index), [MariaDB 10.1.48](../mdb-10148-rn/index) * [CVE-2020-2814](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-2814): [MariaDB 10.4.13](../mdb-10413-rn/index), [MariaDB 10.3.23](../mdb-10323-rn/index), [MariaDB 10.2.32](../mdb-10232-rn/index), [MariaDB 10.1.45](../mdb-10145-rn/index) * [CVE-2020-2812](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-2812): [MariaDB 5.5.68](../mdb-5568-rn/index), [MariaDB 10.4.13](../mdb-10413-rn/index), [MariaDB 10.3.23](../mdb-10323-rn/index), [MariaDB 10.2.32](../mdb-10232-rn/index), [MariaDB 10.1.45](../mdb-10145-rn/index) * [CVE-2020-2780](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-2780): [MariaDB 5.5.66](../mdb-5566-rn/index), [MariaDB 10.4.9](../mdb-1049-rn/index), [MariaDB 10.3.19](../mdb-10319-rn/index), [MariaDB 10.2.28](../mdb-10228-rn/index), [MariaDB 10.1.42](../mdb-10142-rn/index) * [CVE-2020-2760](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-2760): [MariaDB 10.4.13](../mdb-10413-rn/index), [MariaDB 10.3.23](../mdb-10323-rn/index), [MariaDB 10.2.32](../mdb-10232-rn/index) * [CVE-2020-2752](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-2752): [MariaDB Connector/C 3.1.8](../mcc-318-rn/index), [MariaDB 5.5.68](../mdb-5568-rn/index), [MariaDB 10.4.13](../mdb-10413-rn/index), [MariaDB 10.3.23](../mdb-10323-rn/index), [MariaDB 10.2.32](../mdb-10232-rn/index), [MariaDB 10.1.45](../mdb-10145-rn/index) * [CVE-2020-2574](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-2574): [MariaDB Connector/C 3.1.7](../mcc-317-rn/index), [MariaDB 5.5.67](../mdb-5567-rn/index), [MariaDB 10.4.12](../mdb-10412-rn/index), [MariaDB 10.3.22](../mdb-10322-rn/index), [MariaDB 10.2.31](../mdb-10231-rn/index), [MariaDB 10.1.44](../mdb-10144-rn/index) * [CVE-2020-15180](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15180): [MariaDB 10.5.6](../mdb-1056-rn/index), [MariaDB 10.4.15](../mdb-10415-rn/index), [MariaDB 10.3.25](../mdb-10325-rn/index), [MariaDB 10.2.34](../mdb-10234-rn/index), [MariaDB 10.1.47](../mdb-10147-rn/index) * [CVE-2020-14812](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14812): [MariaDB 10.5.7](../mdb-1057-rn/index), [MariaDB 10.4.16](../mdb-10416-rn/index), [MariaDB 10.3.26](../mdb-10326-rn/index), [MariaDB 10.2.35](../mdb-10235-rn/index), [MariaDB 10.1.48](../mdb-10148-rn/index) * [CVE-2020-14789](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14789): [MariaDB 10.5.7](../mdb-1057-rn/index), [MariaDB 10.4.16](../mdb-10416-rn/index), [MariaDB 10.3.26](../mdb-10326-rn/index), [MariaDB 10.2.35](../mdb-10235-rn/index) * [CVE-2020-14776](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14776): [MariaDB 10.5.7](../mdb-1057-rn/index), [MariaDB 10.4.16](../mdb-10416-rn/index), [MariaDB 10.3.26](../mdb-10326-rn/index), [MariaDB 10.2.35](../mdb-10235-rn/index) * [CVE-2020-14765](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14765): [MariaDB 10.5.7](../mdb-1057-rn/index), [MariaDB 10.4.16](../mdb-10416-rn/index), [MariaDB 10.3.26](../mdb-10326-rn/index), [MariaDB 10.2.35](../mdb-10235-rn/index), [MariaDB 10.1.48](../mdb-10148-rn/index) * [CVE-2020-14550](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14550): [MariaDB Connector/C 3.0.5](../mcc-305-rn/index), [MariaDB 5.5.61](../mdb-5561-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2020-13249](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-13249): [MariaDB Connector/C 3.1.8](../mcc-318-rn/index), [MariaDB 10.4.13](../mdb-10413-rn/index), [MariaDB 10.3.23](../mdb-10323-rn/index), [MariaDB 10.2.32](../mdb-10232-rn/index) * [CVE-2019-2974](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2974): [MariaDB 5.5.66](../mdb-5566-rn/index), [MariaDB 10.4.9](../mdb-1049-rn/index), [MariaDB 10.3.19](../mdb-10319-rn/index), [MariaDB 10.2.28](../mdb-10228-rn/index), [MariaDB 10.1.42](../mdb-10142-rn/index) * [CVE-2019-2938](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2938): [MariaDB 10.4.9](../mdb-1049-rn/index), [MariaDB 10.3.19](../mdb-10319-rn/index), [MariaDB 10.2.28](../mdb-10228-rn/index) * [CVE-2019-2805](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2805): [MariaDB 5.5.65](../mdb-5565-rn/index), [MariaDB 10.4.7](../mdb-1047-rn/index), [MariaDB 10.3.17](../mdb-10317-rn/index), [MariaDB 10.2.26](../mdb-10226-rn/index), [MariaDB 10.1.41](../mdb-10141-rn/index) * [CVE-2019-2758](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2758): [MariaDB 10.4.7](../mdb-1047-rn/index), [MariaDB 10.3.17](../mdb-10317-rn/index), [MariaDB 10.2.26](../mdb-10226-rn/index) * [CVE-2019-2740](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2740): [MariaDB 5.5.65](../mdb-5565-rn/index), [MariaDB 10.4.7](../mdb-1047-rn/index), [MariaDB 10.3.17](../mdb-10317-rn/index), [MariaDB 10.2.26](../mdb-10226-rn/index), [MariaDB 10.1.41](../mdb-10141-rn/index) * [CVE-2019-2739](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2739): [MariaDB 5.5.65](../mdb-5565-rn/index), [MariaDB 10.4.7](../mdb-1047-rn/index), [MariaDB 10.3.17](../mdb-10317-rn/index), [MariaDB 10.2.26](../mdb-10226-rn/index), [MariaDB 10.1.41](../mdb-10141-rn/index) * [CVE-2019-2737](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2737): [MariaDB 5.5.65](../mdb-5565-rn/index), [MariaDB 10.4.7](../mdb-1047-rn/index), [MariaDB 10.3.17](../mdb-10317-rn/index), [MariaDB 10.2.26](../mdb-10226-rn/index), [MariaDB 10.1.41](../mdb-10141-rn/index) * [CVE-2019-2628](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2628): [MariaDB 10.4.5](../mdb-1045-rn/index), [MariaDB 10.3.15](../mdb-10315-rn/index), [MariaDB 10.2.24](../mdb-10224-rn/index) * [CVE-2019-2627](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2627): [MariaDB 5.5.64](../mdb-5564-rn/index), [MariaDB 10.4.5](../mdb-1045-rn/index), [MariaDB 10.3.15](../mdb-10315-rn/index), [MariaDB 10.2.24](../mdb-10224-rn/index), [MariaDB 10.1.39](../mdb-10139-rn/index) * [CVE-2019-2614](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2614): [MariaDB 5.5.64](../mdb-5564-rn/index), [MariaDB 10.4.5](../mdb-1045-rn/index), [MariaDB 10.3.15](../mdb-10315-rn/index), [MariaDB 10.2.24](../mdb-10224-rn/index), [MariaDB 10.1.39](../mdb-10139-rn/index) * [CVE-2019-2537](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2537): [MariaDB 10.3.13](../mdb-10313-rn/index), [MariaDB 10.2.22](../mdb-10222-rn/index), [MariaDB 10.1.38](../mdb-10138-rn/index), [MariaDB 10.0.38](../mdb-10038-rn/index) * [CVE-2019-2529](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2529): [MariaDB 5.5.63](../mdb-5563-rn/index), [MariaDB 10.1.38](../mdb-10138-rn/index), [MariaDB 10.0.38](../mdb-10038-rn/index) * [CVE-2019-2510](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2510): [MariaDB 10.3.13](../mdb-10313-rn/index), [MariaDB 10.2.22](../mdb-10222-rn/index) * [CVE-2019-2503](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2503): [MariaDB 5.5.62](../mdb-5562-rn/index), [MariaDB 10.3.10](../mdb-10310-rn/index), [MariaDB 10.2.18](../mdb-10218-rn/index), [MariaDB 10.1.36](../mdb-10136-rn/index), [MariaDB 10.0.37](../mdb-10037-rn/index) * [CVE-2019-2481](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2481): [MariaDB 5.5.37](https://mariadb.com/kb/en/mariadb-5537-release-notes/), [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) * [CVE-2019-2455](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-2455): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-3284](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3284): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index) * [CVE-2018-3282](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3282): [MariaDB 5.5.62](../mdb-5562-rn/index), [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index), [MariaDB 10.1.37](../mdb-10137-rn/index), [MariaDB 10.0.37](../mdb-10037-rn/index) * [CVE-2018-3277](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3277): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index) * [CVE-2018-3251](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3251): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index), [MariaDB 10.1.37](../mdb-10137-rn/index), [MariaDB 10.0.37](../mdb-10037-rn/index) * [CVE-2018-3200](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3200): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index) * [CVE-2018-3185](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3185): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index) * [CVE-2018-3174](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3174): [MariaDB 5.5.62](../mdb-5562-rn/index), [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index), [MariaDB 10.1.37](../mdb-10137-rn/index), [MariaDB 10.0.37](../mdb-10037-rn/index) * [CVE-2018-3173](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3173): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index) * [CVE-2018-3162](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3162): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index) * [CVE-2018-3156](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3156): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index), [MariaDB 10.1.37](../mdb-10137-rn/index), [MariaDB 10.0.37](../mdb-10037-rn/index) * [CVE-2018-3143](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3143): [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index), [MariaDB 10.1.37](../mdb-10137-rn/index), [MariaDB 10.0.37](../mdb-10037-rn/index) * [CVE-2018-3133](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3133): [MariaDB 5.5.59](../mdb-5559-rn/index), [MariaDB 10.2.12](../mdb-10212-rn/index), [MariaDB 10.1.30](../mdb-10130-rn/index), [MariaDB 10.0.34](../mdb-10034-rn/index) * [CVE-2018-3081](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3081): [MariaDB Connector/C 3.0.5](../mcc-305-rn/index), [MariaDB Connector/C 2.3.7](../mcc-237-rn/index) [[2](../mcc-237-cl/index)], [MariaDB 5.5.61](../mdb-5561-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-3066](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3066): [MariaDB 5.5.61](../mdb-5561-rn/index), [MariaDB 10.3.9](../mdb-1039-rn/index), [MariaDB 10.2.17](../mdb-10217-rn/index), [MariaDB 10.1.35](../mdb-10135-rn/index), [MariaDB 10.0.36](../mdb-10036-rn/index) * [CVE-2018-3064](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3064): [MariaDB 10.3.9](../mdb-1039-rn/index), [MariaDB 10.2.17](../mdb-10217-rn/index), [MariaDB 10.1.35](../mdb-10135-rn/index), [MariaDB 10.0.36](../mdb-10036-rn/index) * [CVE-2018-3063](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3063): [MariaDB 5.5.61](../mdb-5561-rn/index), [MariaDB 10.3.9](../mdb-1039-rn/index), [MariaDB 10.2.17](../mdb-10217-rn/index), [MariaDB 10.1.35](../mdb-10135-rn/index), [MariaDB 10.0.36](../mdb-10036-rn/index) * [CVE-2018-3060](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3060): [MariaDB 10.3.9](../mdb-1039-rn/index), [MariaDB 10.2.17](../mdb-10217-rn/index) * [CVE-2018-3058](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-3058): [MariaDB 5.5.61](../mdb-5561-rn/index), [MariaDB 10.3.9](../mdb-1039-rn/index), [MariaDB 10.2.17](../mdb-10217-rn/index), [MariaDB 10.1.35](../mdb-10135-rn/index), [MariaDB 10.0.36](../mdb-10036-rn/index) * [CVE-2018-2819](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2819): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2817](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2817): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2813](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2813): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2810](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2810): [MariaDB 10.2.15](../mdb-10215-rn/index) * [CVE-2018-2787](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2787): [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2786](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2786): [MariaDB 10.2.15](../mdb-10215-rn/index) * [CVE-2018-2784](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2784): [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2782](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2782): [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2781](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2781): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2777](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2777): [MariaDB 10.2.15](../mdb-10215-rn/index) * [CVE-2018-2771](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2771): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2767](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2767): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2766](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2766): [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2761](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2761): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2759](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2759): [MariaDB 10.2.15](../mdb-10215-rn/index) * [CVE-2018-2755](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2755): [MariaDB 5.5.60](../mdb-5560-rn/index), [MariaDB 10.2.15](../mdb-10215-rn/index), [MariaDB 10.1.33](../mdb-10133-rn/index), [MariaDB 10.0.35](../mdb-10035-rn/index) * [CVE-2018-2668](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2668): [MariaDB 5.5.59](../mdb-5559-rn/index), [MariaDB 10.2.13](../mdb-10213-rn/index), [MariaDB 10.1.31](../mdb-10131-rn/index), [MariaDB 10.0.34](../mdb-10034-rn/index) * [CVE-2018-2665](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2665): [MariaDB 5.5.59](../mdb-5559-rn/index), [MariaDB 10.2.13](../mdb-10213-rn/index), [MariaDB 10.1.31](../mdb-10131-rn/index), [MariaDB 10.0.34](../mdb-10034-rn/index) * [CVE-2018-2640](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2640): [MariaDB 5.5.59](../mdb-5559-rn/index), [MariaDB 10.2.13](../mdb-10213-rn/index), [MariaDB 10.1.31](../mdb-10131-rn/index), [MariaDB 10.0.34](../mdb-10034-rn/index) * [CVE-2018-2622](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2622): [MariaDB 5.5.59](../mdb-5559-rn/index), [MariaDB 10.2.13](../mdb-10213-rn/index), [MariaDB 10.1.31](../mdb-10131-rn/index), [MariaDB 10.0.34](../mdb-10034-rn/index) * [CVE-2018-2612](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2612): [MariaDB 10.2.13](../mdb-10213-rn/index), [MariaDB 10.1.31](../mdb-10131-rn/index), [MariaDB 10.0.34](../mdb-10034-rn/index) * [CVE-2018-2562](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-2562): [MariaDB 5.5.59](../mdb-5559-rn/index), [MariaDB 10.2.13](../mdb-10213-rn/index), [MariaDB 10.1.31](../mdb-10131-rn/index), [MariaDB 10.0.34](../mdb-10034-rn/index) * [CVE-2018-25032](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-25032): [MariaDB Connector/C 3.3.1](../mcc-331-rn/index), [MariaDB Connector/C 3.2.7](../mcc-327-rn/index), [MariaDB Connector/C 3.1.17](../mcc-3117-rn/index), [MariaDB 10.9.2](../mdb-1092-rn/index), [MariaDB 10.8.4](../mdb-1084-rn/index), [MariaDB 10.7.5](../mdb-1075-rn/index), [MariaDB 10.6.9](../mdb-1069-rn/index), [MariaDB 10.5.17](../mdb-10517-rn/index), [MariaDB 10.4.26](../mdb-10426-rn/index), [MariaDB 10.3.36](../mdb-10336-rn/index) * [CVE-2017-3653](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3653): [MariaDB 5.5.57](../mdb-5557-rn/index), [MariaDB 10.2.8](../mdb-1028-rn/index), [MariaDB 10.1.26](../mdb-10126-rn/index), [MariaDB 10.0.32](../mdb-10032-rn/index) * [CVE-2017-3651](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3651): [MariaDB 5.5.53](../mdb-5553-rn/index), [MariaDB 10.1.19](../mdb-10119-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2017-3641](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3641): [MariaDB 5.5.57](../mdb-5557-rn/index), [MariaDB 10.2.8](../mdb-1028-rn/index), [MariaDB 10.1.26](../mdb-10126-rn/index), [MariaDB 10.0.32](../mdb-10032-rn/index) * [CVE-2017-3636](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3636): [MariaDB 5.5.57](../mdb-5557-rn/index), [MariaDB 10.2.8](../mdb-1028-rn/index), [MariaDB 10.1.26](../mdb-10126-rn/index), [MariaDB 10.0.32](../mdb-10032-rn/index) * [CVE-2017-3600](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3600): [MariaDB 5.5.53](../mdb-5553-rn/index), [MariaDB 10.1.19](../mdb-10119-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2017-3464](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3464): [MariaDB 5.5.55](../mdb-5555-rn/index), [MariaDB 10.2.6](../mdb-1026-rn/index), [MariaDB 10.1.23](../mdb-10123-rn/index), [MariaDB 10.0.31](../mdb-10031-rn/index) * [CVE-2017-3456](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3456): [MariaDB 5.5.55](../mdb-5555-rn/index), [MariaDB 10.2.6](../mdb-1026-rn/index), [MariaDB 10.1.23](../mdb-10123-rn/index), [MariaDB 10.0.31](../mdb-10031-rn/index) * [CVE-2017-3453](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3453): [MariaDB 5.5.55](../mdb-5555-rn/index), [MariaDB 10.2.6](../mdb-1026-rn/index), [MariaDB 10.1.23](../mdb-10123-rn/index), [MariaDB 10.0.31](../mdb-10031-rn/index) * [CVE-2017-3318](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3318): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3317](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3317): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3313](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3313): [MariaDB 5.5.55](../mdb-5555-rn/index), [MariaDB 10.2.5](../mdb-1025-rn/index), [MariaDB 10.1.22](../mdb-10122-rn/index), [MariaDB 10.0.30](../mdb-10030-rn/index) * [CVE-2017-3312](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3312): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3309](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3309): [MariaDB 5.5.55](../mdb-5555-rn/index), [MariaDB 10.2.6](../mdb-1026-rn/index), [MariaDB 10.1.23](../mdb-10123-rn/index), [MariaDB 10.0.31](../mdb-10031-rn/index) * [CVE-2017-3308](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3308): [MariaDB 5.5.55](../mdb-5555-rn/index), [MariaDB 10.2.6](../mdb-1026-rn/index), [MariaDB 10.1.23](../mdb-10123-rn/index), [MariaDB 10.0.31](../mdb-10031-rn/index) * [CVE-2017-3302](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3302): [MariaDB 5.5.55](../mdb-5555-rn/index), [MariaDB 10.2.5](../mdb-1025-rn/index), [MariaDB 10.1.22](../mdb-10122-rn/index), [MariaDB 10.0.30](../mdb-10030-rn/index) * [CVE-2017-3291](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3291): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3265](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3265): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3258](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3258): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3257](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3257): [MariaDB 10.2.8](../mdb-1028-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3244](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3244): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3243](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3243): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-3238](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3238): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2017-15365](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-15365): [MariaDB 10.2.10](../mdb-10210-rn/index), [MariaDB 10.1.30](../mdb-10130-rn/index) * [CVE-2017-10384](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-10384): [MariaDB 5.5.57](../mdb-5557-rn/index), [MariaDB 10.2.8](../mdb-1028-rn/index), [MariaDB 10.1.26](../mdb-10126-rn/index), [MariaDB 10.0.32](../mdb-10032-rn/index) * [CVE-2017-10379](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-10379): [MariaDB 5.5.57](../mdb-5557-rn/index), [MariaDB 10.2.8](../mdb-1028-rn/index), [MariaDB 10.1.26](../mdb-10126-rn/index), [MariaDB 10.0.32](../mdb-10032-rn/index) * [CVE-2017-10378](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-10378): [MariaDB 5.5.58](../mdb-5558-rn/index), [MariaDB 10.2.10](../mdb-10210-rn/index), [MariaDB 10.1.29](../mdb-10129-rn/index), [MariaDB 10.0.33](../mdb-10033-rn/index) * [CVE-2017-10365](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-10365): [MariaDB 10.2.8](../mdb-1028-rn/index) * [CVE-2017-10320](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-10320): [MariaDB 10.2.8](../mdb-1028-rn/index) * [CVE-2017-10286](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-10286): [MariaDB 10.2.8](../mdb-1028-rn/index), [MariaDB 10.1.26](../mdb-10126-rn/index), [MariaDB 10.0.32](../mdb-10032-rn/index) * [CVE-2017-10268](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-10268): [MariaDB 5.5.58](../mdb-5558-rn/index), [MariaDB 10.2.10](../mdb-10210-rn/index), [MariaDB 10.1.29](../mdb-10129-rn/index), [MariaDB 10.0.33](../mdb-10033-rn/index) * [CVE-2016-9843](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-9843): [MariaDB 5.5.62](../mdb-5562-rn/index), [MariaDB 10.3.11](../mdb-10311-rn/index), [MariaDB 10.2.19](../mdb-10219-rn/index), [MariaDB 10.1.37](../mdb-10137-rn/index), [MariaDB 10.0.37](../mdb-10037-rn/index) * [CVE-2016-8283](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-8283): [MariaDB 5.5.52](../mdb-5552-rn/index), [MariaDB 10.1.18](../mdb-10118-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-7440](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7440): [MariaDB 5.5.53](../mdb-5553-rn/index), [MariaDB 10.1.19](../mdb-10119-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-6664](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6664): [MariaDB 5.5.54](../mdb-5554-rn/index), [MariaDB 10.1.21](../mdb-10121-rn/index), [MariaDB 10.0.29](../mdb-10029-rn/index) * [CVE-2016-6663](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6663): [MariaDB 5.5.52](../mdb-5552-rn/index), [MariaDB 10.1.18](../mdb-10118-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-6662](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6662): [MariaDB 5.5.51](../mdb-5551-rn/index), [MariaDB 10.1.17](../mdb-10117-rn/index), [MariaDB 10.0.27](../mdb-10027-rn/index) * [CVE-2016-5630](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5630): [MariaDB 10.0.27](../mdb-10027-rn/index) * [CVE-2016-5629](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5629): [MariaDB 5.5.52](../mdb-5552-rn/index), [MariaDB 10.1.18](../mdb-10118-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-5626](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5626): [MariaDB 5.5.52](../mdb-5552-rn/index), [MariaDB 10.1.18](../mdb-10118-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-5624](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5624): [MariaDB 5.5.52](../mdb-5552-rn/index), [MariaDB 10.1.18](../mdb-10118-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-5616](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5616): [MariaDB 5.5.52](../mdb-5552-rn/index), [MariaDB 10.1.18](../mdb-10118-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-5612](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5612): [MariaDB 5.5.51](../mdb-5551-rn/index), [MariaDB 10.0.27](../mdb-10027-rn/index) * [CVE-2016-5584](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5584): [MariaDB 5.5.53](../mdb-5553-rn/index), [MariaDB 10.1.19](../mdb-10119-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-5483](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5483): [MariaDB 5.5.53](../mdb-5553-rn/index), [MariaDB 10.1.19](../mdb-10119-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-5444](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5444): [MariaDB 5.5.49](../mdb-5549-rn/index), [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-5440](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5440): [MariaDB 5.5.50](../mdb-5550-rn/index), [MariaDB 10.1.15](../mdb-10115-rn/index), [MariaDB 10.0.26](../mdb-10026-rn/index) * [CVE-2016-3615](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3615): [MariaDB 5.5.50](../mdb-5550-rn/index), [MariaDB 10.1.15](../mdb-10115-rn/index), [MariaDB 10.0.26](../mdb-10026-rn/index) * [CVE-2016-3521](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3521): [MariaDB 5.5.50](../mdb-5550-rn/index), [MariaDB 10.1.15](../mdb-10115-rn/index), [MariaDB 10.0.26](../mdb-10026-rn/index) * [CVE-2016-3492](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3492): [MariaDB 5.5.52](../mdb-5552-rn/index), [MariaDB 10.1.18](../mdb-10118-rn/index), [MariaDB 10.0.28](../mdb-10028-rn/index) * [CVE-2016-3477](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3477): [MariaDB 5.5.50](../mdb-5550-rn/index), [MariaDB 10.1.15](../mdb-10115-rn/index), [MariaDB 10.0.26](../mdb-10026-rn/index) * [CVE-2016-3471](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3471): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2016-3459](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3459): [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-3452](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3452): [MariaDB 5.5.49](../mdb-5549-rn/index), [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-2047](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-2047): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0668](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0668): [MariaDB 10.1.12](../mdb-10112-rn/index), [MariaDB 10.0.24](../mdb-10024-rn/index) * [CVE-2016-0666](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0666): [MariaDB 5.5.49](../mdb-5549-rn/index), [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-0655](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0655): [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-0651](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0651): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0650](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0650): [MariaDB 5.5.48](../mdb-5548-rn/index), [MariaDB 10.1.12](../mdb-10112-rn/index), [MariaDB 10.0.24](../mdb-10024-rn/index) * [CVE-2016-0649](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0649): [MariaDB 5.5.48](../mdb-5548-rn/index), [MariaDB 10.1.12](../mdb-10112-rn/index), [MariaDB 10.0.24](../mdb-10024-rn/index) * [CVE-2016-0648](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0648): [MariaDB 5.5.49](../mdb-5549-rn/index), [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-0647](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0647): [MariaDB 5.5.49](../mdb-5549-rn/index), [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-0646](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0646): [MariaDB 5.5.48](../mdb-5548-rn/index), [MariaDB 10.1.12](../mdb-10112-rn/index), [MariaDB 10.0.24](../mdb-10024-rn/index) * [CVE-2016-0644](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0644): [MariaDB 5.5.48](../mdb-5548-rn/index), [MariaDB 10.1.12](../mdb-10112-rn/index), [MariaDB 10.0.24](../mdb-10024-rn/index) * [CVE-2016-0643](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0643): [MariaDB 5.5.49](../mdb-5549-rn/index), [MariaDB 10.1.14](../mdb-10114-rn/index), [MariaDB 10.0.25](../mdb-10025-rn/index) * [CVE-2016-0642](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0642): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0641](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0641): [MariaDB 5.5.48](../mdb-5548-rn/index), [MariaDB 10.1.12](../mdb-10112-rn/index), [MariaDB 10.0.24](../mdb-10024-rn/index) * [CVE-2016-0640](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0640): [MariaDB 5.5.48](../mdb-5548-rn/index), [MariaDB 10.1.12](../mdb-10112-rn/index), [MariaDB 10.0.24](../mdb-10024-rn/index) * [CVE-2016-0616](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0616): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0610](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0610): [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2016-0609](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0609): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0608](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0608): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0606](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0606): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0600](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0600): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0598](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0598): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0597](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0597): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0596](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0596): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0546](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0546): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0505](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0505): [MariaDB 5.5.47](../mdb-5547-rn/index), [MariaDB 10.1.10](../mdb-10110-rn/index), [MariaDB 10.0.23](../mdb-10023-rn/index) * [CVE-2016-0502](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0502): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2015-7744](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-7744): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.9](https://mariadb.com/kb/en/mariadb-1019-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4913](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4913): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4895](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4895): [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.21](https://mariadb.com/kb/en/mariadb-10021-release-notes/) * [CVE-2015-4879](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4879): [MariaDB 5.5.45](https://mariadb.com/kb/en/mariadb-5545-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.21](https://mariadb.com/kb/en/mariadb-10021-release-notes/) * [CVE-2015-4870](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4870): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4866](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4866): [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-4864](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4864): [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * [CVE-2015-4861](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4861): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4858](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4858): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4836](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4836): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4830](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4830): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4826](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4826): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4819](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4819): [MariaDB 5.5.45](https://mariadb.com/kb/en/mariadb-5545-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.21](https://mariadb.com/kb/en/mariadb-10021-release-notes/) * [CVE-2015-4816](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4816): [MariaDB 5.5.45](https://mariadb.com/kb/en/mariadb-5545-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.21](https://mariadb.com/kb/en/mariadb-10021-release-notes/) * [CVE-2015-4815](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4815): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4807](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4807): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4802](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4802): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4792](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4792): [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/), [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/), [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * [CVE-2015-4757](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4757): [MariaDB 5.5.43](https://mariadb.com/kb/en/mariadb-5543-release-notes/), [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-4752](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4752): [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/), [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * [CVE-2015-3152](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3152): [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/), [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * [CVE-2015-2648](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2648): [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/), [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * [CVE-2015-2643](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2643): [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/), [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * [CVE-2015-2620](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2620): [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/), [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * [CVE-2015-2582](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2582): [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/), [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * [CVE-2015-2573](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2573): [MariaDB 5.5.42](https://mariadb.com/kb/en/mariadb-5542-release-notes/), [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) * [CVE-2015-2571](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2571): [MariaDB 5.5.43](https://mariadb.com/kb/en/mariadb-5543-release-notes/), [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-2568](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2568): [MariaDB 5.5.42](https://mariadb.com/kb/en/mariadb-5542-release-notes/), [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) * [CVE-2015-2326](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2326): [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-2325](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2325): [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-0505](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0505): [MariaDB 5.5.43](https://mariadb.com/kb/en/mariadb-5543-release-notes/), [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-0501](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0501): [MariaDB 5.5.43](https://mariadb.com/kb/en/mariadb-5543-release-notes/), [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-0499](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0499): [MariaDB 5.5.43](https://mariadb.com/kb/en/mariadb-5543-release-notes/), [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2015-0441](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0441): [MariaDB 5.5.42](https://mariadb.com/kb/en/mariadb-5542-release-notes/), [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) * [CVE-2015-0433](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0433): [MariaDB 5.5.42](https://mariadb.com/kb/en/mariadb-5542-release-notes/), [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) * [CVE-2015-0432](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0432): [MariaDB 5.5.41](https://mariadb.com/kb/en/mariadb-5541-release-notes/), [MariaDB 10.0.16](https://mariadb.com/kb/en/mariadb-10016-release-notes/) * [CVE-2015-0411](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0411): [MariaDB 5.5.41](https://mariadb.com/kb/en/mariadb-5541-release-notes/), [MariaDB 10.0.16](https://mariadb.com/kb/en/mariadb-10016-release-notes/) * [CVE-2015-0391](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0391): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2015-0382](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0382): [MariaDB 5.5.41](https://mariadb.com/kb/en/mariadb-5541-release-notes/), [MariaDB 10.0.16](https://mariadb.com/kb/en/mariadb-10016-release-notes/) * [CVE-2015-0381](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0381): [MariaDB 5.5.41](https://mariadb.com/kb/en/mariadb-5541-release-notes/), [MariaDB 10.0.16](https://mariadb.com/kb/en/mariadb-10016-release-notes/) * [CVE-2015-0374](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0374): [MariaDB 5.5.41](https://mariadb.com/kb/en/mariadb-5541-release-notes/), [MariaDB 10.0.16](https://mariadb.com/kb/en/mariadb-10016-release-notes/) * [CVE-2014-8964](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-8964): [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * [CVE-2014-6568](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6568): [MariaDB 5.5.41](https://mariadb.com/kb/en/mariadb-5541-release-notes/), [MariaDB 10.0.16](https://mariadb.com/kb/en/mariadb-10016-release-notes/) * [CVE-2014-6564](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6564): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6559](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6559): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6555](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6555): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6551](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6551): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6530](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6530): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6520](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6520): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6507](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6507): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6505](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6505): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6500](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6500): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6496](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6496): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6495](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6495): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6494](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6494): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6491](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6491): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6489](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6489): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6484](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6484): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6478](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6478): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6474](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6474): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-6469](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6469): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6464](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6464): [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/), [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * [CVE-2014-6463](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6463): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-4287](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4287): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-4274](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4274): [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/), [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-4260](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4260): [MariaDB 5.5.38](https://mariadb.com/kb/en/mariadb-5538-release-notes/), [MariaDB 10.0.12](https://mariadb.com/kb/en/mariadb-10012-release-notes/) * [CVE-2014-4258](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4258): [MariaDB 5.5.38](https://mariadb.com/kb/en/mariadb-5538-release-notes/), [MariaDB 10.0.12](https://mariadb.com/kb/en/mariadb-10012-release-notes/) * [CVE-2014-4243](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4243): [MariaDB 5.5.36](https://mariadb.com/kb/en/mariadb-5536-release-notes/), [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/) * [CVE-2014-4207](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4207): [MariaDB 5.5.38](https://mariadb.com/kb/en/mariadb-5538-release-notes/), [MariaDB 10.0.12](https://mariadb.com/kb/en/mariadb-10012-release-notes/) * [CVE-2014-3470](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3470): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-2494](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2494): [MariaDB 5.5.38](https://mariadb.com/kb/en/mariadb-5538-release-notes/), [MariaDB 10.0.12](https://mariadb.com/kb/en/mariadb-10012-release-notes/) * [CVE-2014-2440](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2440): [MariaDB 5.5.37](https://mariadb.com/kb/en/mariadb-5537-release-notes/), [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) * [CVE-2014-2438](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2438): [MariaDB 5.5.36](https://mariadb.com/kb/en/mariadb-5536-release-notes/), [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/) * [CVE-2014-2436](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2436): [MariaDB 5.5.37](https://mariadb.com/kb/en/mariadb-5537-release-notes/), [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) * [CVE-2014-2432](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2432): [MariaDB 5.5.36](https://mariadb.com/kb/en/mariadb-5536-release-notes/), [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/) * [CVE-2014-2431](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2431): [MariaDB 5.5.37](https://mariadb.com/kb/en/mariadb-5537-release-notes/), [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) * [CVE-2014-2430](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2430): [MariaDB 5.5.37](https://mariadb.com/kb/en/mariadb-5537-release-notes/), [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) * [CVE-2014-2419](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2419): [MariaDB 5.5.36](https://mariadb.com/kb/en/mariadb-5536-release-notes/), [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/) * [CVE-2014-0437](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0437): [MariaDB 5.5.35](https://mariadb.com/kb/en/mariadb-5535-release-notes/), [MariaDB 10.0.8](https://mariadb.com/kb/en/mariadb-1008-release-notes/) * [CVE-2014-0420](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0420): [MariaDB 5.5.35](https://mariadb.com/kb/en/mariadb-5535-release-notes/), [MariaDB 10.0.8](https://mariadb.com/kb/en/mariadb-1008-release-notes/) * [CVE-2014-0412](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0412): [MariaDB 5.5.35](https://mariadb.com/kb/en/mariadb-5535-release-notes/), [MariaDB 10.0.8](https://mariadb.com/kb/en/mariadb-1008-release-notes/) * [CVE-2014-0402](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0402): [MariaDB 5.5.34](https://mariadb.com/kb/en/mariadb-5534-release-notes/), [MariaDB 10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/) * [CVE-2014-0401](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0401): [MariaDB 5.5.35](https://mariadb.com/kb/en/mariadb-5535-release-notes/), [MariaDB 10.0.8](https://mariadb.com/kb/en/mariadb-1008-release-notes/) * [CVE-2014-0393](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0393): [MariaDB 5.5.34](https://mariadb.com/kb/en/mariadb-5534-release-notes/), [MariaDB 10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/) * [CVE-2014-0386](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0386): [MariaDB 5.5.34](https://mariadb.com/kb/en/mariadb-5534-release-notes/), [MariaDB 10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/) * [CVE-2014-0384](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0384): [MariaDB 5.5.36](https://mariadb.com/kb/en/mariadb-5536-release-notes/), [MariaDB 10.0.9](https://mariadb.com/kb/en/mariadb-1009-release-notes/) * [CVE-2014-0224](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0224): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-0221](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0221): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-0198](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0198): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2014-0195](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0195): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2013-5908](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5908): [MariaDB 5.5.35](https://mariadb.com/kb/en/mariadb-5535-release-notes/), [MariaDB 10.0.8](https://mariadb.com/kb/en/mariadb-1008-release-notes/) * [CVE-2013-5891](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5891): [MariaDB 5.5.34](https://mariadb.com/kb/en/mariadb-5534-release-notes/), [MariaDB 10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/) * [CVE-2013-5807](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5807): [MariaDB 5.5.33](https://mariadb.com/kb/en/mariadb-5533-release-notes/), [MariaDB 10.0.5](https://mariadb.com/kb/en/mariadb-1005-release-notes/) * [CVE-2013-3839](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3839): [MariaDB 5.5.33](https://mariadb.com/kb/en/mariadb-5533-release-notes/), [MariaDB 10.0.5](https://mariadb.com/kb/en/mariadb-1005-release-notes/) * [CVE-2013-3812](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3812): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2013-3809](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3809): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2013-3808](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3808): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-3805](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3805): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-3804](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3804): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2013-3802](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3802): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2013-3801](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3801): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-3794](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3794): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-3793](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3793): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2013-3783](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3783): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2013-2392](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-2392): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-2391](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-2391): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-2389](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-2389): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-2378](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-2378): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-2376](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-2376): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-2375](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-2375): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-1861](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1861): [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), [MariaDB 10.0.4](https://mariadb.com/kb/en/mariadb-1004-release-notes/) * [CVE-2013-1555](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1555): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-1552](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1552): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-1548](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1548): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2013-1544](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1544): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-1532](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1532): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-1531](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1531): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-1526](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1526): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-1523](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1523): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-1521](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1521): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-1512](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1512): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-1511](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1511): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-1506](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1506): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2013-1502](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1502): [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), [MariaDB 10.0.3](https://mariadb.com/kb/en/mariadb-1003-release-notes/) * [CVE-2013-0389](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0389): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-0386](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0386): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-0385](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0385): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-0384](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0384): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-0383](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0383): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-0375](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0375): [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/) * [CVE-2013-0371](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0371): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-0368](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0368): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2013-0367](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-0367): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-5627](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5627): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5529-changelog/)], [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5312-changelog/)], [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5214-changelog/)], [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-5615](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5615): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5529-changelog/)], [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5312-changelog/)], [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5214-changelog/)], [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-5614](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5614): [MariaDB 5.5.30](https://mariadb.com/kb/en/mariadb-5530-release-notes/), [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) * [CVE-2012-5612](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5612): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5529-changelog/)], [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-5611](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5611): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.5.28](https://mariadb.com/kb/en/mariadb-5528a-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.3.11](https://mariadb.com/kb/en/mariadb-5311-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.2.13](https://mariadb.com/kb/en/mariadb-5213-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-5096](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5096): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-5060](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-5060): [MariaDB 5.5.28](https://mariadb.com/kb/en/mariadb-5528-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-4414](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-4414): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5527-changelog/)], [MariaDB 5.3.8](https://mariadb.com/kb/en/mariadb-538-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-538-changelog/)], [MariaDB 5.2.13](https://mariadb.com/kb/en/mariadb-5213-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5213-changelog/)], [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-5166-changelog/)], [MariaDB 10.0.0](https://mariadb.com/kb/en/mariadb-1000-release-notes/) [[2](https://mariadb.com/kb/en/mariadb-1000-changelog/)] * [CVE-2012-3197](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3197): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3180](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3180): [MariaDB 5.5.28](https://mariadb.com/kb/en/mariadb-5528-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3177](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3177): [MariaDB 5.5.28](https://mariadb.com/kb/en/mariadb-5528-release-notes/), [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3173](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3173): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3167](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3167): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3166](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3166): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3163](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3163): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3160](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3160): [MariaDB 5.5.28](https://mariadb.com/kb/en/mariadb-5528-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3158](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3158): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-3150](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-3150): [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-2750](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-2750): [MariaDB 5.5.23](https://mariadb.com/kb/en/mariadb-5523-release-notes/) * [CVE-2012-1757](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1757): [MariaDB 5.5.24](https://mariadb.com/kb/en/mariadb-5524-release-notes/) * [CVE-2012-1756](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1756): [MariaDB 5.5.24](https://mariadb.com/kb/en/mariadb-5524-release-notes/) * [CVE-2012-1735](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1735): [MariaDB 5.5.24](https://mariadb.com/kb/en/mariadb-5524-release-notes/) * [CVE-2012-1734](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1734): [MariaDB 5.5.24](https://mariadb.com/kb/en/mariadb-5524-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-1705](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1705): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-1703](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1703): [MariaDB 5.5.22](https://mariadb.com/kb/en/mariadb-5522-release-notes/), [MariaDB 5.1.62](https://mariadb.com/kb/en/mariadb-5162-release-notes/) * [CVE-2012-1702](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1702): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-1697](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1697): [MariaDB 5.5.22](https://mariadb.com/kb/en/mariadb-5522-release-notes/) * [CVE-2012-1690](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1690): [MariaDB 5.5.22](https://mariadb.com/kb/en/mariadb-5522-release-notes/), [MariaDB 5.1.62](https://mariadb.com/kb/en/mariadb-5162-release-notes/) * [CVE-2012-1689](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1689): [MariaDB 5.5.23](https://mariadb.com/kb/en/mariadb-5523-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2012-1688](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1688): [MariaDB 5.5.22](https://mariadb.com/kb/en/mariadb-5522-release-notes/), [MariaDB 5.1.62](https://mariadb.com/kb/en/mariadb-5162-release-notes/) * [CVE-2012-0578](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0578): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-0574](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0574): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-0572](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0572): [MariaDB 5.5.29](https://mariadb.com/kb/en/mariadb-5529-release-notes/), [MariaDB 5.3.12](https://mariadb.com/kb/en/mariadb-5312-release-notes/), [MariaDB 5.2.14](https://mariadb.com/kb/en/mariadb-5214-release-notes/), [MariaDB 5.1.67](https://mariadb.com/kb/en/mariadb-5167-release-notes/), [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) * [CVE-2012-0540](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0540): [MariaDB 5.5.24](https://mariadb.com/kb/en/mariadb-5524-release-notes/), [MariaDB 5.1.66](https://mariadb.com/kb/en/mariadb-5166-release-notes/) * [CVE-2010-5298](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-5298): [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * [CVE-2005-0004](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-0004): [MariaDB 5.5.66](../mdb-5566-cl/index) ### CVEs without specific version numbers: The following CVEs were fixed in [MariaDB 5.1](../what-is-mariadb-51/index) and/or [MariaDB 5.5](../what-is-mariadb-55/index) as indicated, but the fix is not tied to a specific MariaDB version. * [CVE-2012-0113](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0113): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2011-2262](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-2262): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0116](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0116): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0118](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0118): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0496](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0496): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0087](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0087): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.1](../what-is-mariadb-51/index) * [CVE-2012-0101](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0101): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.1](../what-is-mariadb-51/index) * [CVE-2012-0102](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0102): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.1](../what-is-mariadb-51/index) * [CVE-2012-0115](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0115): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0119](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0119): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0120](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0120): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0484](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0484): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0485](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0485): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0486](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0486): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0487](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0487): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0488](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0488): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0489](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0489): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0490](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0490): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0491](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0491): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0495](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0495): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0112](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0112): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0117](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0117): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0114](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0114): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0492](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0492): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0493](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0493): [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0075](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0075): [MariaDB 5.1](../what-is-mariadb-51/index), [MariaDB 5.5](../what-is-mariadb-55/index) * [CVE-2012-0494](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0494): [MariaDB 5.5](../what-is-mariadb-55/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb MariaDB ColumnStore software upgrade 1.0.5 to 1.0.6 MariaDB ColumnStore software upgrade 1.0.5 to 1.0.6 =================================================== MariaDB ColumnStore software upgrade 1.0.5 to 1.0.6 --------------------------------------------------- Note: Columnstore.xml modifications you manually made are not automatically carried forward on an upgrade. These modifications will need to be incorporated back into .XML once the upgrade has occurred. The previous configuration file will be saved as /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave. If you have specified a root database password (which is good practice), then you must configure a .my.cnf file with user credentials for the upgrade process to use. Create a .my.cnf file in the user home directory with 600 file permissions with the following content (updating PASSWORD as appropriate): ``` [mysqladmin] user = root password = PASSWORD ``` ### Choosing the type of upgrade #### Root User Installs #### Upgrading MariaDB ColumnStore using RPMs Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Download the package mariadb-columnstore-1.0.6-1-centos#.x86\_64.rpm.tar.gz to the PM1 server where you are installing MariaDB ColumnStore.** Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate a set of RPMs that will reside in the /root/ directory. `tar -zxf mariadb-columnstore-1.0.6-1-centos#.x86_64.rpm.tar.gz` * Upgrade the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. ``` rpm -e --nodeps $(rpm -qa | grep '^mariadb-columnstore') rpm -ivh mariadb-columnstore-*1.0.6*rpm ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml.rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` For RPM Upgrade, the previous configuration file will be saved as: /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /usr/local directory -mariadb-columnstore-1.0.6-1.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: `mcsadmin shutdownsystem y` * Run pre-uninstall script `/usr/local/mariadb/columnstore/bin/pre-uninstall` * Unpack the tarball, in the /usr/local/ directory. `tar -zxvf -mariadb-columnstore-1.0.6-1.x86_64.bin.tar.gz` * Run post-install scripts `/usr/local/mariadb/columnstore/bin/post-install` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave `/usr/local/mariadb/columnstore/bin/postConfigure -u` ### Upgrading MariaDB ColumnStore using the DEB package A DEB upgrade would be done on a system that supports DEBs like Debian or Ubuntu systems. Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /root directory ``` mariadb-columnstore-1.0.6-1.amd64.deb.tar.gz ``` (DEB 64-BIT) to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate DEBs. ``` tar -zxf mariadb-columnstore-1.0.6-1.amd64.deb.tar.gz ``` * Remove, purge and install all MariaDB ColumnStore debs ``` cd /root/ dpkg -r mariadb-columnstore*deb dpkg -P mariadb-columnstore*deb ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` /usr/local/mariadb/columnstore/bin/postConfigure -u ``` #### Non-Root User Installs ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /home/'non-root-user" directory mariadb-columnstore-1.0.6-1.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: `mcsadmin shutdownsystem y` * Run pre-uninstall script `$HOME/mariadb/columnstore/bin/pre-uninstall -i /home/guest/mariadb/columnstore` * Unpack the tarball, which will generate the $HOME/ directory. `tar -zxvf -mariadb-columnstore-1.0.6-1.x86_64.bin.tar.gz` * Run post-install scripts 1. $HOME/mariadb/columnstore/bin/post-install -i /home/guest/mariadb/columnstore * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave `$HOME/mariadb/columnstore/bin/postConfigure -u -i /home/guest/mariadb/columnstore` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb HeidiSQL HeidiSQL ======== [HeidiSQL](http://www.heidisql.com/) is a Windows client for MariaDB and MySQL, and is bundled with the Windows version of MariaDB. | HeidiSQL Version | Introduced | | --- | --- | | HeidiSQL 11.0 | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), [MariaDB 10.4.13](https://mariadb.com/kb/en/mariadb-10413-release-notes/), [MariaDB 10.3.23](https://mariadb.com/kb/en/mariadb-10323-release-notes/), [MariaDB 10.2.32](https://mariadb.com/kb/en/mariadb-10232-release-notes/), [MariaDB 10.1.45](https://mariadb.com/kb/en/mariadb-10145-release-notes/), [MariaDB 5.5.68](https://mariadb.com/kb/en/mariadb-5568-release-notes/) | | HeidiSQL 10.2 | [MariaDB 10.4.7](https://mariadb.com/kb/en/mariadb-1047-release-notes/), [MariaDB 10.3.17](https://mariadb.com/kb/en/mariadb-10317-release-notes/), [MariaDB 10.2.26](https://mariadb.com/kb/en/mariadb-10226-release-notes/), [MariaDB 10.1.41](https://mariadb.com/kb/en/mariadb-10141-release-notes/), [MariaDB 5.5.65](https://mariadb.com/kb/en/mariadb-5565-release-notes/) | | HeidiSQL 9.5 | [MariaDB 10.3.13](https://mariadb.com/kb/en/mariadb-10313-release-notes/), [MariaDB 10.2.22](https://mariadb.com/kb/en/mariadb-10222-release-notes/), [MariaDB 10.1.38](https://mariadb.com/kb/en/mariadb-10138-release-notes/), [MariaDB 10.0.38](https://mariadb.com/kb/en/mariadb-10038-release-notes/), [MariaDB 5.5.63](https://mariadb.com/kb/en/mariadb-5563-release-notes/) | | HeidiSQL 9.4 | [MariaDB 10.1.20](https://mariadb.com/kb/en/mariadb-10120-release-notes/), [MariaDB 10.0.29](https://mariadb.com/kb/en/mariadb-10029-release-notes/), [MariaDB 5.5.54](https://mariadb.com/kb/en/mariadb-5554-release-notes/) | | HeidiSQL 9.3 | [MariaDB 10.1.15](https://mariadb.com/kb/en/mariadb-10115-release-notes/), [MariaDB 10.0.26](https://mariadb.com/kb/en/mariadb-10026-release-notes/), [MariaDB 5.5.50](https://mariadb.com/kb/en/mariadb-5550-release-notes/) | | HeidiSQL 9.1 | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/), [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/), [MariaDB 5.5.42](https://mariadb.com/kb/en/mariadb-5542-release-notes/) | | HeidiSQL 8.3 | [MariaDB 10.0.12](https://mariadb.com/kb/en/mariadb-10012-release-notes/), [MariaDB 5.5.38](https://mariadb.com/kb/en/mariadb-5538-release-notes/) | | HeidiSQL 8.0 | [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/), [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/) | | HeidiSQL 7.0 | [MariaDB 10.0.0](https://mariadb.com/kb/en/mariadb-1000-release-notes/), [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | HeidiSQL can: * Connect to multiple servers in one window * Connect to servers via commandline * Create and edit tables, views, stored routines, triggers and scheduled events. * Generate nice SQL-exports * Export from one server/database directly to another server/database * Manage user-privileges * Import text-files * Export table rows as CSV, HTML, XML, SQL, LaTeX and Wiki Markup * Browse and edit table-data using a comfortable grid * Bulk edit tables (move to db, change engine, collation etc.) * Batch-insert ascii or binary files into tables * Write queries with customizable syntax-highlighting and code-completion * Pretty reformat disordered SQL * Monitor and kill client-processes * Find specific text in all tables of all databases of one server * Optimize and repair tables in a batch manner * And more... More information, including [Screenshots of HeidiSQL](http://www.heidisql.com/screenshots.php) are available at the [HeidiSQL Website](http://www.heidisql.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Source Configuration Options MariaDB Source Configuration Options ==================================== All CMake configuration options for MariaDB can be displayed with: ``` cmake . -LH ``` See Also -------- * [Get the Code, Build it, Test it](https://mariadb.org/get-involved/getting-started-for-developers/get-code-build-test/) (mariadb.org) * [Generic Build Instructions](../generic-build-instructions/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SQL_MODE SQL\_MODE ========= MariaDB supports several different modes which allow you to tune it to suit your needs. The most important ways for doing this are using `SQL_MODE` (controlled by the [sql\_mode](../server-system-variables/index#sql_mode) system variable) and [OLD\_MODE](../old_mode/index) (the [old\_mode](../server-system-variables/index#old_mode) system variable). `SQL_MODE` is used for getting MariaDB to emulate behavior from other SQL servers, while [OLD\_MODE](../old_mode/index) is used for emulating behavior from older MariaDB or MySQL versions. `SQL_MODE`is a string with different options separated by commas ('`,`') without spaces. The options are case insensitive. You can check the local and global value of it with: ``` SELECT @@SQL_MODE, @@GLOBAL.SQL_MODE; ``` Setting SQL\_MODE ----------------- ### Defaults | From version | Default sql\_mode setting | | --- | --- | | [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) | STRICT\_TRANS\_TABLES, ERROR\_FOR\_DIVISION\_BY\_ZERO , NO\_AUTO\_CREATE\_USER, NO\_ENGINE\_SUBSTITUTION | | [MariaDB 10.1.7](https://mariadb.com/kb/en/mariadb-1017-release-notes/) | NO\_ENGINE\_SUBSTITUTION, NO\_AUTO\_CREATE\_USER | | <= [MariaDB 10.1.6](https://mariadb.com/kb/en/mariadb-1016-release-notes/) | No value | You can set the `SQL\_MODE` either from the [command line](../mysqld-options-full-list/index) (the `--sql-mode` option) or by setting the [sql\_mode](../server-system-variables/index#sql_mode) system variable. ``` SET sql_mode = 'modes'; SET GLOBAL sql_mode = 'modes'; ``` The session value only affects the current client, and can be changed by the client when required. To set the global value, the SUPER privilege is required, and the change affects any clients that connect from that point on. SQL\_MODE Values ---------------- The different `SQL_MODE` values are: #### ALLOW\_INVALID\_DATES Allow any day between 1-31 in the day part. This is convenient when you want to read in all (including wrong data) into the database and then manipulate it there. #### ANSI Changes the SQL syntax to be closer to ANSI SQL. Sets: [REAL\_AS\_FLOAT](#real_as_float), [PIPES\_AS\_CONCAT](#pipes_as_concat), [ANSI\_QUOTES](#ansi_quotes), [IGNORE\_SPACE](#ignore_space). It also adds a restriction: an error will be returned if a subquery uses an [aggregating function](../functions-and-modifiers-for-use-with-group-by/index) with a reference to a column from an outer query in a way that cannot be resolved. If set, [SHOW CREATE TABLE](../show-create-table/index) output will not display MariaDB-specific table attributes. #### ANSI\_QUOTES Changes `"` to be treated as ```, the identifier quote character. This may break old MariaDB applications which assume that `"` is used as a string quote character. #### DB2 Same as: [PIPES\_AS\_CONCAT](#pipes_as_concat), [ANSI\_QUOTES](#ansi_quotes) , [IGNORE\_SPACE](#ignore_space), [DB2](#db2), [NO\_KEY\_OPTIONS](#no_key_options), [NO\_TABLE\_OPTIONS](#no_table_options), [NO\_FIELD\_OPTIONS](#no_field_options) If set, [SHOW CREATE TABLE](../show-create-table/index) output will not display MariaDB-specific table attributes. #### EMPTY\_STRING\_IS\_NULL Oracle-compatibility option that translates Item\_string created in the parser to Item\_null, and translates binding an empty string as prepared statement parameters to binding NULL. For example, `SELECT '' IS NULL` returns TRUE, `INSERT INTO t1 VALUES ('')` inserts NULL. Since [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) #### ERROR\_FOR\_DIVISION\_BY\_ZERO If not set, division by zero returns NULL. If set returns an error if one tries to update a column with 1/0 and returns a warning as well. Also see [MDEV-8319](https://jira.mariadb.org/browse/MDEV-8319). Default since [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/). #### HIGH\_NOT\_PRECEDENCE Compatibility option for MySQL 5.0.1 and before; This changes `NOT a BETWEEN b AND c` to be parsed as `(NOT a) BETWEEN b AND c` #### IGNORE\_BAD\_TABLE\_OPTIONS If this is set generate a warning (not an error) for wrong table option in CREATE TABLE. Also, since 10.0.13, do not comment out these wrong table options in [SHOW CREATE TABLE](../show-create-table/index). #### IGNORE\_SPACE Allow one to have spaces (including tab characters and new line characters) between function name and '('. The drawback is that this causes built in functions to become [reserved words](../reserved-words/index). #### MAXDB Same as: [PIPES\_AS\_CONCAT](#pipes_as_concat), [ANSI\_QUOTES](#ansi_quotes), [IGNORE\_SPACE](#ignore_space), [MAXDB](#maxdb), [NO\_KEY\_OPTIONS](#no_key_options), [NO\_TABLE\_OPTIONS](#no_table_options), [NO\_FIELD\_OPTIONS](#no_field_options), [NO\_AUTO\_CREATE\_USER](#no_auto_create_user). Also has the effect of silently converting [TIMESTAMP](../timestamp/index) fields into [DATETIME](../datetime/index) fields when created or modified. If set, [SHOW CREATE TABLE](../show-create-table/index) output will not display MariaDB-specific table attributes. #### MSSQL Additionally implies the following: [PIPES\_AS\_CONCAT](#pipes_as_concat), [ANSI\_QUOTES](#ansi_quotes), [IGNORE\_SPACE](#ignore_space), [NO\_KEY\_OPTIONS](#no_key_options), [NO\_TABLE\_OPTIONS](#no_table_options), [NO\_FIELD\_OPTIONS](#no_field_options). Additionally from [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/), implements a limited subset of Microsoft SQL Server's language. See [SQL\_MODE=MSSQL](../sql_modemssql/index) for more. If set, [SHOW CREATE TABLE](../show-create-table/index) output will not display MariaDB-specific table attributes. #### MYSQL323 Same as: [NO\_FIELD\_OPTIONS](#no_field_options), [HIGH\_NOT\_PRECEDENCE](#high_not_precedence). #### MYSQL40 Same as: [NO\_FIELD\_OPTIONS](#no_field_options), [HIGH\_NOT\_PRECEDENCE](#high_not_precedence). #### NO\_AUTO\_CREATE\_USER Don't automatically create users with `GRANT` unless authentication information is specified. If none is provided, will produce a 1133 error: "Can't find any matching row in the user table". Default since [MariaDB 10.1.7](https://mariadb.com/kb/en/mariadb-1017-release-notes/). #### NO\_AUTO\_VALUE\_ON\_ZERO If set, don't generate an [AUTO\_INCREMENT](../auto_increment/index) on [INSERT](../insert/index) of zero in an `AUTO_INCREMENT` column, or when adding an [AUTO\_INCREMENT](../auto_increment/index) attribute with the [ALTER TABLE](../alter-table/index) statement. Normally both `zero` and `NULL` generate new `AUTO_INCREMENT` values. #### NO\_BACKSLASH\_ESCAPES Disables using the backslash character `\` as an escape character within strings, making it equivalent to an ordinary character. #### NO\_DIR\_IN\_CREATE Ignore all INDEX DIRECTORY and DATA DIRECTORY directives when creating a table. Can be useful on slave [replication](../replication/index) servers. #### NO\_ENGINE\_SUBSTITUTION If not set, if the available storage engine specified by a CREATE TABLE is not available, a warning is given and the default storage engine is used instead. If set, generate a 1286 error when creating a table if the specified [storage engine](../storage-engines/index) is not available. See also [enforce\_storage\_engine](../server-system-variables/index#enforce_storage_engine). Default since [MariaDB 10.1.7](https://mariadb.com/kb/en/mariadb-1017-release-notes/). #### NO\_FIELD\_OPTIONS Remove MariaDB-specific column options from the output of [SHOW CREATE TABLE](../show-create-table/index). This is also used by the portability mode of [mariadb-dump/mysqldump](../mysqldump/index). #### NO\_KEY\_OPTIONS Remove MariaDB-specific index options from the output of [SHOW CREATE TABLE](../show-create-table/index). This is also used by the portability mode of [mariadb-dump/mysqldump](../mysqldump/index). #### NO\_TABLE\_OPTIONS Remove MariaDB-specific table options from the output of [SHOW CREATE TABLE](../show-create-table/index). This is also used by the portability mode of [mariadb-dump/mysqldump](../mysqldump/index). #### NO\_UNSIGNED\_SUBTRACTION When enabled, subtraction results are signed even if the operands are unsigned. #### NO\_ZERO\_DATE Don't allow '0000-00-00' as a valid date in strict mode (produce a 1525 error). Zero dates can be inserted with [IGNORE](../ignore/index). If not in strict mode, a warning is generated. #### NO\_ZERO\_IN\_DATE Don't allow dates where the year is not zero but the month or day parts of the date *are* zero (produce a 1525 error). For example, with this set, '0000-00-00' is allowed, but '1970-00-10' or '1929-01-00' are not. If the ignore option is used, MariaDB will insert '0000-00-00' for those types of dates. If not in strict mode, a warning is generated instead. #### ONLY\_FULL\_GROUP\_BY For [SELECT ... GROUP BY](../select/index#group-by) queries, disallow [SELECTing](../select/index) columns which are not referred to in the GROUP BY clause, unless they are passed to an aggregate function like [COUNT()](../count/index) or [MAX()](../max/index). Produce a 1055 error. #### ORACLE In all versions of MariaDB up to [MariaDB 10.2](../what-is-mariadb-102/index), this sets `sql_mode` that is equivalent to: [PIPES\_AS\_CONCAT](#pipes_as_concat), [ANSI\_QUOTES](#ansi_quotes), [IGNORE\_SPACE](#ignore_space), [NO\_KEY\_OPTIONS](#no_key_options), [NO\_TABLE\_OPTIONS](#no_table_options), [NO\_FIELD\_OPTIONS](#no_field_options), [NO\_AUTO\_CREATE\_USER](#no_auto_create_user) From [MariaDB 10.3](../what-is-mariadb-103/index), this mode also sets [SIMULTANEOUS\_ASSIGNMENT](#simultaneous_assignment) and configures the server to understand a large subset of Oracle's PL/SQL language instead of MariaDB's traditional syntax for stored routines. See [SQL\_MODE=ORACLE From MariaDB 10.3](../sql_modeoracle-from-mariadb-103/index). If set, [SHOW CREATE TABLE](../show-create-table/index) output will not display MariaDB-specific table attributes. #### PAD\_CHAR\_TO\_FULL\_LENGTH Trailing spaces in [CHAR](../char/index) columns are by default trimmed upon retrieval. With PAD\_CHAR\_TO\_FULL\_LENGTH enabled, no trimming occurs. Does not apply to [VARCHARs](../varchar/index). #### PIPES\_AS\_CONCAT Allows using the pipe character (ASCII 124) as string concatenation operator. This means that `"A" || "B"` can be used in place of `CONCAT("A", "B")`. #### POSTGRESQL Same as: [PIPES\_AS\_CONCAT](#pipes_as_concat), [ANSI\_QUOTES](#ansi_quotes), [IGNORE\_SPACE](#ignore_space), [POSTGRESQL](#postgresql), [NO\_KEY\_OPTIONS](#no_key_options), [NO\_TABLE\_OPTIONS](#no_table_options), [NO\_FIELD\_OPTIONS](#no_field_options). If set, [SHOW CREATE TABLE](../show-create-table/index) output will not display MariaDB-specific table attributes. #### REAL\_AS\_FLOAT `REAL` is a synonym for [FLOAT](../float/index) rather than [DOUBLE](../double/index). #### SIMULTANEOUS\_ASSIGNMENT Setting this makes the SET part of the [UPDATE](../update/index) statement evaluate all assignments simultaneously, not left-to-right. From [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/). #### STRICT\_ALL\_TABLES Strict mode. Statements with invalid or missing data are aborted and rolled back. For a non-transactional storage engine with a statement affecting multiple rows, this may mean a partial insert or update if the error is found in a row beyond the first. #### STRICT\_TRANS\_TABLES Strict mode. Statements with invalid or missing data are aborted and rolled back, except that for non-transactional storage engines and statements affecting multiple rows where the invalid or missing data is not the first row, MariaDB will convert the invalid value to the closest valid value, or, if a value is missing, insert the column default value. Default since [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/). #### TIME\_ROUND\_FRACTIONAL With this mode unset, MariaDB truncates fractional seconds when changing precision to smaller. When set, MariaDB will round when converting to TIME, DATETIME and TIMESTAMP, and truncate when converting to DATE. Since [MariaDB 10.4.1](https://mariadb.com/kb/en/mariadb-1041-release-notes/) #### TRADITIONAL Makes MariaDB work like a traditional SQL server. Same as: [STRICT\_TRANS\_TABLES](#strict_trans_tables), [STRICT\_ALL\_TABLES](#strict_all_tables), [NO\_ZERO\_IN\_DATE](#no_zero_in_date), [NO\_ZERO\_DATE](#no_zero_date), [ERROR\_FOR\_DIVISION\_BY\_ZERO](#error_for_division_by_zero), [TRADITIONAL](#traditional), [NO\_AUTO\_CREATE\_USER](#no_auto_create_user). Strict Mode ----------- A mode where at least one of `STRICT_TRANS_TABLES` or `STRICT_ALL_TABLES` is enabled is called *strict mode*. With strict mode set (default from [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)), statements that modify tables (either transactional for `STRICT_TRANS_TABLES` or all for `STRICT_ALL_TABLES`) will fail, and an error will be returned instead. The IGNORE keyword can be used when strict mode is set to convert the error to a warning. With strict mode not set (default in version <= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)), MariaDB will automatically adjust invalid values, for example, truncating strings that are too long, or adjusting numeric values that are out of range, and produce a warning. Statements that don't modify data will return a warning when adjusted regardless of mode. SQL\_MODE and Stored Programs ----------------------------- [Stored programs and views](../stored-programs-and-views/index) always use the SQL\_MODE that was active when they were created. This means that users can safely change session or global SQL\_MODE; the stored programs they use will still work as usual. It is possible to change session SQL\_MODE within a stored program. In this case, the new SQL\_MODE will be in effect only in the body of the current stored program. If it calls some stored procedures, they will not be affected by the change. Some Information Schema tables (such as [ROUTINES](../information-schema-routines-table/index)) and SHOW CREATE statements such as [SHOW CREATE PROCEDURE](../show-create-procedure/index) show the SQL\_MODE used by the stored programs. Examples -------- This example shows how to get a readable list of enabled SQL\_MODE flags: ``` SELECT REPLACE(@@SQL_MODE, ',', '\n'); +-------------------------------------------------------------------------+ | REPLACE(@@SQL_MODE, ',', '\n') | +-------------------------------------------------------------------------+ | STRICT_TRANS_TABLES NO_ZERO_IN_DATE NO_ZERO_DATE NO_ENGINE_SUBSTITUTION | +-------------------------------------------------------------------------+ ``` Adding a new flag: ``` SET @@SQL_MODE = CONCAT(@@SQL_MODE, ',NO_ENGINE_SUBSTITUTION'); ``` If the specified flag is already ON, the above example has no effect but does not produce an error. How to unset a flag: ``` SET @@SQL_MODE = REPLACE(@@SQL_MODE, 'NO_ENGINE_SUBSTITUTION', ''); ``` How to check if a flag is set: ``` SELECT @@SQL_MODE LIKE '%NO_ZERO_DATE%'; +----------------------------------+ | @@SQL_MODE LIKE '%NO_ZERO_DATE%' | +----------------------------------+ | 1 | +----------------------------------+ ``` Without and with strict mode: ``` CREATE TABLE strict (s CHAR(5), n TINYINT); INSERT INTO strict VALUES ('MariaDB', '128'); Query OK, 1 row affected, 2 warnings (0.14 sec) SHOW WARNINGS; +---------+------+--------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------+ | Warning | 1265 | Data truncated for column 's' at row 1 | | Warning | 1264 | Out of range value for column 'n' at row 1 | +---------+------+--------------------------------------------+ 2 rows in set (0.00 sec) SELECT * FROM strict; +-------+------+ | s | n | +-------+------+ | Maria | 127 | +-------+------+ SET sql_mode='STRICT_TRANS_TABLES'; INSERT INTO strict VALUES ('MariaDB', '128'); ERROR 1406 (22001): Data too long for column 's' at row 1 ``` Overriding strict mode with the IGNORE keyword: ``` INSERT IGNORE INTO strict VALUES ('MariaDB', '128'); Query OK, 1 row affected, 2 warnings (0.15 sec) ``` See Also -------- * [SQL\_MODE=MSSQL](../sql_modemssql/index) * [SQL\_MODE=ORACLE](../sql_modeoracle-from-mariadb-103/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb MERGE MERGE ===== Description ----------- The MERGE storage engine, also known as the MRG\_MyISAM engine, is a collection of identical [MyISAM](../myisam/index) tables that can be used as one. "Identical" means that all tables have identical column and index information. You cannot merge MyISAM tables in which the columns are listed in a different order, do not have exactly the same columns, or have the indexes in different order. However, any or all of the MyISAM tables can be compressed with [myisampack](../myisampack/index). Columns names and indexes names can be different, as long as data types and NULL/NOT NULL clauses are the same. Differences in table options such as AVG\_ROW\_LENGTH, MAX\_ROWS, or PACK\_KEYS do not matter. Each index in a MERGE table must match an index in underlying MyISAM tables, but the opposite is not true. Also, a MERGE table cannot have a PRIMARY KEY or UNIQUE indexes, because it cannot enforce uniqueness over all underlying tables. The following options are meaningful for MERGE tables: * `UNION`. This option specifies the list of the underlying MyISAM tables. The list is enclosed between parentheses and separated with commas. * `INSERT_METHOD`. This options specifies whether, and how, INSERTs are allowed for the table. Allowed values are: `NO` (INSERTs are not allowed), `FIRST` (new rows will be written into the first table specified in the `UNION` list), `LAST` (new rows will be written into the last table specified in the `UNION` list). The default value is `NO`. If you define a MERGE table with a definition which is different from the underlying MyISAM tables, or one of the underlying tables is not MyISAM, the CREATE TABLE statement will not return any error. But any statement which involves the table will produce an error like the following: ``` ERROR 1168 (HY000): Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist ``` A `[CHECK TABLE](../check-table/index)` will show more information about the problem. The error is also produced if the table is properly define, but an underlying table's definition changes at some point in time. If you try to insert a new row into a MERGE table with INSERT\_METHOD=NO, you will get an error like the following: ``` ERROR 1036 (HY000): Table 'tbl_name' is read only ``` It is possible to build a MERGE table on MyISAM tables which have one or more [virtual columns](../virtual-columns/index). MERGE itself does not support virtual columns, thus such columns will be seen as regular columns. The data types and sizes will still need to be identical, and they cannot be NOT NULL. Examples -------- ``` CREATE TABLE t1 ( a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, message CHAR(20)) ENGINE=MyISAM; CREATE TABLE t2 ( a INT NOT NULL AUTO_INCREMENT PRIMARY KEY, message CHAR(20)) ENGINE=MyISAM; INSERT INTO t1 (message) VALUES ('Testing'),('table'),('t1'); INSERT INTO t2 (message) VALUES ('Testing'),('table'),('t2'); CREATE TABLE total ( a INT NOT NULL AUTO_INCREMENT, message CHAR(20), INDEX(a)) ENGINE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST; SELECT * FROM total; +---+---------+ | a | message | +---+---------+ | 1 | Testing | | 2 | table | | 3 | t1 | | 1 | Testing | | 2 | table | | 3 | t2 | +---+---------+ ``` In the following example, we'll create three MyISAM tables, and then a MERGE table on them. However, one of them uses a different data type for the column b, so a SELECT will produce an error: ``` CREATE TABLE t1 ( a INT, b INT ) ENGINE = MyISAM; CREATE TABLE t2 ( a INT, b INT ) ENGINE = MyISAM; CREATE TABLE t3 ( a INT, b TINYINT ) ENGINE = MyISAM; CREATE TABLE t_mrg ( a INT, b INT ) ENGINE = MERGE,UNION=(t1,t2,t3); SELECT * FROM t_mrg; ERROR 1168 (HY000): Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist ``` To find out what's wrong, we'll use a CHECK TABLE: ``` CHECK TABLE t_mrg\G *************************** 1. row *************************** Table: test.t_mrg Op: check Msg_type: Error Msg_text: Table 'test.t3' is differently defined or of non-MyISAM type or doesn't exist *************************** 2. row *************************** Table: test.t_mrg Op: check Msg_type: Error Msg_text: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist *************************** 3. row *************************** Table: test.t_mrg Op: check Msg_type: error Msg_text: Corrupt ``` Now, we know that the problem is in `t3`'s definition. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb 10.1.26 Release Upgrade Tests 10.1.26 Release Upgrade Tests ============================= Upgrade from 10.0 ----------------- ### Tested revision 535910ae5f20e36405631030e9c0eb22fe40a7c4 ### Test date 2017-08-09 14:16:17 ### Summary (PASS) All tests passed ### Details | # | type | pagesize | OLD version | file format | encrypted | compressed | | NEW version | file format | encrypted | compressed | readonly | result | notes | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 1 | crash | 4 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 2 | crash | 4 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 3 | crash | 4 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 4 | crash | 4 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 5 | crash | 8 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 6 | crash | 8 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 7 | crash | 8 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 8 | crash | 8 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 9 | crash | 16 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 10 | crash | 16 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 11 | crash | 16 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 12 | crash | 16 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 13 | normal | 4 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 14 | normal | 4 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 15 | normal | 4 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 16 | normal | 4 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 17 | normal | 8 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 18 | normal | 8 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 19 | normal | 8 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 20 | normal | 8 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 21 | normal | 16 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 22 | normal | 16 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 23 | normal | 16 | 10.0.28 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 24 | normal | 16 | 10.0.28 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | Upgrade from 10.1 ----------------- ### Tested revision 535910ae5f20e36405631030e9c0eb22fe40a7c4 ### Test date 2017-08-09 15:06:34 ### Summary (FAIL) [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112), [MDEV-13165](https://jira.mariadb.org/browse/MDEV-13165) ### Details | # | type | pagesize | OLD version | file format | encrypted | compressed | | NEW version | file format | encrypted | compressed | readonly | result | notes | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 1 | crash | 64 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 2 | crash | 64 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 3 | crash | 64 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(49) | | 4 | crash | 64 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 5 | crash | 64 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 6 | crash | 64 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 7 | crash | 64 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 8 | crash | 64 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 9 | crash | 8 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 10 | crash | 8 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 11 | crash | 8 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 12 | crash | 8 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(14) | | 13 | crash | 8 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 14 | crash | 8 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 15 | crash | 8 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 16 | crash | 8 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 17 | crash | 16 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 18 | crash | 16 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 19 | crash | 16 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(37) | | 20 | crash | 16 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 21 | crash | 16 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 22 | crash | 16 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 23 | crash | 16 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 24 | crash | 16 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 25 | crash | 32 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 26 | crash | 32 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 27 | crash | 32 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 28 | crash | 32 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 29 | crash | 32 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(29) | | 30 | crash | 32 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 31 | crash | 32 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 32 | crash | 32 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 33 | crash | 4 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(43) | | 34 | crash | 4 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 35 | crash | 4 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | UPGRADE\_FAILURE [MDEV-13165](https://jira.mariadb.org/browse/MDEV-13165) | | 36 | crash | 4 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 37 | crash | 4 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 38 | crash | 4 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 39 | crash | 4 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 40 | crash | 4 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 41 | normal | 8 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 42 | normal | 8 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 43 | normal | 8 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 44 | normal | 8 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 45 | normal | 8 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 46 | normal | 8 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 47 | normal | 8 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | OK | | | 48 | normal | 8 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 49 | normal | 64 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 50 | normal | 64 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | OK | | | 51 | normal | 64 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 52 | normal | 64 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 53 | normal | 64 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 54 | normal | 64 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 55 | normal | 64 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 56 | normal | 64 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 57 | normal | 32 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 58 | normal | 32 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | OK | | | 59 | normal | 32 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 60 | normal | 32 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 61 | normal | 32 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 62 | normal | 32 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 63 | normal | 32 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 64 | normal | 32 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 65 | normal | 16 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 66 | normal | 16 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | OK | | | 67 | normal | 16 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 68 | normal | 16 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 69 | normal | 16 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 70 | normal | 16 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 71 | normal | 16 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 72 | normal | 16 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 73 | normal | 4 | 10.1.20 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 74 | normal | 4 | 10.1.20 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 75 | normal | 4 | 10.1.20 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 76 | normal | 4 | 10.1.20 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 77 | normal | 4 | 10.1.20 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 78 | normal | 4 | 10.1.20 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | OK | | | 79 | normal | 4 | 10.1.20 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 80 | normal | 4 | 10.1.20 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | Upgrade from MySQL 5.6 ---------------------- ### Tested revision 535910ae5f20e36405631030e9c0eb22fe40a7c4 ### Test date 2017-08-09 18:24:38 ### Summary (PASS) All tests passed ### Details | # | type | pagesize | OLD version | file format | encrypted | compressed | | NEW version | file format | encrypted | compressed | readonly | result | notes | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 1 | normal | 16 | 5.6.35 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 2 | normal | 16 | 5.6.35 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 3 | normal | 16 | 5.6.35 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 4 | normal | 16 | 5.6.35 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 5 | normal | 4 | 5.6.35 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 6 | normal | 4 | 5.6.35 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 7 | normal | 4 | 5.6.35 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 8 | normal | 4 | 5.6.35 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 9 | normal | 8 | 5.6.35 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 10 | normal | 8 | 5.6.35 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 11 | normal | 8 | 5.6.35 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 12 | normal | 8 | 5.6.35 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | Crash Recovery -------------- ### Tested revision 535910ae5f20e36405631030e9c0eb22fe40a7c4 ### Test date 2017-08-09 18:52:03 ### Summary (FAIL) [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112) ### Details | # | type | pagesize | OLD version | file format | encrypted | compressed | | NEW version | file format | encrypted | compressed | readonly | result | notes | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 1 | crash | 16 | 10.1.26 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 2 | crash | 16 | 10.1.26 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 3 | crash | 16 | 10.1.26 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 4 | crash | 16 | 10.1.26 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 5 | crash | 16 | 10.1.26 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 6 | crash | 16 | 10.1.26 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(54) | | 7 | crash | 16 | 10.1.26 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 8 | crash | 16 | 10.1.26 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 9 | crash | 4 | 10.1.26 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 10 | crash | 4 | 10.1.26 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 11 | crash | 4 | 10.1.26 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 12 | crash | 4 | 10.1.26 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 13 | crash | 4 | 10.1.26 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(48) | | 14 | crash | 4 | 10.1.26 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 15 | crash | 4 | 10.1.26 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 16 | crash | 4 | 10.1.26 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 17 | crash | 32 | 10.1.26 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 18 | crash | 32 | 10.1.26 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(16) | | 19 | crash | 32 | 10.1.26 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 20 | crash | 32 | 10.1.26 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 21 | crash | 32 | 10.1.26 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 22 | crash | 32 | 10.1.26 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 23 | crash | 32 | 10.1.26 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 24 | crash | 32 | 10.1.26 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 25 | crash | 64 | 10.1.26 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | | 26 | crash | 64 | 10.1.26 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 27 | crash | 64 | 10.1.26 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 28 | crash | 64 | 10.1.26 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 29 | crash | 64 | 10.1.26 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(21) | | 30 | crash | 64 | 10.1.26 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 31 | crash | 64 | 10.1.26 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 32 | crash | 64 | 10.1.26 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 33 | crash | 8 | 10.1.26 (inbuilt) | Barracuda | on | zlib | => | 10.1.26 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(18) | | 34 | crash | 8 | 10.1.26 (inbuilt) | Antelope | on | zlib | => | 10.1.26 (inbuilt) | Antelope | on | zlib | - | OK | | | 35 | crash | 8 | 10.1.26 (inbuilt) | Antelope | - | zlib | => | 10.1.26 (inbuilt) | Antelope | - | zlib | - | OK | | | 36 | crash | 8 | 10.1.26 (inbuilt) | Barracuda | - | zlib | => | 10.1.26 (inbuilt) | Barracuda | - | zlib | - | OK | | | 37 | crash | 8 | 10.1.26 (inbuilt) | Antelope | on | - | => | 10.1.26 (inbuilt) | Antelope | on | - | - | OK | | | 38 | crash | 8 | 10.1.26 (inbuilt) | Barracuda | on | - | => | 10.1.26 (inbuilt) | Barracuda | on | - | - | OK | | | 39 | crash | 8 | 10.1.26 (inbuilt) | Barracuda | - | - | => | 10.1.26 (inbuilt) | Barracuda | - | - | - | OK | | | 40 | crash | 8 | 10.1.26 (inbuilt) | Antelope | - | - | => | 10.1.26 (inbuilt) | Antelope | - | - | - | OK | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Why to Automate MariaDB Deployments and Management Why to Automate MariaDB Deployments and Management ================================================== MariaDB includes a powerful [configuration system](../configuring-mariadb-with-option-files/index). This is enough when we need to deploy a single MariaDB instance, or a small number of instances. But many modern organisations have many database servers. Deploying and upgrading them manually could require too much time, and would be error-prone. Infrastructure as Code ---------------------- Several tools exist to deploy and manage several servers automatically. These tools operate at a higher level, and execute tasks like installing MariaDB, running queries, or generating new configuration files based on a template. Instead of upgrading servers manually, users can launch a command to upgrade a group of servers, and the automation software will run the necessary tasks. Servers can be described in a code repository. This description can include MariaDB version, its configuration, users, backup jobs, and so on. This code is human-readable, and can serve as a documentation of which servers exist and how they are configured. The code is typically versioned in a repository, to allow collaborative development and track the changes that occurred over time. This is a paradigm called **Infrastructure as Code**. Automation code is high-level and one usually doesn’t care how operations are implemented. Their implementation is delegated to modules that handle specific components of the infrastructure. For example a module could equally work with apt and yum package managers. Other modules can implement operations for a specific cloud vendor, so we declare we want a snapshot to be done, but we don’t need to write the commands to make it happen. For special cases, it is of course possible to write Bash commands, or scripts in every language, and declare that they must be run. Manual interventions on the servers will still be possible. This is useful, for example, to investigate performance problems. But it is important to leave the servers in the state that is described by the code. This code is not something you write once and never touch again. It is periodically necessary to modify infrastructures to update some software, add new replicas, and so on. Once the base code is in place, making such changes is often trivial and potentially it can be done in minutes. Automated Failover ------------------ Once [replication](../standard-replication/index) is in place, two important aspects to automate are load balancing and failover. Proxies can implement load balancing, redirecting the queries they receive to different server, trying to distribute the load equally. They can also monitor that MariaDB servers are running and in good health, thus avoiding sending queries to a server that is down or struggling. However, this does not solve the problem with replication: if a primary server crashes, its replicas should point to another server. Usually this means that an existing replica is promoted to a master. This kind of changes are possible thanks to MariaDB [GTID](../gtid/index). One can promote a replica to a primary by making change to existing automation code. This is typically simple and relatively quick to do for a human operator. But this operation takes time, and in the meanwhile the service could be down. Automating failover will minimise the time to recover. A way to do it is to use Orchestrator, a tool that can automatically promote a replica to a primary. The choice of the replica to promote is done in a smart way, keeping into account things like the servers versions and the [binary log](../binary-log/index) format. Resources --------- * [Continuous configuration automation on Wikipedia](https://en.wikipedia.org/wiki/Continuous_configuration_automation). * [Infrastructure as code on Wikipedia](https://en.wikipedia.org/wiki/Infrastructure_as_code). --- Content initially contributed by [Vettabase Ltd](https://vettabase.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Troubleshooting Connection Issues Troubleshooting Connection Issues ================================= If you are completely new to MariaDB and relational databases, you may want to start with the [MariaDB Primer](../a-mariadb-primer/index). Also, make sure you understand the connection parameters discussed in the [Connecting to MariaDB](../connecting-to-mariadb/index) article. There are a number of common problems that can occur when connecting to MariaDB. ### Server Not Running in Specified Location If the error you get is something like: ``` mysql -uname -p ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2 "No such file or directory") ``` or ``` mysql -uname -p --port=3307 --protocol=tcp ERROR 2003 (HY000): Can't connect to MySQL server on 'localhost' (111 "Connection refused") ``` the server is either not running, or not running on the specified port, socket or pipe. Make sure you are using the correct [host](../connecting-to-mariadb/index#host), [port](../connecting-to-mariadb/index#port), [pipe](../connecting-to-mariadb/index#pipe), [socket](../connecting-to-mariadb/index#socket) and [protocol](../connecting-to-mariadb/index#protocol) options, or alternatively, see [Getting, Installing and Upgrading MariaDB](../getting-installing-and-upgrading-mariadb/index), [Starting and Stopping MariaDB](../starting-and-stopping-mariadb/index) or [Troubleshooting Installation Issues](../troubleshooting-installation-issues/index). The socket file can be in a non-standard path. In this case, the `socket` option is probably written in the my.cnf file. Check that its value is identical in the [mysqld] and [client] sections; if not, the client will look for a socket in a wrong place. If unsure where the Unix socket file is running, it's possible to find this out, for example: ``` netstat -ln | grep mysqld unix 2 [ ACC ] STREAM LISTENING 33209505 /var/run/mysqld/mysqld.sock ``` ### Unable to Connect from a Remote Location Usually, the MariaDB server does not by default accept connections from a remote client or connecting with tcp and a hostname and has to be configured to permit these. ``` (/my/maria-10.4) ./client/mysql --host=myhost --protocol=tcp --port=3306 test ERROR 2002 (HY000): Can't connect to MySQL server on 'myhost' (115) (/my/maria-10.4) telnet myhost 3306 Trying 192.168.0.11... telnet: connect to address 192.168.0.11: Connection refused (/my/maria-10.4) perror 115 OS error code 115: Operation now in progress ``` To solve this, see [Configuring MariaDB for Remote Client Access](../configuring-mariadb-for-remote-client-access/index) ### Authentication Problems Note that from [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/), the [unix\_socket authentication plugin](../authentication-plugin-unix-socket/index) is enabled by default on Unix-like systems. This uses operating system credentials when connecting to MariaDB via the local Unix socket file. See [unix\_socket authentication plugin](../authentication-plugin-unix-socket/index) for instructions on connecting and on switching to password-based authentication as well as [Authentication from MariaDB 10.4](../authentication-from-mariadb-104/index) for an overview of the [MariaDB 10.4](../what-is-mariadb-104/index) changes.. Authentication is granted to a particular username/host combination. `user1'@'localhost'`, for example, is not the same as `user1'@'166.78.144.191'`. See the [GRANT](../grant/index) article for details on granting permissions. Passwords are hashed with [PASSWORD](../password/index) function. If you have set a password with the [SET PASSWORD](../set-password/index) statement, or used [INSERT](../insert/index) or [UPDATE](../update/index) to update the [permissions table](../mysqluser-table/index) directly, the [PASSWORD](../password/index) function must be used at the same time. For example, `SET PASSWORD FOR 'bob'@'%.loc.gov' = PASSWORD('newpass')` rather than just `SET PASSWORD FOR 'bob'@'%.loc.gov' = 'newpass'`; If grant tables have been changed directly, the new passwords or authentication data will not immediately be active. A [FLUSH PRIVILEGES](../flush/index) statement, or the [flush-privileges mysqladmin](../mysqladmin/index) option must be run in order for the changes to take effect. #### Problems Exporting Query Results If you can run regular queries, but get an authentication error when running the [SELECT ... INTO OUTFILE](../select-into-outfile/index), [SELECT ... INTO DUMPFILE](../select-into-dumpfile/index) or [LOAD DATA INFILE](../load-data-infile/index) statements, you do not have permission to write files to the server. This requires the FILE privilege. See the [GRANT](../grant/index) article. #### Access to the Server, but not to a Database If you can connect to the server, but not to a database, for example: ``` USE test; ERROR 1044 (42000): Access denied for user 'ian'@'localhost' to database 'test' ``` or can connect to a particular database, but not another, for example `mysql -u name db1` works but not `mysql -u name db2`, you have not been granted permission for the particular database. See the [GRANT](../grant/index) article. #### Option Files and Environment Variables It's possible that option files or environment variables may be providing incorrect connection parameters. Check the values provided in any option files read by the client you are using (see [mysqld Configuration Files and Groups](../mysqld-configuration-files-and-groups/index) and the documentation for the particular client you're using - see [Clients and Utilities](../clients-and-utilities/index)). Option files can usually be suppressed with `no-defaults` option, for example: ``` mysqlimport --no-defaults ... ``` #### Unable to Connect to a Running Server / Lost root Password If you are unable to connect to a server, for example because you have lost the root password, you can start the server without using the privilege tables by running the `[--skip-grant-tables](../mysqld-options/index#-skip-grant-tables)` option, which gives users full access to all tables. You can then run [FLUSH PRIVILEGES](../flush/index) to resume using the grant tables, followed by [SET PASSWORD](../set-password/index) to change the password for an account. #### localhost and % You may have created a user with something like: ``` CREATE USER melisa identified by 'password'; ``` This creates a user with the '%' wildcard host. ``` select user,host from mysql.user where user='melisa'; +--------+------+ | user | host | +--------+------+ | melisa | % | +--------+------+ ``` However, you may still be failing to login from localhost. Some setups create anonymous users, including localhost. So the following records exist in the user table: ``` select user,host from mysql.user where user='melisa' or user=''; +--------+-----------+ | user | host | +--------+-----------+ | melisa | % | | | localhost | +--------+-----------+ ``` Since you are connecting from localhost, the anonymous credentials, rather than those for the 'melisa' user, are used. The solution is either to add a new user specific to localhost, or to remove the anonymous localhost user. ### See Also * [CREATE USER](../create-user/index) * [GRANT](../grant/index) * [Authentication from MariaDB 10.4](../authentication-from-mariadb-104/index) * [Authentication from MariaDB 10 4 video tutorial](https://www.youtube.com/watch?v=aWFG4uLbimM) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb 10.1.30 Release Upgrade Tests 10.1.30 Release Upgrade Tests ============================= ### Tested revision 461cf3e5a3c2d346d75b1407b285f8daf9d01f67 ### Test date 2017-12-23 ### Summary Some tests failed with known bug [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112). Undo upgrade from 10.0.18 failed because the old server hang on shutdown (a known problem with old servers). Crash upgrade from 10.1.10 (4K, zlib, XtraDB, Barracuda) failed ([MDEV-14759](https://jira.mariadb.org/browse/MDEV-14759)). ### Details | type | pagesize | OLD version | file format | encrypted | compressed | | NEW version | file format | encrypted | compressed | readonly | result | notes | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | recovery | 16 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 16 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(52) | | recovery | 4 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 4 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(59) | | recovery | 32 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | recovery | 32 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 64 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 64 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(20) | | recovery | 8 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 8 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(71) | | recovery | 16 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 16 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 4 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 4 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 32 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 32 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 64 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 64 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 8 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 8 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 16 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 4 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 32 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 64 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 8 | 10.1.30 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 16 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 4 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 32 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 64 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 8 | 10.1.30 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 16 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 4 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 32 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 64 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 8 | 10.1.30 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 16 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 4 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 32 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 64 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 8 | 10.1.30 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 16 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 4 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 4 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 8 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 8 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 16 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 16 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 4 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 4 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 8 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 8 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 16 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 16 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(17) | | crash | 4 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 4 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(43) | | crash | 32 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(36) | | crash | 32 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(47) | | crash | 8 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 8 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(60) | | crash | 16 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 16 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 4 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 4 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 8 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 8 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 16 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 4 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 32 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 64 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 8 | 10.1.29 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 16 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 4 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 32 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 64 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 8 | 10.1.29 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 16 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 4 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 32 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 64 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 8 | 10.1.29 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 16 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 4 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 32 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 64 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 8 | 10.1.29 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 16 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 4 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 4 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 8 | 10.1.13 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 8 | 10.1.13 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 16 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 16 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 4 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 4 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 8 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 8 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 16 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 16 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(33) | | crash | 4 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 4 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(19) | | crash | 32 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(44) | | crash | 32 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(29) | | crash | 8 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 8 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | **FAIL** | KNOWN\_BUGS [MDEV-13112](https://jira.mariadb.org/browse/MDEV-13112)(66) | | crash | 16 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 16 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 4 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 4 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | **FAIL** | UPGRADE\_FAILURE | | crash | 32 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 8 | 10.1.10 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 8 | 10.1.10 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | on | - | => | 10.1.30 (inbuilt) | Barracuda | on | - | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | - | - | => | 10.1.30 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | on | zlib | => | 10.1.30 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 16 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 4 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 32 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 64 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 8 | 10.1.22 (inbuilt) | Barracuda | - | zlib | => | 10.1.30 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 16 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 4 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 8 | 10.0.33 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 16 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 4 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 8 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 16 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 4 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 8 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 16 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 4 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 8 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 16 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 4 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 8 | 10.0.14 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 16 | 10.0.18 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 4 | 10.0.18 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 8 | 10.0.18 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | **FAIL** | TEST\_FAILURE | | undo | 16 | 10.0.18 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 4 | 10.0.18 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 8 | 10.0.18 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | normal | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | normal | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | crash | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | crash | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | on | - | - | OK | | | undo | 16 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 4 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | | undo | 8 | 5.6.38 (inbuilt) | | - | - | => | 10.1.30 (inbuilt) | | - | - | - | OK | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb format_bytes format\_bytes ============= Syntax ------ ``` sys.format_bytes(double) ``` Description ----------- `format_bytes` is a [stored function](../stored-functions/index) available with the [Sys Schema](../sys-schema/index). Given a byte count, returns a string consisting of a value and the units in a human-readable format. The units will be in bytes, KiB (kibibytes), MiB (mebibytes), GiB (gibibytes), TiB (tebibytes), or PiB (pebibytes). The binary prefixes (kibi, mebi, gibi, tebi and pebi) were created in December 1998 by the International Electrotechnical Commission to avoid possible ambiguity, as the widely-used prefixes kilo, mega, giga, tera and peta can be used to refer to both the power-of-10 decimal system multipliers and the power-of-two binary system multipliers. Examples -------- ``` SELECT sys.format_bytes(1000),sys.format_bytes(1024); +------------------------+------------------------+ | sys.format_bytes(1000) | sys.format_bytes(1024) | +------------------------+------------------------+ | 1000 bytes | 1.00 KiB | +------------------------+------------------------+ SELECT sys.format_bytes(1000000),sys.format_bytes(1048576); +---------------------------+---------------------------+ | sys.format_bytes(1000000) | sys.format_bytes(1048576) | +---------------------------+---------------------------+ | 976.56 KiB | 1.00 MiB | +---------------------------+---------------------------+ SELECT sys.format_bytes(1000000000),sys.format_bytes(1073741874); +------------------------------+------------------------------+ | sys.format_bytes(1000000000) | sys.format_bytes(1073741874) | +------------------------------+------------------------------+ | 953.67 MiB | 1.00 GiB | +------------------------------+------------------------------+ SELECT sys.format_bytes(1000000000000),sys.format_bytes(1099511627776); +---------------------------------+---------------------------------+ | sys.format_bytes(1000000000000) | sys.format_bytes(1099511627776) | +---------------------------------+---------------------------------+ | 931.32 GiB | 1.00 TiB | +---------------------------------+---------------------------------+ SELECT sys.format_bytes(1000000000000000),sys.format_bytes(1125899906842624); +------------------------------------+------------------------------------+ | sys.format_bytes(1000000000000000) | sys.format_bytes(1125899906842624) | +------------------------------------+------------------------------------+ | 909.49 TiB | 1.00 PiB | +------------------------------------+------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb System Variables Added in MariaDB 10.2 System Variables Added in MariaDB 10.2 ====================================== This is a list of [system variables](../server-system-variables/index) that have been added in the [MariaDB 10.2](../what-is-mariadb-102/index) series. The list does not include variables that are not part of the default release. | Variable | Added | | --- | --- | | [aria\_recover\_options](../aria-system-variables/index#aria_recover_options) | [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) | | [eq\_range\_index\_dive\_limit](../server-system-variables/index#eq_range_index_dive_limit) | [MariaDB 10.2.18](https://mariadb.com/kb/en/mariadb-10218-release-notes/) | | [innodb\_adaptive\_hash\_index\_parts](../xtradbinnodb-server-system-variables/index#innodb_adaptive_hash_index_parts) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_deadlock\_detect](../xtradbinnodb-server-system-variables/index#innodb_deadlock_detect) | [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) | | [innodb\_default\_row\_format](../xtradbinnodb-server-system-variables/index#innodb_default_row_format) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_encrypt\_temporary\_ables](../xtradbinnodb-server-system-variables/index#innodb_encrypt_temporary_tables) | [MariaDB 10.2.26](https://mariadb.com/kb/en/mariadb-10226-release-notes/) | | [innodb\_fill\_factor](../xtradbinnodb-server-system-variables/index#innodb_fill_factor) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_flush\_sync](../xtradbinnodb-server-system-variables/index#innodb_flush_sync) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_lock\_schedule\_algorithm](../xtradbinnodb-server-system-variables/index#innodb_lock_schedule_algorithm) | [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) | | [innodb\_log\_checksums](../xtradbinnodb-server-system-variables/index#innodb_log_checksums) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_log\_optimize\_ddl](../xtradbinnodb-server-system-variables/index#innodb_log_optimize_ddl) | [MariaDB 10.2.17](https://mariadb.com/kb/en/mariadb-10217-release-notes/) | | [innodb\_log\_write\_ahead\_size](../xtradbinnodb-server-system-variables/index#innodb_log_write_ahead_size) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_max\_undo\_log\_size](../xtradbinnodb-server-system-variables/index#innodb_max_undo_log_size) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_page\_cleaners](../xtradbinnodb-server-system-variables/index#innodb_page_cleaners) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_purge\_rseg\_truncate\_frequency](../xtradbinnodb-server-system-variables/index#innodb_purge_rseg_truncate_frequency) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [innodb\_safe\_truncate](../xtradbinnodb-server-system-variables/index#innodb_safe_truncate) | [MariaDB 10.2.19](https://mariadb.com/kb/en/mariadb-10219-release-notes/) | | [innodb\_stats\_include\_delete\_marked](../xtradbinnodb-server-system-variables/index#innodb_stats_include_delete_marked) | [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) | | [innodb\_temp\_data\_file\_path](../xtradbinnodb-server-system-variables/index#innodb_temp_data_file_path) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [max\_recursive\_iterations](../server-system-variables/index#max_recursive_iterations) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [read\_binlog\_speed\_limit](../replication-and-binary-log-server-system-variables/index#read_binlog_speed_limit) | [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) | | [session\_track\_schema](../server-system-variables/index#session_track_schema) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [session\_track\_state\_change](../server-system-variables/index#session_track_state_change) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [session\_track\_system\_variables](../server-system-variables/index#session_track_system_variables) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [session\_track\_transaction\_info](../server-system-variables/index#session_track_transaction_info) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [slave\_parallel\_workers](../replication-and-binary-log-server-system-variables/index#slave_parallel_workers) | [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) | | [table\_open\_cache\_instances](../server-system-variables/index#table_open_cache_instances) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [thread\_pool\_prio\_kickup\_timer](../thread-pool-system-and-status-variables/index#thread_pool_prio_kickup_timer) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [thread\_pool\_priority](../thread-pool-system-and-status-variables/index#thread_pool_priority) | [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) | | [tmp\_disk\_table\_size](../server-system-variables/index#tmp_disk_table_size) | [MariaDB 10.2.7](https://mariadb.com/kb/en/mariadb-1027-release-notes/) | | [tmp\_memory\_table\_size](../server-system-variables/index#tmp_memory_table_size) | [MariaDB 10.2.7](https://mariadb.com/kb/en/mariadb-1027-release-notes/) | | [wsrep\_certification\_rules](../galera-cluster-system-variables/index#wsrep_certification_rules) | [MariaDB 10.2.22](https://mariadb.com/kb/en/mariadb-10222-release-notes/) | See Also -------- * [Status Variables Added in MariaDB 10.2](../status-variables-added-in-mariadb-102/index) * [System Variables Added in MariaDB 10.3](../system-variables-added-in-mariadb-103/index) * [System Variables Added in MariaDB 10.1](../system-variables-added-in-mariadb-101/index) * [System Variables Added in MariaDB 10.0](../system-variables-added-in-mariadb-100/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ALTER SEQUENCE ALTER SEQUENCE ============== **MariaDB starting with [10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/)**`ALTER SEQUENCE` was introduced in [MariaDB 10.3](../what-is-mariadb-103/index). Syntax ------ ``` ALTER SEQUENCE [IF EXISTS] sequence_name [ INCREMENT [ BY | = ] increment ] [ MINVALUE [=] minvalue | NO MINVALUE | NOMINVALUE ] [ MAXVALUE [=] maxvalue | NO MAXVALUE | NOMAXVALUE ] [ START [ WITH | = ] start ] [ CACHE [=] cache ] [ [ NO ] CYCLE ] [ RESTART [[WITH | =] restart] ``` `ALTER SEQUENCE` allows one to change any values for a `SEQUENCE` created with [CREATE SEQUENCE](../create-sequence/index). The options for `ALTER SEQUENCE` can be given in any order. Description ----------- `ALTER SEQUENCE` changes the parameters of an existing sequence generator. Any parameters not specifically set in the `ALTER SEQUENCE` command retain their prior settings. `ALTER SEQUENCE` requires the [ALTER privilege](../grant/index). ### Arguments to `ALTER SEQUENCE` The following options may be used: | Option | Default value | Description | | --- | --- | --- | | `INCREMENT` | 1 | Increment to use for values. May be negative. | | `MINVALUE` | 1 if `INCREMENT` > 0 and -9223372036854775807 if `INCREMENT` < 0 | Minimum value for the sequence. | | `MAXVALUE` | 9223372036854775806 if `INCREMENT` > 0 and -1 if `INCREMENT` < 0 | Max value for sequence. | | `START` | `MINVALUE` if `INCREMENT` > 0 and `MAX_VALUE` if `INCREMENT`< 0 | First value that the sequence will generate. | | `CACHE` | 1000 | Number of values that should be cached. 0 if no `CACHE`. The underlying table will be updated first time a new sequence number is generated and each time the cache runs out. | | `CYCLE` | 0 (= `NO CYCLE`) | 1 if the sequence should start again from `MINVALUE`# after it has run out of values. | | `RESTART` | `START` if `restart` value not is given | If `RESTART` option is used, `NEXT VALUE` will return the restart value. | The optional clause `RESTART [ WITH restart ]` sets the next value for the sequence. This is equivalent to calling the [SETVAL()](../setval/index) function with the `is_used` argument as 0. The specified value will be returned by the next call of nextval. Using `RESTART` with no restart value is equivalent to supplying the start value that was recorded by [CREATE SEQUENCE](../create-sequence/index) or last set by `ALTER SEQUENCE START WITH`. `ALTER SEQUENCE` will not allow you to change the sequence so that it's inconsistent. For example: ``` CREATE SEQUENCE s1; ALTER SEQUENCE s1 MINVALUE 10; ERROR 4061 (HY000): Sequence 'test.t1' values are conflicting ALTER SEQUENCE s1 MINVALUE 10 RESTART 10; ERROR 4061 (HY000): Sequence 'test.t1' values are conflicting ALTER SEQUENCE s1 MINVALUE 10 START 10 RESTART 10; ``` ### INSERT To allow `SEQUENCE` objects to be backed up by old tools, like [mysqldump](../mysqldump/index), one can use `SELECT` to read the current state of a `SEQUENCE` object and use an `INSERT` to update the `SEQUENCE` object. `INSERT` is only allowed if all fields are specified: ``` CREATE SEQUENCE s1; INSERT INTO s1 VALUES(1000,10,2000,1005,1,1000,0,0); SELECT * FROM s1; +------------+-----------+-----------+-------+-----------+-------+-------+-------+ | next_value | min_value | max_value | start | increment | cache | cycle | round | +------------+-----------+-----------+-------+-----------+-------+-------+-------+ | 1000 | 10 | 2000 | 1005 | 1 | 1000 | 0 | 0 | +------------+-----------+-----------+-------+-----------+-------+-------+-------+ SHOW CREATE SEQUENCE s1; +-------+--------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +-------+--------------------------------------------------------------------------------------------------------------+ | s1 | CREATE SEQUENCE `s1` start with 1005 minvalue 10 maxvalue 2000 increment by 1 cache 1000 nocycle ENGINE=Aria | +-------+--------------------------------------------------------------------------------------------------------------+ ``` ### Notes `ALTER SEQUENCE` will instantly affect all future `SEQUENCE` operations. This is in contrast to some other databases where the changes requested by `ALTER SEQUENCE` will not be seen until the sequence cache has run out. `ALTER SEQUENCE` will take a full table lock of the sequence object during its (brief) operation. This ensures that `ALTER SEQUENCE` is replicated correctly. If you only want to set the next sequence value to a higher value than current, then you should use [SETVAL()](../setval/index) instead, as this is not blocking. If you want to change storage engine, sequence comment or rename the sequence, you can use [ALTER TABLE](../alter-table/index) for this. See Also -------- * [Sequence Overview](../sequence-overview/index) * [CREATE SEQUENCE](../create-sequence/index) * [DROP SEQUENCE](../drop-sequence/index) * [NEXT VALUE FOR](../next-value-for-sequence_name/index) * [PREVIOUS VALUE FOR](../previous-value-for-sequence_name/index) * [SETVAL()](../setval/index). Set next value for the sequence. * [AUTO INCREMENT](../auto_increment/index) * [ALTER TABLE](../alter-table/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb COLUMN_GET COLUMN\_GET =========== Syntax ------ ``` COLUMN_GET(dyncol_blob, column_nr as type); COLUMN_GET(dyncol_blob, column_name as type); ``` Description ----------- Gets the value of a [dynamic column](../dynamic-columns/index) by its name. If no column with the given name exists, `NULL` will be returned. **`column_name as type`** requires that one specify the datatype of the dynamic column they are reading. This may seem counter-intuitive: why would one need to specify which datatype they're retrieving? Can't the dynamic columns system figure the datatype from the data being stored? The answer is: SQL is a statically-typed language. The SQL interpreter needs to know the datatypes of all expressions before the query is run (for example, when one is using prepared statements and runs `"select COLUMN_GET(...)"`, the prepared statement API requires the server to inform the client about the datatype of the column being read before the query is executed and the server can see what datatype the column actually has). ### Lengths If you're running queries like: ``` SELECT COLUMN_GET(blob, 'colname' as CHAR) ... ``` without specifying a maximum length (i.e. using `as CHAR`, not `as CHAR(n)`), MariaDB will report the maximum length of the resultset column to be 16,777,216. This may cause excessive memory usage in some client libraries, because they try to pre-allocate a buffer of maximum resultset width. To avoid this problem, use CHAR(n) whenever you're using COLUMN\_GET in the select list. See [Dynamic Columns:Datatypes](../dynamic-columns/index#datatypes) for more information about datatypes. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MyRocks Performance Troubleshooting MyRocks Performance Troubleshooting =================================== MyRocks exposes its performance metrics through several interfaces: * Status variables * SHOW ENGINE ROCKSDB STATUS * RocksDB's perf context the contents slightly overlap, but each source has its own unique information, so be sure to check all three. ### Status Variables Check the output of ``` SHOW STATUS like 'Rocksdb%' ``` See [MyRocks Status Variables](../myrocks-status-variables/index) for more information. ### SHOW ENGINE ROCKSDB STATUS This produces a lot of information. One particularly interesting part is compaction statistics. It shows the amount of data on each SST level and other details: ``` *************************** 4. row *************************** Type: CF_COMPACTION Name: default Status: ** Compaction Stats [default] ** Level Files Size Score Read(GB) Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) Moved(GB) W-Amp Rd(MB/s) Wr(MB/s) Comp(sec) Comp(cnt) Avg(sec) KeyIn KeyDrop ---------------------------------------------------------------------------------------------------------------------------------------------------------- L0 3/0 30.16 MB 1.0 0.0 0.0 0.0 11.9 11.9 0.0 1.0 0.0 76.6 159 632 0.251 0 0 L1 5/0 247.54 MB 1.0 0.7 0.2 0.5 0.5 0.0 11.6 2.6 58.5 44.1 12 4 2.926 30M 10M L2 112/0 2.41 GB 1.0 0.6 0.0 0.6 0.5 -0.1 11.4 43.4 55.2 45.9 11 1 10.827 21M 3588K L3 466/0 8.91 GB 0.4 0.0 0.0 0.0 0.0 0.0 8.9 0.0 0.0 0.0 0 0 0.000 0 0 Sum 586/0 11.59 GB 0.0 1.3 0.2 1.0 12.8 11.8 32.0 1.1 7.1 72.6 181 637 0.284 52M 13M Int 0/0 0.00 KB 0.0 0.9 0.1 0.8 0.8 0.0 0.1 20.5 48.4 45.3 19 6 3.133 33M 3588K ``` ### Performance Context RocksDB has an internal mechanism called "perf context". The counter values are exposed through two tables: * [INFORMATION\_SCHEMA.ROCKSDB\_PERF\_CONTEXT\_GLOBAL](../information-schema-rocksdb_perf_context_global-table/index) - global counters * [INFORMATION\_SCHEMA.ROCKSDB\_PERF\_CONTEXT](../information-schema-rocksdb_perf_context-table/index) - Per-table/partition counters By default statistics are NOT collected. One needs to set [rocksdb\_perf\_context\_level](../myrocks-system-variables/index#rocksdb_perf_context_level) to some value (e.g. 3) to enable collection. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb >= >= == Syntax ------ ``` >= ``` Description ----------- Greater than or equal operator. Evaluates both SQL expressions and returns 1 if the left value is greater than or equal to the right value and 0 if it is not, or `NULL` if either expression is NULL. If the expressions return different data types, (for instance, a number and a string), performs type conversion. When used in row comparisons these two queries return the same results: ``` SELECT (t1.a, t1.b) >= (t2.x, t2.y) FROM t1 INNER JOIN t2; SELECT (t1.a > t2.x) OR ((t1.a = t2.x) AND (t1.b >= t2.y)) FROM t1 INNER JOIN t2; ``` Examples -------- ``` SELECT 2 >= 2; +--------+ | 2 >= 2 | +--------+ | 1 | +--------+ SELECT 'A' >= 'a'; +------------+ | 'A' >= 'a' | +------------+ | 1 | +------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CONNECT - OEM Table Example CONNECT - OEM Table Example =========================== This is an example showing how an OEM table can be implemented. The header File `my_global.h`: ``` /***********************************************************************/ /* Definitions needed by the included files. */ /***********************************************************************/ #if !defined(MY_GLOBAL_H) #define MY_GLOBAL_H typedef unsigned int uint; typedef unsigned int uint32; typedef unsigned short ushort; typedef unsigned long ulong; typedef unsigned long DWORD; typedef char *LPSTR; typedef const char *LPCSTR; typedef int BOOL; #if defined(__WIN__) typedef void *HANDLE; #else typedef int HANDLE; #endif typedef char *PSZ; typedef const char *PCSZ; typedef unsigned char BYTE; typedef unsigned char uchar; typedef long long longlong; typedef unsigned long long ulonglong; typedef char my_bool; struct charset_info_st {}; typedef const charset_info_st CHARSET_INFO; #define FALSE 0 #define TRUE 1 #define Item char #define MY_MAX(a,b) ((a>b)?(a):(b)) #define MY_MIN(a,b) ((a<b)?(a):(b)) #endif // MY_GLOBAL_H ``` Note: This is a fake `my_global.h` that just contains what is useful for the `jmgoem.cpp`source file. The source File `jmgoem.cpp`: ``` /************* jmgoem C++ Program Source Code File (.CPP) **************/ /* PROGRAM NAME: jmgoem Version 1.0 */ /* (C) Copyright to the author Olivier BERTRAND 2017 */ /* This program is the Java MONGO OEM module definition. */ /***********************************************************************/ /***********************************************************************/ /* Definitions needed by the included files. */ /***********************************************************************/ #include "my_global.h" /***********************************************************************/ /* Include application header files: */ /* global.h is header containing all global declarations. */ /* plgdbsem.h is header containing the DB application declarations. */ /* (x)table.h is header containing the TDBASE declarations. */ /* tabext.h is header containing the TDBEXT declarations. */ /* mongo.h is header containing the MONGO declarations. */ /***********************************************************************/ #include "global.h" #include "plgdbsem.h" #if defined(HAVE_JMGO) #include "csort.h" #include "javaconn.h" #endif // HAVE_JMGO #include "xtable.h" #include "tabext.h" #include "mongo.h" /***********************************************************************/ /* These functions are exported from the MONGO library. */ /***********************************************************************/ extern "C" { PTABDEF __stdcall GetMONGO(PGLOBAL, void*); PQRYRES __stdcall ColMONGO(PGLOBAL, PTOS, void*, char*, char*, bool); } // extern "C" /***********************************************************************/ /* DB static variables. */ /***********************************************************************/ int TDB::Tnum; int DTVAL::Shift; #if defined(HAVE_JMGO) int CSORT::Limit = 0; double CSORT::Lg2 = log(2.0); size_t CSORT::Cpn[1000] = {0}; /* Precalculated cmpnum values */ #if defined(HAVE_JAVACONN) char *JvmPath = NULL; char *ClassPath = NULL; char *GetPluginDir(void) {return "C:/mongo-java-driver/mongo-java-driver-3.4.2.jar;" "C:/MariaDB-10.1/MariaDB/storage/connect/";} char *GetJavaWrapper(void) {return (char*)"wrappers/Mongo3Interface";} #else // !HAVE_JAVACONN HANDLE JAVAConn::LibJvm; // Handle to the jvm DLL CRTJVM JAVAConn::CreateJavaVM; GETJVM JAVAConn::GetCreatedJavaVMs; #if defined(_DEBUG) GETDEF JAVAConn::GetDefaultJavaVMInitArgs; #endif // _DEBUG #endif // !HAVE_JAVACONN #endif // HAVE_JMGO /***********************************************************************/ /* This function returns a Mongo definition class. */ /***********************************************************************/ PTABDEF __stdcall GetMONGO(PGLOBAL g, void *memp) { return new(g, memp) MGODEF; } // end of GetMONGO #ifdef NOEXP /***********************************************************************/ /* Functions to be defined if not exported by the CONNECT version. */ /***********************************************************************/ bool IsNum(PSZ s) { for (char *p = s; *p; p++) if (*p == ']') break; else if (!isdigit(*p) || *p == '-') return false; return true; } // end of IsNum #endif /***********************************************************************/ /* Return the columns definition to MariaDB. */ /***********************************************************************/ PQRYRES __stdcall ColMONGO(PGLOBAL g, PTOS tp, char *tab, char *db, bool info) { #ifdef NOMGOCOL // Cannot use discovery strcpy(g->Message, "No discovery, MGOColumns is not accessible"); return NULL; #else return MGOColumns(g, db, NULL, tp, info); #endif } // end of ColMONGO ``` The file `mongo.def`: (required only on Windows) ``` LIBRARY MONGO EXPORTS GetMONGO @1 ColMONGO @2 ``` ### Compiling this OEM To compile this OEM module, first make the two or three required files by copy/pasting from the above listings. Even if this module is to be used with a binary distribution, you need some source files in order to successfully compile it. At least the CONNECT header files that are included in `jmgoem.cpp` and the ones they can include. This can be obtained by downloading the MariaDB source file tar.gz and extracting from it the CONNECT sources files in a directory that will be added to the additional source directories if it is not the directory containing the above files. The module must be linked to the `ha_connect.lib` of the binary version it will used with. Recent distributions add this lib in the plugin directory. The resulting module, for instance `mongo.so` or `mongo.dll`, must be placed in the plugin directory of the MariaDB server. Then, you will be able to use MONGO like tables simply replacing in the CREATE TABLE statement the option `TABLE_TYPE=MONGO` with `TABLE_TYPE=OEM SUBTYPE=MONGO MODULE=’mongo.(so|dll)’`. Actually, the module name, here supposedly ‘mongo’, can be anything you like. This will work with the last (not yet) distributed versions of [MariaDB 10.0](../what-is-mariadb-100/index) and 10.1 because, even it is not enabled, the MONGO type is included in them. This is also the case for [MariaDB 10.2.9](https://mariadb.com/kb/en/mariadb-1029-release-notes/) but then, on Windows, you will have to define NOEXP and NOMGOCOL because these functions are not exported by this version. To implement for older versions that do not contain the MONGO type, you can add the corresponding source files, namely `javaconn.cpp`, `jmgfam.cpp`, `jmgoconn.cpp`, `mongo.cpp` and `tabjmg.cpp` that you should find in the CONNECT extracted source files if you downloaded a recent version. As they include `my_global.h`, this is the reason why the included file was named this way. In addition, your compiling should define `HAVE_JMGO` and `HAVE_JAVACONN`. Of course, this is possible only if `ha_connect.lib` is available. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Installing OQGRAPH Installing OQGRAPH ================== The Open Query GRAPH computation engine, or OQGRAPH as the engine itself is called, allows you to handle hierarchies (tree structures) and complex graphs (nodes having many connections in several directions). Installation ------------ The OQGRAPH storage engine exists as a separate package in the repositories for [MariaDB 10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/) and later. On Ubuntu and Debian the package is called `mariadb-oqgraph-engine-10.0` or `mariadb-plugin-oqgraph`. On Red Hat, CentOS, and Fedora the package is called `MariaDB-oqgraph-engine`. To install the plugin, first install the appropriate package and then install the plugin using the [INSTALL SONAME](../install-soname/index) or [INSTALL PLUGIN](../install-plugin/index) commands. ### Debian and Ubuntu On Debian and Ubuntu, install the package as follows: ``` sudo apt-get install mariadb-plugin-oqgraph ``` or (for [MariaDB 10.0](../what-is-mariadb-100/index)) ``` sudo apt-get install mariadb-oqgraph-engine-10.0 ``` ### Fedora/Red Hat/CentOS Note that OQGRAPH v3 requires libjudy, which is not in the official Red Hat/Fedora repositories. This needs to be installed first, for example: ``` wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm rpm -Uvh epel-release-6-8.noarch.rpm ``` Then install the package, as follows: ``` sudo yum install MariaDB-oqgraph-engine ``` ### Installing the Plugin On either system you can then launch the `mysql` command-line client and install the plugin in MariaDB as follows: ``` INSTALL SONAME 'ha_oqgraph'; ``` See Also -------- More information on this engine is found on the OpenQuery website: <https://openquery.com.au/products/graph-engine> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_waits_summary_by_instance Table Performance Schema events\_waits\_summary\_by\_instance Table ============================================================= The [Performance Schema](../performance-schema/index) `events_waits_summary_by_instance` table contains wait events summarized by instance. It contains the following columns: | Column | Description | | --- | --- | | `EVENT_NAME` | Event name. Used together with `OBJECT_INSTANCE_BEGIN` for grouping events. | | `OBJECT_INSTANCE_BEGIN` | If an instrument creates multiple instances, each instance has a unique `OBJECT_INSTANCE_BEGIN` value to allow for grouping by instance. | | `COUNT_STAR` | Number of summarized events | | `SUM_TIMER_WAIT` | Total wait time of the summarized events that are timed. | | `MIN_TIMER_WAIT` | Minimum wait time of the summarized events that are timed. | | `AVG_TIMER_WAIT` | Average wait time of the summarized events that are timed. | | `MAX_TIMER_WAIT` | Maximum wait time of the summarized events that are timed. | The `*_TIMER_WAIT` columns only calculate results for timed events, as non-timed events have a `NULL` wait time. Example ------- ``` SELECT * FROM events_waits_summary_by_instance\G ... *************************** 202. row *************************** EVENT_NAME: wait/io/file/sql/binlog OBJECT_INSTANCE_BEGIN: 140578961969856 COUNT_STAR: 6 SUM_TIMER_WAIT: 90478331960 MIN_TIMER_WAIT: 263344 AVG_TIMER_WAIT: 15079721848 MAX_TIMER_WAIT: 67760576376 *************************** 203. row *************************** EVENT_NAME: wait/io/file/sql/dbopt OBJECT_INSTANCE_BEGIN: 140578961970560 COUNT_STAR: 6 SUM_TIMER_WAIT: 39891428472 MIN_TIMER_WAIT: 387168 AVG_TIMER_WAIT: 6648571412 MAX_TIMER_WAIT: 24503293304 *************************** 204. row *************************** EVENT_NAME: wait/io/file/sql/dbopt OBJECT_INSTANCE_BEGIN: 140578961971264 COUNT_STAR: 6 SUM_TIMER_WAIT: 39902495024 MIN_TIMER_WAIT: 177888 AVG_TIMER_WAIT: 6650415692 MAX_TIMER_WAIT: 21026400404 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.time_zone Table mysql.time\_zone Table ====================== The `mysql.time_zone` table is one of the mysql system tables that can contain [time zone](../time-zones/index) information. It is usually preferable for the system to handle the time zone, in which case the table will be empty (the default), but you can populate the mysql time zone tables using the [mysql\_tzinfo\_to\_sql](../mysql_tzinfo_to_sql/index) utility. See [Time Zones](../time-zones/index) for details. **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this table uses the [Aria](../aria/index) storage engine. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. The `mysql.time_zone` table contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | `Time_zone_id` | `int(10) unsigned` | NO | PRI | `NULL` | ID field, auto\_increments. | | `Use_leap_seconds` | `enum('Y','N')` | NO | | N | Whether or not leap seconds are used. | Example ------- ``` SELECT * FROM mysql.time_zone; +--------------+------------------+ | Time_zone_id | Use_leap_seconds | +--------------+------------------+ | 1 | N | | 2 | N | | 3 | N | | 4 | N | | 5 | N | | 6 | N | | 7 | N | | 8 | N | | 9 | N | | 10 | N | ... +--------------+------------------+ ``` See Also -------- * [mysql.time\_zone\_leap\_second table](../mysqltime_zone_leap_second-table/index) * [mysql.time\_zone\_name table](../mysqltime_zone_name-table/index) * [mysql.time\_zone\_transition table](../mysqltime_zone_transition-table/index) * [mysql.time\_zone\_transition\_type table](../mysqltime_zone_transition_type-table/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MYSQL_JSON MYSQL\_JSON =========== The JSON type in MySQL stores the JSON object in its own native form, while in MariaDB the [JSON type](../json-data-type/index) is a [LONGTEXT](../longtext/index). The mysql\_json plugin is used to make it easier to upgrade to MariaDB. See [Making MariaDB understand MySQL JSON](https://mariadb.org/making-mariadb-understand-mysql-json/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Time Zones Time Zones ========== MariaDB keeps track of several time zone settings. Setting the Time Zone --------------------- The [time\_zone](../server-system-variables/index#time_zone) system variable is the primary way to set the time zone. It can be specified in one of the following formats: * The default value is `SYSTEM`, which indicates that the system time zone defined in the [system\_time\_zone](../server-system-variables/index#system_time_zone) system variable will be used. See [System Time Zone](#system-time-zone) below for more information. * An offset from [Coordinated Universal Time (UTC)](../coordinated-universal-time/index), such as `+5:00` or `-9:00`, can also be used. * If the time zone tables in the [mysql](../the-mysql-database-tables/index) database were loaded, then a named time zone, such as `America/New_York`, `Africa/Johannesburg`, or `Europe/Helsinki`, is also permissible. See [mysql Time Zone Tables](#mysql-time-zone-tables) below for more information. There are two time zone settings that can be set within MariaDB--the global server time zone, and the time zone for your current session. There is also a third time zone setting which may be relevant--the system time zone. ### Global Server Time Zone The global server time zone can be changed at server startup by setting the `--default-time-zone` option either on the command-line or in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... default_time_zone = 'America/New_York' ``` The global server time zone can also be changed dynamically by setting the [time\_zone](../server-system-variables/index#time_zone) system variable as a user account that has the [SUPER](../grant/index#super) privilege. For example: ``` SET GLOBAL time_zone = 'America/New_York'; ``` The current global server time zone can be viewed by looking at the global value of the [time\_zone](../server-system-variables/index#time_zone) system variable. For example: ``` SHOW GLOBAL VARIABLES LIKE 'time_zone'; +---------------+--------+ | Variable_name | Value | +---------------+--------+ | time_zone | SYSTEM | +---------------+--------+ ``` ### Session Time Zone Each session that connects to the server will also have its own time zone. This time zone is initially inherited from the global value of the [time\_zone](../server-system-variables/index#time_zone) system variable, which sets the session value of the same variable. A session's time zone can be changed dynamically by setting the [time\_zone](../server-system-variables/index#time_zone) system variable. For example: ``` SET time_zone = 'America/New_York'; ``` The current session time zone can be viewed by looking at the session value of the [time\_zone](../server-system-variables/index#time_zone) system variable. For example: ``` SHOW SESSION VARIABLES LIKE 'time_zone'; +---------------+--------+ | Variable_name | Value | +---------------+--------+ | time_zone | SYSTEM | +---------------+--------+ ``` ### System Time Zone The system time zone is determined when the server starts, and it sets the value of the [system\_time\_zone](../server-system-variables/index#system_time_zone) system variable. The system time zone is usually read from the operating system's environment. You can change the system time zone in several different ways, such as: * If you are starting the server with [mysqld\_safe](../mysqld_safe/index), then you can set the system time zone with the `--timezone` option either on the command-line or in the [mysqld\_safe] [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mysqld_safe] timezone='America/New_York' ``` * If you are using a Unix-like operating system, then you can set the system time zone by setting the `TZ` [environment variable](../mariadb-environment-variables/index) in your shell before starting the server. For example: ``` $ export TZ='America/New_York' $ service mysql start ``` * On some Linux operating systems, you can change the default time zone for the whole system by making the [/etc/localtime](https://www.freedesktop.org/software/systemd/man/localtime.html) symbolic link point to the desired time zone. For example: ``` $ sudo rm /etc/localtime $ sudo ln -s /usr/share/zoneinfo/America/New_York /etc/localtime ``` * On some Debian-based Linux operating systems, you can change the default time zone for the whole system by executing the following: ``` sudo dpkg-reconfigure tzdata ``` * On Linux operating systems that use [systemd](../systemd/index), you can change the default time zone for the whole system by using the [timedatectl](https://www.freedesktop.org/software/systemd/man/timedatectl.html) utility. For example: ``` sudo timedatectl set-timezone America/New_York ``` Time Zone Effects ----------------- ### Time Zone Effects on Functions Some functions are affected by the time zone settings. These include: * [NOW()](../now/index) * [SYSDATE()](../sysdate/index) * [CURDATE()](../curdate/index) * [CURTIME()](../curtime/index) * [UNIX\_TIMESTAMP()](../unix_timestamp/index) Some functions are not affected. These include: * [UTC\_DATE()](../utc_date/index) * [UTC\_TIME()](../utc_time/index) * [UTC\_TIMESTAMP()](../utc_timestamp/index) ### Time Zone Effects on Data Types Some data types are affected by the time zone settings. * [TIMESTAMP](../timestamp/index) - See [TIMESTAMP: Time Zones](../timestamp/index#time-zones) for information on how this data type is effected by time zones. * [DATETIME](../datetime/index) - See [DATETIME: Time Zones](../datetime/index#time-zones) for information on how this data type is effected by time zones. mysql Time Zone Tables ---------------------- The [mysql](../the-mysql-database-tables/index) database contains a number of time zone tables: * [time\_zone](../mysqltime_zone-table/index) * [time\_zone\_leap\_second](../mysqltime_zone_leap_second-table/index) * [time\_zone\_name](../mysqltime_zone_name-table/index) * [time\_zone\_transition](../mysqltime_zone_transition-table/index) * [time\_zone\_transition\_type](../mysqltime_zone_transition_type-table/index) By default, these time zone tables in the [mysql](../the-mysql-database-tables/index) database are created, but not populated. If you are using a Unix-like operating system, then you can populate these tables using the [mariadb-tzinfo-to-sql / mysql\_tzinfo\_to\_sql](../mysql_tzinfo_to_sql/index) utility, which uses the [zoneinfo](https://linux.die.net/man/5/tzfile) data available on Linux, Mac OS X, FreeBSD and Solaris. If you are using Windows, then you will need to import pre-populated time zone tables. These are available at [MariaDB mirrors](https://mirror.mariadb.org/zoneinfo/). Time zone data needs to be updated on occasion. When that happens, the time zone tables may need to be reloaded. See Also -------- * [LinuxJedi in Spacetime: Properly Handling Time and Date](https://www.youtube.com/watch?v=IV8q_mbZzEo) (video) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb apt-upgrade Fails, But the Database is Running apt-upgrade Fails, But the Database is Running ============================================== After running `apt-upgrade mariadb`, it's possible that apt shows a fail in trying to start the server, but in fact the database is up and running, which then provokes apt to remain in a non finished state. For example: ``` # apt-get upgrade Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 2 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Setting up mariadb-server-10.1 (10.1.10+maria-1~trusty) ... * Stopping MariaDB database server mysqld ...done. * Starting MariaDB database server mysqld ...fail! invoke-rc.d: initscript mysql, action "start" failed. dpkg: error processing package mariadb-server-10.1 (--configure): subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mariadb-server: mariadb-server depends on mariadb-server-10.1 (= 10.1.10+maria-1~trusty); however: Package mariadb-server-10.1 is not configured yet. dpkg: error processing package mariadb-server (--configure): dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure. Errors were encountered while processing: mariadb-server-10.1 mariadb-server E: Sub-process /usr/bin/dpkg returned an error code (1) ``` This situation could occur if the timeout for the init script was too short. For example, see [MDEV-9382](https://jira.mariadb.org/browse/MDEV-9382), a situation where the timeout was 30 seconds, but the server was taking 48 seconds to start. To overcome this, the timeout needs to be increased. This can be achieved as follows: * **On systems where systemd is not enabled/supported:** The timeout can be increased by setting MYSQLD\_STARTUP\_TIMEOUT either directly in the script or via the command line. In [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/) and later versions, the init script also sources /etc/default/mariadb, so it can also be used to set MYSQLD\_STARTUP\_TIMEOUT to persistently change the startup timeout. The default timeout has been increased from 30s to 60s in [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/). * **On systems that support systemd**: The startup timeout can be increased by setting [TimeoutStartSec systemd](../systemd/index) option. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb QA Datasets QA Datasets ============ Realistic datasets are essential for proper testing. | Title | Description | | --- | --- | | [DBT-3 Dataset](../dbt-3-dataset/index) | This page describes our setup for DBT-3 tests. A very cogent resource on th... | | [OpenStreetMap Dataset](../openstreetmap-dataset/index) | This page describes how to use the OpenStreetMap dataset in testing. Databa... | | [osmdb06.sql](../osmdb06sql/index) | Below is the schema described in the OpenStreetMap Dataset Use article. To ... | | [DBT-3 Queries](../dbt-3-queries/index) | Q1 See MDEV-4309 (just speeding up temptable-based GROUP BY execution). Opt... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb LibreOffice Base LibreOffice Base ================ [LibreOffice Base](https://www.libreoffice.org/discover/base/) is an open source RDBMS (relational database management system) front-end tool to create and manage various databases. Preparing the ODBC Connection ----------------------------- First, make sure to prepare MariaDB Connector/ODBC as explained in [MariaDB Connector/ODBC](../about-mariadb-connector-odbc/index). That includes: * Download [the latest MariaDB Connector/ODBC](https://mariadb.com/downloads/#connectors) * Copy the shared library *libmaodbc.so* to */usr/lib/[multi-arch]* * Install the *unixodbc, unixodbc-dev, openssh-client, odbcinst* packages * Create a template file for the [ODBC driver](../creating-a-data-source-with-mariadb-connectorodbc/index#configuring-mariadb-connectorodbc-as-a-unixodbc-driver-on-linux). A sample *“MariaDB\_odbc\_driver\_template.ini”* could be: | | | --- | | [MariaDB ODBC 3.1 Driver] | | Description = MariaDB Connector/ODBC v.3.1 | | Driver = /usr/lib/x86\_64-linux-gnu/libmaodbc.so | * Install the ODBC driver from the template file by running: ``` $ sudo odbcinst -i -d -f MariaDB_odbc_driver_template.ini odbcinst: Driver installed. Usage count increased to 1. Target directory is /etc ``` Verify successful installation in */etc/odbcinst.ini* file (this path is obtained by the config info */-j*/ option, where drivers are installed in that predefined location). ``` $ odbcinst -j unixODBC 2.3.6 DRIVERS............: /etc/odbcinst.ini SYSTEM DATA SOURCES: /etc/odbc.ini FILE DATA SOURCES..: /etc/ODBCDataSources USER DATA SOURCES..: /home/anel/.odbc.ini SQLULEN Size.......: 8 SQLLEN Size........: 8 SQLSETPOSIROW Size.: 8 $ cat /etc/odbcinst.ini [MariaDB ODBC 3.1 Driver] Description=MariaDB Connector/ODBC v.3.1 Driver=/usr/lib/x86_64-linux-gnu/libmaodbc.so UsageCount=1 ``` * Create a template file for the [Data Source Name (DSN)](../creating-a-data-source-with-mariadb-connectorodbc/index#configuring-a-dsn-with-unixodbc-on-linux). A sample *“MariaDB\_odbc\_data\_source\_template.ini”* could be: | | | --- | | [MariaDB-server] | | Description=MariaDB server | | Driver=MariaDB ODBC 3.1 Driver | | SERVER=localhost | | USER=anel | | PASSWORD= | | DATABASE=test | | PORT=3306 | * Install data source: ``` odbcinst -i -s -h -f MariaDB_odbc_data_source_template.ini ``` * Verify successful installation in the */.odbc.ini* file ``` $ cat ~/.odbc.ini [MariaDB-server] Description=MariaDB server Driver=MariaDB ODBC 3.1 Driver SERVER=MariaDB USER=anel PASSWORD= DATABASE=test PORT=3306 ``` * Verify successful installation also using the [isql](../creating-a-data-source-with-mariadb-connectorodbc/index#verifying-a-dsn-configuration-with-unixodbc-on-linux) utility, for example: ``` $ isql MariaDB-server +---------------------------------------+ | Connected! | | | | sql-statement | | help [tablename] | | quit | | | +---------------------------------------+ SQL> show tables; +--------------------------------------------------------------------------+ | Tables_in_test | +--------------------------------------------------------------------------+ | Authors | | tbl_names | | webposts | | webusers | +--------------------------------------------------------------------------+ SQLRowCount returns 4 4 rows fetched ``` Start with LibreOffice Base --------------------------- Start Libreoffice Base from the terminal by running *lobase* (make sure to install the *libreoffice-base* package if needed). The default option is to create a new database, which is *HSQLDB*. In order to connect to a running MariaDB server, choose *“Connect to an existing database”* and choose *“ODBC”* driver as shown below: After that, choose DSN (the one that we created in the previous step) and click *“Next”*: Provide a user name (and password if needed) and again check the connection (with the *“Test Connection”* button) and click *“Next”*: After that, we have options to register the database. Registration in this sense means that the database is viewable by other LibreOffice modules (like *LibreOffice Calc* and *LibreOffice Writer*). So this step is optional. In this example, we will save as *“fosdem21\_mariadb.odb”*. See [Using a Registered Database](##using-a-registered-database). It opens the following window: It consists of three windows/panels: 1. *“Database”* window with the options 1. *"Tables"*, 2. *"Queries"*, 3. *"Forms"*, 4. *"Reports"*. 2. "Tasks window (dependent on what is selected in the *“Database”* window). When *“Tables”* is selected, the options are: 1. *"Create Table in Design View"*, 2. *"Use Wizard to Create Table"* and 3. *"Create View"*. 3. *"Tables"* window - shows list of tables that are created. As we can see, there are system tables in the *“mysql”* database as well as *“test”* database. Let’s say we create a table using the REST API from JSON data from <http://jsonplaceholder.typicode.com/posts>, and another table using the same mechanism from <http://jsonplaceholder.typicode.com/users>, and let’s call them *webposts* and *webusers*. In order to do so, we have to enable the **CONNECT** storage engine plugin and start with REST\_API. See more in the [CONNECT - Files Retrieved Using Rest Queries](../connect-files-retrieved-using-rest-queries/index) article. The queries we need to run in MariaDB are: ``` CREATE TABLE webusers ENGINE=CONNECT TABLE_TYPE=JSON HTTP='http://jsonplaceholder.typicode.com/users'; CREATE TABLE webposts ENGINE=CONNECT TABLE_TYPE=JSON HTTP='http://jsonplaceholder.typicode.com/posts'; ``` The result in LibreOffice Base will be as shown below: Double clicking on the table opens a new window with the data displayed to inspect: To create the table from the *“Tasks”* window, use the option *“Create Table in Design View”*, where one can specify specific field names and types as shown: From the “Tasks” window one can create a table using the option *“Use Wizard to Create Table”* to create some sample tables. One can fill the data in the existing table, or create and define the new table from the *LibreOffice Calc* module with simple copy-paste (in the *"Tasks"* window). Using a Registered Database --------------------------- Other modules can use the registered database, for example, open *"LibreOffice Calc"* and go to *"Tools"*, *"Options"* and you will see the *"odb"* file we registered when starting *"LibreOffice Base"*. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb System Variables Added in MariaDB 5.5 System Variables Added in MariaDB 5.5 ===================================== This is a list of [system variables](../server-system-variables/index) that were added in the [MariaDB 5.5](../what-is-mariadb-55/index) series. The list excludes variables related to non-default storage engines and plugins that can be added to [MariaDB 5.5](../what-is-mariadb-55/index): | Variable | Added | | --- | --- | | [innodb\_adaptive\_flushing\_method](../xtradbinnodb-server-system-variables/index#innodb_adaptive_flushing_method) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_adaptive\_hash\_index\_partitions](../xtradbinnodb-server-system-variables/index#innodb_adaptive_hash_index_partitions) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_blocking\_buffer\_pool\_restore](../xtradbinnodb-server-system-variables/index#innodb_blocking_buffer_pool_restore) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_buffer\_pool\_instances](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_instances) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [nnodb\_buffer\_pool\_restore\_at\_startup](../xtradbinnodb-server-system-variables/index#innodb_buffer_pool_restore_at_startup) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_change\_buffering\_debug](../xtradbinnodb-server-system-variables/index#innodb_change_buffering_debug) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_corrupt\_table\_action](../xtradbinnodb-server-system-variables/index#innodb_corrupt_table_action) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_flush\_checkpoint\_debug](../xtradbinnodb-server-system-variables/index#innodb_flush_checkpoint_debug) | | [innodb\_force\_load\_corrupted](../xtradbinnodb-server-system-variables/index#innodb_force_load_corrupted) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_import\_table\_from\_xtrabackup](../xtradbinnodb-server-system-variables/index#innodb_import_table_from_xtrabackup) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_large\_prefix](../xtradbinnodb-server-system-variables/index#innodb_large_prefix) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_purge\_batch\_size](../xtradbinnodb-server-system-variables/index#innodb_purge_batch_size) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_purge\_threads](../xtradbinnodb-server-system-variables/index#innodb_purge_threads) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_recovery\_update\_relay\_log](../xtradbinnodb-server-system-variables/index#innodb_recovery_update_relay_log) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_rollback\_segments](../xtradbinnodb-server-system-variables/index#innodb_rollback_segments) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_use\_global\_flush\_log\_at\_trx\_commit](../xtradbinnodb-server-system-variables/index#innodb_use_global_flush_log_at_trx_commit) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | | [innodb\_use\_native\_aio](../xtradbinnodb-server-system-variables/index#innodb_use_native_aio) | [MariaDB 5.5.20](https://mariadb.com/kb/en/mariadb-5520-release-notes/) | See also -------- * [System Variables Added in MariaDB 10.0](../system-variables-added-in-mariadb-100/index) * [Upgrading from MariaDB 5.3 to MariaDB 5.5](../upgrading-from-mariadb-55-to-mariadb-100/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema Tables Information Schema Tables ========================== | Title | Description | | --- | --- | | [Information Schema InnoDB Tables](../information-schema-innodb-tables/index) | All InnoDB-specific Information Schema tables. | | [Information Schema MyRocks Tables](../information-schema-myrocks-tables/index) | List of Information Schema tables specifically related to MyRocks. | | [Information Schema XtraDB Tables](../information-schema-xtradb-tables/index) | All XtraDB-specific Information Schema tables. | | [ColumnStore Information Schema Tables](../columnstore-information-schema-tables/index) | ColumnStore-related Information Schema tables | | [Information Schema ALL\_PLUGINS Table](../all-plugins-table-information-schema/index) | Information about server plugins, whether installed or not. | | [Information Schema APPLICABLE\_ROLES Table](../information-schema-applicable_roles-table/index) | Roles available to be used. | | [Information Schema CHARACTER\_SETS Table](../information-schema-character_sets-table/index) | Supported character sets. | | [Information Schema CHECK\_CONSTRAINTS Table](../information-schema-check_constraints-table/index) | Supported check constraints. | | [Information Schema CLIENT\_STATISTICS Table](../information-schema-client_statistics-table/index) | Statistics about client connections. | | [Information Schema COLLATION\_CHARACTER\_SET\_APPLICABILITY Table](../information-schema-collation_character_set_applicability-table/index) | Collations and associated character sets | | [Information Schema COLLATIONS Table](../information-schema-collations-table/index) | Supported collations. | | [Information Schema COLUMN\_PRIVILEGES Table](../information-schema-column_privileges-table/index) | Column privileges | | [Information Schema COLUMNS Table](../information-schema-columns-table/index) | Information about table fields. | | [Information Schema DISKS Table](../information-schema-disks-table/index) | Plugin that allows the disk space situation to be monitored. | | [Information Schema ENABLED\_ROLES Table](../information-schema-enabled_roles-table/index) | Enabled roles for the current session. | | [Information Schema ENGINES Table](../information-schema-engines-table/index) | Storage engine information. | | [Information Schema EVENTS Table](../information-schema-events-table/index) | Server event information | | [Information Schema FEEDBACK Table](../information-schema-feedback-table/index) | Contents submitted by the Feedback Plugin | | [Information Schema FILES Table](../information-schema-files-table/index) | The FILES tables is unused in MariaDB. | | [Information Schema GEOMETRY\_COLUMNS Table](../information-schema-geometry_columns-table/index) | Support for Spatial Reference systems for GIS data | | [Information Schema GLOBAL\_STATUS and SESSION\_STATUS Tables](../information-schema-global_status-and-session_status-tables/index) | Global and session status variables | | [Information Schema GLOBAL\_VARIABLES and SESSION\_VARIABLES Tables](../information-schema-global_variables-and-session_variables-tables/index) | Global and session system variables | | [Information Schema INDEX\_STATISTICS Table](../information-schema-index_statistics-table/index) | Statistics on index usage | | [Information Schema KEY\_CACHES Table](../information-schema-key_caches-table/index) | Segmented key cache statistics. | | [Information Schema KEY\_COLUMN\_USAGE Table](../information-schema-key_column_usage-table/index) | Key columns that have constraints. | | [Information Schema KEYWORDS Table](../information-schema-keywords-table/index) | MariaDB keywords. | | [Information Schema LOCALES Table](../information-schema-locales-table/index) | Compiled-in server locales. | | [Information Schema METADATA\_LOCK\_INFO Table](../information-schema-metadata_lock_info-table/index) | Active metadata locks. | | [Information Schema MROONGA\_STATS Table](../information-schema-mroonga_stats-table/index) | Mroonga activities statistics. | | [Information Schema OPTIMIZER\_TRACE Table](../information-schema-optimizer_trace-table/index) | Contains Optimizer Trace information. | | [Information Schema PARAMETERS Table](../information-schema-parameters-table/index) | Information about stored procedures and stored functions parameters. | | [Information Schema PARTITIONS Table](../information-schema-partitions-table/index) | Table partition information | | [Information Schema PLUGINS Table](../plugins-table-information-schema/index) | Information Schema table containing information on plugins installed on a server. | | [Information Schema PROCESSLIST Table](../information-schema-processlist-table/index) | Thread information. | | [Information Schema PROFILING Table](../information-schema-profiling-table/index) | Statement resource usage | | [Information Schema QUERY\_CACHE\_INFO Table](../information-schema-query_cache_info-table/index) | View the contents of the query cache. | | [Information Schema QUERY\_RESPONSE\_TIME Table](../information-schema-query_response_time-table/index) | Query time information. | | [Information Schema REFERENTIAL\_CONSTRAINTS Table](../information-schema-referential_constraints-table/index) | Foreign key information | | [Information Schema ROUTINES Table](../information-schema-routines-table/index) | Stored procedures and stored functions information | | [Information Schema SCHEMA\_PRIVILEGES Table](../information-schema-schema_privileges-table/index) | Database privilege information | | [Information Schema SCHEMATA Table](../information-schema-schemata-table/index) | Information about databases. | | [Information Schema SPATIAL\_REF\_SYS Table](../information-schema-spatial_ref_sys-table/index) | Information on each spatial reference system used in the database | | [Information Schema SPIDER\_ALLOC\_MEM Table](../information-schema-spider_alloc_mem-table/index) | Information about Spider's memory usage. | | [Information Schema SPIDER\_WRAPPER\_PROTOCOLS Table](../information-schema-spider_wrapper_protocols-table/index) | Installed along with the Spider storage engine. | | [Information Schema SQL\_FUNCTIONS Table](../information-schema-sql_functions-table/index) | Functions in MariaDB. | | [Information Schema STATISTICS Table](../information-schema-statistics-table/index) | Table index information. | | [Information Schema SYSTEM\_VARIABLES Table](../information-schema-system_variables-table/index) | Current global and session values and various metadata of all system variables. | | [Information Schema TABLE\_CONSTRAINTS Table](../information-schema-table_constraints-table/index) | Tables containing constraints. | | [Information Schema TABLE\_PRIVILEGES Table](../information-schema-table_privileges-table/index) | Table privileges | | [Information Schema TABLE\_STATISTICS Table](../information-schema-table_statistics-table/index) | Statistics on table usage. | | [Information Schema TABLES Table](../information-schema-tables-table/index) | Database table information. | | [Information Schema TABLESPACES Table](../information-schema-tablespaces-table/index) | Information about active tablespaces. | | [Information Schema THREAD\_POOL\_GROUPS Table](../information-schema-thread_pool_groups-table/index) | Information Schema THREAD\_POOL\_GROUPS Table. | | [Information Schema THREAD\_POOL\_QUEUES Table](../information-schema-thread_pool_queues-table/index) | Information Schema THREAD\_POOL\_QUEUES Table. | | [Information Schema THREAD\_POOL\_STATS Table](../information-schema-thread_pool_stats-table/index) | Information Schema THREAD\_POOL\_STATS Table. | | [Information Schema THREAD\_POOL\_WAITS Table](../information-schema-thread_pool_waits-table/index) | Information Schema THREAD\_POOL\_WAITS Table. | | [Information Schema TRIGGERS Table](../information-schema-triggers-table/index) | Information about triggers | | [Information Schema USER\_PRIVILEGES Table](../information-schema-user_privileges-table/index) | Global user privilege information derived from the mysql.user grant table | | [Information Schema USER\_STATISTICS Table](../information-schema-user_statistics-table/index) | User activity | | [Information Schema USER\_VARIABLES Table](../information-schema-user_variables-table/index) | User-defined variable information. | | [Information Schema VIEWS Table](../information-schema-views-table/index) | Information about views. | | [Information Schema WSREP\_MEMBERSHIP Table](../information-schema-wsrep_membership-table/index) | Galera node cluster membership information. | | [Information Schema WSREP\_STATUS Table](../information-schema-wsrep_status-table/index) | Galera node cluster status information. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Statistics for Optimizing Queries Statistics for Optimizing Queries ================================== Different statistics provided by MariaDB to help you optimize your queries | Title | Description | | --- | --- | | [Engine-Independent Table Statistics](../engine-independent-table-statistics/index) | Table statistics independent of the storage engine. | | [Histogram-Based Statistics](../histogram-based-statistics/index) | Histogram-based statistics can improve the optimizer query plan in certain situations. | | [Index Statistics](../index-statistics/index) | Index statistics and the query optimizer. | | [InnoDB Persistent Statistics](../innodb-persistent-statistics/index) | InnoDB persistent statistics are stored on disk, leading to more consistent query plans. | | [Slow Query Log Extended Statistics](../slow-query-log-extended-statistics/index) | The slow query log makes extended statistics available. | | [User Statistics](../user-statistics/index) | User Statistics. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DATE FUNCTION DATE FUNCTION ============= Syntax ------ ``` DATE(expr) ``` Description ----------- Extracts the date part of the date or datetime expression expr. Examples -------- ``` SELECT DATE('2013-07-18 12:21:32'); +-----------------------------+ | DATE('2013-07-18 12:21:32') | +-----------------------------+ | 2013-07-18 | +-----------------------------+ ``` Error Handling -------------- Until [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/), some versions of MariaDB returned `0000-00-00` when passed an invalid date. From 5.5.32, NULL is returned. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Understanding Denormalization Understanding Denormalization ============================= *Denormalization* is the process of reversing the transformations made during [normalization](../database-normalization/index) for performance reasons. It's a topic that stirs controversy among database experts; there are those who claim the cost is too high and never denormalize, and there are those that tout its benefits and routinely denormalize. For proponents of denormalization, the thinking is as follows: normalization creates more tables as you proceed towards higher normal forms, but more tables mean there are more joins to be made when data is retrieved, which in turn slows down your queries. For that reason, to improve the performance of certain queries, you can override the advantages to data integrity and return the data structure to a lower normal form. A practical approach makes sense, taking into account the limitations of SQL and MariaDB in particular, but being cautious not to needless denormalize. Here are some suggestions: * if your performance with a normalized structure is acceptable, you should not denormalize. * if your performance is unacceptable, make sure normalizing will cause it to become acceptable. There are very likely to be other alternatives, such as better hardware, load balancing, etc. It's hard to undo structural changes later. * be sure you are willing to trade decreased data integrity for the increase in performance. * consider possible future scenario, where applications may place different requirements on the data. Denormalizing to enhance performance of a specific application makes your data structure dependent on that application, when in an ideal situation it will be application-independent. The table below introduces a common structure where it may not be in your best interests to denormalize. Which normal form is it in? | Customer table | | --- | | *ID* | | First name | | Surname | | Address line 1 | | Address line 2 | | Town | | Zip code | It must be in [1st normal form](../database-normalization-1st-normal-form/index) because it has a primary key and there are no repeating groups. It must be in [2nd normal form](../database-normalization-2nd-normal-form/index) because there's only one key, so there cannot be any partial dependencies. And [3rd normal form](../database-normalization-3rd-normal-form/index)? Are there any transitive dependencies? It looks like it. *Zip Code* is probably determined by the town attribute. To transform it into [3rd normal form](../database-normalization-3rd-normal-form/index), you should take out *Zi..p code*, putting it in a separate table with town as the key. In most cases, though, this is not worth doing. So although this table is not in 3rd normal form, separating the table is not worth the trouble. The more tables you have, the more joins you need to do, which slows the system down. The reason you normalize at all is to reduce the size of the tables by removing redundant data, and doing do can often speed up the system. But you also need to look at how your tables are used. *Town* and *Zip code* would almost always be returned together, as part of the address. In most cases, the small amount of space you save by removing the duplicate town/zip code combinations would not offset the slowing down of the system because of the extra joins. In some situations, this may be useful, perhaps where you need to sort addresses according to zip codes or towns for many thousands of customers, and the distribution of data means that a query to the new, smaller table can return the results substantially quicker. In the end, experienced database designers can go beyond rigidly following the steps, as they understand how the data will be used. And that is something only experience can teach you. Normalization is just a helpful set of steps that most often produces an efficient table structure, and not a rule for database design. There are some scary database designs out there, almost always because of not normalizing rather than too much normalization. So if you're unsure, normalize! Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb UTC_TIME UTC\_TIME ========= Syntax ------ ``` UTC_TIME UTC_TIME([precision]) ``` Description ----------- Returns the current [UTC time](../coordinated-universal-time/index) as a value in 'HH:MM:SS' or HHMMSS.uuuuuu format, depending on whether the function is used in a string or numeric context. The optional *precision* determines the microsecond precision. See [Microseconds in MariaDB](../microseconds-in-mariadb/index). Examples -------- ``` SELECT UTC_TIME(), UTC_TIME() + 0; +------------+----------------+ | UTC_TIME() | UTC_TIME() + 0 | +------------+----------------+ | 17:32:34 | 173234.000000 | +------------+----------------+ ``` With precision: ``` SELECT UTC_TIME(5); +----------------+ | UTC_TIME(5) | +----------------+ | 07:52:50.78369 | +----------------+ ``` See Also -------- * [Microseconds in MariaDB](../microseconds-in-mariadb/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Beginner MariaDB Articles Beginner MariaDB Articles ========================== These tutorial articles were written for those who very little about databases and nothing about MariaDB. They are articles for newcomers and beginners. | Title | Description | | --- | --- | | [A MariaDB Primer](../a-mariadb-primer/index) | A 10-minute primer on using MariaDB. | | [MariaDB Basics](../mariadb-basics/index) | Basic article on using MariaDB. | | [Getting Data from MariaDB](../getting-data-from-mariadb/index) | Extensive tutorial on using the SELECT statement. | | [Adding and Changing Data in MariaDB](../adding-and-changing-data-in-mariadb/index) | Tutorial on using INSERT and UPDATE statements. | | [Altering Tables in MariaDB](../altering-tables-in-mariadb/index) | Tutorial on using the ALTER TABLE statement. | | [Changing Times in MariaDB](../changing-times-in-mariadb/index) | Tutorial on using various time and date functions in MariaDB. | | [Doing Time with MariaDB](../doing-time-with-mariadb/index) | Tutorial about temporal data types and functions. | | [Importing Data into MariaDB](../importing-data-into-mariadb/index) | Tutorial on using the LOAD DATA INFILE statement. | | [Making Backups with mysqldump](../making-backups-with-mysqldump/index) | Tutorial article on how to make back-ups with mysqldump. | | [MariaDB String Functions](../mariadb-string-functions/index) | Extensive tutorial on how to use several string functions. | | [Restoring Data from Dump Files](../restoring-data-from-dump-files/index) | Tutorial on how to restore data from a mysqldump backup. | | [Basic SQL Statements](../basic-sql-statements/index) | Basic SQL statements for structuring and manipulating data. | | [Connecting to MariaDB](../connecting-to-mariadb/index) | Connecting to MariaDB with the basic connection parameters. | | [External Tutorials](../external-tutorials/index) | Links to external MariaDB, MySQL and SQL tutorials. | | [Useful MariaDB Queries](../useful-mariadb-queries/index) | Quick reference of commonly-used MariaDB queries. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Automating MariaDB Tasks with Events Automating MariaDB Tasks with Events ==================================== MariaDB has an event scheduler that can be used to automate tasks, making them run at regular intervals of time. This page is about using events for [automation](../automated-mariadb-deployment-and-administration/index). For more information about events themselves, and how to work with them, see [event scheduler](../event-scheduler/index). Pros and Cons of Using Events for Automation -------------------------------------------- Events can be compared to Unix cron jobs or Windows scheduled tasks. MariaDB events have at least the following benefits compared to those tools: * Events are system-independent. The same code can run on any system. * Events are written in procedural SQL. There is no need to install other languages or libraries. * If you use [user-defined functions](../user-defined-functions/index), you can still take advantage of them in your events. * Events run in MariaDB. An implication, for example, is that the results of queries remain in MariaDB itself and are not sent to a client. This means that network glitches don't affect events, there is no overhead due to data roundtrip, and therefore locks are held for a shorter time. Some drawbacks of using events are the following: * Events can only perform tasks that can be developed in SQL. So, for example, it is not possible to send alerts. Access to files or remote databases is limited. * The event scheduler runs as a single thread. If any event is supposed to start while another event is running, its execution will be skipped. It cannot be just postponed. This can be a big problem when automating a number of tasks that should run in a limited time range. But this is fine when running a limited number of tasks that may occasionally be skipped without remarkable consequences. * For more events limitations, see [Event Limitations](../event-limitations/index). In many cases you may prefer to develop scripts in an external programming language. However, you should know that simple tasks consisting of a few queries can easily be implemented as events. Good Practices -------------- When using events to automate tasks, there are good practices one may want to follow. Move your SQL code in a stored procedure. All the event will do is to call a stored procedures. Several events may call the same stored procedure, maybe with different parameters. The procedure may also be called manually, if necessary. This will avoid code duplication. This will separate the logic from the schedule, making it possible to change an event without a risk of making changes to the logic, and the other way around. Just like cron jobs, events should log whether if they succeed or not. Logging debug messages may also be useful for non-trivial events. This information can be logged into a dedicated table. The contents of the table can be monitored by a monitoring tool like Grafana. This allows to visualize in a dashboard the status of events, and send alerts in case of a failure. Examples -------- Some examples of tasks that could easily be automated with events: * Copying data from a remote table to a local table by night, using the [CONNECT](../connect/index) storage engine. This can be a good idea if many rows need be copied, because data won't be sent to an external client. * Periodically delete historical data. For example, rows that are older than 5 years. Nothing prevents us from doing this with an external script, but probably this wouldn't add any value. * Periodically delete invalid rows. In an e-commerce, they could be abandoned carts. In a messaging system, they could be messages to users that don't exist anymore. * Add a new [partition](../partitioning-tables/index) to a table and drop the oldest one (partition rotation). --- Content initially contributed by [Vettabase Ltd](https://vettabase.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema ENABLED_ROLES Table Information Schema ENABLED\_ROLES Table ======================================= The [Information Schema](../information_schema/index) `ENABLED_ROLES` table shows the enabled [roles](../roles/index) for the current session. It contains the following column: | Column | Description | | --- | --- | | `ROLE_NAME` | The enabled role name, or `NULL`. | This table lists all roles that are currently enabled, one role per row — the current role, roles granted to the current role, roles granted to these roles and so on. If no role is set, the row contains a `NULL` value. The roles that the current user can enable are listed in the [APPLICABLE\_ROLES](../information-schema-applicable_roles-table/index) Information Schema table. See also [CURRENT\_ROLE()](../current_role/index). Examples -------- ``` SELECT * FROM information_schema.ENABLED_ROLES; +-----------+ | ROLE_NAME | +-----------+ | NULL | +-----------+ SET ROLE staff; SELECT * FROM information_schema.ENABLED_ROLES; +-----------+ | ROLE_NAME | +-----------+ | staff | +-----------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb System Variables Added in MariaDB 10.5 System Variables Added in MariaDB 10.5 ====================================== This is a list of [system variables](../server-system-variables/index) that have been added in the [MariaDB 10.5](../what-is-mariadb-105/index) series. The list does not include variables that are not part of the default release. | Variable | Added | | --- | --- | | [binlog\_row\_metadata](../replication-and-binary-log-system-variables/index#binlog_row_metadata) | [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) | | [innodb\_instant\_alter\_column\_allowed](../innodb-system-variables/index#innodb_instant_alter_column_allowed) | [MariaDB 10.5.3](https://mariadb.com/kb/en/mariadb-1053-release-notes/) | | [innodb\_lru\_flush\_size](../innodb-system-variables/index#innodb_lru_flush_size) | [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/) | | [innodb\_max\_purge\_lag\_wait](../innodb-system-variables/index#innodb_max_purge_lag_wait) | [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/) | | [optimizer\_max\_sel\_arg\_weight](../server-system-variables/index#optimizer_max_sel_arg_weight) | [MariaDB 10.5.9](https://mariadb.com/kb/en/mariadb-1059-release-notes/) | | [performance\_schema\_events\_transactions\_history\_long\_size](../performance-schema-system-variables/index#performance_schema_events_transactions_history_long_size) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_events\_transactions\_history\_size](../performance-schema-system-variables/index#performance_schema_events_transactions_history_size) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_index\_stat](../performance-schema-system-variables/index#performance_schema_max_index_stat) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_memory\_classes](../performance-schema-system-variables/index#performance_schema_max_memory_classes) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_metadata\_locks](../performance-schema-system-variables/index#performance_schema_max_metadata_locks) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_prepared\_statement\_instances](../performance-schema-system-variables/index#performance_schema_max_prepared_statement_instances) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_program\_instances](../performance-schema-system-variables/index#performance_schema_max_program_instances) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_sql\_text\_length](../performance-schema-system-variables/index#performance_schema_max_sql_text_length) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_statement\_stack](../performance-schema-system-variables/index#performance_schema_max_statement_stack) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [performance\_schema\_max\_table\_lock\_stat](../performance-schema-system-variables/index#performance_schema_max_table_lock_stat) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [require\_secure\_transport](../server-system-variables/index#require_secure_transport) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [s3\_access\_key](../s3-storage-engine-system-variables/index#s3_access_key) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_block\_size](../s3-storage-engine-system-variables/index#s3_block_size) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_bucket](../s3-storage-engine-system-variables/index#s3_bucket) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_debug](../s3-storage-engine-system-variables/index#s3_debug) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_host\_name](../s3-storage-engine-system-variables/index#s3_host_name) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_pagecache\_age\_threshold](../s3-storage-engine-system-variables/index#s3_pagecache_age_threshold) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_pagecache\_buffer\_size](../s3-storage-engine-system-variables/index#s3_pagecache_buffer_size) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_pagecache\_division\_limit](../s3-storage-engine-system-variables/index#s3_pagecache_division_limit) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_pagecache\_file\_hash\_size](../s3-storage-engine-system-variables/index#s3_pagecache_file_hash_size) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_protocol\_version](../s3-storage-engine-system-variables/index#s3_protocol_version) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_region](../s3-storage-engine-system-variables/index#s3_region) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [s3\_secret\_key](../s3-storage-engine-system-variables/index#s3_secret_key) | [MariaDB 10.5](../what-is-mariadb-105/index) | | [sql\_if\_exists](../server-system-variables/index#sql_if_exists) | [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/) | | [thread\_pool\_dedicated\_listener](../thread-pool-system-status-variables/index#thread_pool_dedicated_listener) | [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) | | [thread\_pool\_exact\_stats](../thread-pool-system-status-variables/index#thread_pool_exact_stats) | [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) | See Also -------- * [Status Variables Added in MariaDB 10.5](../status-variables-added-in-mariadb-105/index) * [System Variables Added in MariaDB 10.4](../system-variables-added-in-mariadb-104/index) * [System Variables Added in MariaDB 10.3](../system-variables-added-in-mariadb-103/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Buildbot Setup for VM host Buildbot Setup for VM host ========================== This page documents the general setup process for a server that is acting as virtual machine host, like those documented in the [Buildbot Setup for Virtual Machines](../buildbot-setup-for-virtual-machines/index) section. 1. Provision hardware with most recent Ubuntu LTS release 2. Add host to DNS 3. Apply updates (replace `<host>` with hostname) ``` ssh <host>.mariadb.net sudo apt-get update sudo apt-get dist-upgrade ``` 4. install some favorite packages (these aren't necessarily required, but I like them) ``` sudo apt-get install tree renameutils vim-nox ``` 5. a buildbot admin needs to add the new host to the allowed list of rsync clients on the VM master (whichever host is the *official* host of VM files) The VM master changes periodically, so check to make sure you have the correct one. ``` vi /etc/rsyncd.conf ``` 6. make a `/kvm/` dir and rsync it with the VM master above. The dir often resides at `/home/kvm/` (or wherever the storage drive is) and is then linked to `/kvm/`. The VMs rely on the `/kvm/vms/` path, so the `/kvm/` location is required. ``` vm_master="hostname" # ask for this from a buildbot admin mkdir /home/kvm ln -sv /home/kvm /kvm rsync --dry-run --delete --exclude=deprecated \\ --exclude=iso --exclude=lost+found -avPL ${vm_master}::kvm/ /home/kvm/ # assuming the dry-run looks good, start the "real" rsync in a screen session screen rsync --delete --exclude=deprecated --exclude=iso --exclude=lost+found -avPL ${vm_master}::kvm/ /home/kvm/ ``` 7. detatch from screen session with `Ctrl+a d` 8. Configure vim.basic as the default editor (optional) ``` update-alternatives --config editor ``` 9. install buildbot-slave, bzr, and kvm ``` sudo apt-get install bzr git buildbot-slave qemu kvm sudo apt-get install libsdl2-2.0-0 ``` 10. add a default user, and then add the user to the appropriate groups ``` username="mydefaultusername" sudo adduser ${username} for group in sudo tty kvm;do sudo adduser ${username} ${group} done ``` 11. logout then back in as the default user and change the password 13. set up the `/.ssh/authorized_keys` file so you can login that way 14. create other standard users and set up their ssh keys (optional) 15. turn off password login (WARNING: be sure to have your ssh key setup before doing this!) and disallow all root logins and password logins (it is safer to only allow logins using ssh keys with regular users): ``` sudo perl -i -pe "s/#PasswordAuthentication yes/PasswordAuthentication no/" /etc/ssh/sshd_config sudo perl -i -pe "s/PermitRootLogin yes/PermitRootLogin no/" /etc/ssh/sshd_config sudo /etc/init.d/ssh restart ``` 16. checkout mariadb-tools ``` mkdir ~/src cd ~/src/ bzr branch lp:mariadb-tools ``` 17. put runvm in the right place ``` sudo cp -v ~/src/mariadb-tools/buildbot/runvm /usr/local/bin/ ls -l /usr/local/bin/ ``` 18. add the buildbot user to the kvm and tty groups ``` sudo adduser buildbot kvm sudo adduser buildbot tty ``` 19. A buildbot admin will need to add this builder to the `maria-master-private.cfg` file on the `${buildmaster}` and also add it to the `c['slaves']` array in `maria-master.cfg` then create the buildslave using the hostname and whatever `${password}` was agreed upon by you and the buildbot admin: ``` sudo buildslave create-slave /var/lib/buildbot/slaves/maria buildbot.askmonty.org ${host} ${password} ``` 20. add the following to `/etc/default/buildslave` (replace `${hostname}` with the name of the host) ``` HOME=/var/lib/buildbot SLAVE_ENABLED[1]=1 SLAVE_NAME[1]="${hostname} maria slave" SLAVE_USER[1]="buildbot" SLAVE_BASEDIR[1]="$HOME/slaves/maria" SLAVE_OPTIONS[1]="" SLAVE_PREFIXCMD[1]="" ``` 21. edit the admin and host files and add contact information and details on the builder: ``` sudo vi /var/lib/buildbot/slaves/maria/info/* ``` 22. copy over the buildbot .ssh dir from terrier: ``` scp terrier.askmonty.org:buildbot-ssh.tar.gz . cd /var/lib/buildbot sudo tar -zxvf ~/buildbot-ssh.tar.gz sudo chown -Rv buildbot: .ssh sudo chmod -v 700 .ssh sudo chmod -Rv go-r .ssh ``` 23. Edit /etc/passwd and change the buildbot user's shell from `/bin/false` to `/bin/bash` 24. su to the buildbot user and copy in the `/etc/skel` files ``` sudo su - buildbot cp -v /etc/skel/.bash* . cp -v /etc/skel/.profile . exit ``` 25. change ownership of the `buildbot/slaves` dir to `buildbot:buildbot` ``` sudo chown -Rv buildbot:buildbot ~buildbot/slaves ``` 26. move the `/var/lib/buildbot` directory to `/home` (or whatever location you want to use to store things) and then link it back ``` sudo mv -vi /var/lib/buildbot /home/;cd /var/lib/;sudo ln -sv /home/buildbot ./ ``` 27. update `/etc/default/locale` and change it to: `LANG=en_US.UTF-8` ``` sudo vi /etc/default/locale sudo locale-gen ``` 28. monitor the rsync, wait for it to finish 29. once the rsync is finished, test the runvm script ``` sudo su - buildbot for i in '/kvm/vms/vm-xenial-amd64-serial.qcow2 6666 qemu64' '/kvm/vms/vm-xenial-i386-serial.qcow2 6666 qemu64' ; do \ set $i; \ runvm --user=buildbot --logfile=kernel_$2.log --base-image=$1 --port=$2 --cpu=$3 "$(echo $1 | sed -e 's/serial/testtest/')" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get update" \ "sudo DEBIAN_FRONTEND=noninteractive apt-get install -y patch libaio1 debconf-utils unixodbc libxml2 libjudydebian1" \ "= scp -P $2 /kvm/vms/my55.seed /kvm/vms/sources.append buildbot@localhost:/tmp/" \ "sudo debconf-set-selections /tmp/my55.seed" \ "sudo sh -c 'cat /tmp/sources.append >> /etc/apt/sources.list'"; \ done ``` 30. Remove the "testtest" VMs we created above ``` rm -v /kvm/vms/*testtest* ``` 31. Start the buildslave ``` sudo /etc/init.d/buildslave start tail -f ~buildbot/slaves/maria/twistd.log ``` 32. ssh to `${buildmaster}` and add this new host to `kvm_slaves` in the `maria-master.cfg` file ``` sudo vi /etc/buildbot/maria-master.cfg ``` 33. still on `${buildmaster}`, test and then reload buildbot ``` cd /etc/buildbot sudo -u buildbot PYTHONPATH=/usr/local/buildbot/lib/python python -c 'exec open("maria-master.cfg", "r")' sudo /etc/init.d/buildmaster reload sudo tail -f /var/lib/buildbot/maria/twistd.log ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Intermediate and Advanced Books Intermediate and Advanced Books =============================== Below is a list of books on MariaDB for Intermediate and Advanced Developers and Administrators, listed in order by date of publication—the most recent first. We've provided links to Amazon.com or the publisher for convenience, but they can be found at many bookstores. *[Migrating to MariaDB](https://www.apress.com/gp/book/9781484239964)* by William Wood, December 2018 Describes the process and lessons learned during a migration from a proprietary database management engine to the MariaDB open source solution. *[Query Answers with MariaDB: Volume II: Introduction to SQL Queries](https://www.amazon.co.uk/Query-Answers-MariaDB-Depth-Querying/dp/1999617258/ref=sr_1_5?keywords=mariadb&qid=1558010639&s=books&sr=1-5)* by Adam Aspin, Karine Aspin , October 2018 Helps you further develop your analytical abilities as you discover how to write powerful SQL queries. *[Query Answers with MariaDB: Volume I: Introduction to SQL Queries](https://www.amazon.com/Query-Answers-MariaDB-Introduction-Queries/dp/199961724X?tag=uuid10-20)* by Adam Aspin, Karine Aspin , October 2018 Helps you develop your analytical abilities as you discover how to write powerful SQL queries. *[MariaDB and MySQL Common Table Expressions and Window Functions Revealed](http://apress.com/9781484231197)* by Daniel Bartholomew, November 2017 An introduction to [Common Table Expressions](../common-table-expressions/index) (CTEs) and [Window Functions](../window-functions/index) in MariaDB and MySQL. *[MariaDB : Administration et optimisation](https://www.amazon.co.uk/MariaDB-Administration-optimisation-St%C3%A9phane-Combaudon/dp/2409008550)* by Stéphane Combaudon, July 2017 (French) S'adresse aux développeurs et administrateurs MySQL ou MariaDB désireux de consolider leurs connaissances sur la principale variante de MySQL. *[MariaDB High Performance](https://www.packtpub.com/application-development/mariadb-high-performance)* by Pierre Mavro, September 2014 For system administrators/architects or DBAs with existing MariaDB knowledge who want to learn more about how to grow their current infrastructure to support larger traffic. *[Mastering MariaDB](https://www.packtpub.com/application-development/mastering-mariadb)* by Federico Razzoli, September 2014 Aimed at intermediate users who want to learn how to administrate a MariaDB server or a set of servers. *[MariaDB Cookbook](https://www.packtpub.com/big-data-and-business-intelligence/mariadb-cookbook)* by Daniel Bartholomew, March 2014 A cookbook filled with useful MariaDB recipes. Chapters cover such things as [Sphinx](../sphinxse/index), [Connect](../connect/index), [Cassandra](../cassandra/index), [virtual](../virtual-columns/index) and [dynamic columns](../dynamic-columns/index), [TokuDB](../tokudb/index), and more. *[Building a Web Application with PHP and MariaDB: A Reference Guide](https://www.packtpub.com/application-development/building-web-application-php-and-mariadb-reference-guide)* by Sai Srinivas Sriparasa, June 2014 A how-to guide for creating scalable and secure web applications with PHP and MariaDB Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysqldumpslow mysqldumpslow ============= **MariaDB starting with [10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/)**From [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), `mariadb-dumpslow` is a symlink to `mysqldumpslow`. **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), `mariadb-dumpslow` is the name of the tool, with `mysqldumpslow` a symlink . `mysqldumpslow` is a tool to examine the [slow query log](../slow-query-log/index). It parses the slow query log files, printing a summary result. Normally, mysqldumpslow groups queries that are similar except for the particular values of number and string data values. It “abstracts” these values to N and ´S´ when displaying summary output. The `-a` and `-n` options can be used to modify value abstracting behavior. Usage ----- ``` mysqldumpslow [ options... ] [ logs... ] ``` Options ------- | Option | Description | | --- | --- | | `-a` | Don't abstract all numbers to N and strings to 'S' | | `-d`, `--debug` | Debug | | `-g PATTERN` | Grep: only consider statements that include this string | | `--help` | Display help | | `-h HOSTNAME` | Hostname of db server for \*-slow.log filename (can be wildcard), default is '\*', i.e. match all | | `-i NAME` | Name of server instance (if using mysql.server startup script) | | `-l` | Don't subtract lock time from total time | | `-n NUM` | Abstract numbers with at least *NUM* digits within names | | `-r` | Reverse the sort order (largest last instead of first) | | `-s ORDER` | What to sort by (aa, ae, al, ar, at, a, c, e, l, r, t). `at` is default. `aa` average rows affected `ae` aggregated number of rows examined `al` average lock time `ar` average rows sent `at` average query time `a` rows affected `c` count `e` rows examined `l` lock time `r` rows sent `t` query time | | `-t NUM` | Just show the top *NUM* queries. | | `-v`, `--verbose` | Verbose mode. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_GEOMETRYN ST\_GEOMETRYN ============= Syntax ------ ``` ST_GeometryN(gc,N) GeometryN(gc,N) ``` Description ----------- Returns the N-th geometry in the GeometryCollection *`gc`.* Geometries are numbered beginning with 1. `ST_GeometryN()` and `GeometryN()` are synonyms. Example ------- ``` SET @gc = 'GeometryCollection(Point(1 1),LineString(12 14, 9 11))'; SELECT AsText(GeometryN(GeomFromText(@gc),1)); +----------------------------------------+ | AsText(GeometryN(GeomFromText(@gc),1)) | +----------------------------------------+ | POINT(1 1) | +----------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_BUFFER_PAGE Table Information Schema INNODB\_BUFFER\_PAGE Table ============================================= The [Information Schema](../information_schema/index) `INNODB_BUFFER_PAGE` table contains information about pages in the [buffer pool](../xtradbinnodb-memory-buffer/index). The `PROCESS` [privilege](../grant/index) is required to view the table. It has the following columns: | Column | Description | | --- | --- | | `POOL_ID` | Buffer Pool identifier. From [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/) returns a value of 0, since multiple InnoDB buffer pool instances has been removed. | | `BLOCK_ID` | Buffer Pool Block identifier. | | `SPACE` | Tablespace identifier. Matches the `SPACE` value in the `[INNODB\_SYS\_TABLES](../information-schema-innodb_sys_tables-table/index)` table. | | `PAGE_NUMBER` | Buffer pool page number. | | `PAGE_TYPE` | Page type; one of `allocated` (newly-allocated page), `index` (B-tree node), `undo_log` (undo log page), `inode` (index node), `ibuf_free_list` (insert buffer free list), `ibuf_bitmap` (insert buffer bitmap), `system` (system page), `trx_system` (transaction system data), `file_space_header` (file space header), `extent_descriptor` (extent descriptor page), `blob` (uncompressed blob page), `compressed_blob` (first compressed blob page), `compressed_blob2` (subsequent compressed blob page) or `unknown`. | | `FLUSH_TYPE` | Flush type. | | `FIX_COUNT` | Count of the threads using this block in the buffer pool. When it is zero, the block can be evicted from the buffer pool. | | `IS_HASHED` | Whether or not a hash index has been built on this page. | | `NEWEST_MODIFICATION` | Most recent modification's Log Sequence Number. | | `OLDEST_MODIFICATION` | Oldest modification's Log Sequence Number. | | `ACCESS_TIME` | Abstract number representing the time the page was first accessed. | | `TABLE_NAME` | Table that the page belongs to. | | `INDEX_NAME` | Index that the page belongs to, either a clustered index or a secondary index. | | `NUMBER_RECORDS` | Number of records the page contains. | | `DATA_SIZE` | Size in bytes of all the records contained in the page. | | `COMPRESSED_SIZE` | Compressed size in bytes of the page, or `NULL` for pages that aren't compressed. | | `PAGE_STATE` | Page state; one of `FILE_PAGE` (page from a file) or `MEMORY` (page from an in-memory object) for valid data, or one of `NULL`, `READY_FOR_USE`, `NOT_USED`, `REMOVE_HASH`. | | `IO_FIX` | Whether there is I/O pending for the page; one of `IO_NONE` (no pending I/O), `IO_READ` (read pending), `IO_WRITE` (write pending). | | `IS_OLD` | Whether the page is old or not. | | `FREE_PAGE_CLOCK` | Freed\_page\_clock counter, which tracks the number of blocks removed from the end of the least recently used (LRU) list, at the time the block was last placed at the head of the list. | The related [INFORMATION\_SCHEMA.INNODB\_BUFFER\_PAGE\_LRU](../information-schema-innodb_buffer_page_lru-table/index) table contains the same information, but with an LRU (least recently used) position rather than block id. Examples -------- ``` DESC information_schema.innodb_buffer_page; +---------------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------------------+---------------------+------+-----+---------+-------+ | POOL_ID | bigint(21) unsigned | NO | | 0 | | | BLOCK_ID | bigint(21) unsigned | NO | | 0 | | | SPACE | bigint(21) unsigned | NO | | 0 | | | PAGE_NUMBER | bigint(21) unsigned | NO | | 0 | | | PAGE_TYPE | varchar(64) | YES | | NULL | | | FLUSH_TYPE | bigint(21) unsigned | NO | | 0 | | | FIX_COUNT | bigint(21) unsigned | NO | | 0 | | | IS_HASHED | varchar(3) | YES | | NULL | | | NEWEST_MODIFICATION | bigint(21) unsigned | NO | | 0 | | | OLDEST_MODIFICATION | bigint(21) unsigned | NO | | 0 | | | ACCESS_TIME | bigint(21) unsigned | NO | | 0 | | | TABLE_NAME | varchar(1024) | YES | | NULL | | | INDEX_NAME | varchar(1024) | YES | | NULL | | | NUMBER_RECORDS | bigint(21) unsigned | NO | | 0 | | | DATA_SIZE | bigint(21) unsigned | NO | | 0 | | | COMPRESSED_SIZE | bigint(21) unsigned | NO | | 0 | | | PAGE_STATE | varchar(64) | YES | | NULL | | | IO_FIX | varchar(64) | YES | | NULL | | | IS_OLD | varchar(3) | YES | | NULL | | | FREE_PAGE_CLOCK | bigint(21) unsigned | NO | | 0 | | +---------------------+---------------------+------+-----+---------+-------+ ``` ``` SELECT * FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE\G ... *************************** 6. row *************************** POOL_ID: 0 BLOCK_ID: 5 SPACE: 0 PAGE_NUMBER: 11 PAGE_TYPE: INDEX FLUSH_TYPE: 1 FIX_COUNT: 0 IS_HASHED: NO NEWEST_MODIFICATION: 2046835 OLDEST_MODIFICATION: 0 ACCESS_TIME: 2585566280 TABLE_NAME: `SYS_INDEXES` INDEX_NAME: CLUST_IND NUMBER_RECORDS: 57 DATA_SIZE: 4016 COMPRESSED_SIZE: 0 PAGE_STATE: FILE_PAGE IO_FIX: IO_NONE IS_OLD: NO FREE_PAGE_CLOCK: 0 ... ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Partitions Files Partitions Files ================ A partitioned table is stored in multiple files. By default, these files are stored in the MariaDB (or InnoDB) data directory. It is possible to keep them in different paths by specifying [DATA\_DIRECTORY and INDEX\_DIRECTORY](../create-table/index#data-directoryindex-directory) table options. This is useful to store different partitions on different devices. Note that, if the [innodb\_file\_per\_table](../xtradbinnodb-server-system-variables/index#innodb_file_per_table) server system variable is set to 0 at the time of the table creation, all partitions will be stored in the system tablespace. The following files exist for each partitioned tables: | File name | Notes | | --- | --- | | table\_name.frm | Contains the table definition. Non-partitioned tables have this file, too. | | table\_name.par | Contains the partitions definitions. | | table\_name#P#partition\_name.ext | Normal files created by the storage engine use this pattern for names. The extension depends on the storage engine. | For example, an InnoDB table with 4 partitions will have the following files: ``` orders.frm orders.par orders#P#p0.ibd orders#P#p1.ibd orders#P#p2.ibd orders#P#p3.ibd ``` If we convert the table to MyISAM, we will have these files: ``` orders.frm orders.par orders#P#p0.MYD orders#P#p0.MYI orders#P#p1.MYD orders#P#p1.MYI orders#P#p2.MYD orders#P#p2.MYI orders#P#p3.MYD orders#P#p3.MYI ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb RANGE Partitioning Type RANGE Partitioning Type ======================= The RANGE partitioning type is used to assign each partition a range of values generated by the partitioning expression. Ranges must be ordered, contiguous and non-overlapping. The minimum value is always included in the first range. The highest value may or may not be included in the last range. A variant of this partitioning method, [RANGE COLUMNS](../range-columns-and-list-columns-partitioning-types/index), allows us to use multiple columns and more datatypes. Syntax ------ The last part of a [CREATE TABLE](../create-table/index) statement can be definition of the new table's partitions. In the case of RANGE partitioning, the syntax is the following: ``` PARTITION BY RANGE (partitioning_expression) ( PARTITION partition_name VALUES LESS THAN (value), [ PARTITION partition_name VALUES LESS THAN (value), ... ] ) ``` PARTITION BY RANGE indicates that the partitioning type is RANGE. The `partitioning_expression` is an SQL expression that returns a value from each row. In the simplest cases, it is a column name. This value is used to determine which partition should contain a row. `partition_name` is the name of a partition. `value` indicates the upper bound for that partition. The values must be ascending. For the first partition, the lower limit is NULL. When trying to insert a row, if its value is higher than the upper limit of the last partition, the row will be rejected (with an error, if the [IGNORE](../ignore/index) keyword is not used). If this is a problem, MAXVALUE can be specified as a value for the last partition. Note however that it is not possible to split partitions of an existing RANGE partitioned table. New partitions can be appended, but this will not be possible if the last partition's higher bound is MAXVALUE. Use Cases --------- A typical use case is when we want to partition a table whose rows refer to a moment or period in time; for example commercial transactions, blog posts, or events of some kind. We can partition the table by year, to keep all recent data in one partition and distribute historical data in big partitions that are stored on slower disks. Or, if our queries always read rows which refer to the same month or week, we can partition the table by month or year week (in this case, historical data and recent data will be stored together). [AUTO\_INCREMENT](../auto_increment/index) values also represent a chronological order. So, these values can be used to store old data in separate partitions. However, partitioning by id is not the best choice if we usually query a table by date. Examples -------- In the following example, we will partition a log table by year. ``` CREATE TABLE log ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, timestamp DATETIME NOT NULL, user INT UNSIGNED, ip BINARY(16) NOT NULL, action VARCHAR(20) NOT NULL, PRIMARY KEY (id, timestamp) ) ENGINE = InnoDB PARTITION BY RANGE (YEAR(timestamp)) ( PARTITION p0 VALUES LESS THAN (2013), PARTITION p1 VALUES LESS THAN (2014), PARTITION p2 VALUES LESS THAN (2015), PARTITION p3 VALUES LESS THAN (2016) ); ``` As an alternative, we can partition the table by both year and month: ``` CREATE TABLE log ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, timestamp TIMESTAMP NOT NULL, user INT UNSIGNED, ip BINARY(16) NOT NULL, action VARCHAR(20) NOT NULL, PRIMARY KEY (id, timestamp) ) ENGINE = InnoDB PARTITION BY RANGE (UNIX_TIMESTAMP(timestamp)) ( PARTITION p0 VALUES LESS THAN (UNIX_TIMESTAMP('2014-08-01 00:00:00')), PARTITION p1 VALUES LESS THAN (UNIX_TIMESTAMP('2014-11-01 00:00:00')), PARTITION p2 VALUES LESS THAN (UNIX_TIMESTAMP('2015-01-01 00:00:00')), PARTITION p3 VALUES LESS THAN (UNIX_TIMESTAMP('2015-02-01 00:00:00')) ); ``` As you can see, we used the [UNIX\_TIMESTAMP](../unix_timestamp/index) function to accomplish the purpose. Also, the first two partitions cover longer periods of time (probably because the logged activities were less intensive). In both cases, when our tables become huge and we don't need to store all historical data any more, we can drop the oldest partitions in this way: ``` ALTER TABLE log DROP PARTITION p0; ``` We will still be able to drop a partition that does not contain the oldest data, but all rows stored in it will disappear. Example of an error when inserting outside a defined partition range: ``` INSERT INTO log(id,timestamp) VALUES (1, '2016-01-01 01:01:01'), (2, '2015-01-01 01:01:01'); ERROR 1526 (HY000): Table has no partition for value 2016 ``` Unless the IGNORE keyword is used: ``` INSERT IGNORE INTO log(id,timestamp) VALUES (1, '2016-01-01 01:01:01'), (2, '2015-01-01 01:01:01'); SELECT * FROM log; +----+---------------------+------+------------------+--------+ | id | timestamp | user | ip | action | +----+---------------------+------+------------------+--------+ | 2 | 2015-01-01 01:01:01 | NULL | | | +----+---------------------+------+------------------+--------+ ``` An alternative definition with MAXVALUE as a catchall: ``` CREATE TABLE log ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, timestamp DATETIME NOT NULL, user INT UNSIGNED, ip BINARY(16) NOT NULL, action VARCHAR(20) NOT NULL, PRIMARY KEY (id, timestamp) ) ENGINE = InnoDB PARTITION BY RANGE (YEAR(timestamp)) ( PARTITION p0 VALUES LESS THAN (2013), PARTITION p1 VALUES LESS THAN (2014), PARTITION p2 VALUES LESS THAN (2015), PARTITION p3 VALUES LESS THAN (2016), PARTITION p4 VALUES LESS THAN MAXVALUE ); ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Moon Modeler Moon Modeler ============ [Moon Modeler](https://www.datensen.com/) is a database design tool for MariaDB and other relational and NoSQL databases. Draw diagrams, reverse engineer existing database structures and generate SQL code. **Supported platforms include:** * MariaDB * PostgreSQL * MongoDB * Mongoose * GraphQL **Key features:** * Database modeling & schema design * Visualization of JSON structures and nested types * Reverse engineering * Support for database-specific settings * Three display modes: metadata, sample data or descriptions * Default values for newly created objects * Export to PDF * Dark and Light themes * SQL script generation ![mariadb-database-design](https://mariadb.com/kb/en/moon-modeler/+image/mariadb-database-design "mariadb-database-design") **Freeware version** Feature limited freeware version is available for Windows, Linux and macOS. **More information** See <https://www.datensen.com> for more information. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CREATE ROLE CREATE ROLE =========== Syntax ------ ``` CREATE [OR REPLACE] ROLE [IF NOT EXISTS] role [WITH ADMIN {CURRENT_USER | CURRENT_ROLE | user | role}] ``` Description ----------- The `CREATE ROLE` statement creates one or more MariaDB [roles](../roles/index). To use it, you must have the global [CREATE USER](../grant/index#create-user) privilege or the [INSERT](../grant/index#table-privileges) privilege for the mysql database. For each account, `CREATE ROLE` creates a new row in the [mysql.user](../mysqluser-table/index) table that has no privileges, and with the corresponding `is_role` field set to `Y`. It also creates a record in the [mysql.roles\_mapping](../mysqlroles_mapping-table/index) table. If any of the specified roles already exist, `ERROR 1396 (HY000)` results. If an error occurs, `CREATE ROLE` will still create the roles that do not result in an error. The maximum length for a role is 128 characters. Role names can be quoted, as explained in the [Identifier names](../identifier-names/index) page. Only one error is produced for all roles which have not been created: ``` ERROR 1396 (HY000): Operation CREATE ROLE failed for 'a','b','c' ``` Failed `CREATE` or `DROP` operations, for both users and roles, produce the same error code. `PUBLIC` and `NONE` are reserved, and cannot be used as role names. `NONE` is used to [unset a role](../set-role/index) and `PUBLIC` has a special use in other systems, such as Oracle, so is reserved for compatibility purposes. For valid identifiers to use as role names, see [Identifier Names](../identifier-names/index). #### WITH ADMIN The optional `WITH ADMIN` clause determines whether the current user, the current role or another user or role has use of the newly created role. If the clause is omitted, `WITH ADMIN CURRENT_USER` is treated as the default, which means that the current user will be able to [GRANT](../grant/index#roles) this role to users. #### OR REPLACE If the optional `OR REPLACE` clause is used, it acts as a shortcut for: ``` DROP ROLE IF EXISTS name; CREATE ROLE name ...; ``` #### IF NOT EXISTS When the `IF NOT EXISTS` clause is used, MariaDB will return a warning instead of an error if the specified role already exists. Cannot be used together with the `OR REPLACE` clause. Examples -------- ``` CREATE ROLE journalist; CREATE ROLE developer WITH ADMIN lorinda@localhost; ``` Granting the role to another user. Only user `lorinda@localhost` has permission to grant the `developer` role: ``` SELECT USER(); +-------------------+ | USER() | +-------------------+ | henning@localhost | +-------------------+ ... GRANT developer TO ian@localhost; Access denied for user 'henning'@'localhost' SELECT USER(); +-------------------+ | USER() | +-------------------+ | lorinda@localhost | +-------------------+ GRANT m_role TO ian@localhost; ``` The `OR REPLACE` and `IF NOT EXISTS` clauses. The `journalist` role already exists: ``` CREATE ROLE journalist; ERROR 1396 (HY000): Operation CREATE ROLE failed for 'journalist' CREATE OR REPLACE ROLE journalist; Query OK, 0 rows affected (0.00 sec) CREATE ROLE IF NOT EXISTS journalist; Query OK, 0 rows affected, 1 warning (0.00 sec) ``` ``` SHOW WARNINGS; +-------+------+---------------------------------------------------+ | Level | Code | Message | +-------+------+---------------------------------------------------+ | Note | 1975 | Can't create role 'journalist'; it already exists | +-------+------+---------------------------------------------------+ ``` See Also -------- * [Identifier Names](../identifier-names/index) * [Roles Overview](../roles-overview/index) * [DROP ROLE](../drop-role/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb UUID Data Type UUID Data Type ============== **MariaDB starting with [10.7.0](https://mariadb.com/kb/en/mariadb-1070-release-notes/)**The UUID data type was added in a [MariaDB 10.7.0](https://mariadb.com/kb/en/mariadb-1070-release-notes/) preview. Syntax ------ ``` UUID ``` Description ----------- The `UUID` data type is intended for the storage of 128-bit UUID (Universally Unique Identifier) data. See the [UUID function](../uuid/index) page for more details on UUIDs themselves. ### Retrieval Data retrieved by this data type is in the string representation defined in [RFC4122](https://datatracker.ietf.org/doc/html/rfc4122). ### Casting [String literals](../string-literals/index) of hexadecimal characters and [CHAR](../char/index)/[VARCHAR](../varchar/index)/[TEXT](../text/index) can be cast to the UUID data type. Likewise [hexadecimal literals](../hexadecimal-literals/index), [binary-literals](../binary-literals/index), and [BINARY](../binary/index)/[VARBINARY](../varbinary/index)/[BLOB](../blob/index) types can also be cast to UUID. The data type will not accept a short UUID generated with the [UUID\_SHORT](../uuid_short/index) function, but will accept a value without the `-` character generated by the [SYS\_GUID](../sys_guid/index) function (or inserted directly). Hyphens can be partially omitted as well, or included after any group of two digits. The type does not accept UUIDs in braces, permitted by some implementations. ### Storage UUID are stored in an index friendly manner, the order of a UUID of llllllll-mmmm-Vhhh-vsss-nnnnnnnnnnnn is stored as: ``` nnnnnnnnnnnn-vsss-Vhhh-mmmm-llllllll ``` This provides a sorting order, if a UUIDv1 (node and timestamp) is used, of the node, followed by the timestamp. Examples -------- ``` CREATE TABLE t1 (id UUID); ``` Directly Inserting via [string literals](../string-literals/index): ``` INSERT INTO t1 VALUES('123e4567-e89b-12d3-a456-426655440000'); ``` Directly Inserting via [hexadecimal literals](../hexadecimal-literals/index): ``` INSERT INTO t1 VALUES (x'fffffffffffffffffffffffffffffffe'); ``` Generating and inserting via the [UUID function](../uuid/index). ``` INSERT INTO t1 VALUES (UUID()); ``` Retrieval: ``` SELECT * FROM t1; +--------------------------------------+ | id | +--------------------------------------+ | 123e4567-e89b-12d3-a456-426655440000 | | ffffffff-ffff-ffff-ffff-fffffffffffe | | 93aac041-1a14-11ec-ab4e-f859713e4be4 | +--------------------------------------+ ``` The [UUID\_SHORT](../uuid_short/index) function does not generate valid full-length UUID: ``` INSERT INTO t1 VALUES (UUID_SHORT()); ERROR 1292 (22007): Incorrect uuid value: '99440417627439104' for column `test`.`t1`.`id` at row 1 ``` Accepting a value without the `-` character, either directly or generated by the [SYS\_GUID](../sys_guid/index) function: ``` INSERT INTO t1 VALUES (SYS_GUID()); SELECT * FROM t1; +--------------------------------------+ | id | +--------------------------------------+ | 123e4567-e89b-12d3-a456-426655440000 | | ffffffff-ffff-ffff-ffff-fffffffffffe | | 93aac041-1a14-11ec-ab4e-f859713e4be4 | | ea0368d3-1a14-11ec-ab4e-f859713e4be4 | +--------------------------------------+ SELECT SYS_GUID(); +----------------------------------+ | SYS_GUID() | +----------------------------------+ | ff5b6bcc1a1411ecab4ef859713e4be4 | +----------------------------------+ INSERT INTO t1 VALUES ('ff5b6bcc1a1411ecab4ef859713e4be4'); SELECT * FROM t1; +--------------------------------------+ | id | +--------------------------------------+ | 123e4567-e89b-12d3-a456-426655440000 | | ffffffff-ffff-ffff-ffff-fffffffffffe | | 93aac041-1a14-11ec-ab4e-f859713e4be4 | | ea0368d3-1a14-11ec-ab4e-f859713e4be4 | | ff5b6bcc-1a14-11ec-ab4e-f859713e4be4 | +--------------------------------------+ ``` Valid and invalid hyphen and brace usage: ``` TRUNCATE t1; INSERT INTO t1 VALUES ('f8aa-ed66-1a1b-11ec-ab4e-f859-713e-4be4'); INSERT INTO t1 VALUES ('1b80667f1a1c-11ecab4ef859713e4be4'); INSERT INTO t1 VALUES ('2fd6c945-1a-1c-11ec-ab4e-f859713e4be4'); INSERT INTO t1 VALUES ('49-c9-f9-59-1a-1c-11ec-ab4e-f859713e4be4'); INSERT INTO t1 VALUES ('57-96-da-c1-1a-1c-11-ec-ab-4e-f8-59-71-3e-4b-e4'); INSERT INTO t1 VALUES ('6-eb74f8f-1a1c-11ec-ab4e-f859713e4be4'); INSERT INTO t1 VALUES ('{29bad136-1a1d-11ec-ab4e-f859713e4be4}'); ERROR 1292 (22007): Incorrect uuid value: '{29bad136-1a1d-11ec-ab4e-f859713e4be4}' for column `test`.`t1`.`id` at row 1 SELECT * FROM t1; +--------------------------------------+ | id | +--------------------------------------+ | f8aaed66-1a1b-11ec-ab4e-f859713e4be4 | | 1b80667f-1a1c-11ec-ab4e-f859713e4be4 | | 2fd6c945-1a1c-11ec-ab4e-f859713e4be4 | | 49c9f959-1a1c-11ec-ab4e-f859713e4be4 | | 5796dac1-1a1c-11ec-ab4e-f859713e4be4 | | 6eb74f8f-1a1c-11ec-ab4e-f859713e4be4 | +--------------------------------------+ ``` See Also -------- * [10.7 preview feature: UUID Data Type](https://mariadb.org/10-7-preview-feature-uuid-data-type/) (mariadb.org blog post) * [UUID function](../uuid/index) * [UUID\_SHORT function](../uuid_short/index) * [SYS\_GUID](../sys_guid/index) - UUID without the `-` character for Oracle compatibility Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema setup_actors Table Performance Schema setup\_actors Table ====================================== The `setup_actors` table contains information for determining whether monitoring should be enabled for new client connection threads. The default size is 100 rows, which can be changed by modifying the `[performance\_schema\_setup\_actors\_size](../performance-schema-system-variables/index#performance_schema_setup_actors_size)` system variable at server startup. If a row in the table matches a new foreground thread's client and host, the matching `INSTRUMENTED` column in the [threads](../performance-schema-threads-table/index) table is set to either `YES` or `NO`, which allows selective application of instrumenting by host, by user, or combination thereof. | Column | Description | | --- | --- | | `HOST` | Host name, either a literal, or the `%` wildcard representing any host. | | `USER` | User name, either a literal or the `%` wildcard representing any name. | | `ROLE` | Unused | Initially, any user and host is matched: ``` SELECT * FROM performance_schema.setup_actors; +------+------+------+ | HOST | USER | ROLE | +------+------+------+ | % | % | % | +------+------+------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MyISAM Overview MyISAM Overview =============== The MyISAM storage engine was the default storage engine from MySQL 3.23 until it was replaced by [InnoDB](../innodb/index) in MariaDB and MySQL 5.5. Historically, MyISAM is a replacement for the older ISAM engine, removed in MySQL 4.1. It's a light, non-transactional engine with great performance, is easy to copy between systems and has a small data footprint. You're encouraged to rather use the [Aria](../aria/index) storage engine for new applications, which has even better performance in most cases and the goal of being crash-safe. A MyISAM table is stored in three files on disk. There's a table definition file with an extension of `.frm`, a data file with the extension `.MYD`, and an index file with the extension `.MYI`. MyISAM features --------------- * Does not support [transactions](../transactions/index). * Does not support foreign keys. * Supports [FULLTEXT indexes](../full-text-indexes/index). * Supports [GIS](../gis-functionality/index) data types. * Storage limit of 256TB. * Maximum of 64 indexes per table. * Maximum of 32 columns per index. * Maximum index length of 1000 bytes. * Limit of (232)2 (1.844E+19) rows per table. * Supports large files up to 63-bits in length where the underlying system supports this. * All data is stored with the low byte first, so all files will still work if copied to other systems or other machines. * The data file and the index file can be placed on different devices to improve speed. * Supports table locking, not row locking. * Supports a key buffer that is [segmented](../segmented-key-cache/index) in MariaDB. * Supports [concurrent inserts](../concurrent-inserts/index). * Supports fixed length, dynamic and compressed formats - see [MyISAM Storage Formats](../myisam-storage-formats/index). * Numeric index values are stored with the high byte first, which enables more efficient index compression. * Data values are stored with the low byte first, making it mostly machine and operating system independent. The only exceptions are if a machine doesn't use two's-complement signed integers and the IEEE floating-point format. * Can be copied between databases or systems with normal system tools, as long as the files are not open on either system. Use [FLUSH\_TABLES](../flush/index) to ensure files are not in use. * There are a number of tools for working with MyISAM tables. These include: + [mysqlcheck](../mysqlcheck/index) for checking or repairing + [myisamchk](../myisamchk/index) for checking or repairing + [myisampack](../myisampack/index) for compressing * It is possible to build a [MERGE](../merge/index) table on the top of one or more MyISAM tables. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Information Schema REFERENTIAL_CONSTRAINTS Table Information Schema REFERENTIAL\_CONSTRAINTS Table ================================================= The [Information Schema](../information_schema/index) `REFERENTIAL_CONSTRAINTS` table contains information about [foreign keys](../foreign-keys/index). The single columns are listed in the `[KEY\_COLUMN\_USAGE](../information-schema-key_column_usage-table/index)` table. It has the following columns: | Column | Description | | --- | --- | | `CONSTRAINT_CATALOG` | Always `def`. | | `CONSTRAINT_SCHEMA` | Database name, together with `CONSTRAINT_NAME` identifies the foreign key. | | `CONSTRAINT_NAME` | Foreign key name, together with `CONSTRAINT_SCHEMA` identifies the foreign key. | | `UNIQUE_CONSTRAINT_CATALOG` | Always `def`. | | `UNIQUE_CONSTRAINT_SCHEMA` | Database name, together with `UNIQUE_CONSTRAINT_NAME` and `REFERENCED_TABLE_NAME` identifies the referenced key. | | `UNIQUE_CONSTRAINT_NAME` | Referenced key name, together with `UNIQUE_CONSTRAINT_SCHEMA` and `REFERENCED_TABLE_NAME` identifies the referenced key. | | `MATCH_OPTION` | Always `NONE`. | | `UPDATE_RULE` | The Update Rule; one of `CASCADE`, `SET NULL`, `SET DEFAULT`, `RESTRICT`, `NO ACTION`. | | `DELETE_RULE` | The Delete Rule; one of `CASCADE`, `SET NULL`, `SET DEFAULT`, `RESTRICT`, `NO ACTION`. | | `TABLE_NAME` | Table name from the `TABLE_CONSTRAINTS` table. | | `REFERENCED_TABLE_NAME` | Referenced key table name, together with `UNIQUE_CONSTRAINT_SCHEMA` and `UNIQUE_CONSTRAINT_NAME` identifies the referenced key. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHOW CREATE SEQUENCE SHOW CREATE SEQUENCE ==================== **MariaDB starting with [10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/)**Sequences were introduced in [MariaDB 10.3](../what-is-mariadb-103/index). Syntax ------ ``` SHOW CREATE SEQUENCE sequence_name; ``` Description ----------- Shows the [CREATE SEQUENCE](../create-sequence/index) statement that created the given sequence. The statement requires the `SELECT` privilege for the table. Example ------- ``` CREATE SEQUENCE s1 START WITH 50; SHOW CREATE SEQUENCE s1\G; *************************** 1. row *************************** Table: s1 Create Table: CREATE SEQUENCE `s1` start with 50 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=InnoDB ``` Notes ----- If you want to see the underlying table structure used for the `SEQUENCE` you can use [SHOW CREATE TABLE](../show-create-table/index) on the `SEQUENCE`. You can also use `SELECT` to read the current recorded state of the `SEQUENCE`: ``` SHOW CREATE TABLE s1\G *************************** 1. row *************************** Table: s1 Create Table: CREATE TABLE `s1` ( `next_not_cached_value` bigint(21) NOT NULL, `minimum_value` bigint(21) NOT NULL, `maximum_value` bigint(21) NOT NULL, `start_value` bigint(21) NOT NULL COMMENT 'start value when sequences is created or value if RESTART is used', `increment` bigint(21) NOT NULL COMMENT 'increment value', `cache_size` bigint(21) unsigned NOT NULL, `cycle_option` tinyint(1) unsigned NOT NULL COMMENT '0 if no cycles are allowed, 1 if the sequence should begin a new cycle when maximum_value is passed', `cycle_count` bigint(21) NOT NULL COMMENT 'How many cycles have been done' ) ENGINE=InnoDB SEQUENCE=1 SELECT * FROM s1\G *************************** 1. row *************************** next_not_cached_value: 50 minimum_value: 1 maximum_value: 9223372036854775806 start_value: 50 increment: 1 cache_size: 1000 cycle_option: 0 cycle_count: 0 ``` See Also -------- * [CREATE SEQUENCE](../create-sequence/index) * [ALTER SEQUENCE](../alter-sequence/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Floating-point Accuracy Floating-point Accuracy ======================= Due to their nature, not all floating-point numbers can be stored with exact precision. Hardware architecture, the CPU or even the compiler version and optimization level may affect the precision. If you are comparing [DOUBLEs](../double/index) or [FLOATs](../float/index) with numeric decimals, it is not safe to use the [equality](../equal/index) operator. Sometimes, changing a floating-point number from single-precision (FLOAT) to double-precision (DOUBLE) will fix the problem. Example ------- f1, f2 and f3 have seemingly identical values across each row, but due to floating point accuracy, the results may be unexpected. ``` CREATE TABLE fpn (id INT, f1 FLOAT, f2 DOUBLE, f3 DECIMAL (10,3)); INSERT INTO fpn VALUES (1,2,2,2),(2,0.1,0.1,0.1); SELECT * FROM fpn WHERE f1*f1 = f2*f2; +------+------+------+-------+ | id | f1 | f2 | f3 | +------+------+------+-------+ | 1 | 2 | 2 | 2.000 | +------+------+------+-------+ ``` The reason why only one instead of two rows was returned becomes clear when we see how the floating point squares were evaluated. ``` SELECT f1*f1, f2*f2, f3*f3 FROM fpn; +----------------------+----------------------+----------+ | f1*f1 | f2*f2 | f3*f3 | +----------------------+----------------------+----------+ | 4 | 4 | 4.000000 | | 0.010000000298023226 | 0.010000000000000002 | 0.010000 | +----------------------+----------------------+----------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb STRCMP STRCMP ====== Syntax ------ ``` STRCMP(expr1,expr2) ``` Description ----------- `STRCMP()` returns `0` if the strings are the same, `-1` if the first argument is smaller than the second according to the current sort order, and `1` if the strings are otherwise not the same. Returns `NULL` is either argument is `NULL`. Examples -------- ``` SELECT STRCMP('text', 'text2'); +-------------------------+ | STRCMP('text', 'text2') | +-------------------------+ | -1 | +-------------------------+ SELECT STRCMP('text2', 'text'); +-------------------------+ | STRCMP('text2', 'text') | +-------------------------+ | 1 | +-------------------------+ SELECT STRCMP('text', 'text'); +------------------------+ | STRCMP('text', 'text') | +------------------------+ | 0 | +------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Compiling with the InnoDB Plugin from Oracle Compiling with the InnoDB Plugin from Oracle ============================================ From [MariaDB 10.2](../what-is-mariadb-102/index), MariaDB uses InnoDB as the default storage engine. Before [MariaDB 10.2](../what-is-mariadb-102/index), MariaDB came by default with [XtraDB](../xtradb/index), an enhanced version of the InnoDB plugin that comes from Oracle. If you want to use Oracle's InnoDB plugin, then you need to compile MariaDB and **not** specify `--without-plugin-innodb_plugin` when configuring. For example, a simple `./configure` without any options will do. When the InnoDB plugin is compiled, the innodb\_plugin test suite will test the InnoDB plugin in addition to xtradb: ``` ./mysql-test-run --suite=innodb_plugin ``` To use the innodb\_plugin instead of xtradb you can do (for [MariaDB 5.5](../what-is-mariadb-55/index)): ``` mysqld --ignore-builtin-innodb --plugin-load=innodb=ha_innodb.so \ --plugin_dir=/usr/local/mysql/lib/mysql/plugin ``` See Also -------- <http://dev.mysql.com/doc/refman/5.1/en/replacing-builtin-innodb.html> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Data Types Data Types =========== Data Types in MariaDB | Title | Description | | --- | --- | ### [Numeric Data Types](../data-types-numeric-data-types/index) | Title | Description | | --- | --- | | [Numeric Data Type Overview](../numeric-data-type-overview/index) | Overview and usage of the numeric data types. | | [TINYINT](../tinyint/index) | Tiny integer, -128 to 127 signed. | | [BOOLEAN](../boolean/index) | Synonym for TINYINT(1). | | [SMALLINT](../smallint/index) | Small integer from -32768 to 32767 signed. | | [MEDIUMINT](../mediumint/index) | Medium integer from -8388608 to 8388607 signed. | | [INT](../int/index) | Integer from -2147483648 to 2147483647 signed. | | [INTEGER](../integer/index) | Synonym for INT | | [BIGINT](../bigint/index) | Large integer. | | [DECIMAL](../decimal/index) | A packed "exact" fixed-point number. | | [DEC, NUMERIC, FIXED](../dec-numeric-fixed/index) | Synonyms for DECIMAL | | [NUMBER](../number/index) | Synonym for DECIMAL in Oracle mode. | | [FLOAT](../float/index) | Single-precision floating-point number | | [DOUBLE](../double/index) | Normal-size (double-precision) floating-point number | | [DOUBLE PRECISION](../double-precision/index) | REAL and DOUBLE PRECISION are synonyms for DOUBLE. | | [BIT](../bit/index) | Bit field type. | | [Floating-point Accuracy](../floating-point-accuracy/index) | Not all floating-point numbers can be stored with exact precision | | [INT1](../int1/index) | A synonym for TINYINT. | | [INT2](../int2/index) | Synonym for SMALLINT. | | [INT3](../int3/index) | Synonym for MEDIUMINT. | | [INT4](../int4/index) | Synonym for INT. | | [INT8](../int8/index) | Synonym for BIGINT. | ### [String Data Types](../string-data-types/index) | Title | Description | | --- | --- | | [String Literals](../string-literals/index) | Strings are sequences of characters and are enclosed with quotes. | | [BINARY](../binary/index) | Fixed-length binary byte string. | | [BLOB](../blob/index) | Binary large object up to 65,535 bytes. | | [BLOB and TEXT Data Types](../blob-and-text-data-types/index) | Binary large object data types and the corresponding TEXT types. | | [CHAR](../char/index) | Fixed-length string. | | [CHAR BYTE](../char-byte/index) | Alias for BINARY. | | [ENUM](../enum/index) | Enumeration, or string object that can have one value chosen from a list of values. | | [INET4](../inet4/index) | For storage of IPv4 addresses. | | [INET6](../inet6/index) | For storage of IPv6 addresses. | | [JSON Data Type](../json-data-type/index) | Compatibility data type that is an alias for LONGTEXT. | | [MEDIUMBLOB](../mediumblob/index) | Medium binary large object up to 16,777,215 bytes. | | [MEDIUMTEXT](../mediumtext/index) | A TEXT column with a maximum length of 16,777,215 characters. | | [LONGBLOB](../longblob/index) | Long BLOB holding up to 4GB. | | [LONG and LONG VARCHAR](../long-and-long-varchar/index) | LONG and LONG VARCHAR are synonyms for MEDIUMTEXT. | | [LONGTEXT](../longtext/index) | A TEXT column with a maximum length of 4,294,967,295 characters. | | [ROW](../row/index) | Data type for stored procedure variables. | | [TEXT](../text/index) | A TEXT column with a maximum length of 65,535 characters. | | [TINYBLOB](../tinyblob/index) | Tiny binary large object up to 255 bytes. | | [TINYTEXT](../tinytext/index) | A TEXT column with a maximum length of 255 characters. | | [VARBINARY](../varbinary/index) | Variable-length binary byte string. | | [VARCHAR](../varchar/index) | Variable-length string. | | [SET Data Type](../set-data-type/index) | Set, or string object that can have 0 or more values chosen from a list of values. | | [UUID Data Type](../uuid-data-type/index) | Data type intended for the storage of UUID data. | | [Data Type Storage Requirements](../data-type-storage-requirements/index) | Storage requirements for the various data types. | | [Supported Character Sets and Collations](../supported-character-sets-and-collations/index) | MariaDB supports the following character sets and collations. | | [Character Sets and Collations](../character-sets/index) | Setting character set and collation for a language. | ### [Date and Time Data Types](../date-and-time-data-types/index) | Title | Description | | --- | --- | | [DATE](../date/index) | The date type YYYY-MM-DD. | | [TIME](../time/index) | Time format HH:MM:SS.ssssss | | [DATETIME](../datetime/index) | Date and time combination displayed as YYYY-MM-DD HH:MM:SS. | | [TIMESTAMP](../timestamp/index) | YYYY-MM-DD HH:MM:SS | | [YEAR Data Type](../year-data-type/index) | A four-digit year. | | [Future developments for temporal types](../future-developments-for-temporal-types/index) | My current project is a forecasting application with dates going out to 263... | | [How to define a date in order to import an empty date from a CSV file?](../how-to-define-a-date-in-order-to-import-an-empty-date-from-a-csv-file/index) | I have a CSV file containing amongst other things a couple of date columns.... | | [Which datatypes are supported by MariaDB](../which-datatypes-are-supported-by-mariadb/index) | I would like to know which datatypes are supported by MariaDB. I'm asking s... | ### Other Data Types Articles | Title | Description | | --- | --- | | [Geometry Types](../geometry-types/index) | Supported geometry types. | | [AUTO\_INCREMENT](../auto_increment/index) | Automatic increment. | | [Data Type Storage Requirements](../data-type-storage-requirements/index) | Storage requirements for the various data types. | | [AUTO\_INCREMENT FAQ](../auto_increment-faq/index) | Frequently-asked questions about auto\_increment. | | [NULL Values](../null-values/index) | NULL represents an unknown value. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb QUOTE QUOTE ===== Syntax ------ ``` QUOTE(str) ``` Description ----------- Quotes a string to produce a result that can be used as a properly escaped data value in an SQL statement. The string is returned enclosed by single quotes and with each instance of single quote ("`'`"), backslash ("`\`"), `ASCII NUL`, and Control-Z preceded by a backslash. If the argument is `NULL`, the return value is the word "`NULL`" without enclosing single quotes. Examples -------- ``` SELECT QUOTE("Don't!"); +-----------------+ | QUOTE("Don't!") | +-----------------+ | 'Don\'t!' | +-----------------+ SELECT QUOTE(NULL); +-------------+ | QUOTE(NULL) | +-------------+ | NULL | +-------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb X X = A synonym for [ST\_X](../st_x/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Minimum Hardware Specification ColumnStore Minimum Hardware Specification ========================================== The following table outlines the minimum recommended production server specifications which can be followed for both on premise and cloud deployments: Per Server ========== | Item | Development Environment | Production Environment | | --- | --- | --- | | Physical Server | 8 Core CPU, 32 GB Memory | 64 Core CPU, 128 GB Memory | | Storage | Local disk | StorageManager (S3) | Network ======= | | | | --- | --- | | Network Interconnect | In a multi server deployment data will be passed around via TCP/IP networking. At least a 1G network is recommended. | Details ======= These are minimum recommendations and in general the system will perform better with more hardware: * More CPU cores and servers will improve query processing response time. * More memory will allow the system to cache more data blocks in memory. We have users running system with anywhere from 64G RAM to 512 G RAM for UM and 32 to 64 G RAM for PM. * Faster network will allow data to flow faster between UM and PM nodes. * SSD's may be used, however the system is optimized towards block streaming which may perform well enough with HDD's for lower cost. * Where it is an option, it is recommended to use bare metal servers for additional performance since ColumnStore will fully consume CPU cores and memory. * In general it makes more sense to use a higher core count / higher memory server for single server or 2 server combined deployments. * In a deployment with multiple UM nodes the system will round robin requests from the mysqld handling the query to any ExeMgr in the cluster for load balancing. A higher bandwidth network such as 10g or 40g will be of benefit for large result set queries. AWS instance sizes ------------------ For AWS our own internal testing generally uses m4.4xlarge instance types as a cost effective middle ground. The R4.8xlarge has also been tested and performs about twice as fast for about twice the price. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Deploying Docker Containers with Ansible Deploying Docker Containers with Ansible ======================================== Ansible can be used to manage Docker container upgrades and configuration changes. Docker has native ways to do this, namely [Dockerfiles](../creating-a-custom-docker-image/index) and [Docker Compose](../setting-up-a-lamp-stack-with-docker-compose/index). But sometimes there are reasons to start basic containers from an image and then manage configuration with Ansible or similar software. See [Benefits of Managing Docker Containers with Automation Software](../benefits-of-managing-docker-containers-with-orchestration-software/index). In this page we'll discuss how to use Ansible to manage Docker containers. How to Deploy a Container with Ansible -------------------------------------- Ansible has modules to manage the Docker server, Docker containers, and Docker Compose. These modules are maintained by the community. A dynamic inventory plugin for Docker exists. It retrieves the list of existing containers from Docker. Docker modules and the Docker inventory plugin communicate with Docker using its API. The connection to the API can use a TSL connection and supports key authenticity verification. To communicate with Docker API, Ansible needs a proper Python module installed on the Ansible node (`docker` or `docker-py`). Several roles exist to deploy Docker and configure it. They can be found in Ansible Galaxy. References ---------- Further information can be found in Ansible documentation. * [Docker Guide](https://docs.ansible.com/ansible/latest/scenario_guides/guide_docker.html). * [docker\_container](https://docs.ansible.com/ansible/latest/collections/community/general/docker_container_module.html) module. --- Content initially contributed by [Vettabase Ltd](https://vettabase.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Status Variables Added in MariaDB 10.1 Status Variables Added in MariaDB 10.1 ====================================== This is a list of [status variables](../server-status-variables/index) that were added in the [MariaDB 10.1](../what-is-mariadb-101/index) series. The list excludes status related to the following storage engines included in [MariaDB 10.1](../what-is-mariadb-101/index): * [Galera Status Variables](../galera-cluster-status-variables/index) | Variable | Added | | --- | --- | | [Acl\_column\_grants](../server-status-variables/index#acl_column_grants) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_database\_grants](../server-status-variables/index#acl_database_grants) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_function\_grants](../server-status-variables/index#acl_function_grants) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_procedure\_grants](../server-status-variables/index#acl_procedure_grants) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_proxy\_users](../server-status-variables/index#acl_proxy_users) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_role\_grants](../server-status-variables/index#acl_role_grants) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_roles](../server-status-variables/index#acl_roles) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_table\_grants](../server-status-variables/index#acl_table_grants) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Acl\_users](../server-status-variables/index#acl_users) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Master\_gtid\_wait\_count](../replication-and-binary-log-status-variables/index#master_gtid_wait_count) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Com\_compound\_sql](../server-status-variables/index#com_compound_sql) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Com\_create\_temporary\_table](../server-status-variables/index#com_create_temporary_table) | [MariaDB 10.1.6](https://mariadb.com/kb/en/mariadb-1016-release-notes/) | | [Com\_create\_drop\_table](../server-status-variables/index#com_create_drop_table) | [MariaDB 10.1.6](https://mariadb.com/kb/en/mariadb-1016-release-notes/) | | [Com\_show\_generic](../server-status-variables/index#com_show_generic) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Innodb\_defragment\_compression\_failures](../xtradbinnodb-server-status-variables/index#innodb_defragment_compression_failures) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Innodb\_defragment\_count](../xtradbinnodb-server-status-variables/index#innodb_defragment_count) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Innodb\_defragment\_failures](../xtradbinnodb-server-status-variables/index#innodb_defragment_failures) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Innodb\_encryption\_rotation\_estimated\_iops](../xtradbinnodb-server-status-variables/index#innodb_encryption_rotation_estimated_iops) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_encryption\_rotation\_pages\_flushed](../xtradbinnodb-server-status-variables/index#innodb_encryption_rotation_pages_flushed) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_encryption\_rotation\_pages\_modified](../xtradbinnodb-server-status-variables/index#innodb_encryption_rotation_pages_modified) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_encryption\_rotation\_pages\_read\_from\_cache](../xtradbinnodb-server-status-variables/index#innodb_encryption_rotation_pages_read_from_cache) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_encryption\_rotation\_pages\_read\_from\_disk](../xtradbinnodb-server-status-variables/index#innodb_encryption_rotation_pages_read_from_disk) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_have\_bzip2](../xtradbinnodb-server-status-variables/index#innodb_have_bzip2) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_have\_lz4](../xtradbinnodb-server-status-variables/index#innodb_have_lz4) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_have\_lzma](../xtradbinnodb-server-status-variables/index#innodb_have_lzma) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_have\_lzo](../xtradbinnodb-server-status-variables/index#innodb_have_lzo) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_have\_snappy](../xtradbinnodb-server-status-variables/index#innodb_have_snappy) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_num\_index\_pages\_written](../xtradbinnodb-server-status-variables/index#innodb_num_index_pages_written) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_num\_non\_index\_pages\_written](../xtradbinnodb-server-status-variables/index#innodb_num_non_index_pages_written) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_onlineddl\_pct\_progress](../xtradbinnodb-server-status-variables/index#innodb_onlineddl_pct_progress) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Innodb\_onlineddl\_rowlog\_pct\_used](../xtradbinnodb-server-status-variables/index#innodb_onlineddl_rowlog_pct_used) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Innodb\_onlineddl\_rowlog\_rows](../xtradbinnodb-server-status-variables/index#innodb_onlineddl_rowlog_rows) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | | [Innodb\_num\_page\_compressed\_trim\_op](../xtradbinnodb-server-status-variables/index#innodb_num_page_compressed_trim_op) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_num\_page\_compressed\_trim\_op\_saved](../xtradbinnodb-server-status-variables/index#innodb_num_page_compressed_trim_op_saved) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_num\_pages\_page\_compressed](../xtradbinnodb-server-status-variables/index#innodb_num_pages_page_compressed) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_num\_pages\_page\_compression\_error](../xtradbinnodb-server-status-variables/index#innodb_num_pages_page_compression_error) | [MariaDB 10.1](../what-is-mariadb-101/index) | | [Innodb\_num\_pages\_page\_decompressed](../xtradbinnodb-server-status-variables/index#innodb_num_pages_page_decompressed) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_num\_pages\_page\_decrypted](../xtradbinnodb-server-status-variables/index#innodb_num_pages_page_decrypted) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_num\_pages\_page\_encrypted](../xtradbinnodb-server-status-variables/index#innodb_num_pages_page_encrypted) | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | | [Innodb\_page\_compression\_saved](../xtradbinnodb-server-status-variables/index#innodb_page_compression_saved) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_page\_compression\_trim\_sect512](../xtradbinnodb-server-status-variables/index#innodb_page_compression_trim_sect512) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_page\_compression\_trim\_sect1024](../xtradbinnodb-server-status-variables/index#innodb_page_compression_trim_sect1024) | [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) | | [Innodb\_page\_compression\_trim\_sect2048](../xtradbinnodb-server-status-variables/index#innodb_page_compression_trim_sect2048) | [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) | | [Innodb\_page\_compression\_trim\_sect4096](../xtradbinnodb-server-status-variables/index#innodb_page_compression_trim_sect4096) | [MariaDB 10.1.0](https://mariadb.com/kb/en/mariadb-1010-release-notes/) | | [Innodb\_page\_compression\_trim\_sect8192](../xtradbinnodb-server-status-variables/index#innodb_page_compression_trim_sect8192) | [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) | | [Innodb\_page\_compression\_trim\_sect16384](../xtradbinnodb-server-status-variables/index#innodb_page_compression_trim_sect16384) | [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) | | [Innodb\_page\_compression\_trim\_sect32768](../xtradbinnodb-server-status-variables/index#innodb_page_compression_trim_sect32768) | [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) | | [Innodb\_secondary\_index\_triggered\_cluster\_reads](../xtradbinnodb-server-status-variables/index#innodb_secondary_index_triggered_cluster_reads) | [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) | | [Innodb\_secondary\_index\_triggered\_cluster\_reads\_avoided](../xtradbinnodb-server-status-variables/index#innodb_secondary_index_triggered_cluster_reads_avoided) | [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) | | [Master\_gtid\_wait\_count](../replication-and-binary-log-status-variables/index#master_gtid_wait_count) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Master\_gtid\_wait\_time](../replication-and-binary-log-status-variables/index#master_gtid_wait_time) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Master\_gtid\_wait\_timeouts](../replication-and-binary-log-status-variables/index#master_gtid_wait_timeouts) | [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) | | [Max\_statement\_time\_exceeded](../server-status-variables/index#max_statement_time_exceeded) | [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) | See Also -------- * [System variables added in MariaDB 10.1](../system-variables-added-in-mariadb-101/index) * [Status variables added in MariaDB 10.2](../status-variables-added-in-mariadb-102/index) * [Status variables added in MariaDB 10.0](../status-variables-added-in-mariadb-100/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.proc Table mysql.proc Table ================ The `mysql.proc` table contains information about [stored procedures](../stored-procedures/index) and [stored functions](../stored-functions/index). It contains similar information to that stored in the [INFORMATION SCHEMA.ROUTINES](../information-schema-routines-table/index) table. **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this table uses the [Aria](../aria/index) storage engine. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. The `mysql.proc` table contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | `db` | `char(64)` | NO | PRI | | Database name. | | `name` | `char(64)` | NO | PRI | | Routine name. | | `type` | `enum('FUNCTION','PROCEDURE','PACKAGE', 'PACKAGE BODY')` | NO | PRI | `NULL` | Whether [stored procedure](../stored-procedures/index), [stored function](../stored-functions/index) or, from [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/), a [package](../create-package/index) or [package body](../create-package-body/index). | | `specific_name` | `char(64)` | NO | | | | | `language` | `enum('SQL')` | NO | | SQL | Always `SQL`. | | `sql_data_access` | `enum('CONTAINS_SQL', 'NO_SQL', 'READS_SQL_DATA', 'MODIFIES_SQL_DATA')` | NO | | `CONTAINS_SQL` | | | `is_deterministic` | `enum('YES','NO')` | NO | | NO | Whether the routine is deterministic (can produce only one result for a given list of parameters) or not. | | `security_type` | `enum('INVOKER','DEFINER')` | NO | | `DEFINER` | `INVOKER` or `DEFINER`. Indicates which user's privileges apply to this routine. | | `param_list` | `blob` | NO | | `NULL` | List of parameters. | | `returns` | `longblob` | NO | | `NULL` | What the routine returns. | | `body` | `longblob` | NO | | `NULL` | Definition of the routine. | | `definer` | `char(141)` | NO | | | If the `security_type` is `DEFINER`, this value indicates which user defined this routine. | | `created` | `timestamp` | NO | | `CURRENT_TIMESTAMP` | Date and time the routine was created. | | `modified` | `timestamp` | NO | | 0000-00-00 00:00:00 | Date and time the routine was modified. | | `sql_mode` | `set('REAL_AS_FLOAT', 'PIPES_AS_CONCAT', 'ANSI_QUOTES', 'IGNORE_SPACE', 'IGNORE_BAD_TABLE_OPTIONS', 'ONLY_FULL_GROUP_BY', 'NO_UNSIGNED_SUBTRACTION', 'NO_DIR_IN_CREATE', 'POSTGRESQL', 'ORACLE', 'MSSQL', 'DB2', 'MAXDB', 'NO_KEY_OPTIONS', 'NO_TABLE_OPTIONS', 'NO_FIELD_OPTIONS', 'MYSQL323', 'MYSQL40', 'ANSI', 'NO_AUTO_VALUE_ON_ZERO', 'NO_BACKSLASH_ESCAPES', 'STRICT_TRANS_TABLES', 'STRICT_ALL_TABLES', 'NO_ZERO_IN_DATE', 'NO_ZERO_DATE', 'INVALID_DATES', 'ERROR_FOR_DIVISION_BY_ZERO', 'TRADITIONAL', 'NO_AUTO_CREATE_USER', 'HIGH_NOT_PRECEDENCE', 'NO_ENGINE_SUBSTITUTION', 'PAD_CHAR_TO_FULL_LENGTH', 'EMPTY_STRING_IS_NULL', 'SIMULTANEOUS_ASSIGNMENT')` | NO | | | The [SQL\_MODE](../sql-mode/index) at the time the routine was created. | | `comment` | `text` | NO | | `NULL` | Comment associated with the routine. | | `character_set_client` | `char(32)` | YES | | `NULL` | The [character set](../data-types-character-sets-and-collations/index) used by the client that created the routine. | | `collation_connection` | `char(32)` | YES | | `NULL` | The [collation](../data-types-character-sets-and-collations/index) (and character set) used by the connection that created the routine. | | `db_collation` | `char(32)` | YES | | `NULL` | The default [collation](../data-types-character-sets-and-collations/index) (and character set) for the database, at the time the routine was created. | | `body_utf8` | `longblob` | YES | | `NULL` | Definition of the routine in utf8. | | `aggregate` | `enum('NONE', 'GROUP')` | NO | | `NONE` | From [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) | | Field | Type | Null | Key | Default | Description | See Also -------- * [Stored Procedure Internals](../stored-procedure-internals/index) * [MySQL to MariaDB migration: handling privilege table differences when using mysqldump](https://mariadb.com/blog/mysql-mariadb-migration-handling-privilege-table-differences-when-using-mysqldump) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHOW TABLES SHOW TABLES =========== Syntax ------ ``` SHOW [FULL] TABLES [FROM db_name] [LIKE 'pattern' | WHERE expr] ``` Description ----------- `SHOW TABLES` lists the non-`TEMPORARY` tables, [sequences](../sequences/index) and [views](../views/index) in a given database. The `LIKE` clause, if present on its own, indicates which table names to match. The `WHERE` and `LIKE` clauses can be given to select rows using more general conditions, as discussed in [Extended SHOW](../extended-show/index). For example, when searching for tables in the `test` database, the column name for use in the `WHERE` and `LIKE` clauses will be `Tables_in_test` The `FULL` modifier is supported such that `SHOW FULL TABLES` displays a second output column. Values for the second column, `Table_type`, are `BASE TABLE` for a table, `VIEW` for a [view](../views/index) and `SEQUENCE` for a [sequence](../sequences/index). You can also get this information using: ``` mysqlshow db_name ``` See [mysqlshow](../mysqlshow/index) for more details. If you have no privileges for a base table or view, it does not show up in the output from `SHOW TABLES` or `mysqlshow *db\_name*`. The [information\_schema.TABLES](../information-schema-tables-table/index) table, as well as the [SHOW TABLE STATUS](../show-table-status/index) statement, provide extended information about tables. Examples -------- ``` SHOW TABLES; +----------------------+ | Tables_in_test | +----------------------+ | animal_count | | animals | | are_the_mooses_loose | | aria_test2 | | t1 | | view1 | +----------------------+ ``` Showing the tables beginning with *a* only. ``` SHOW TABLES WHERE Tables_in_test LIKE 'a%'; +----------------------+ | Tables_in_test | +----------------------+ | animal_count | | animals | | are_the_mooses_loose | | aria_test2 | +----------------------+ ``` Showing tables and table types: ``` SHOW FULL TABLES; +----------------+------------+ | Tables_in_test | Table_type | +----------------+------------+ | s1 | SEQUENCE | | student | BASE TABLE | | v1 | VIEW | +----------------+------------+ ``` See Also -------- * [SHOW TABLE STATUS](../show-table-status/index) * The [information\_schema.TABLES](../information-schema-tables-table/index) table Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_stages_summary_by_host_by_event_name Table Performance Schema events\_stages\_summary\_by\_host\_by\_event\_name Table =========================================================================== The table lists stage events, summarized by host and event name. It contains the following columns: | Column | Description | | --- | --- | | `HOST` | Host. Used together with `EVENT_NAME` for grouping events. | | `EVENT_NAME` | Event name. Used together with `HOST` for grouping events. | | `COUNT_STAR` | Number of summarized events, which includes all timed and untimed events. | | `SUM_TIMER_WAIT` | Total wait time of the timed summarized events. | | `MIN_TIMER_WAIT` | Minimum wait time of the timed summarized events. | | `AVG_TIMER_WAIT` | Average wait time of the timed summarized events. | | `MAX_TIMER_WAIT` | Maximum wait time of the timed summarized events. | Example ------- ``` SELECT * FROM events_stages_summary_by_host_by_event_name\G ... *************************** 216. row *************************** HOST: NULL EVENT_NAME: stage/sql/Waiting for event metadata lock COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 *************************** 217. row *************************** HOST: NULL EVENT_NAME: stage/sql/Waiting for commit lock COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 *************************** 218. row *************************** HOST: NULL EVENT_NAME: stage/aria/Waiting for a resource COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb MEDIAN MEDIAN ====== **MariaDB starting with [10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)**The MEDIAN() [window function](../window-functions/index) was first introduced with in [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/). Syntax ------ ``` MEDIAN(median expression) OVER ( [ PARTITION BY partition_expression ] ) ``` Description ----------- MEDIAN() is a [window function](../window-functions/index) that returns the median value of a range of values. It is a specific case of [PERCENTILE\_CONT](../percentile_cont/index), with an argument of 0.5 and the [ORDER BY](../order-by/index) column the one in `MEDIAN`'s argument. ``` MEDIAN(<median-arg>) OVER ( [ PARTITION BY partition_expression] ) ``` Is equivalent to: ``` PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY <median-arg>) OVER ( [ PARTITION BY partition_expression ]) ``` Examples -------- ``` CREATE TABLE book_rating (name CHAR(30), star_rating TINYINT); INSERT INTO book_rating VALUES ('Lord of the Ladybirds', 5); INSERT INTO book_rating VALUES ('Lord of the Ladybirds', 3); INSERT INTO book_rating VALUES ('Lady of the Flies', 1); INSERT INTO book_rating VALUES ('Lady of the Flies', 2); INSERT INTO book_rating VALUES ('Lady of the Flies', 5); SELECT name, median(star_rating) OVER (PARTITION BY name) FROM book_rating; +-----------------------+----------------------------------------------+ | name | median(star_rating) OVER (PARTITION BY name) | +-----------------------+----------------------------------------------+ | Lord of the Ladybirds | 4.0000000000 | | Lord of the Ladybirds | 4.0000000000 | | Lady of the Flies | 2.0000000000 | | Lady of the Flies | 2.0000000000 | | Lady of the Flies | 2.0000000000 | +-----------------------+----------------------------------------------+ ``` See Also -------- * [PERCENTILE\_CONT](../percentile_cont/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_SYS_INDEXES Table Information Schema INNODB\_SYS\_INDEXES Table ============================================= The [Information Schema](../information_schema/index) `INNODB_SYS_INDEXES` table contains information about InnoDB indexes. The `PROCESS` [privilege](../grant/index) is required to view the table. It has the following columns: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | INDEX\_ID | bigint(21) unsigned | NO | | 0 | A unique index identifier. | | NAME | varchar(64) | NO | | | Index name, lowercase for all user-created indexes, or uppercase for implicitly-created indexes; `PRIMARY` (primary key), `GEN_CLUST_INDEX` (index representing primary key where there isn't one), `ID_IND`, `FOR_IND` (validating foreign key constraint) , `REF_IND`. | | TABLE\_ID | bigint(21) unsigned | NO | | 0 | Table identifier, matching the value from [INNODB\_SYS\_TABLES.TABLE\_ID](../information-schema-innodb_sys_tables-table/index). | | TYPE | int(11) | NO | | 0 | Numeric type identifier; one of `0` (secondary index), `1` (clustered index), `2` (unique index), `3` (primary index), `32` ([full-text index](../full-text-indexes/index)). | | N\_FIELDS | int(11) | NO | | 0 | Number of columns in the index. GEN\_CLUST\_INDEX's have a value of 0 as the index is not based on an actual column in the table. | | PAGE\_NO | int(11) | NO | | 0 | Index B-tree's root page number. `-1` (unused) for full-text indexes, as they are laid out over several auxiliary tables. | | SPACE | int(11) | NO | | 0 | Tablespace identifier where the index resides. `0` represents the InnoDB system tablespace, while any other value represents a table created in file-per-table mode (see the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable). Remains unchanged after a [TRUNCATE TABLE](../truncate-table/index) statement, and not necessarily unique. | | MERGE\_THRESHOLD | int(11) | NO | | 0 | | Example ------- ``` SELECT * FROM information_schema.INNODB_SYS_INDEXES LIMIT 3\G *************************** 1. row *************************** INDEX_ID: 11 NAME: ID_IND TABLE_ID: 11 TYPE: 3 N_FIELDS: 1 PAGE_NO: 302 SPACE: 0 MERGE_THRESHOLD: 50 *************************** 2. row *************************** INDEX_ID: 12 NAME: FOR_IND TABLE_ID: 11 TYPE: 0 N_FIELDS: 1 PAGE_NO: 303 SPACE: 0 MERGE_THRESHOLD: 50 *************************** 3. row *************************** INDEX_ID: 13 NAME: REF_IND TABLE_ID: 11 TYPE: 3 N_FIELDS: 1 PAGE_NO: 304 SPACE: 0 MERGE_THRESHOLD: 50 3 rows in set (0.00 sec) ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Preparing for ColumnStore Installation - 1.2.2 Preparing for ColumnStore Installation - 1.2.2 ============================================== ### Prerequisite With version 1.2.2 of MariaDB ColumnStore, there should be no version of MariaDB Server or MySQL installed on the OS before a MariaDB ColumnStore is installed on the system. If you have an installation of MariaDB Server or MySQL, uninstall it before proceeding. #### Configuration preparation Before installing MariaDB ColumnStore, there is some preparation necessary. You will need to determine the following. Please refer to the MariaDB ColumnStore Architecture Document for additional information. * How many User Modules (UMs) will your system need? * How many Performance Modules (PMs) will your system need? * How much disk space will your system need? * Would you have passwordless ssh access between PMs? * Do you want to run the install as root or an unprivileged user? #### OS information MariaDB ColumnStore is certified to run on: RHEL/CentOS v6, v7 Ubuntu 16.04 LTS, Ubuntu 18.04 LTS Debian v8, v9 SUSE 12 but it should run on any recent Linux system. Make sure all nodes are running the same OS. Make sure the locale setting on all nodes is the same. To set locale to en\_US and UTf-8, as root run: ``` # localedef -i en_US -f UTF-8 en_US.UTF-8 ``` #### System administration information Information your system administrator must provide before installing MariaDB ColumnStore: * The hostnames of each interface on each node (optional). * The IP address of each interface on each node. * The user and password ColumnStore will run as should be consistent across all nodes. MariaDB ColumnStore can be installed as root or an unprivileged user. Example for 3 PM, 1UM system, these are the steps required to configure PM-1 for password-less ssh. The equivalent steps must be repeated on every PM in the system. The equivalent steps must be repeated on every UM in the system if the MariaDB ColumnStore Data Replication feature is enabled during the install process. ``` [root@pm- 1 ~] $ ssh-keygen [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-1 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-2 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-3 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub um-1 ``` If you will be using ssh keys... * and plan to enable Data Replication feature, make sure you can login between all UM nodes and all other UM nodes. * and plan to enable the Local Query Feature, make sure you can login between all UM nodes and all PM nodes. * and plan to enable the Data Redundancy feature, make sure you can login to PM1 from PM1, and between all UM nodes, without an additional prompt. This is required for the Data Redundancy feature. #### Network configuration MariaDB ColumnStore is quite flexible regarding networking. Some options are as follows: * The interconnect between UMs and PMs can be one or more private VLANs. In this case MariaDB ColumnStore will automatically trunk the individual LANs together to provide greater effective bandwidth between the UMs and PMs. * The PMs do not require a public LAN access as they only need to communicate with the UMs, unless the local query feature is desired. * The UMs most likely require at least one public interface to access the MySQL server front end from the site LAN. This interface can be a separate physical or logical connection from the PM interconnect. * You can use whatever security your site requires on the public access to the MySQL server front end on the UMs. By default it is listening on port 3306. * MariaDB ColumnStore software only requires a TCP/IP stack to be present to function. You can use any physical layer you desire. #### MariaDB ColumnStore port usage The MariaDB ColumnStore daemon uses port 3306. You must reserve the following ports to run the MariaDB ColumnStore software: 8600 - 8630, 8700, and 8800 #### Installation and Data Directory Paths MariaDB Columnstore requires that the software gets installed and the data paths in the configuration files don't get changed from their initial settings. The system will not function properly if they are changed or the software is install in the incorrect places. For root user install, it is required that it gets installed and it runs in this location: /usr/local/ For non-root user install, it is required that it gets installed and it runs in this location: /home/'non-root-user-name' Example if installed and running as 'mysq' user, is has to be installed here: /home/mysql/ IMPORTANT: Don't change any of the configuration files, Columnstore.xml or my.cnf, to point to a different install or data location. If you need to have the software or the data (dbroot backend data or the mysql data) placed in a different directory than what is required above, you can use soft-links. To install in a different directory for root user, here is an example of setting up a softlink ``` # ln -s /mnt/columnstore /usr/local/mariadb/columnstore ``` To install in a different directory for non-root user, here is an example of setting up a softlink ``` # ln -s /mnt/columnstore /home/mysql/mariadb/columnstore ``` To have the DBRoot data1 placed in a different directory, here is an example of setting up a softlink ``` # ln -s /mnt/data1 /usr/local/mariadb/columnstore/data1 ``` To have the MariaDB/MySQL aata placed in a different directory, here is an example of setting up a softlink ``` # ln -s /mnt/mysql /usr/local/mariadb/columnstore/mysql/db ``` If you do setup softlinks, make sure the permissions and users are setup for the new directories that match the current directories. #### Storage and Database files (DBRoots) 'DBRoot' is a term used by ColumnStore to refer to a storage unit, located at mariadb/columnstore/data<N>, where N is the identifier for that storage unit. You will see that term throughout the documentation. The name of this location can't be changed. But you can use soft-links to point it to other locations. MariaDB ColumnStore supports many storage options. * Internal - Internal means you will use block storage already mounted and available on each node. The data directories (mariadb/columnstore/dataN) can be links to other locations if preferable. With Internal storage setup, there is no High Availability Performance Module Failover capability. This is one of the limitations to using Internal storage. Its also for systems that have SAN that are mounted to single Performance Module. Its not shared mounted to all Performance Modules. * External - External means the SAN devices used for the DBRoots are shared mounted to all Performance Modules configured in the system. With External storage setup, the High Availability Performance Module Failover capability is supported, because mounts can be moved quickly from one node to another. So this is the only time that 'External' storage should be configured. * Data Redundancy - MariaDB ColumnStore supports Data Redundancy for both internal and external configurations. For Data Redundancy to be an option, the user is required to install the third party GlusterFS software on all Performance Modules. This is discussed later in the Package Dependency section. With Data Redundancy configured, High Availability Performance Module Failover capabilities is supported. IMPORTANT: When using external storage, be sure that only whole DBRoots are on the external filesystem. Do not use higher level directories, which may include the ColumnStore binaries and libraries. For example, /usr/local/mariadb/columnstore/data1 (aka DBRoot 1) would be a good candidate for external storage, but /usr/local/mariadb/columnstore would not be. #### Local database files If you are using internal storage, the DBRoot directories will be created under the installation directory, for example /usr/local/mariadb/columnstore/data<N> where N is the DBRoot number. There is no performance gain from assigning more than one DBRoot to a single storage device. DBRoots can be linked to other locations with more capacity if necessary. #### SAN mounted database files If you are using a SAN for storage, the following must be taken into account: * Each DBRoot must be a separate filesystem. * Each DBRoot should have the same capacity and performance characteristics, and each Performance Module should have the same number of DBRoots assigned for best performance. * MariaDB ColumnStore performs best on filesystems with low overhead, such as the ext family, however it can use any Linux filesystem. ColumnStore writes relatively large files (up to 64MB) compared to other databases, so please take that into account when choosing and configuring your filesystems. * For the failover feature to work, all Performance Modules must be able to mount any DBRoot. * The fstab file on all Performance Modules must include all of the external mounts, all with the 'noauto' option specified. ColumnStore will manage the mounting and unmounting. These lines are an example of an installation with 2 DBRoots configured. ``` /dev/sda1 /usr/local/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto 0 0 /dev/sdd1 /usr/local/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto 0 0 ``` #### Performance optimization considerations There are optimizations that should be made when using MariaDB ColumnStore listed below. As always, please consult with your network administrator for additional optimization considerations for your specific installation needs. #### GbE NIC settings: * Modify /etc/rc.d/rc.local to include the following: ``` /sbin/ifconfig eth0 txqueuelen 10000 ``` * Modify /etc/sysctl.conf for the following: ``` # increase TCP max buffer size net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 # increase Linux autotuning TCP buffer limits # min, default, and max number of bytes to use net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 65536 16777216 # don't cache ssthresh from previous connection net.ipv4.tcp_no_metrics_save = 1 # recommended to increase this for 1000 BT or higher net.core.netdev_max_backlog = 2500 # for 10 GigE, use this net.core.netdev_max_backlog = 30000 ``` NOTE: Make sure there is only 1 setting of net.core.netdev\_max\_backlog in the /etc/sysctl.conf file. * Cache memory settings: The kernel parameter vm.vfs\_cache\_pressure can be set to a lower value than 100 to attempt to retain caches for inode and directory structures. This will help improve read performance. A value of 10 is suggested. The following commands must be run as the root user or with sudo. To check the current value: ``` cat /proc/sys/vm/vfs_cache_pressure ``` To set the current value until the next reboot: ``` sysctl -w vm.vfs_cache_pressure=10 ``` To set the value permanently across reboots, add the following to /etc/sysctl.conf: ``` vm.vfs_cache_pressure = 10 ``` #### System settings considerations ##### umask setting The default setting of 022 is what is recommended. ColumnStore requires that it not end with a 7, like 077. For example, on a root installation, mysqld runs as the mysql user, and needs to be able to read the ColumnStore configuration file, which likely is not owned by mysql. If it were, then the other ColumnStore processes could not read it. The current umask can be determined by running the 'umask' command: A value of 022 can be set in the current session or in /etc/profile with the command: ``` umask 022 ``` #### Firewall considerations The MariaDB ColumnStore uses TCP ports 3306, 8600 - 8630, 8700, and 8800. Port 3306 is the default port for clients to connect to the MariaDB server; the others are for internal communication and will need to be open between ColumnStore nodes. To disable any local firewalls and SELinux on mutli-node installations, as root do the following. CentOS 6 and systems using iptables ``` #service iptables save (Will save your existing IPTable Rules) #service iptables stop (It will disable firewall Temporary) ``` To Disable it Permanentely: ``` #chkconfig iptables off ``` CentOS 7 and systems using systemctl with firewalld ``` #systemctl status firewalld #systemctl stop firewalld #systemctl disable firewalld ``` Ubuntu and systems using ufw ``` #service ufw stop (It will disable firewall Temporary) ``` To Disable it Permanently: ``` #chkconfig ufw off ``` SUSE ``` #/sbin/rcSuSEfirewall2 status #/sbin/rcSuSEfirewall2 stop ``` To disable SELinux, edit "/etc/selinux/config" and find line: ``` SELINUX=enforcing ``` Now replace it with, ``` SELINUX=disabled ``` #### User considerations MariaDB ColumnStore can be installed in different user configurations. #### Root User installation and execution MariaDB ColumnStore is installed by root and the MariaDB ColumnStore commands are run by root. With this installation type, you have the option of install using rpm, deb or binary packages. You can install the packages with the standard tools yum, apt, or zypper. The default package installation directory is /usr/local/mariadb/columnstore The location of the temporary files created by MariaDB ColumnStore is /tmp/columnstore\_tmp. #### Unprivileged user installation and execution MariaDB ColumnStore is installed by an unprivileged user and the MariaDB ColumnStore commands are run by that user. With this installation type, you are required to install using the binary tarball, which can be downloaded from the MariaDB ColumnStore Downloads page: <https://mariadb.com/downloads/#mariadbax> The default package installation directory is the home directory of the user account. The location of the temporary files created by MariaDB ColumnStore is $HOME/.tmp #### Root user installation and unprivileged user execution MariaDB ColumnStore is installed by root user and the MariaDB ColumnStore commands are run by an unprivileged user. This document will show how to configure the system to run commands as an unprivileged user: [https://mariadb.com/kb/en/library/mariadb-columnstore-system-usage/#non-root-user-mariadb-columnstore-admin-console](../library/mariadb-columnstore-system-usage/index#non-root-user-mariadb-columnstore-admin-console) With this installation type, you have the option of install using rpm, deb or binary packages, which you can install with the standard tools yum, apt, zypper. The default package installation directory is /usr/local/mariadb/columnstore The location of the temporary files created by MariaDB ColumnStore is /tmp/columnstore\_tmp. ### Package dependencies #### Boost libraries MariaDB ColumnStore requires that the boost package of 1.53 or newer is installed. For Centos 7, Ubuntu 16, Debian 8, SUSE 12 and other newer OS's, you can just install the default boost package that comes with your distribution. ``` # yum -y install boost ``` or ``` # apt-get -y install libboost-all-dev ``` For SUSE 12, you will need to install the boost-devel package, which is part of the SLE-SDK package. ``` SUSEConnect -p sle-sdk/12.2/x86_64 zypper install boost-devel ``` For CentOS 6, you can either download and install the MariaDB Columnstore Centos 6 boost library package or build version 1.55 from source and deploy it to each ColumnStore node. To download the pre-built libraries from MariaDB, go to binaries download page and download "centos6\_boost\_1\_55.tar.gz" <https://mariadb.com/downloads/columnstore> Click All Versions - > 1.0.x -> centos -> x86\_64 Install package on each server in the cluster. ``` wget https://downloads.mariadb.com/ColumnStore/1.0.14/centos/x86_64/centos6_boost_1_55.tar.gz tar xfz centos6_boost_1_55.tar.gz -C /usr/lib ldconfig ``` Downloading and build the boost libraries from source: NOTE: This requires that the "Development Tools" group and cmake be installed prior to this. ``` yum groupinstall "Development Tools" yum install cmake ``` Here is the procedure to download and build the boost source. As root do the following: ``` cd /usr/ wget http://sourceforge.net/projects/boost/files/boost/1.55.0/boost_1_55_0.tar.gz tar zxvf boost_1_55_0.tar.gz cd boost_1_55_0 ./bootstrap.sh --with-libraries=atomic,date_time,exception,filesystem,iostreams,locale,program_options,regex,signals,system,test,thread,timer,log --prefix=/usr ./b2 install ldconfig ``` #### Other packages Additional packages are required on each ColumnStore node. ##### Centos 6/7 ``` # yum -y install expect perl perl-DBI openssl zlib file sudo libaio rsync snappy net-tools numactl-libs nmap ``` ##### Ubuntu 16/18 ``` # apt-get -y install tzdata libtcl8.6 expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1v5 net-tools libnuma1 nmap ``` ##### Debian 8 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1 net-tools libnuma1 nmap ``` ##### Debian 9 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync net-tools libsnappy1v5 libreadline5 libaio1 libnuma1 nmap ``` ##### SUSE 12 ``` zypper install expect perl perl-DBI openssl file sudo libaio1 rsync net-tools libsnappy1 libnuma1 nmap ``` #### Data Redundancy packages To enable the Data Redundancy feature, install and enable GlusterFS version 3.3.1 or higher on each Performance Module. ##### Centos 6/7 ``` # yum -y install centos-release-gluster # yum -y install glusterfs glusterfs-fuse glusterfs-server start / enable service: # systemctl enable glusterd.service # systemctl start glusterd.service ``` ##### Ubuntu 16/18 ``` # apt-get install glusterfs-server attr start / enable service: # systemctl start glusterfs-server.service # systemctl enable glusterfs-server.service ``` ##### Debian 8 ``` # apt-get -y install glusterfs-server attr start / enable service: # update-rc.d glusterfs-server defaults ``` ##### Debian 9 ``` # apt-get install glusterfs-server attr start / enable service: # systemctl start glusterfs-server.service # systemctl enable glusterfs-server.service ``` ##### SUSE 12 ``` # zypper install glusterfs start / enable service: # chkconfig glusterd on ``` #### System Logging Package MariaDB ColumnStore can use the following standard logging systems. * syslog * rsyslog * syslog-ng ### Download location The standard ColumnStore RPM and DEB packages are available at <https://mariadb.com/downloads/columnstore>. If you need to install ColumnStore without root-level permissions, you must use the binary tarball, which is available at <https://downloads.mariadb.com/ColumnStore/> Note: MariaDB ColumnStore will configure a root user with no password in the MariaDB server initially. Afterward, you may setup users and permissions within MariaDB as you normally would. ### Choosing the type of initial download/install #### Non-Distributed Installation The default MariaDB ColumnStore installation process supports a Non-Distributed installation mode for multi-node deployments. With this option, the user will need to install the ColumnStore packages manually on each node. This option would be used when Package Repo install of rpm/deb packages are the preferred method to install MariaDB ColumnStore. Its also used for MariaDB ColumnStore Docker images. The Pre-install setup time will take longer with the Non-Distributed Installation, but the system Install and startup via the install app 'postConfigure' will be faster. #### Distributed Install With the Distributed option, MariaDB ColumnStore will distribute and install the packages automatically on each node. The user installs ColumnStore on Performance Module 1, then during the postConfigure step, ColumnStore will handle the rest. This option would be used on system with multi-nodes where the package only had to be installed on 1 node, the Performance Module 1, the app 'postConfigure' would distribute and all down to all of the other nodes. The Pre-install setup time would be shorter with the Non-Distributed Installation, but the system Install and startup via the install app 'postConfigure' will be take longer. ### Root user installations #### Initial download/install of MariaDB ColumnStore Packages The MariaDB ColumnStore RPM and DEB Packages can be installed using yum/apt-get commands. Check here for additional Information: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) #### Initial download/install of MariaDB ColumnStore Package with the AX package The MariaDB ColumnStore RPM, DEB and binary packages can be installed along with the other packages that make up the AX package. Check here for additional Information: [https://mariadb.com/kb/en/library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/](../library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/index) #### Initial download & installation of MariaDB ColumnStore RPMs 1. Install MariaDB ColumnStore as user root: Note: MariaDB ColumnStore will configure a root user with no password in the MariaDB server initially. Afterward, you may setup users and permissions within MariaDB as you normally would. Note: The packages will be installed at /usr/local. This is required for root user installations. * Download the appropriate ColumnStore package and place in the /root directory. * Unpack the tarball, which contains multiple RPMs. * Install the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. `rpm -ivh mariadb-columnstore*release#*.rpm` #### Initial download & installation of MariaDB ColumnStore binary package The MariaDB ColumnStore binary packages can be downloaded from <https://downloads.mariadb.com/ColumnStore/>. Select version 1.2.2, then navigate to the appropriate package for your system. The binary package will have the extension '.bin.tar.gz' rather than '.rpm.tar.gz' or '.deb.tar.gz'. * Unpack the tarball in /usr/local/ `tar -zxf mariadb-columnstore-release#.x86_64.bin.tar.gz` Run the post-install script: ``` /usr/local/mariadb/columnstore/bin/post-install ``` #### Initial download & installation of MariaDB ColumnStore DEB package 1. Download the package mariadb-columnstore-release#.amd64.deb.tar.gz into the /root directory of the server where you are installing MariaDB ColumnStore. 2. Unpack the tarball, which contains multiple DEBs. `tar -zxf mariadb-columnstore-release#.amd64.deb.tar.gz` 3. Install the MariaDB ColumnStore DEBs. The MariaDB ColumnStore software will be installed in /usr/ local/. `dpkg -i mariadb-columnstore*release#*.deb` ### Unprivileged user installation MariaDB Columnstore is installed to run as an unprivileged user using the binary package. It will need to be run on all MariaDB ColumnStore nodes. For the purpose of these instructions, the following assumptions are: * Unprivileged user 'mysql' is used in this example * Installation directory is /home/mysql/mariadb/columnstore Tasks involved: * Create the mysql user and group of the same name (by root user) * Update sudo configuration, if needed (by root user) * Set the user file limits (by root user) * Modify fstab if using 'external' storage (by root user) * Uninstall existing MariaDB Columnstore installation if needed (by root user) * Update permissions on certain directories that MariaDB Columnstore writes (by root user) * MariaDB Columnstore Installation (by the new user user) * Enable MariaDB Columnstore to start automatically at boot time #### Creation of a new user (by root user) Before beginning the binary tar file installation you will need your system administrator to set up accounts for you on every MariaDB Columnstore node. The account name & password must be the same on every node. If you change the password on one node, you must change it on every node. The user ID must be the same on every node as well. In the examples below we will use the account name 'mysql' and the password 'mariadb'. * create new user Group ID is an example, can be different than 1000, but needs to be the same on all servers in the cluster `adduser mysql -u 1000` * create group ``` addgroup mysql moduser -g mysql mysql ``` The value for user-id must be the same for all nodes. * Assign a password to newly created user `passwd mysql` * Log in as user mysql `su - mysql` IMPORTANT: It is required that the installation directory will be the home directory of the user account. So it would be '/home/mysql/' in this example. The installation directory must be the same on every node. In the examples below we will use the path '/home/mysql/mariadb/columnstore'. #### Update sudo configuration, if needed (by root user) In the MariaDB ColumnStore 1.2.1 and later, sudo configuration is only required for certain system configurations. These would include: * Data Redundancy * External Storage * Amazon EC2 using EBS storage If your system is not configured with any of these, you can skip this section. #### sudo configuration for Data Redundancy The sudo configuration on each node will need to allow the new user to run the gluster, mount, umount, and chmod commands. Add the following lines to your /etc/sudoers file, changing the paths to those commands if necessary on your system. ``` mysql ALL=NOPASSWD: /sbin/gluster mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount mysql ALL=NOPASSWD: /usr/bin/chmod ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### sudo configuration for External Storage The sudo configuration on each node will need to allow the new user to run the chmod, chown, mount, and umount commands. Add the following lines to your /etc/sudoers file, changing the path of each command if necessary on your system. ``` mysql ALL=NOPASSWD: /usr/bin/chmod mysql ALL=NOPASSWD: /usr/bin/chown mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### sudo configuration for Amazon EC2 using EBS storage The sudo configuration on each node will need to allow the new user to run several commands. Add the following lines to your /etc/sudoers file, changing the path of each command if necessary on your system. ``` mysql ALL=NOPASSWD: /usr/sbin/mkfs.ext2 mysql ALL=NOPASSWD: /usr/bin/chmod mysql ALL=NOPASSWD: /usr/bin/chown mysql ALL=NOPASSWD: /usr/bin/sed mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### Set the user file limits (by root user) ColumnStore needs the open file limit to be increased for the new user. To do this edit the /etc/security/limits.conf file and make the following additions at the end of the file: ``` mysql hard nofile 65536 mysql soft nofile 65536 ``` If you are already logged in as 'mysql' you will need to logout, then login for this change to take effect. #### Modify fstab if using the external storage option (by root user) If you are using an 'external' storage configuration, you will need to allow the new user to mount and unmount those filesystems. Add the 'users' option to those filesystems in your /etc/fstab file. Example entries: /dev/sda1 /home/mysql/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto,users 0 0 /dev/sdd1 /home/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto,users 0 0 The external filesystems will need to be owned by the new user. This is an example command run as root setting the owner and group of dbroot /dev/sda1 to the mysql user: ``` mount /dev/sda1 /tmpdir chown -R mysql:mysql /tmpdir umount /tmpdir ``` #### Update permissions on directories that MariaDB Columnstore writes to (by root user) ColumnStore uses POSIX shared memory segments. On some systems, the entry point /dev/shm does not allow regular users to create new segments. If necessary, permissions on /dev/shm should be set such that the new user or group has full access. The default on most systems is 777. ``` chmod 777 /dev/shm ``` For Data Redundancy using GlusterFS configured system: ``` chmod 777 -R /var/log/glusterfs ``` To allow external storage on an Amazon EC2 instance using EBS storage: ``` chmod 644 /etc/fstab ``` #### Uninstall existing MariaDB Columnstore installation, if needed (by root user) If MariaDB Columnstore has ever before been installed on any of the planned hosts as a root user install, you must have the system administrator verify that no remnants of that installation exist. The unprivileged installation will not be successful if there are MariaDB Columnstore files owned by root on any of the hosts. * Verify the MariaDB Columnstore installation directory does not exist: The /usr/local/mariadb/columnstore directory should not exist at all unless it is your target directory, in which case it must be completely empty and owned by the new user. * Verify the /etc/fstab entries are correct for the new installation. * Verify the /etc/default/columnstore directory does not exist. * Verify the /var/lock/subsys/mysql-Columnstore file does not exist. * Verify the /tmp/StopColumnstore file does not exist. #### MariaDB Columnstore installation (by the new user) You should be familiar with the general MariaDB Columnstore installation instructions in this guide as you will be asked the same questions during installation. If performing the distributed-mode installation across multiple node, the binary package only needs to be installed on Performance Module #1 (pm1). If performing a non-distributed installation, the binary package is required to install the MariaDB ColumnStore on all the nodes in the system. * Log in as the unprivileged user (mysql, in our example) Note: Ensure you are at your home directory before proceeding to the next step * Now place the MariaDB Columnstore binary tar file in your home directory on the host you will be using as PM1. Untar the binary distribution package to the /home/mysql directory: tar -xf mariadb-columnstore-release#.x86\_64.bin.tar.gz * Run post installation: If performing the distributed-mode installation, post-install only needs to be run on Performance Module #1 (pm1). If performing non-distributed installations, post-install needs to be run on all the nodes in the system. NOTE: $HOME is the same as /home/mysql in this example ``` ./mariadb/columnstore/bin/post-install --installdir=$HOME/mariadb/columnstore ``` Here is an example of what is printed by the post-install command ``` NOTE: For non-root install, you will need to run the following commands as root user to setup the MariaDB ColumnStore System Logging export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/syslogSetup.sh --installdir=/home/mysql/mariadb/columnstore --user=mysql install The next steps are: If installing on a pm1 node using non-distributed install export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore If installing on a pm1 node using distributed install export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore -d If installing on a non-pm1 using the non-distributed option: export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/columnstore start ``` * Setup System Logging For an unprivileged user installation, you will need to run the following commands as root on all nodes after the post-install command is run to make log entries go to the right places: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/syslogSetup.sh --installdir=/home/mysql/mariadb/columnstore --user=mysql install ``` Without that, log entries will go to the main system log file, and low-severity logs may not be recorded at all. * Start MariaDB ColumnStore Service for Non-Distributed installations If performing the non-distributed installation mode, the 'columnstore' service needs to be started on all nodes in the system except Performance Module #1 (pm1). postConfigure is on pm1, which is documented in the next section. Starting the 'columnstore' service: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/columnstore start ``` * Running ColumnStore Configuration and Installation Tool, 'postConfigure' On PM1, run the 2 export commands that were printed by the post-install command, then run postConfigure, which would look like the following: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore ``` #### Configure ColumnStore to run automatically at boot To configure MariaDB Columnstore unprivileged installation to start automatically at boot time, perform the following steps on each Columnstore node: * Add the following to your local startup script (/etc/rc.local or similar), modifying as necessary: ``` runuser -l mysql -c "/home/mysql/mariadb/columnstore/bin/columnstore start" ``` Note: Make sure the above entry is added to the rc.local file that gets executed at boot time. Depending on the OS installation, rc.local could be in a different location. * MariaDB Columnstore will setup and log using your current system logging application in the directory /var/log/mariadb/columnstore. ### MariaDB Server Password setup If you plan to setup a root user password in the MariaDB server Database, remember to setup the Password Configuration file on each User Module and Performance Module that has User Modules functionality. [https://mariadb.com/kb/en/library/mariadb-columnstore-system-usage/#logging-into-mariadb-columnstore-mariadb-console](../library/mariadb-columnstore-system-usage/index#logging-into-mariadb-columnstore-mariadb-console) ### ColumnStore Cluster Test Tool This tool can be run before installation. It will verify the setup of all servers that are going to be used in the Columnstore System. [https://mariadb.com/kb/en/mariadb/mariadb-columnstore-cluster-test-tool](../mariadb/mariadb-columnstore-cluster-test-tool) ### How to Configuration and Launch MariaDB Columnstore #### ColumnStore Quick Launch Tools There are 3 Quick Launch Tools that can be used to launch basic systems. These are 1 step command tool where you provide the number of modules or amazon instances and the tool will take care of the rest. 1. Single Server Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-single-server-columnstore-system-12x/#mariadb-columnstore-quick-installer-for-a-single-server-system](../library/installing-and-configuring-a-single-server-columnstore-system-12x/index#mariadb-columnstore-quick-installer-for-a-single-server-system) 2. Multi Server Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-multi-server-columnstore-system-12x/#mariadb-columnstore-quick-installer](../library/installing-and-configuring-a-multi-server-columnstore-system-12x/index#mariadb-columnstore-quick-installer) 3. Amazon AMI Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-columnstore-system-using-the-amazon-ami/#mariadb-columnstore-one-step-quick-installer-script-quick\_installer\_amazonsh](../library/installing-and-configuring-a-columnstore-system-using-the-amazon-ami/index#mariadb-columnstore-one-step-quick-installer-script-quick_installer_amazonsh) #### ColumnStore Configuration and Installation Tool MariaDB Columnstore System Configuration and Installation tool, 'postConfigure', will Configure the MariaDB Columnstore System and will perform a Package Installation of all of the Servers within the System that is being configured. It will prompt the user to for information like IP addresses, storage types, MariaDB Server, and system features. At the end, it will start the ColumnStore system. NOTE: When prompted for password, enter the non-user account password OR just hit enter if you have configured password-less ssh keys on all nodes (Please see the “System Administration Information” section earlier in this guide for more information on ssh keys.) This tool is always run on the Performance Module #1. Example uses of this script are shown in the Single and Multi Server Installations Guides. ``` # /usr/local/mariadb/columnstore/bin/postConfigure -h This is the MariaDB ColumnStore System Configuration and Installation tool. It will Configure the MariaDB ColumnStore System based on Operator inputs and will perform a Package Installation of all of the Modules within the System that is being configured. IMPORTANT: This tool should only be run on a Performance Module Server, preferably Module #1 Instructions: Press 'enter' to accept a value in (), if available or Enter one of the options within [], if available, or Enter a new value Usage: postConfigure [-h][-c][-u][-p][-qs][-qm][-qa][-port][-i][-n][-d][-sn][-pm-ip-addrs][-um-ip-addrs][-pm-count][-um-count] -h Help -c Config File to use to extract configuration data, default is Columnstore.xml.rpmsave -u Upgrade, Install using the Config File from -c, default to Columnstore.xml.rpmsave If ssh-keys aren't setup, you should provide passwords as command line arguments -p Unix Password, used with no-prompting option -qs Quick Install - Single Server -qm Quick Install - Multi Server -port MariaDB ColumnStore Port Address -i Non-root Install directory, Only use for non-root installs -n Non-distributed install, meaning postConfigure will not install packages on remote nodes -d Distributed install, meaning postConfigure will install packages on remote nodes -sn System Name -pm-ip-addrs Performance Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx -um-ip-addrs User Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb DROP TRIGGER DROP TRIGGER ============ Syntax ------ ``` DROP TRIGGER [IF EXISTS] [schema_name.]trigger_name ``` Description ----------- This statement drops a [trigger](../triggers/index). The schema (database) name is optional. If the schema is omitted, the trigger is dropped from the default schema. Its use requires the `TRIGGER` privilege for the table associated with the trigger. Use `IF EXISTS` to prevent an error from occurring for a trigger that does not exist. A `NOTE` is generated for a non-existent trigger when using `IF EXISTS`. See [SHOW WARNINGS](../show-warnings/index). **Note:** Triggers for a table are also dropped if you drop the table. ### Atomic DDL **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**[MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/) supports [Atomic DDL](../atomic-ddl/index) and `DROP TRIGGER` is atomic. Examples -------- ``` DROP TRIGGER test.example_trigger; ``` Using the IF EXISTS clause: ``` DROP TRIGGER IF EXISTS test.example_trigger; Query OK, 0 rows affected, 1 warning (0.01 sec) SHOW WARNINGS; +-------+------+------------------------+ | Level | Code | Message | +-------+------+------------------------+ | Note | 1360 | Trigger does not exist | +-------+------+------------------------+ ``` See Also -------- * [Trigger Overview](../trigger-overview/index) * [CREATE TRIGGER](../create-trigger/index) * [Information Schema TRIGGERS Table](../information-schema-triggers-table/index) * [SHOW TRIGGERS](../show-triggers/index) * [SHOW CREATE TRIGGER](../show-create-trigger/index) * [Trigger Limitations](../trigger-limitations/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Numeric Functions Numeric Functions ================== Functions dealing with numerals, including ABS, CEIL, DIV, EXP, PI, SIN, etc. | Title | Description | | --- | --- | | [Addition Operator (+)](../addition-operator/index) | Addition. | | [Subtraction Operator (-)](../subtraction-operator-/index) | Subtraction and unary minus. | | [Division Operator (/)](../division-operator/index) | Division. | | [Multiplication Operator (\*)](../multiplication-operator/index) | Multiplication. | | [Modulo Operator (%)](../modulo-operator/index) | Modulo operator. Returns the remainder of N divided by M. | | [DIV](../div/index) | Integer division. | | [ABS](../abs/index) | Returns an absolute value. | | [ACOS](../acos/index) | Returns an arc cosine. | | [ASIN](../asin/index) | Returns the arc sine. | | [ATAN](../atan/index) | Returns the arc tangent. | | [ATAN2](../atan2/index) | Returns the arc tangent of two variables. | | [CEIL](../ceil/index) | Synonym for CEILING(). | | [CEILING](../ceiling/index) | Returns the smallest integer not less than X. | | [CONV](../conv/index) | Converts numbers between different number bases. | | [COS](../cos/index) | Returns the cosine. | | [COT](../cot/index) | Returns the cotangent. | | [CRC32](../crc32/index) | Computes a cyclic redundancy check (CRC) value. | | [CRC32C](../crc32c/index) | Computes a cyclic redundancy check (CRC) value using the Castagnoli polynomial. | | [DEGREES](../degrees/index) | Converts from radians to degrees. | | [EXP](../exp/index) | e raised to the power of the argument. | | [FLOOR](../floor/index) | Largest integer value not greater than the argument. | | [GREATEST](../greatest/index) | Returns the largest argument. | | [LEAST](../least/index) | Returns the smallest argument. | | [LN](../ln/index) | Returns natural logarithm. | | [LOG](../log/index) | Returns the natural logarithm. | | [LOG10](../log10/index) | Returns the base-10 logarithm. | | [LOG2](../log2/index) | Returns the base-2 logarithm. | | [MOD](../mod/index) | Modulo operation. Remainder of N divided by M. | | [OCT](../oct/index) | Returns octal value. | | [PI](../pi/index) | Returns the value of π (pi). | | [POW](../pow/index) | Returns X raised to the power of Y. | | [POWER](../power/index) | Synonym for POW(). | | [RADIANS](../radians/index) | Converts from degrees to radians. | | [RAND](../rand/index) | Random floating-point value. | | [ROUND](../round/index) | Rounds a number. | | [SIGN](../sign/index) | Returns 1, 0 or -1. | | [SIN](../sin/index) | Returns the sine. | | [SQRT](../sqrt/index) | Square root. | | [TAN](../tan/index) | Returns the tangent. | | [TRUNCATE](../truncate/index) | The TRUNCATE function truncates a number to a specified number of decimal places. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Administrative Console ColumnStore Administrative Console ================================== The MariaDB ColumnStore Management Console allows you to configure, monitor, and manage the MariaDB ColumnStore system and servers. Once you have a running ColumnStore cluster, you can invoke the console from any of the [UM](../columnstore-user-module/index) or [PM](../columnstore-performance-module/index) nodes. The console utility is called mcsadmin ``` [myuser@srv1~]# mcsadmin MariaDB Columnstore Admin Console enter 'help' for list of commands enter 'exit' to exit the MariaDB Columnstore Command Console use up/down arrows to recall commands Active Alarm Counts: Critical = 0, Major = 0, Minor = 0, Warning = 0, Info = 0 Critical Active Alarms: mcsadmin> quit ``` You can use one of the following commands in the console ``` Command Description ------------------------------ -------------------------------------------------------- ? Get help on the Console Commands addDbroot Add DBRoot Disk storage to the MariaDB Columnstore System addModule Add a Module within the MariaDB Columnstore System alterSystem-disableModule Disable a Module and Alter the MariaDB Columnstore System alterSystem-enableModule Enable a Module and Alter the MariaDB Columnstore System assignDbrootPmConfig Assign unassigned DBroots to Performance Module assignElasticIPAddress Assign Amazon Elastic IP Address to a module disableLog Disable the levels of process and debug logging disableMySQLReplication Disable MySQL Replication functionality on the system enableLog Enable the levels of process and debug logging enableMySQLReplication Enable MySQL Replication functionality on the system exit Exit from the Console tool findObjectFile Get the name of the directory containing the first file of the object getActiveAlarms Get Active Alarm list getActiveSQLStatements Get List Active SQL Statements within the System getAlarmConfig Get Alarm Configuration Information getAlarmHistory Get system alarms getAlarmSummary Get Summary counts of Active Alarm getLogConfig Get the System log file configuration getModuleConfig Get Module Name Configuration Information getModuleCpu Get a Module CPU usage getModuleCpuUsers Get a Module Top Processes utilizing CPU getModuleDisk Get a Module Disk usage getModuleHostNames Get a list of Module host names (NIC 1 only) getModuleMemory Get a Module Memory usage getModuleMemoryUsers Get a Module Top Processes utilizing Memory getModuleResourceUsage Get a Module Resource usage getModuleTypeConfig Get Module Type Configuration Information getProcessConfig Get Process Configuration Information getProcessStatus Get MariaDB Columnstore Process Statuses getSoftwareInfo Get the MariaDB Columnstore Package information getStorageConfig Get System Storage Configuration Information getStorageStatus Get System Storage Status getSystemCpu Get System CPU usage on all modules getSystemCpuUsers Get System Top Processes utilizing CPU getSystemDirectories Get System Installation and Temporary Logging Directories getSystemDisk Get System Disk usage on all modules getSystemInfo Get the Over-all System Statuses getSystemMemory Get System Memory usage on all modules getSystemMemoryUsers Get System Top Processes utilizing Memory getSystemNetworkConfig Get System Network Configuration Information getSystemResourceUsage Get System Resource usage on all modules getSystemStatus Get System and Modules Status help Get help on the Console Commands monitorAlarms Monitor alarms in realtime mode movePmDbrootConfig Move DBroots from one Performance Module to another quit Exit from the Console tool redistributeData Redistribute table data accross all dbroots to balance disk usage removeDbroot Remove DBRoot Disk storage from the MariaDB Columnstore System removeModule Remove a Module within the MariaDB Columnstore System resetAlarm Resets an Active Alarm restartSystem Restarts a stopped or shutdown MariaDB Columnstore System resumeDatabaseWrites Resume performing writes to the MariaDB Columnstore Database setAlarmConfig Set a Alarm Configuration parameter setModuleTypeConfig Set a Module Type Configuration parameter setProcessConfig Set a Process Configuration parameter shutdownSystem Shuts down the MariaDB Columnstore System startSystem Starts a stopped or shutdown MariaDB Columnstore System stopSystem Stops the processing of the MariaDB Columnstore System suspendDatabaseWrites Suspend performing writes to the MariaDB Columnstore Database switchParentOAMModule Switches the Active Parent OAM Module to another Performance Module system Execute a system shell command unassignDbrootPmConfig Unassign DBroots from a Performance Module unassignElasticIPAddress Unassign Amazon Elastic IP Address ``` ### Help command The help command displays supported commands. You can view brief help definitions or verbose definitions. You can also enter partial command names with the help command to view verbose definitions. For example, type help *enableLog* to get the verbose definition of the *enableLog* command as shown below. ``` mcsadmin> mcsadmin> help enableLog help Fri Jun 10 19:26:26 2016 Command: enableLog Description: Enable the levels of process and debug logging Arguments: Required: 'system' or Module-name where logging is being enabled Required: 'all' or the specific level to enable Levels: critical, error, warning, info, and debug mcsadmin> ``` ### Case sensitivity Commands are not case sensitive; however parameters and device names, like server and processes, are case sensitive. ### Recall command history Use the up and down arrow keys on your keyboard to scroll through the command history. ### Command repeat option Commands can be run continuously using the “-r” option. The repeat option repeats a command every 5 seconds. You can change the repeat interval to be between 1 and 60 seconds by adding the number of seconds after the command. This is useful to check status in real-time mode. For example to repeat the *GetProcessStatus* command every 2 seconds: ``` mcsadmin> getProcessStatus -r2 repeating the command 'GetProcessStatus' every 2 seconds, enter CTRL-D to stop getprocessstatus Fri Jun 10 19:31:28 2016 MariaDB Columnstore Process statuses Process Module Status Last Status Change Process ID ------------------ ------ --------------- ------------------------ ---------- ProcessMonitor pm1 ACTIVE Fri Jun 10 01:50:04 2016 2487 ProcessManager pm1 ACTIVE Fri Jun 10 01:50:10 2016 2673 SNMPTrapDaemon pm1 ACTIVE Fri Jun 10 01:50:16 2016 3534 DBRMControllerNode pm1 ACTIVE Fri Jun 10 01:50:20 2016 3585 ServerMonitor pm1 ACTIVE Fri Jun 10 01:50:22 2016 3625 DBRMWorkerNode pm1 ACTIVE Fri Jun 10 01:50:22 2016 3665 DecomSvr pm1 ACTIVE Fri Jun 10 01:50:26 2016 3742 PrimProc pm1 ACTIVE Fri Jun 10 01:50:28 2016 3770 ExeMgr pm1 ACTIVE Fri Jun 10 01:50:32 2016 3844 WriteEngineServer pm1 ACTIVE Fri Jun 10 01:50:36 2016 3934 DDLProc pm1 ACTIVE Fri Jun 10 01:50:40 2016 3991 DMLProc pm1 ACTIVE Fri Jun 10 01:50:45 2016 4058 mysqld pm1 ACTIVE Fri Jun 10 01:50:22 2016 2975 ``` ### Unix Command Line entry mcsadmin commands can be run from the linux command line prompt ``` # mcsadmin getSystemInfo ``` ### Command Name Short-cutting mcsadmin commands can be short-cutted. This example would execute getSystemInfo. The is the first command it would find alphabetically with 'getsystemi' ``` # mcsadmin getsystemi ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Create View ColumnStore Create View ======================= Creates a stored query in the MariaDB ColumnStore Syntax ------ ``` CREATE [OR REPLACE] VIEW view_name [(column_list)] AS select_statement ``` Notes to CREATE VIEW: * If you describe a view in MariaDB ColumnStore, the column types reported may not match the actual column types in the underlying tables. This is normal and can be ignored. The following statement creates a customer view of orders with status: ``` CREATE VIEW v_cust_orders (cust_name, order_number, order_status) as select c.cust_name, o.ordernum, o.status from customer c, orders o where c.custnum = o.custnum; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Moving from MySQL to MariaDB in Debian 9 Moving from MySQL to MariaDB in Debian 9 ======================================== [MariaDB 10.1](../what-is-mariadb-101/index) is now the default mysql server in Debian 9 "Stretch". This page provides information on this change and instructions to help with upgrading your Debian 8 "Jessie" version of MySQL or MariaDB to [MariaDB 10.1](../what-is-mariadb-101/index) in Debian 9 "Stretch". Background information ---------------------- The version of MySQL in Debian 8 "Jessie" is 5.5. When installing, most users will install the `mysql-server` package, which depends on the `mysql-server-5.5 package`. In Debian 9 "Stretch" the `mysql-server` package depends on a new package called `default-mysql-server`. This package in turn depends on `mariadb-server-10.1`. There is no `default-mysql-server` package in Jessie. In both Jessie and Stretch there is also a `mariadb-server` package which is a MariaDB-specific analog to the `mysql-server` package. In Jessie this package depends on `mariadb-server-10.0` and in Stretch this package depends on `mariadb-server-10.1` (the same as the `default-mysql-server` package). So, the main repository difference in Debian 9 "Stretch" is that when you install the `mysql-server` package on Stretch you will get [MariaDB 10.1](../what-is-mariadb-101/index) instead of MySQL, like you would with previous versions of Debian. Note that `mysql-server` is just an empty transitional meta-package and users are encouraged to install MariaDB using the actual package `mariadb-server`. All apps and tools, such as the popular LAMP stack, in the repositories that depend on the `mysql-server` package will continue to work using MariaDB as the database. For new installs there is nothing different that needs to be done when installing the mysql-server or mariadb-server packages. Before you upgrade ------------------ If you are currently running MySQL 5.5 on Debian 8 "Jessie" and are planning an upgrade to [MariaDB 10.1](../what-is-mariadb-101/index) on Debian 9 "Stretch", there are some things to keep in mind: ### Backup before you begin This is a major upgrade, and so complete database backups are strongly suggested before you begin. [MariaDB 10.1](../what-is-mariadb-101/index) is compatible on disk and wire with MySQL 5.5, and the MariaDB developer team has done extensive development and testing to make upgrades as painless and trouble-free as possible. Even so, it's always a good idea to do regular backups, especially before an upgrade. As the database has to shutdown anyway for the upgrade, this is a good opportunity to do a backup! ### Changed, renamed, and removed options Some default values have been changed, some have been renamed, and others have been removed between MySQL 5.5 and [MariaDB 10.1](../what-is-mariadb-101/index). The following sections detail them. #### Options with changed default values Most of the following options have increased a bit in value to give better performance. They should not use much additional memory, but some of them do use a bit more disk space. [[1](#_note-0)] | Option | Old default value | New default value | | --- | --- | --- | | `[aria-sort-buffer-size](../aria-system-variables/index#aria_sort_buffer_size)` | `128M` | `256M` | | `[back\_log](../server-system-variables/index#back_log)` | `50` | `150` | | `[innodb-concurrency-tickets](../xtradbinnodb-server-system-variables/index#innodb_concurrency_tickets)` | `500` | `5000` | | `[innodb-log-file-size](../xtradbinnodb-server-system-variables/index#innodb_log_file_size)` | `5M` | `48M` | | `[innodb\_log\_compressed\_pages](../xtradbinnodb-server-system-variables/index#innodb_log_compressed_pages)` | `ON` | `OFF` | | `[innodb-old-blocks-time](../xtradbinnodb-server-system-variables/index#innodb_old_blocks_time)` | `0` | `1000` | | `[innodb-open-files](../xtradbinnodb-server-system-variables/index#innodb_open_files)` | `300` | `400` [[2]](#_note-1) | | `[innodb-purge-batch-size](../xtradbinnodb-server-system-variables/index#innodb_purge_batch_size)` | `20` | `300` | | `[innodb-undo-logs](../xtradbinnodb-server-system-variables/index#innodb_undo_logs)` | `ON` | `20` | | `[join\_buffer\_size](../server-system-variables/index#join_buffer_size)` | `128K` | `256K` | | `[max\_allowed\_packet](../server-system-variables/index#max_allowed_packet)` | `1M` | `4M` | | `[max-connect-errors](../server-system-variables/index#max_connect_errors)` | `10` | `100` | | `[max-relay-log-size](../server-system-variables/index#max_relay_log_size)` | `0` | `1024M` | | `[myisam-sort-buffer-size](../myisam-server-system-variables/index#myisam_sort_buffer_size)` | `8M` | `128M` | | `[optimizer-switch](../server-system-variables/index#optimizer_switch)` | ... | Added `extended_keys=on, exists_to_in=on` | | `[query\_alloc\_block\_size](../server-system-variables/index#query_alloc_block_size)` | `8192` | `16384` | | `[query\_cache\_size](../server-system-variables/index#query_cache_size)` | `0` | `1M` | | `[query\_cache\_type](../server-system-variables/index#query_cache_type)` | `ON` | `OFF` | | `[query\_prealloc\_size](../server-system-variables/index#query_prealloc_size)` | `8192` | `24576` | | `[secure\_auth](../server-system-variables/index#secure_auth)` | `OFF` | `ON` | | `[sql\_log\_bin](../replication-and-binary-log-server-system-variables/index#sql_log_bin)` | | No longer affects replication of events in a Galera cluster. | | `[sql\_mode](../server-system-variables/index#sql_mode)` | `empty` | `NO_AUTO_CREATE_USER, NO_ENGINE_SUBSTITUTION` | | `[sync\_master\_info](../replication-and-binary-log-server-system-variables/index#sync_master_info)` | `0` | `10000` | | `[sync\_relay\_log](../replication-and-binary-log-server-system-variables/index#sync_relay_log)` | `0` | `10000` | | `[sync\_relay\_log\_info](../replication-and-binary-log-server-system-variables/index#sync_relay_log_info)` | `0` | `10000` | | `[table\_open\_cache](../server-system-variables/index#table_open_cache)` | `400` | `2000` | | `[thread\_pool\_max\_threads](../server-system-variables/index#thread_pool_max_threads)` | `500` | `1000` | #### Options that have been removed or renamed The following options should be removed or renamed if you use them in your config files: | Option | Reason | | --- | --- | | `engine-condition-pushdown` | Replaced with `[set optimizer\_switch='engine\_condition\_pushdown=on'](../index-condition-pushdown/index)` | | `innodb-adaptive-flushing-method` | Removed by [XtraDB](../xtradb/index) | | `innodb-autoextend-increment` | Removed by [XtraDB](../xtradb/index) | | `innodb-blocking-buffer-pool-restore` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-pages` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-pages-blob` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-pages-index` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-restore-at-startup` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-shm-checksum` | Removed by [XtraDB](../xtradb/index) | | `innodb-buffer-pool-shm-key` | Removed by [XtraDB](../xtradb/index) | | `innodb-checkpoint-age-target` | Removed by [XtraDB](../xtradb/index) | | `innodb-dict-size-limit` | Removed by [XtraDB](../xtradb/index) | | `innodb-doublewrite-file` | Removed by [XtraDB](../xtradb/index) | | `innodb-fast-checksum` | Renamed to [innodb-checksum-algorithm](../xtradbinnodb-server-system-variables/index#innodb_checksum_algorithm) | | `innodb-flush-neighbor-pages` | Renamed to [innodb-flush-neighbors](../xtradbinnodb-server-system-variables/index#innodb_flush_neighbors) | | `innodb-ibuf-accel-rate` | Removed by [XtraDB](../xtradb/index) | | `innodb-ibuf-active-contract` | Removed by [XtraDB](../xtradb/index) | | `innodb-ibuf-max-size` | Removed by [XtraDB](../xtradb/index) | | `innodb-import-table-from-xtrabackup` | Removed by [XtraDB](../xtradb/index) | | `innodb-index-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-lazy-drop-table` | Removed by [XtraDB](../xtradb/index) | | `innodb-merge-sort-block-size` | Removed by [XtraDB](../xtradb/index) | | `innodb-persistent-stats-root-page` | Removed by [XtraDB](../xtradb/index) | | `innodb-read-ahead` | Removed by [XtraDB](../xtradb/index) | | `innodb-recovery-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-recovery-update-relay-log` | Removed by [XtraDB](../xtradb/index) | | `innodb-stats-auto-update` | Renamed to `innodb-stats-auto-recalc` | | `innodb-stats-update-need-lock` | Removed by [XtraDB](../xtradb/index) | | `innodb-sys-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-table-stats` | Removed by [XtraDB](../xtradb/index) | | `innodb-thread-concurrency-timer-based` | Removed by [XtraDB](../xtradb/index) | | `innodb-use-sys-stats-table` | Removed by [XtraDB](../xtradb/index) | | `[rpl\_recovery\_rank](../server-system-variables/index#rpl_recovery_rank)` | Unused in 10.0+ | | `xtradb-admin-command` | Removed by [XtraDB](../xtradb/index) | ### Suggested upgrade procedure for replication If you have a [master-slave setup](../standard-replication/index), the normal procedure is to first upgrade your slaves to MariaDB, then move one of your slaves to be the master and then upgrade your original master. In this scenario you can upgrade from MySQL to MariaDB or upgrade later to a new version of MariaDB without any downtime. ### Other resources to consult before beginning your upgrade It may also be useful to check out the [Upgrading MariaDB](../upgrading/index) section. It contains several articles on upgrading from MySQL to MariaDB and from one version of MariaDB to another. For upgrade purposes, MySQL 5.5 and [MariaDB 5.5](../what-is-mariadb-55/index) are very similar. In particular, see the [Upgrading from MariaDB 5.5 to MariaDB 10.0](../upgrading-from-mariadb-55-to-mariadb-100/index) and [Upgrading from MariaDB 10.0 to MariaDB 10.1](../upgrading-from-mariadb-100-to-mariadb-101/index) articles. If you need help with upgrading or setting up replication, you can always [contact the MariaDB corporation](https://mariadb.com/contact) to find experts to help you with this. Upgrading to [MariaDB 10.1](../what-is-mariadb-101/index) from MySQL 5.5 ------------------------------------------------------------------------ The suggested upgrade procedure is: 1. Set [innodb\_fast\_shutdown](../xtradbinnodb-server-system-variables/index#innodb_fast_shutdown) to `0`. This is to ensure that if you make a backup as part of the upgrade, all data is written to the InnoDB data files, which simplifies any restore in the future. 2. Shutdown MySQL 5.5 3. Take a [backup](../backup-and-restore-overview/index) * when the server is shut down is the perfect time to take a backup of your databases * store a copy of the backup on external media or a different machine for safety 4. Perform the upgrade from Debian 8 to Debian 9 5. During the upgrade, the [mysql\_upgrade](../mysql_upgrade/index) script will be run automatically; this script does two things: 1. Upgrades the permission tables in the `mysql` database with some new fields 2. Does a very quick check of all tables and marks them as compatible with [MariaDB 10.1](../what-is-mariadb-101/index) * In most cases this should be a fast operation (depending of course on the number of tables) 6. Add new options to [my.cnf](../configuring-mariadb-with-mycnf/index) to enable features * If you change `my.cnf` then you need to restart `mysqld` with e.g. `sudo service mysql restart` or `sudo service mariadb restart`. Upgrading to [MariaDB 10.1](../what-is-mariadb-101/index) from an older version of MariaDB ------------------------------------------------------------------------------------------ If you have installed [MariaDB 5.5](../what-is-mariadb-55/index) or [MariaDB 10.0](../what-is-mariadb-100/index) on your Debian 8 "Jessie" machine from the MariaDB repositories you will need to upgrade to [MariaDB 10.1](../what-is-mariadb-101/index) when upgrading to Debian 9 "Stretch". You can choose to continue using the MariaDB repositories or move to using the Debian repositories. If you want to continue using the MariaDB repositories edit the MariaDB entry in your sources.list and change every instance of 5.5 or 10.0 to 10.1. Then upgrade as suggested [above](#upgrading-to-mariadb-101-from-mysql-55). If you want to move to using [MariaDB 10.1](../what-is-mariadb-101/index) from the Debian repositories, delete or comment out the MariaDB entries in your sources.list file. Then upgrade as suggested [above](#upgrading-to-mariadb-101-from-mysql-55). If you are already using [MariaDB 10.1](../what-is-mariadb-101/index) on your Debian 8 "Jessie" machine, you can choose to continue to use the MariaDB repositories or move to using the Debian repositories as with [MariaDB 5.5](../what-is-mariadb-55/index) and 10.0. In either case, the upgrade will at most be just a minor upgrade from one version of [MariaDB 10.1](../what-is-mariadb-101/index) to a newer version. In the case that you are already on the current version of MariaDB that exists in the Debian repositories or a newer one) MariaDB will not be upgraded during the system upgrade but will be upgraded when future versions of MariaDB are released. You should always perform a compete backup of your data prior to performing any major system upgrade, even if MariaDB itself is not being upgraded! MariaDB Galera Cluster ---------------------- If you have been using MariaDB Galera Cluster 5.5 or 10.0 on Debian 8 "Jessie" it is worth mentioning that [Galera Cluster](../galera/index) is included by default in [MariaDB 10.1](../what-is-mariadb-101/index), there is no longer a need to install a separate `mariadb-galera-server` package. Configuration options for advanced database users ------------------------------------------------- To get better performance from MariaDB used in production environments, here are some suggested additions to [your configuration file](../configuring-mariadb-with-mycnf/index) which in Debian is at `/etc/mysql/mariadb.d/my.cnf`: ``` [[mysqld]] # Cache for disk based temporary files aria_pagecache_buffer_size=128M # If you are not using MyISAM tables directly (most people are using InnoDB) key_buffer_size=64K ``` The reason for the above change is that MariaDB is using the newer [Aria](../aria-storage-engine/index) storage engine for disk based temporary files instead of MyISAM. The main benefit of Aria is that it can cache both indexes and rows and thus gives better performance than MyISAM for large queries. Secure passwordless root accounts only on new installs ------------------------------------------------------ Unlike the old MySQL packages in Debian, [MariaDB 10.0](../what-is-mariadb-100/index) onwards in Debian uses unix socket authentication on new installs to avoid root password management issues and thus be more secure and easier to use with provision systems of the cloud age. This only affects new installs. Upgrades from old versions will continue to use whatever authentication and user accounts already existed. This is however good to know, because it can affect upgrades of dependant systems, typically e.g. require users to rewrite their Ansible scripts and similar tasks. The new feature is much easier than the old, so adjusting for it requires little work. See also -------- * [Differences in MariaDB in Debian (and Ubuntu)](../differences-in-mariadb-in-debian-and-ubuntu/index) * [Configuring MariaDB for optimal performance](../configuring-mariadb-for-optimal-performance/index) * [New features in MariaDB you should considering using](../mariadb-vs-mysql-features/index) * [What is MariaDB 10.1](../what-is-mariadb-101/index) * [General instructions for upgrading from MySQL to MariaDB](../upgrading-from-mysql-to-mariadb/index) Comments and suggestions ------------------------ If you have comments or suggestions on things we can add or change to improve this page. Please add them as comments below. Notes ----- 1. [↑](#_ref-0) The `innodb-open-files` variable defaults to the value of `table-open-cache` (`400` is the default) if it is set to any value less than `10` so long as `innodb-file-per-table` is set to `1` or `TRUE` (the default). If `innodb_file_per_table` is set to `0` or `FALSE` **and** `innodb-open-files` is set to a value less than `10`, the default is `300` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SHOW ENGINES SHOW ENGINES ============ Syntax ------ ``` SHOW [STORAGE] ENGINES ``` Description ----------- `SHOW ENGINES` displays status information about the server's storage engines. This is particularly useful for checking whether a storage engine is supported, or to see what the default engine is. `SHOW TABLE TYPES` is a deprecated synonym. The `[information\_schema.ENGINES](../information-schema-engines-table/index)` table provides the same information. Since storage engines are plugins, different information about them is also shown in the `[information\_schema.PLUGINS](../information_schemaplugins-table/index)` table and by the `[SHOW PLUGINS](../show-plugins/index)` statement. Note that both MySQL's InnoDB and Percona's XtraDB replacement are labeled as `InnoDB`. However, if XtraDB is in use, it will be specified in the `COMMENT` field. See [XtraDB and InnoDB](../xtradb-and-innodb/index). The same applies to [FederatedX](../federatedx/index). The output consists of the following columns: * `Engine` indicates the engine's name. * `Support` indicates whether the engine is installed, and whether it is the default engine for the current session. * `Comment` is a brief description. * `Transactions`, `XA` and `Savepoints` indicate whether [transactions](../transactions/index), [XA transactions](../xa-transactions/index) and [transaction savepoints](../savepoint/index) are supported by the engine. Examples -------- ``` SHOW ENGINES\G *************************** 1. row *************************** Engine: InnoDB Support: DEFAULT Comment: Supports transactions, row-level locking, and foreign keys Transactions: YES XA: YES Savepoints: YES *************************** 2. row *************************** Engine: CSV Support: YES Comment: CSV storage engine Transactions: NO XA: NO Savepoints: NO *************************** 3. row *************************** Engine: MyISAM Support: YES Comment: MyISAM storage engine Transactions: NO XA: NO Savepoints: NO *************************** 4. row *************************** Engine: BLACKHOLE Support: YES Comment: /dev/null storage engine (anything you write to it disappears) Transactions: NO XA: NO Savepoints: NO *************************** 5. row *************************** Engine: FEDERATED Support: YES Comment: FederatedX pluggable storage engine Transactions: YES XA: NO Savepoints: YES *************************** 6. row *************************** Engine: MRG_MyISAM Support: YES Comment: Collection of identical MyISAM tables Transactions: NO XA: NO Savepoints: NO *************************** 7. row *************************** Engine: ARCHIVE Support: YES Comment: Archive storage engine Transactions: NO XA: NO Savepoints: NO *************************** 8. row *************************** Engine: MEMORY Support: YES Comment: Hash based, stored in memory, useful for temporary tables Transactions: NO XA: NO Savepoints: NO *************************** 9. row *************************** Engine: PERFORMANCE_SCHEMA Support: YES Comment: Performance Schema Transactions: NO XA: NO Savepoints: NO *************************** 10. row *************************** Engine: Aria Support: YES Comment: Crash-safe tables with MyISAM heritage Transactions: NO XA: NO Savepoints: NO 10 rows in set (0.00 sec) ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb BINARY Operator BINARY Operator =============== This page describes the BINARY operator. For details about the data type, see [Binary Data Type](../binary/index). Syntax ------ ``` BINARY ``` Description ----------- The `BINARY` operator casts the string following it to a binary string. This is an easy way to force a column comparison to be done byte by byte rather than character by character. This causes the comparison to be case sensitive even if the column isn't defined as `[BINARY](../binary/index)` or `[BLOB](../string-data-types-blob-data-types/index)`. `BINARY` also causes trailing spaces to be significant. Examples -------- ``` SELECT 'a' = 'A'; +-----------+ | 'a' = 'A' | +-----------+ | 1 | +-----------+ SELECT BINARY 'a' = 'A'; +------------------+ | BINARY 'a' = 'A' | +------------------+ | 0 | +------------------+ SELECT 'a' = 'a '; +------------+ | 'a' = 'a ' | +------------+ | 1 | +------------+ SELECT BINARY 'a' = 'a '; +-------------------+ | BINARY 'a' = 'a ' | +-------------------+ | 0 | +-------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb JSON_DEPTH JSON\_DEPTH =========== **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**JSON functions were added in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). Syntax ------ ``` JSON_DEPTH(json_doc) ``` Description ----------- Returns the maximum depth of the given JSON document, or NULL if the argument is null. An error will occur if the argument is an invalid JSON document. * Scalar values or empty arrays or objects have a depth of 1. * Arrays or objects that are not empty but contain only elements or member values of depth 1 will have a depth of 2. * In other cases, the depth will be greater than 2. Examples -------- ``` SELECT JSON_DEPTH('[]'), JSON_DEPTH('true'), JSON_DEPTH('{}'); +------------------+--------------------+------------------+ | JSON_DEPTH('[]') | JSON_DEPTH('true') | JSON_DEPTH('{}') | +------------------+--------------------+------------------+ | 1 | 1 | 1 | +------------------+--------------------+------------------+ SELECT JSON_DEPTH('[1, 2, 3]'), JSON_DEPTH('[[], {}, []]'); +-------------------------+----------------------------+ | JSON_DEPTH('[1, 2, 3]') | JSON_DEPTH('[[], {}, []]') | +-------------------------+----------------------------+ | 2 | 2 | +-------------------------+----------------------------+ SELECT JSON_DEPTH('[1, 2, [3, 4, 5, 6], 7]'); +---------------------------------------+ | JSON_DEPTH('[1, 2, [3, 4, 5, 6], 7]') | +---------------------------------------+ | 3 | +---------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb AUTO_INCREMENT Handling in InnoDB AUTO\_INCREMENT Handling in InnoDB ================================== AUTO\_INCREMENT Lock Modes -------------------------- The [innodb\_autoinc\_lock\_mode](../innodb-system-variables/index#innodb_autoinc_lock_mode) system variable determines the lock mode when generating [AUTO\_INCREMENT](../auto_increment/index) values for [InnoDB](../innodb/index) tables. These modes allow [InnoDB](../innodb/index) to make significant performance optimizations in certain circumstances. The [innodb\_autoinc\_lock\_mode](../innodb-system-variables/index#innodb_autoinc_lock_mode) system variable may be removed in a future release. See [MDEV-19577](https://jira.mariadb.org/browse/MDEV-19577) for more information. ### Traditional Lock Mode When [innodb\_autoinc\_lock\_mode](../innodb-system-variables/index#innodb_autoinc_lock_mode) is set to `0`, [InnoDB](../innodb/index) uses the traditional lock mode. In this mode, [InnoDB](../innodb/index) holds a table-level lock for all [INSERT](../insert/index) statements until the statement completes. ### Consecutive Lock Mode When [innodb\_autoinc\_lock\_mode](../innodb-system-variables/index#innodb_autoinc_lock_mode) is set to `1`, [InnoDB](../innodb/index) uses the consecutive lock mode. In this mode, [InnoDB](../innodb/index) holds a table-level lock for all bulk [INSERT](../insert/index) statements (such as [LOAD DATA](../load-data-infile/index) or [INSERT ... SELECT](../insert-select/index)) until the end of the statement. For simple [INSERT](../insert/index) statements, no table-level lock is held. Instead, a lightweight mutex is used which scales significantly better. This is the default setting. ### Interleaved Lock Mode When [innodb\_autoinc\_lock\_mode](../innodb-system-variables/index#innodb_autoinc_lock_mode) is set to `2`, [InnoDB](../innodb/index) uses the interleaved lock mode. In this mode, [InnoDB](../innodb/index) does not hold any table-level locks at all. This is the fastest and most scalable mode, but is not safe for [statement-based](../binary-log-formats/index#statement-based) replication. Setting AUTO\_INCREMENT Values ------------------------------ The [AUTO\_INCREMENT](../auto_increment/index) value for an [InnoDB](../innodb/index) table can be set for a table by executing the [ALTER TABLE](../alter-table/index) statement and specifying the [AUTO\_INCREMENT](../create-table/index#auto_increment) table option. For example: ``` ALTER TABLE tab AUTO_INCREMENT=100; ``` However, in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) and before, [InnoDB](../innodb/index) stores the table's [AUTO\_INCREMENT](../auto_increment/index) counter in memory. In these versions, when the server restarts, the counter is re-initialized to the highest value found in the table. This means that the above operation can be undone if the server is restarted before any rows are written to the table. In [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/) and later, the [AUTO\_INCREMENT](../auto_increment/index) counter is persistent, so this restriction is no longer present. Persistent, however, does not mean transactional. Gaps may still occur in some cases, such as if a [INSERT IGNORE](../insert-ignore/index) statement fails, or if a user executes [ROLLBACK](../rollback/index) or [ROLLBACK TO SAVEPOINT](../savepoint/index). For example: ``` CREATE TABLE t1 (pk INT AUTO_INCREMENT PRIMARY KEY, i INT, UNIQUE (i)) ENGINE=InnoDB; INSERT INTO t1 (i) VALUES (1),(2),(3); INSERT IGNORE INTO t1 (pk, i) VALUES (100,1); Query OK, 0 rows affected, 1 warning (0.099 sec) SELECT * FROM t1; +----+------+ | pk | i | +----+------+ | 1 | 1 | | 2 | 2 | | 3 | 3 | +----+------+ SHOW CREATE TABLE t1\G *************************** 1. row *************************** Table: t1 Create Table: CREATE TABLE `t1` ( `pk` int(11) NOT NULL AUTO_INCREMENT, `i` int(11) DEFAULT NULL, PRIMARY KEY (`pk`), UNIQUE KEY `i` (`i`) ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1 ``` If the server is restarted at this point, then the [AUTO\_INCREMENT](../auto_increment/index) counter will revert to `101`, which is the persistent value set as part of the failed [INSERT IGNORE](../insert-ignore/index). ``` # Restart server SHOW CREATE TABLE t1\G *************************** 1. row *************************** Table: t1 Create Table: CREATE TABLE `t1` ( `pk` int(11) NOT NULL AUTO_INCREMENT, `i` int(11) DEFAULT NULL, PRIMARY KEY (`pk`), UNIQUE KEY `i` (`i`) ) ENGINE=InnoDB AUTO_INCREMENT=101 DEFAULT CHARSET=latin1 ``` See Also -------- * [AUTO\_INCREMENT](../auto_increment/index) * [AUTO\_INCREMENT FAQ](../autoincrement-faq/index) * [LAST\_INSERT\_ID](../last_insert_id/index) * [Sequences](../sequences/index) - an alternative to auto\_increment available from [MariaDB 10.3](../what-is-mariadb-103/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DATETIME DATETIME ======== Syntax ------ ``` DATETIME [(microsecond precision)] ``` Description ----------- A date and time combination. MariaDB displays `DATETIME` values in '`YYYY-MM-DD HH:MM:SS.ffffff`' format, but allows assignment of values to `DATETIME` columns using either strings or numbers. For details, see [date and time literals](../date-and-time-literals/index). DATETIME columns also accept [CURRENT\_TIMESTAMP](../now/index) as the default value. [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) introduced the [--mysql56-temporal-format](../server-system-variables/index#mysql56_temporal_format) option, on by default, which allows MariaDB to store DATETMEs using the same low-level format MySQL 5.6 uses. For more information, see [Internal Format](#internal-format), below. For storage requirements, see [Data Type Storage Requirements](../data-type-storage-requirements/index). Supported Values ---------------- MariaDB stores values that use the `DATETIME` data type in a format that supports values between `1000-01-01 00:00:00.000000` and `9999-12-31 23:59:59.999999`. MariaDB can also store [microseconds](../microseconds-in-mariadb/index) with a precision between 0 and 6. If no microsecond precision is specified, then 0 is used by default. MariaDB also supports '`0000-00-00`' as a special *zero-date* value, unless [NO\_ZERO\_DATE](../sql-mode/index#no_zero_date) is specified in the [SQL\_MODE](../sql-mode/index). Similarly, individual components of a date can be set to `0` (for example: '`2015-00-12`'), unless [NO\_ZERO\_IN\_DATE](../sql-mode/index#no_zero_in_date) is specified in the [SQL\_MODE](../sql-mode/index). In many cases, the result of en expression involving a zero-date, or a date with zero-parts, is `NULL`. If the [ALLOW\_INVALID\_DATES](../sql-mode/index#allow_invalid_dates) SQL\_MODE is enabled, if the day part is in the range between 1 and 31, the date does not produce any error, even for months that have less than 31 days. Time Zones ---------- If a column uses the `DATETIME` data type, then any inserted values are stored as-is, so no automatic time zone conversions are performed. MariaDB also does not currently support time zone literals that contain time zone identifiers. See [MDEV-11829](https://jira.mariadb.org/browse/MDEV-11829) for more information. MariaDB validates `DATETIME` literals against the session's time zone. For example, if a specific time range never occurred in a specific time zone due to daylight savings time, then `DATETIME` values within that range would be invalid for that time zone. For example, daylight savings time started on March 10, 2019 in the US, so the time range between 02:00:00 and 02:59:59 is invalid for that day in US time zones: ``` SET time_zone = 'America/New_York'; Query OK, 0 rows affected (0.000 sec) INSERT INTO timestamp_test VALUES ('2019-03-10 02:55:05'); ERROR 1292 (22007): Incorrect datetime value: '2019-03-10 02:55:05' for column `db1`.`timestamp_test`.`timestamp_test` at row 1 ``` But that same time range is fine in other time zones, such as [Coordinated Universal Time (UTC)](../coordinated-universal-time/index). For example: ``` SET time_zone = 'UTC'; Query OK, 0 rows affected (0.000 sec) INSERT INTO timestamp_test VALUES ('2019-03-10 02:55:05'); Query OK, 1 row affected (0.002 sec) ``` Oracle Mode ----------- **MariaDB starting with [10.3](../what-is-mariadb-103/index)**In [Oracle mode from MariaDB 10.3](../sql_modeoracle-from-mariadb-103/index#synonyms-for-basic-sql-types), `DATE` with a time portion is a synonym for `DATETIME`. See also [mariadb\_schema](../mariadb_schema/index). Internal Format --------------- In [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) a new temporal format was introduced from MySQL 5.6 that alters how the `TIME`, `DATETIME` and `TIMESTAMP` columns operate at lower levels. These changes allow these temporal data types to have fractional parts and negative values. You can disable this feature using the [mysql56\_temporal\_format](../server-system-variables/index#mysql56_temporal_format) system variable. Tables that include `TIMESTAMP` values that were created on an older version of MariaDB or that were created while the [mysql56\_temporal\_format](../server-system-variables/index#mysql56_temporal_format) system variable was disabled continue to store data using the older data type format. In order to update table columns from the older format to the newer format, execute an [ALTER TABLE... MODIFY COLUMN](../alter-table/index#modify-column) statement that changes the column to the \*same\* data type. This change may be needed if you want to export the table's tablespace and import it onto a server that has `mysql56_temporal_format=ON` set (see [MDEV-15225](https://jira.mariadb.org/browse/MDEV-15225)). For instance, if you have a `DATETIME` column in your table: ``` SHOW VARIABLES LIKE 'mysql56_temporal_format'; +-------------------------+-------+ | Variable_name | Value | +-------------------------+-------+ | mysql56_temporal_format | ON | +-------------------------+-------+ ALTER TABLE example_table MODIFY ts_col DATETIME; ``` When MariaDB executes the [ALTER TABLE](../alter-table/index) statement, it converts the data from the older temporal format to the newer one. In the event that you have several tables and columns using temporal data types that you want to switch over to the new format, make sure the system variable is enabled, then perform a dump and restore using `mysqldump`. The columns using relevant temporal data types are restored using the new temporal format. Starting from [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/) columns with old temporal formats are marked with a `/* mariadb-5.3 */` comment in the output of [SHOW CREATE TABLE](../show-create-table/index), [SHOW COLUMNS](../show-columns/index), [DESCRIBE](../describe/index) statements, as well as in the `COLUMN_TYPE` column of the [INFORMATION\_SCHEMA.COLUMNS Table](../information-schema-columns-table/index). ``` SHOW CREATE TABLE mariadb5312_datetime\G *************************** 1. row *************************** Table: mariadb5312_datetime Create Table: CREATE TABLE `mariadb5312_datetime` ( `dt0` datetime /* mariadb-5.3 */ DEFAULT NULL, `dt6` datetime(6) /* mariadb-5.3 */ DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 ``` Examples -------- ``` CREATE TABLE t1 (d DATETIME); INSERT INTO t1 VALUES ("2011-03-11"), ("2012-04-19 13:08:22"), ("2013-07-18 13:44:22.123456"); SELECT * FROM t1; +---------------------+ | d | +---------------------+ | 2011-03-11 00:00:00 | | 2012-04-19 13:08:22 | | 2013-07-18 13:44:22 | +---------------------+ ``` ``` CREATE TABLE t2 (d DATETIME(6)); INSERT INTO t2 VALUES ("2011-03-11"), ("2012-04-19 13:08:22"), ("2013-07-18 13:44:22.123456"); SELECT * FROM t2; +----------------------------+ | d | +----------------------------+ | 2011-03-11 00:00:00.000000 | | 2012-04-19 13:08:22.000000 | | 2013-07-18 13:44:22.123456 | +----------------------------++ ``` Strings used in datetime context are automatically converted to datetime(6). If you want to have a datetime without seconds, you should use [CONVERT(..,datetime)](../convert/index). ``` SELECT CONVERT('2007-11-30 10:30:19',datetime); +-----------------------------------------+ | CONVERT('2007-11-30 10:30:19',datetime) | +-----------------------------------------+ | 2007-11-30 10:30:19 | +-----------------------------------------+ SELECT CONVERT('2007-11-30 10:30:19',datetime(6)); +--------------------------------------------+ | CONVERT('2007-11-30 10:30:19',datetime(6)) | +--------------------------------------------+ | 2007-11-30 10:30:19.000000 | +--------------------------------------------+ ``` See Also -------- * [Data Type Storage Requirements](../data-type-storage-requirements/index) * [CONVERT()](../convert/index) * [Oracle mode from MariaDB 10.3](../sql_modeoracle-from-mariadb-103/index#synonyms-for-basic-sql-types) * [mariadb\_schema](../mariadb_schema/index) data type qualifier Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb REVOKE REVOKE ====== Privileges ---------- ### Syntax ``` REVOKE priv_type [(column_list)] [, priv_type [(column_list)]] ... ON [object_type] priv_level FROM user [, user] ... REVOKE ALL PRIVILEGES, GRANT OPTION FROM user [, user] ... ``` ### Description The `REVOKE` statement enables system administrators to revoke privileges (or roles - see [section below](#roles)) from MariaDB accounts. Each account is named using the same format as for the `GRANT` statement; for example, '`jeffrey'@'localhost`'. If you specify only the user name part of the account name, a host name part of '``%``' is used. For details on the levels at which privileges exist, the allowable `priv_type` and `priv_level` values, and the syntax for specifying users and passwords, see [GRANT](../grant/index). To use the first `REVOKE` syntax, you must have the `GRANT OPTION` privilege, and you must have the privileges that you are revoking. To revoke all privileges, use the second syntax, which drops all global, database, table, column, and routine privileges for the named user or users: ``` REVOKE ALL PRIVILEGES, GRANT OPTION FROM user [, user] ... ``` To use this `REVOKE` syntax, you must have the global [CREATE USER](../create-user/index) privilege or the [UPDATE](../update/index) privilege for the mysql database. See [GRANT](../grant/index). ### Examples ``` REVOKE SUPER ON *.* FROM 'alexander'@'localhost'; ``` Roles ----- ### Syntax ``` REVOKE role [, role ...] FROM grantee [, grantee2 ... ] REVOKE ADMIN OPTION FOR role FROM grantee [, grantee2] ``` ### Description `REVOKE` is also used to remove a [role](../roles/index) from a user or another role that it's previously been assigned to. If a role has previously been set as a [default role](../set-default-role/index), `REVOKE` does not remove the record of the default role from the [mysql.user](../mysqluser-table/index) table. If the role is subsequently granted again, it will again be the user's default. Use [SET DEFAULT ROLE NONE](../set-default-role/index) to explicitly remove this. Before [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/), the `REVOKE role` statement was not permitted in [prepared statements](../prepared-statements/index). ### Example ``` REVOKE journalist FROM hulda ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Preparing for ColumnStore Installation - 1.2.5 Preparing for ColumnStore Installation - 1.2.5 ============================================== ### Prerequisite With version 1.2.5 of MariaDB ColumnStore, there should be no version of MariaDB Server or MySQL installed on the OS before a MariaDB ColumnStore is installed on the system. If you have an installation of MariaDB Server or MySQL, uninstall it before proceeding. #### Configuration preparation Before installing MariaDB ColumnStore, there is some preparation necessary. You will need to determine the following. Please refer to the MariaDB ColumnStore Architecture Document for additional information. * How many User Modules (UMs) will your system need? * How many Performance Modules (PMs) will your system need? * How much disk space will your system need? * Would you have passwordless ssh access between PMs? * Do you want to run the install as root or an unprivileged user? #### OS information MariaDB ColumnStore is certified to run on: RHEL/CentOS v6, v7 Ubuntu 16.04 LTS, Ubuntu 18.04 LTS Debian v8, v9 SUSE 12 but it should run on any recent Linux system. Make sure all nodes are running the same OS. Make sure the locale setting on all nodes is the same. To set locale to en\_US and UTf-8, as root run: ``` # localedef -i en_US -f UTF-8 en_US.UTF-8 ``` #### System administration information Information your system administrator must provide before installing MariaDB ColumnStore: * The hostnames of each interface on each node (optional). * The IP address of each interface on each node. * The user and password ColumnStore will run as should be consistent across all nodes. MariaDB ColumnStore can be installed as root or an unprivileged user. Example for 3 PM, 1UM system, these are the steps required to configure PM-1 for password-less ssh. The equivalent steps must be repeated on every PM in the system. The equivalent steps must be repeated on every UM in the system if the MariaDB ColumnStore Data Replication feature is enabled during the install process. ``` [root@pm- 1 ~] $ ssh-keygen [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-1 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-2 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-3 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub um-1 ``` If you will be using ssh keys... * and plan to enable Data Replication feature, make sure you can login between all UM nodes and all other UM nodes. * and plan to enable the Local Query Feature, make sure you can login between all UM nodes and all PM nodes. * and plan to enable the Data Redundancy feature, make sure you can login to PM1 from PM1, and between all UM nodes, without an additional prompt. This is required for the Data Redundancy feature. #### Network configuration MariaDB ColumnStore is quite flexible regarding networking. Some options are as follows: * The interconnect between UMs and PMs can be one or more private VLANs. In this case MariaDB ColumnStore will automatically trunk the individual LANs together to provide greater effective bandwidth between the UMs and PMs. * The PMs do not require a public LAN access as they only need to communicate with the UMs, unless the local query feature is desired. * The UMs most likely require at least one public interface to access the MySQL server front end from the site LAN. This interface can be a separate physical or logical connection from the PM interconnect. * You can use whatever security your site requires on the public access to the MySQL server front end on the UMs. By default it is listening on port 3306. * MariaDB ColumnStore software only requires a TCP/IP stack to be present to function. You can use any physical layer you desire. #### MariaDB ColumnStore port usage The MariaDB ColumnStore daemon uses port 3306. You must reserve the following ports to run the MariaDB ColumnStore software: 8600 - 8630, 8700, and 8800 #### Installation and Data Directory Paths MariaDB Columnstore requires that the software gets installed and the data paths in the configuration files don't get changed from their initial settings. The system will not function properly if they are changed or the software is install in the incorrect places. For root user install, it is required that it gets installed and it runs in this location: /usr/local/ For non-root user install, it is required that it gets installed and it runs in this location: /home/'non-root-user-name' Example if installed and running as 'mysq' user, is has to be installed here: /home/mysql/ IMPORTANT: Don't change any of the configuration files, Columnstore.xml or my.cnf, to point to a different install or data location. If you need to have the software or the data (dbroot backend data or the mysql data) placed in a different directory than what is required above, you can use soft-links. To install in a different directory for root user, here is an example of setting up a softlink ``` # ln -s /mnt/columnstore /usr/local/mariadb/columnstore ``` To install in a different directory for non-root user, here is an example of setting up a softlink ``` # ln -s /mnt/columnstore /home/mysql/mariadb/columnstore ``` To have the DBRoot data1 placed in a different directory, here is an example of setting up a softlink ``` # ln -s /mnt/data1 /usr/local/mariadb/columnstore/data1 ``` To have the MariaDB/MySQL aata placed in a different directory, here is an example of setting up a softlink ``` # ln -s /mnt/mysql /usr/local/mariadb/columnstore/mysql/db ``` If you do setup softlinks, make sure the permissions and users are setup for the new directories that match the current directories. #### Storage and Database files (DBRoots) 'DBRoot' is a term used by ColumnStore to refer to a storage unit, located at mariadb/columnstore/data<N>, where N is the identifier for that storage unit. You will see that term throughout the documentation. The name of this location can't be changed. But you can use soft-links to point it to other locations. MariaDB ColumnStore supports many storage options. * Internal - Internal means you will use block storage already mounted and available on each node. The data directories (mariadb/columnstore/dataN) can be links to other locations if preferable. With Internal storage setup, there is no High Availability Performance Module Failover capability. This is one of the limitations to using Internal storage. Its also for systems that have SAN that are mounted to single Performance Module. Its not shared mounted to all Performance Modules. * External - External means the SAN devices used for the DBRoots are shared mounted to all Performance Modules configured in the system. With External storage setup, the High Availability Performance Module Failover capability is supported, because mounts can be moved quickly from one node to another. So this is the only time that 'External' storage should be configured. * Data Redundancy - MariaDB ColumnStore supports Data Redundancy for both internal and external configurations. For Data Redundancy to be an option, the user is required to install the third party GlusterFS software on all Performance Modules. This is discussed later in the Package Dependency section. With Data Redundancy configured, High Availability Performance Module Failover capabilities is supported. IMPORTANT: When using external storage, be sure that only whole DBRoots are on the external filesystem. Do not use higher level directories, which may include the ColumnStore binaries and libraries. For example, /usr/local/mariadb/columnstore/data1 (aka DBRoot 1) would be a good candidate for external storage, but /usr/local/mariadb/columnstore would not be. #### Local database files If you are using internal storage, the DBRoot directories will be created under the installation directory, for example /usr/local/mariadb/columnstore/data<N> where N is the DBRoot number. There is no performance gain from assigning more than one DBRoot to a single storage device. DBRoots can be linked to other locations with more capacity if necessary. #### SAN mounted database files If you are using a SAN for storage, the following must be taken into account: * Each DBRoot must be a separate filesystem. * Each DBRoot should have the same capacity and performance characteristics, and each Performance Module should have the same number of DBRoots assigned for best performance. * MariaDB ColumnStore performs best on filesystems with low overhead, such as the ext family, however it can use any Linux filesystem. ColumnStore writes relatively large files (up to 64MB) compared to other databases, so please take that into account when choosing and configuring your filesystems. * For the failover feature to work, all Performance Modules must be able to mount any DBRoot. * The fstab file on all Performance Modules must include all of the external mounts, all with the 'noauto' option specified. ColumnStore will manage the mounting and unmounting. These lines are an example of an installation with 2 DBRoots configured. ``` /dev/sda1 /usr/local/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto 0 0 /dev/sdd1 /usr/local/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto 0 0 ``` #### Performance optimization considerations There are optimizations that should be made when using MariaDB ColumnStore listed below. As always, please consult with your network administrator for additional optimization considerations for your specific installation needs. #### GbE NIC settings: * Modify /etc/rc.d/rc.local to include the following: ``` /sbin/ifconfig eth0 txqueuelen 10000 ``` * Modify /etc/sysctl.conf for the following: ``` # increase TCP max buffer size net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 # increase Linux autotuning TCP buffer limits # min, default, and max number of bytes to use net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 65536 16777216 # don't cache ssthresh from previous connection net.ipv4.tcp_no_metrics_save = 1 # recommended to increase this for 1000 BT or higher net.core.netdev_max_backlog = 2500 # for 10 GigE, use this net.core.netdev_max_backlog = 30000 ``` NOTE: Make sure there is only 1 setting of net.core.netdev\_max\_backlog in the /etc/sysctl.conf file. * Cache memory settings: The kernel parameter vm.vfs\_cache\_pressure can be set to a lower value than 100 to attempt to retain caches for inode and directory structures. This will help improve read performance. A value of 10 is suggested. The following commands must be run as the root user or with sudo. To check the current value: ``` cat /proc/sys/vm/vfs_cache_pressure ``` To set the current value until the next reboot: ``` sysctl -w vm.vfs_cache_pressure=10 ``` To set the value permanently across reboots, add the following to /etc/sysctl.conf: ``` vm.vfs_cache_pressure = 10 ``` #### System settings considerations ##### umask setting The default setting of 022 is what is recommended. ColumnStore requires that it not end with a 7, like 077. For example, on a root installation, mysqld runs as the mysql user, and needs to be able to read the ColumnStore configuration file, which likely is not owned by mysql. If it were, then the other ColumnStore processes could not read it. The current umask can be determined by running the 'umask' command: A value of 022 can be set in the current session or in /etc/profile with the command: ``` umask 022 ``` #### Firewall considerations The MariaDB ColumnStore uses TCP ports 3306, 8600 - 8630, 8700, and 8800. Port 3306 is the default port for clients to connect to the MariaDB server; the others are for internal communication and will need to be open between ColumnStore nodes. To disable any local firewalls and SELinux on mutli-node installations, as root do the following. CentOS 6 and systems using iptables ``` #service iptables save (Will save your existing IPTable Rules) #service iptables stop (It will disable firewall Temporary) ``` To Disable it Permanentely: ``` #chkconfig iptables off ``` CentOS 7 and systems using systemctl with firewalld ``` #systemctl status firewalld #systemctl stop firewalld #systemctl disable firewalld ``` Ubuntu and systems using ufw ``` #service ufw stop (It will disable firewall Temporary) ``` To Disable it Permanently: ``` #chkconfig ufw off ``` SUSE ``` #/sbin/rcSuSEfirewall2 status #/sbin/rcSuSEfirewall2 stop ``` To disable SELinux, edit "/etc/selinux/config" and find line: ``` SELINUX=enforcing ``` Now replace it with, ``` SELINUX=disabled ``` #### User considerations MariaDB ColumnStore can be installed in different user configurations. #### Root User installation and execution MariaDB ColumnStore is installed by root and the MariaDB ColumnStore commands are run by root. With this installation type, you have the option of install using rpm, deb or binary packages. You can install the packages with the standard tools yum, apt, or zypper. The default package installation directory is /usr/local/mariadb/columnstore The location of the temporary files created by MariaDB ColumnStore is /tmp/columnstore\_tmp. #### Unprivileged user installation and execution MariaDB ColumnStore is installed by an unprivileged user and the MariaDB ColumnStore commands are run by that user. With this installation type, you are required to install using the binary tarball, which can be downloaded from the MariaDB ColumnStore Downloads page: <https://mariadb.com/downloads/#mariadbax> The default package installation directory is the home directory of the user account. The location of the temporary files created by MariaDB ColumnStore is $HOME/.tmp #### Root user installation and unprivileged user execution MariaDB ColumnStore is installed by root user and the MariaDB ColumnStore commands are run by an unprivileged user. This document will show how to configure the system to run commands as an unprivileged user: [https://mariadb.com/kb/en/library/mariadb-columnstore-system-usage/#non-root-user-mariadb-columnstore-admin-console](../library/mariadb-columnstore-system-usage/index#non-root-user-mariadb-columnstore-admin-console) With this installation type, you have the option of install using rpm, deb or binary packages, which you can install with the standard tools yum, apt, zypper. The default package installation directory is /usr/local/mariadb/columnstore The location of the temporary files created by MariaDB ColumnStore is /tmp/columnstore\_tmp. ### Package dependencies #### libjemalloc dependency ColumnStore 1.2.3 onward requires libjemalloc to be installed. For Ubuntu & Debian based distributions this is installed using the package "libjemalloc1" in the standard repositories. For CentOS the package is in RedHat's EPEL repository: This does require either root user access or SUDO setup to install: ``` sudo yum -y install epel-release sudo yum install -y jemalloc ``` #### Boost libraries MariaDB ColumnStore requires that the boost package of 1.53 or newer is installed. For Centos 7, Ubuntu 16, Debian 8, SUSE 12 and other newer OS's, you can just install the default boost package that comes with your distribution. ``` # yum -y install boost ``` or ``` # apt-get -y install libboost-all-dev ``` For SUSE 12, you will need to install the boost-devel package, which is part of the SLE-SDK package. ``` SUSEConnect -p sle-sdk/12.2/x86_64 zypper install boost-devel ``` For CentOS 6, you can either download and install the MariaDB Columnstore Centos 6 boost library package or build version 1.55 from source and deploy it to each ColumnStore node. To download the pre-built libraries from MariaDB, go to binaries download page and download "centos6\_boost\_1\_55.tar.gz" <https://mariadb.com/downloads/columnstore> Click All Versions - > 1.0.x -> centos -> x86\_64 Install package on each server in the cluster. ``` wget https://downloads.mariadb.com/ColumnStore/1.0.14/centos/x86_64/centos6_boost_1_55.tar.gz tar xfz centos6_boost_1_55.tar.gz -C /usr/lib ldconfig ``` Downloading and build the boost libraries from source: NOTE: This requires that the "Development Tools" group and cmake be installed prior to this. ``` yum groupinstall "Development Tools" yum install cmake ``` Here is the procedure to download and build the boost source. As root do the following: ``` cd /usr/ wget http://sourceforge.net/projects/boost/files/boost/1.55.0/boost_1_55_0.tar.gz tar zxvf boost_1_55_0.tar.gz cd boost_1_55_0 ./bootstrap.sh --with-libraries=atomic,date_time,exception,filesystem,iostreams,locale,program_options,regex,signals,system,test,thread,timer,log --prefix=/usr ./b2 install ldconfig ``` #### Other packages Additional packages are required on each ColumnStore node. ##### Centos 6/7 ``` # yum -y install expect perl perl-DBI openssl zlib file sudo libaio rsync snappy net-tools numactl-libs nmap ``` ##### Ubuntu 16/18 ``` # apt-get -y install tzdata libtcl8.6 expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1v5 net-tools libnuma1 nmap ``` ##### Debian 8 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1 net-tools libnuma1 nmap ``` ##### Debian 9 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync net-tools libsnappy1v5 libreadline5 libaio1 libnuma1 nmap ``` ##### SUSE 12 ``` zypper install expect perl perl-DBI openssl file sudo libaio1 rsync net-tools libsnappy1 libnuma1 nmap ``` #### Data Redundancy packages To enable the Data Redundancy feature, install and enable GlusterFS version 3.3.1 or higher on each Performance Module. ##### Centos 6/7 ``` # yum -y install centos-release-gluster # yum -y install glusterfs glusterfs-fuse glusterfs-server start / enable service: # systemctl enable glusterd.service # systemctl start glusterd.service ``` ##### Ubuntu 16/18 ``` # apt-get install glusterfs-server attr start / enable service: # systemctl start glusterfs-server.service # systemctl enable glusterfs-server.service ``` ##### Debian 8 ``` # apt-get -y install glusterfs-server attr start / enable service: # update-rc.d glusterfs-server defaults ``` ##### Debian 9 ``` # apt-get install glusterfs-server attr start / enable service: # systemctl start glusterfs-server.service # systemctl enable glusterfs-server.service ``` ##### SUSE 12 ``` # zypper install glusterfs start / enable service: # chkconfig glusterd on ``` #### System Logging Package MariaDB ColumnStore can use the following standard logging systems. * syslog * rsyslog * syslog-ng ### Download location The standard ColumnStore RPM and DEB packages are available at <https://mariadb.com/downloads/columnstore>. If you need to install ColumnStore without root-level permissions, you must use the binary tarball, which is available at <https://downloads.mariadb.com/ColumnStore/> Note: MariaDB ColumnStore will configure a root user with no password in the MariaDB server initially. Afterward, you may setup users and permissions within MariaDB as you normally would. ### Choosing the type of initial download/install #### Non-Distributed Installation The default MariaDB ColumnStore installation process supports a Non-Distributed installation mode for multi-node deployments. With this option, the user will need to install the ColumnStore packages manually on each node. This option would be used when Package Repo install of rpm/deb packages are the preferred method to install MariaDB ColumnStore. Its also used for MariaDB ColumnStore Docker images. The Pre-install setup time will take longer with the Non-Distributed Installation, but the system Install and startup via the install app 'postConfigure' will be faster. #### Distributed Install With the Distributed option, MariaDB ColumnStore will distribute and install the packages automatically on each node. The user installs ColumnStore on Performance Module 1, then during the postConfigure step, ColumnStore will handle the rest. This option would be used on system with multi-nodes where the package only had to be installed on 1 node, the Performance Module 1, the app 'postConfigure' would distribute and all down to all of the other nodes. The Pre-install setup time would be shorter with the Non-Distributed Installation, but the system Install and startup via the install app 'postConfigure' will be take longer. ### Root user installations #### Initial download/install of MariaDB ColumnStore Packages The MariaDB ColumnStore RPM and DEB Packages can be installed using yum/apt-get commands. Check here for additional Information: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) #### Initial download/install of MariaDB ColumnStore Package with the AX package The MariaDB ColumnStore RPM, DEB and binary packages can be installed along with the other packages that make up the AX package. Check here for additional Information: [https://mariadb.com/kb/en/library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/](../library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/index) #### Initial download & installation of MariaDB ColumnStore RPMs 1. Install MariaDB ColumnStore as user root: Note: MariaDB ColumnStore will configure a root user with no password in the MariaDB server initially. Afterward, you may setup users and permissions within MariaDB as you normally would. Note: The packages will be installed at /usr/local. This is required for root user installations. * Download the appropriate ColumnStore package and place in the /root directory. * Unpack the tarball, which contains multiple RPMs. * Install the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. `rpm -ivh mariadb-columnstore*release#*.rpm` #### Initial download & installation of MariaDB ColumnStore binary package The MariaDB ColumnStore binary packages can be downloaded from <https://downloads.mariadb.com/ColumnStore/>. Select version 1.2.5, then navigate to the appropriate package for your system. The binary package will have the extension '.bin.tar.gz' rather than '.rpm.tar.gz' or '.deb.tar.gz'. * Unpack the tarball in /usr/local/ `tar -zxf mariadb-columnstore-release#.x86_64.bin.tar.gz` Run the post-install script: ``` /usr/local/mariadb/columnstore/bin/post-install ``` #### Initial download & installation of MariaDB ColumnStore DEB package 1. Download the package mariadb-columnstore-release#.amd64.deb.tar.gz into the /root directory of the server where you are installing MariaDB ColumnStore. 2. Unpack the tarball, which contains multiple DEBs. `tar -zxf mariadb-columnstore-release#.amd64.deb.tar.gz` 3. Install the MariaDB ColumnStore DEBs. The MariaDB ColumnStore software will be installed in /usr/ local/. `dpkg -i mariadb-columnstore*release#*.deb` ### Unprivileged user installation MariaDB Columnstore is installed to run as an unprivileged user using the binary package. It will need to be run on all MariaDB ColumnStore nodes. For the purpose of these instructions, the following assumptions are: * Unprivileged user 'mysql' is used in this example * Installation directory is /home/mysql/mariadb/columnstore Tasks involved: * Create the mysql user and group of the same name (by root user) * Update sudo configuration, if needed (by root user) * Set the user file limits (by root user) * Modify fstab if using 'external' storage (by root user) * Uninstall existing MariaDB Columnstore installation if needed (by root user) * Update permissions on certain directories that MariaDB Columnstore writes (by root user) * MariaDB Columnstore Installation (by the new user user) * Enable MariaDB Columnstore to start automatically at boot time #### Creation of a new user (by root user) Before beginning the binary tar file installation you will need your system administrator to set up accounts for you on every MariaDB Columnstore node. The account name & password must be the same on every node. If you change the password on one node, you must change it on every node. The user ID must be the same on every node as well. In the examples below we will use the account name 'mysql' and the password 'mariadb'. * create new user Group ID is an example, can be different than 1000, but needs to be the same on all servers in the cluster `adduser mysql -u 1000` * create group ``` addgroup mysql moduser -g mysql mysql ``` The value for user-id must be the same for all nodes. * Assign a password to newly created user `passwd mysql` * Log in as user mysql `su - mysql` IMPORTANT: It is required that the installation directory will be the home directory of the user account. So it would be '/home/mysql/' in this example. The installation directory must be the same on every node. In the examples below we will use the path '/home/mysql/mariadb/columnstore'. #### Update sudo configuration, if needed (by root user) In the MariaDB ColumnStore 1.2.1 and later, sudo configuration is only required for certain system configurations. These would include: * Data Redundancy * External Storage * Amazon EC2 using EBS storage If your system is not configured with any of these, you can skip this section. #### sudo configuration for Data Redundancy The sudo configuration on each node will need to allow the new user to run the gluster, mount, umount, and chmod commands. Add the following lines to your /etc/sudoers file, changing the paths to those commands if necessary on your system. ``` mysql ALL=NOPASSWD: /sbin/gluster mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount mysql ALL=NOPASSWD: /usr/bin/chmod ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### sudo configuration for External Storage The sudo configuration on each node will need to allow the new user to run the chmod, chown, mount, and umount commands. Add the following lines to your /etc/sudoers file, changing the path of each command if necessary on your system. ``` mysql ALL=NOPASSWD: /usr/bin/chmod mysql ALL=NOPASSWD: /usr/bin/chown mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### sudo configuration for Amazon EC2 using EBS storage The sudo configuration on each node will need to allow the new user to run several commands. Add the following lines to your /etc/sudoers file, changing the path of each command if necessary on your system. ``` mysql ALL=NOPASSWD: /usr/sbin/mkfs.ext2 mysql ALL=NOPASSWD: /usr/bin/chmod mysql ALL=NOPASSWD: /usr/bin/chown mysql ALL=NOPASSWD: /usr/bin/sed mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### Set the user file limits (by root user) ColumnStore needs the open file limit to be increased for the new user. To do this edit the /etc/security/limits.conf file and make the following additions at the end of the file: ``` mysql hard nofile 65536 mysql soft nofile 65536 ``` If you are already logged in as 'mysql' you will need to logout, then login for this change to take effect. #### Modify fstab if using the external storage option (by root user) If you are using an 'external' storage configuration, you will need to allow the new user to mount and unmount those filesystems. Add the 'users' option to those filesystems in your /etc/fstab file. Example entries: /dev/sda1 /home/mysql/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto,users 0 0 /dev/sdd1 /home/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto,users 0 0 The external filesystems will need to be owned by the new user. This is an example command run as root setting the owner and group of dbroot /dev/sda1 to the mysql user: ``` mount /dev/sda1 /tmpdir chown -R mysql:mysql /tmpdir umount /tmpdir ``` #### Update permissions on directories that MariaDB Columnstore writes to (by root user) ColumnStore uses POSIX shared memory segments. On some systems, the entry point /dev/shm does not allow regular users to create new segments. If necessary, permissions on /dev/shm should be set such that the new user or group has full access. The default on most systems is 777. ``` chmod 777 /dev/shm ``` For Data Redundancy using GlusterFS configured system: ``` chmod 777 -R /var/log/glusterfs ``` To allow external storage on an Amazon EC2 instance using EBS storage: ``` chmod 644 /etc/fstab ``` #### Uninstall existing MariaDB Columnstore installation, if needed (by root user) If MariaDB Columnstore has ever before been installed on any of the planned hosts as a root user install, you must have the system administrator verify that no remnants of that installation exist. The unprivileged installation will not be successful if there are MariaDB Columnstore files owned by root on any of the hosts. * Verify the MariaDB Columnstore installation directory does not exist: The /usr/local/mariadb/columnstore directory should not exist at all unless it is your target directory, in which case it must be completely empty and owned by the new user. * Verify the /etc/fstab entries are correct for the new installation. * Verify the /etc/default/columnstore directory does not exist. * Verify the /var/lock/subsys/mysql-Columnstore file does not exist. * Verify the /tmp/StopColumnstore file does not exist. #### MariaDB Columnstore installation (by the new user) You should be familiar with the general MariaDB Columnstore installation instructions in this guide as you will be asked the same questions during installation. If performing the distributed-mode installation across multiple node, the binary package only needs to be installed on Performance Module #1 (pm1). If performing a non-distributed installation, the binary package is required to install the MariaDB ColumnStore on all the nodes in the system. * Log in as the unprivileged user (mysql, in our example) Note: Ensure you are at your home directory before proceeding to the next step * Now place the MariaDB Columnstore binary tar file in your home directory on the host you will be using as PM1. Untar the binary distribution package to the /home/mysql directory: tar -xf mariadb-columnstore-release#.x86\_64.bin.tar.gz * Run post installation: If performing the distributed-mode installation, post-install only needs to be run on Performance Module #1 (pm1). If performing non-distributed installations, post-install needs to be run on all the nodes in the system. NOTE: $HOME is the same as /home/mysql in this example ``` ./mariadb/columnstore/bin/post-install --installdir=$HOME/mariadb/columnstore ``` Here is an example of what is printed by the post-install command ``` NOTE: For non-root install, you will need to run the following commands as root user to setup the MariaDB ColumnStore System Logging export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/syslogSetup.sh --installdir=/home/mysql/mariadb/columnstore --user=mysql install The next steps are: If installing on a pm1 node using non-distributed install export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore If installing on a pm1 node using distributed install export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore -d If installing on a non-pm1 using the non-distributed option: export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/columnstore start ``` * Setup System Logging For an unprivileged user installation, you will need to run the following commands as root on all nodes after the post-install command is run to make log entries go to the right places: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/syslogSetup.sh --installdir=/home/mysql/mariadb/columnstore --user=mysql install ``` Without that, log entries will go to the main system log file, and low-severity logs may not be recorded at all. * Start MariaDB ColumnStore Service for Non-Distributed installations If performing the non-distributed installation mode, the 'columnstore' service needs to be started on all nodes in the system except Performance Module #1 (pm1). postConfigure is on pm1, which is documented in the next section. Starting the 'columnstore' service: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/columnstore start ``` * Running ColumnStore Configuration and Installation Tool, 'postConfigure' On PM1, run the 2 export commands that were printed by the post-install command, then run postConfigure, which would look like the following: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore ``` #### Configure ColumnStore to run automatically at boot To configure MariaDB Columnstore unprivileged installation to start automatically at boot time, perform the following steps on each Columnstore node: * Add the following to your local startup script (/etc/rc.local or similar), modifying as necessary: ``` runuser -l mysql -c "/home/mysql/mariadb/columnstore/bin/columnstore start" ``` Note: Make sure the above entry is added to the rc.local file that gets executed at boot time. Depending on the OS installation, rc.local could be in a different location. * MariaDB Columnstore will setup and log using your current system logging application in the directory /var/log/mariadb/columnstore. ### MariaDB Server Password setup If you plan to setup a root user password in the MariaDB server Database, remember to setup the Password Configuration file on each User Module and Performance Module that has User Modules functionality. [https://mariadb.com/kb/en/library/mariadb-columnstore-system-usage/#logging-into-mariadb-columnstore-mariadb-console](../library/mariadb-columnstore-system-usage/index#logging-into-mariadb-columnstore-mariadb-console) ### ColumnStore Cluster Test Tool This tool can be run before installation. It will verify the setup of all servers that are going to be used in the Columnstore System. [https://mariadb.com/kb/en/mariadb/mariadb-columnstore-cluster-test-tool](../mariadb/mariadb-columnstore-cluster-test-tool) ### How to Configuration and Launch MariaDB Columnstore #### ColumnStore Quick Launch Tools There are 3 Quick Launch Tools that can be used to launch basic systems. These are 1 step command tool where you provide the number of modules or amazon instances and the tool will take care of the rest. 1. Single Server Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-single-server-columnstore-system-12x/#mariadb-columnstore-quick-installer-for-a-single-server-system](../library/installing-and-configuring-a-single-server-columnstore-system-12x/index#mariadb-columnstore-quick-installer-for-a-single-server-system) 2. Multi Server Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-multi-server-columnstore-system-12x/#mariadb-columnstore-quick-installer](../library/installing-and-configuring-a-multi-server-columnstore-system-12x/index#mariadb-columnstore-quick-installer) 3. Amazon AMI Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-columnstore-system-using-the-amazon-ami/#mariadb-columnstore-one-step-quick-installer-script-quick\_installer\_amazonsh](../library/installing-and-configuring-a-columnstore-system-using-the-amazon-ami/index#mariadb-columnstore-one-step-quick-installer-script-quick_installer_amazonsh) #### ColumnStore Configuration and Installation Tool MariaDB Columnstore System Configuration and Installation tool, 'postConfigure', will Configure the MariaDB Columnstore System and will perform a Package Installation of all of the Servers within the System that is being configured. It will prompt the user to for information like IP addresses, storage types, MariaDB Server, and system features. At the end, it will start the ColumnStore system. NOTE: When prompted for password, enter the non-user account password OR just hit enter if you have configured password-less ssh keys on all nodes (Please see the “System Administration Information” section earlier in this guide for more information on ssh keys.) This tool is always run on the Performance Module #1. Example uses of this script are shown in the Single and Multi Server Installations Guides. ``` # /usr/local/mariadb/columnstore/bin/postConfigure -h This is the MariaDB ColumnStore System Configuration and Installation tool. It will Configure the MariaDB ColumnStore System based on Operator inputs and will perform a Package Installation of all of the Modules within the System that is being configured. IMPORTANT: This tool should only be run on a Performance Module Server, preferably Module #1 Instructions: Press 'enter' to accept a value in (), if available or Enter one of the options within [], if available, or Enter a new value Usage: postConfigure [-h][-c][-u][-p][-qs][-qm][-qa][-port][-i][-n][-d][-sn][-pm-ip-addrs][-um-ip-addrs][-pm-count][-um-count] -h Help -c Config File to use to extract configuration data, default is Columnstore.xml.rpmsave -u Upgrade, Install using the Config File from -c, default to Columnstore.xml.rpmsave If ssh-keys aren't setup, you should provide passwords as command line arguments -p Unix Password, used with no-prompting option -qs Quick Install - Single Server -qm Quick Install - Multi Server -port MariaDB ColumnStore Port Address -i Non-root Install directory, Only use for non-root installs -n Non-distributed install, meaning postConfigure will not install packages on remote nodes -d Distributed install, meaning postConfigure will install packages on remote nodes -sn System Name -pm-ip-addrs Performance Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx -um-ip-addrs User Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Thread Pool Thread Pool ============ [MariaDB 5.1](../what-is-mariadb-51/index) introduced a thread pool, while [MariaDB 5.5](../what-is-mariadb-55/index) introduced an improved version. | Title | Description | | --- | --- | | [Thread Pool in MariaDB](../thread-pool-in-mariadb/index) | Thread pool introduced in MariaDB 5.5. | | [Thread Groups in the Unix Implementation of the Thread Pool](../thread-groups-in-the-unix-implementation-of-the-thread-pool/index) | On Unix, the thread pool divides up client connections into independent sets of threads. | | [Thread Pool System and Status Variables](../thread-pool-system-status-variables/index) | System and status variables related to the MariaDB thread pool. | | [Thread Pool in MariaDB 5.1 - 5.3](../thread-pool-in-mariadb-51-53/index) | The old thread pool introduced in MariaDB 5.1 | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Plugins Plugins ======== MariaDB supports the use of plugins, software components that may be added to the core software without having to rebuild the MariaDB server from source code. Therefore, plugins can be loaded at start-up, or loaded and unloaded while the server is running without interruption. Plugins are commonly used for adding desired storage engines, additional security requirements, and logging special information about the server. | Title | Description | | --- | --- | | [Plugin Overview](../plugin-overview/index) | Basics of listing, installing and uninstalling plugins. | | [Information on Plugins](../information-on-plugins/index) | Information on installed and disabled plugins on a MariaDB Server. | | [Plugin SQL Statements](../plugin-sql-statements/index) | List of SQL statements related to plugins. | | [Creating and Building Plugins](../creating-and-building-plugins/index) | Documentation on how to create new plugins and build existing ones. | | [MariaDB Audit Plugin](../mariadb-audit-plugin/index) | Logging user activity with the MariaDB Audit Plugin. | | [Authentication Plugins](../authentication-plugins/index) | Authentication plugins allow various authentication methods to be used, and new ones developed. | | [Password Validation Plugins](../password-validation-plugins/index) | Ensuring that user passwords meet certain minimal security requirements. | | [Key Management and Encryption Plugins](../key-management-and-encryption-plugins/index) | MariaDB uses plugins to handle key management and encryption of data. | | [MariaDB Replication & Cluster Plugins](../mariadb-replication-cluster-plugins/index) | Plugins related to MariaDB replication and other replication cluster systems. | | [Storage Engines](../storage-engines/index) | Various storage engines available for MariaDB. | | [Other Plugins](../other-plugins/index) | Information on installing and using other plugins. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Using MariaDB Replication with MariaDB Galera Cluster Using MariaDB Replication with MariaDB Galera Cluster ===================================================== [MariaDB replication](../high-availability-performance-tuning-mariadb-replication/index) and [MariaDB Galera Cluster](../galera-cluster/index) can be used together. However, there are some things that have to be taken into account. Tutorials --------- If you want to use [MariaDB replication](../high-availability-performance-tuning-mariadb-replication/index) and [MariaDB Galera Cluster](../galera-cluster/index) together, then the following tutorials may be useful: * [Configuring MariaDB Replication between MariaDB Galera Cluster and MariaDB Server](../using-mariadb-replication-with-mariadb-galera-cluster-configuring-mariadb-r/index) * [Configuring MariaDB Replication between Two MariaDB Galera Clusters](../configuring-mariadb-replication-between-two-mariadb-galera-clusters/index) Configuring a Cluster Node as a Replication Master -------------------------------------------------- If a Galera Cluster node is also a [replication master](../replication-overview/index), then some additional configuration may be needed. Like with [MariaDB replication](../high-availability-performance-tuning-mariadb-replication/index), write sets that are received by a node with [Galera Cluster's certification-based replication](../about-galera-replication/index) are not written to the [binary log](../binary-log/index) by default. If the node is a replication master, then its replication slaves only replicate transactions which are in the binary log, so this means that the transactions that correspond to Galera Cluster write-sets would not be replicated by any replication slaves by default. If you would like a node to write its replicated write sets to the [binary log](../binary-log/index), then you will have to set `[log\_slave\_updates=ON](../replication-and-binary-log-system-variables/index#log_slave_updates)`. If the node has any replication slaves, then this would also allow those slaves to replicate the transactions that corresponded to those write sets. See [Configuring MariaDB Galera Cluster: Writing Replicated Write Sets to the Binary Log](../configuring-mariadb-galera-cluster/index#writing-replicated-write-sets-to-the-binary-log) for more information. Configuring a Cluster Node as a Replication Slave ------------------------------------------------- If a Galera Cluster node is also a [replication slave](../replication-overview/index), then some additional configuration may be needed. If the node is a replication slave, then the node's [slave SQL thread](../replication-threads/index#slave-sql-thread) will be applying transactions that it replicates from its replication master. Transactions applied by the slave SQL thread will only generate Galera Cluster write-sets if the node has `[log\_slave\_updates=ON](../replication-and-binary-log-system-variables/index#log_slave_updates)` set. Therefore, in order to replicate these transactions to the rest of the nodes in the cluster, `[log\_slave\_updates=ON](../replication-and-binary-log-system-variables/index#log_slave_updates)` must be set. If the node is a replication slave, then it is probably also a good idea to enable `[wsrep\_restart\_slave](../galera-cluster-system-variables/index#wsrep_restart_slave)`. When this is enabled, the node will restart its [slave threads](../replication-threads/index#threads-on-the-slave) whenever it rejoins the cluster. Replication Filters ------------------- Both [MariaDB replication](../high-availability-performance-tuning-mariadb-replication/index) and [MariaDB Galera Cluster](../galera-cluster/index) support [replication filters](../replication-filters/index), so extra caution must be taken when using all of these features together. See [Configuring MariaDB Galera Cluster: Replication Filters](../configuring-mariadb-galera-cluster/index#replication-filters) for more details on how MariaDB Galera Cluster interprets replication filters. Setting server\_id on Cluster Nodes ----------------------------------- ### Setting the Same server\_id on Each Cluster Node It is most common to set `[server\_id](../replication-and-binary-log-system-variables/index#server_id)` to the same value on each node in a given cluster. Since [MariaDB Galera Cluster](../galera-cluster/index) uses a [virtually synchronous certification-based replication](../about-galera-replication/index), all nodes should have the same data, so in a logical sense, a cluster can be considered in many cases a single logical server for purposes related to [MariaDB replication](../high-availability-performance-tuning-mariadb-replication/index). The [binary logs](../binary-log/index) of each cluster node might even contain roughly the same transactions and [GTIDs](../gtid/index) if `[log\_slave\_updates=ON](../replication-and-binary-log-system-variables/index#log_slave_updates)` is set and if [wsrep GTID mode](../using-mariadb-gtids-with-mariadb-galera-cluster/index#wsrep-gtid-mode) is enabled and if non-Galera transactions are not being executed on any nodes. ### Setting a Different server\_id on Each Cluster Node There are cases when it might make sense to set a different `[server\_id](../replication-and-binary-log-system-variables/index#server_id)` value on each node in a given cluster. For example, if `[log\_slave\_updates=OFF](../replication-and-binary-log-system-variables/index#log_slave_updates)` is set and if another cluster or a standard MariaDB Server is using [multi-source replication](../multi-source-replication/index) to replicate transactions from each cluster node individually, then it would be required to set a different `[server\_id](../replication-and-binary-log-system-variables/index#server_id)` value on each node for this to work. Keep in mind that if replication is set up in a scenario where each cluster node has a different `[server\_id](../replication-and-binary-log-system-variables/index#server_id)` value, and if the replication topology is set up in such a way that a cluster node can replicate the same transactions through Galera and through MariaDB replication, then you may need to configure the cluster node to ignore these transactions when setting up MariaDB replication. You can do so by setting `[IGNORE\_SERVER\_IDS](../change-master-to/index#ignore_server_ids)` to the server IDs of all nodes in the same cluster when executing `[CHANGE MASTER TO](../change-master-to/index)`. For example, this might be required when circular replication is set up between two separate clusters, and each cluster node as a different `[server\_id](../replication-and-binary-log-system-variables/index#server_id)` value, and each cluster has `[log\_slave\_updates=ON](../replication-and-binary-log-system-variables/index#log_slave_updates)` set. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb S3 Storage Engine Internals S3 Storage Engine Internals =========================== **MariaDB starting with [10.5](../what-is-mariadb-105/index)**The [S3 storage engine](../s3-storage-engine/index) has been available since [MariaDB 10.5.4](https://mariadb.com/kb/en/mariadb-1054-release-notes/). The [S3 storage engine](../s3-storage-engine/index) is based on the [Aria](../aria-storage-engine/index) code. Internally the S3 storage inherits from the Aria code, with hooks that change reads, so that instead of reading data from the local disk it reads things from S3. The S3 engine uses it's own page cache, modified to be able to handle reading blocks from S3 (of size `s3_block_size`). Internally the S3 page cache uses pages of [aria-block-size](../aria-system-variables/index#aria_block_size) for splitting the blocks read from S3. ALTER TABLE ----------- [ALTER TABLE](../alter-table/index) will first create a local table in the normal Aria on disk format and then move both index and data to S3 in buckets of S3\_BLOCK\_SIZE. The .frm file is also copied to S3 for discovery to support discovery for other MariaDB servers. One can also use ALTER TABLE to change the structure of an S3 table. Partitioning Tables ------------------- Starting from [MariaDB 10.5.3](https://mariadb.com/kb/en/mariadb-1053-release-notes/), S3 tables can also be used with [Partitioning tables](../partitioning-tables/index). All [ALTER PARTITION](../alter-table/index) operations are supported except: * REBUILD PARTITION * TRUNCATE PARTITION * REORGANIZE PARTITION Big Reads --------- One of the properties of many S3 implementations is that they favor large reads. It's said that 4M gives the best performance, which is why the default value for `S3_BLOCK_SIZE` is 4M. Compression ----------- If compression (`COMPRESSION_ALGORITHM=zlib`) is used, then all index blocks and data blocks are compressed. The `.frm` file and Aria definition header (first page/pages in the index file) are not compressed as these are used by discovery/open. If compression is used, then the local block size is `S3_BLOCK_SIZE`, but the block stored in S3 will be the size of the compressed block. Typical compression we have seen is in the range of 80% saved space. Structure Stored on S3 ---------------------- The table will be copied in S3 into the following locations: ``` frm file (for discovery): s3_bucket/database/table/frm First index block (contains description of the Aria file): s3_bucket/database/table/aria Rest of the index file: s3_bucket/database/table/index/block_number Data file: s3_bucket/database/table/data/block_number ``` block\_number is a 6-digit decimal number, prefixed with 0 (Can be larger than 6 numbers, the prefix is just for nice output) Using the awsctl Python Tool to Examine Data -------------------------------------------- ### Installing awsctl on Linux ``` # install python-pip (on an OpenSuse distribution) # use the appropriate command for your distribution zypper install python-pip pip install --upgrade pip # the following installs awscli tools in ~/.local/bin pip install --upgrade --user awscli export PATH=~/.local/bin:$PATH # configure your aws credentials aws configure ``` ### Using the awsctl Tool One can use the `aws` python tool to see how things are stored on S3: ``` shell> aws s3 ls --recursive s3://mariadb-bucket/ 2019-05-10 17:46:48 8192 foo/test1/aria 2019-05-10 17:46:49 3227648 foo/test1/data/000001 2019-05-10 17:46:48 942 foo/test1/frm 2019-05-10 17:46:48 1015808 foo/test1/index/000001 ``` To delete an obsolete table `foo.test1` one can do: ``` shell> ~/.local/bin/aws s3 rm --recursive s3://mariadb-bucket/foo/test1 delete: s3://mariadb-bucket/foo/test1/aria delete: s3://mariadb-bucket/foo/test1/data/000001 delete: s3://mariadb-bucket/foo/test1/frm delete: s3://mariadb-bucket/foo/test1/index/000001 ``` See Also -------- * [Using the S3 storage engine](../using-the-s3-storage-engine/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ADD_MONTHS ADD\_MONTHS =========== **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**The ADD\_MONTHS function was introduced in [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/) to enhance Oracle compatibility. Similar functionality can be achieved with the [DATE\_ADD](../date_add/index) function. Syntax ------ ``` ADD_MONTHS(date, months) ``` Description ----------- `ADD_MONTHS` adds an integer *months* to a given *date* ([DATE](../date/index), [DATETIME](../datetime/index) or [TIMESTAMP](../timestamp/index)), returning the resulting date. *months* can be positive or negative. The resulting day component will remain the same as that specified in *date*, unless the resulting month has fewer days than the day component of the given date, in which case the day will be the last day of the resulting month. Returns NULL if given an invalid date, or a NULL argument. Examples -------- ``` SELECT ADD_MONTHS('2012-01-31', 2); +-----------------------------+ | ADD_MONTHS('2012-01-31', 2) | +-----------------------------+ | 2012-03-31 | +-----------------------------+ SELECT ADD_MONTHS('2012-01-31', -5); +------------------------------+ | ADD_MONTHS('2012-01-31', -5) | +------------------------------+ | 2011-08-31 | +------------------------------+ SELECT ADD_MONTHS('2011-01-31', 1); +-----------------------------+ | ADD_MONTHS('2011-01-31', 1) | +-----------------------------+ | 2011-02-28 | +-----------------------------+ SELECT ADD_MONTHS('2012-01-31', 1); +-----------------------------+ | ADD_MONTHS('2012-01-31', 1) | +-----------------------------+ | 2012-02-29 | +-----------------------------+ SELECT ADD_MONTHS('2012-01-31', 2); +-----------------------------+ | ADD_MONTHS('2012-01-31', 2) | +-----------------------------+ | 2012-03-31 | +-----------------------------+ SELECT ADD_MONTHS('2012-01-31', 3); +-----------------------------+ | ADD_MONTHS('2012-01-31', 3) | +-----------------------------+ | 2012-04-30 | +-----------------------------+ ``` See Also -------- * [SQL\_MODE=ORACLE](../sql_modeoracle/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ps_is_instrument_default_enabled ps\_is\_instrument\_default\_enabled ==================================== Syntax ------ ``` sys.ps_is_instrument_default_enabled(instrument) ``` Description ----------- `ps_is_instrument_default_enabled` is a [stored function](../stored-functions/index) available with the [Sys Schema](../sys-schema/index). It returns `YES` if the given Performance Schema *instrument* is enabled by default, and `NO` if it is not, does not exist, or is a NULL value. Examples -------- ``` SELECT sys.ps_is_instrument_default_enabled('statement/sql/select'); +--------------------------------------------------------------+ | sys.ps_is_instrument_default_enabled('statement/sql/select') | +--------------------------------------------------------------+ | YES | +--------------------------------------------------------------+ SELECT sys.ps_is_instrument_default_enabled('memory/sql/udf_mem'); +------------------------------------------------------------+ | sys.ps_is_instrument_default_enabled('memory/sql/udf_mem') | +------------------------------------------------------------+ | NO | +------------------------------------------------------------+ SELECT sys.ps_is_instrument_default_enabled('memory/sql/nonexistent'); +----------------------------------------------------------------+ | sys.ps_is_instrument_default_enabled('memory/sql/nonexistent') | +----------------------------------------------------------------+ | NO | +----------------------------------------------------------------+ SELECT sys.ps_is_instrument_default_enabled(NULL); +--------------------------------------------+ | sys.ps_is_instrument_default_enabled(NULL) | +--------------------------------------------+ | NO | +--------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Status Variables Added in MariaDB 10.6 Status Variables Added in MariaDB 10.6 ====================================== This is a list of [status variables](../server-status-variables/index) that were added in the [MariaDB 10.6](../what-is-mariadb-106/index) series. | Variable | Added | | --- | --- | | [Innodb\_buffer\_pool\_pages\_lru\_freed](../innodb-status-variables/index#innodb_buffer_pool_pages_lru_freed) | [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) | | [resultset\_metadata\_skipped](../server-status-variables/index#resultset_metadata_skipped) | [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) | See Also -------- * [System variables added in MariaDB 10.6](../system-variables-added-in-mariadb-106/index) * [Status variables added in MariaDB 10.5](../status-variables-added-in-mariadb-105/index) * [Status variables added in MariaDB 10.4](../status-variables-added-in-mariadb-104/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Thread States Thread States ============== Thread states can be viewed with the `STATE` values listed by the [SHOW PROCESSLIST](../show-processlist/index) statement or in the [Information Schema PROCESSLIST Table](../information-schema-processlist-table/index) as well as the `PROCESSLIST_STATE` value listed in the [Performance Schema threads Table](../performance-schema-threads-table/index). `Slave_IO_State` shown by [SHOW SLAVE STATUS](../show-slave-status/index) also shows slave-related thread states. | Title | Description | | --- | --- | | [Delayed Insert Connection Thread States](../delayed-insert-connection-thread-states/index) | Thread states related to the connection thread that processes INSERT DELAYED statements | | [Delayed Insert Handler Thread States](../delayed-insert-handler-thread-states/index) | Thread states related to the handler thread that inserts the results of INSERT DELAYED statements | | [Event Scheduler Thread States](../event-scheduler-thread-states/index) | Thread states related to the Event Scheduler | | [General Thread States](../general-thread-states/index) | Thread states | | [Master Thread States](../master-thread-states/index) | Thread states related to replication master threads | | [Query Cache Thread States](../query-cache-thread-states/index) | Thread states related to the query cache | | [Slave Connection Thread States](../slave-connection-thread-states/index) | Thread states related to slave connection threads | | [Slave I/O Thread States](../slave-io-thread-states/index) | Thread states related to replication slave I/O threads | | [Slave SQL Thread States](../slave-sql-thread-states/index) | Thread states related to replication slave SQL threads. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SLEEP SLEEP ===== Syntax ------ ``` SLEEP(duration) ``` Description ----------- Sleeps (pauses) for the number of seconds given by the duration argument, then returns `0`. If `SLEEP()` is interrupted, it returns `1`. The duration may have a fractional part given in microseconds. Statements using the SLEEP() function are not [safe for replication](../unsafe-statements-for-replication/index). Example ------- ``` SELECT SLEEP(5.5); +------------+ | SLEEP(5.5) | +------------+ | 0 | +------------+ 1 row in set (5.50 sec) ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mariadb-plugin mariadb-plugin ============== **MariaDB starting with [10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/)**From [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), `mariadb-plugin` is a symlink to `mysql_plugin`, the tool for enabling or disabling [plugins](../mariadb-plugins/index). **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), `mysql_plugin` is the symlink, and `mariadb-plugin` the binary name. See [mysql\_plugin](../mysql_plugin/index) for details. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb JSON_SEARCH JSON\_SEARCH ============ **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**JSON functions were added in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). Syntax ------ ``` JSON_SEARCH(json_doc, return_arg, search_str[, escape_char[, path] ...]) ``` Description ----------- Returns the path to the given string within a JSON document, or NULL if any of *json\_doc*, *search\_str* or a path argument is NULL; if the search string is not found, or if no path exists within the document. A warning will occur if the JSON document is not valid, any of the path arguments are not valid, if *return\_arg* is neither *one* nor *all*, or if the escape character is not a constant. NULL will be returned. *return\_arg* can be one of two values: * `'one`: Terminates after finding the first match, so will return one path string. If there is more than one match, it is undefined which is considered first. * `all`: Returns all matching path strings, without duplicates. Multiple strings are autowrapped as an array. The order is undefined. Examples -------- ``` SET @json = '["A", [{"B": "1"}], {"C":"AB"}, {"D":"BC"}]'; SELECT JSON_SEARCH(@json, 'one', 'AB'); +---------------------------------+ | JSON_SEARCH(@json, 'one', 'AB') | +---------------------------------+ | "$[2].C" | +---------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_SYS_COLUMNS Table Information Schema INNODB\_SYS\_COLUMNS Table ============================================= The [Information Schema](../information_schema/index) `INNODB_SYS_COLUMNS` table contains information about InnoDB fields. The `PROCESS` [privilege](../grant/index) is required to view the table. It has the following columns: | Column | Description | | --- | --- | | `TABLE_ID` | Table identifier, matching the value from [INNODB\_SYS\_TABLES.TABLE\_ID](../information-schema-innodb_sys_tables-table/index). | | `NAME` | Column name. | | `POS` | Ordinal position of the column in the table, starting from `0`. This value is adjusted when columns are added or removed. | | `MTYPE` | Numeric column type identifier, (see the table below for an explanation of its values). | | `PRTYPE` | Binary value of the InnoDB precise type, representing the data type, character set code and nullability. | | `LEN` | Column length. For multi-byte character sets, represents the length in bytes. | The column `MTYPE` uses a numeric column type identifier, which has the following values: | Column Type Identifier | Description | | --- | --- | | `1` | `[VARCHAR](../varchar/index)` | | `2` | `[CHAR](../char/index)` | | `3` | `FIXBINARY` | | `4` | `[BINARY](../binary/index)` | | `5` | `[BLOB](../blob/index)` | | `6` | `[INT](../int/index)` | | `7` | `SYS_CHILD` | | `8` | `SYS` | | `9` | `[FLOAT](../float/index)` | | `10` | `[DOUBLE](../double/index)` | | `11` | `[DECIMAL](../decimal/index)` | | `12` | `VARMYSQL` | | `13` | `MYSQL` | Example ------- ``` SELECT * FROM information_schema.INNODB_SYS_COLUMNS LIMIT 3\G *************************** 1. row *************************** TABLE_ID: 11 NAME: ID POS: 0 MTYPE: 1 PRTYPE: 524292 LEN: 0 *************************** 2. row *************************** TABLE_ID: 11 NAME: FOR_NAME POS: 0 MTYPE: 1 PRTYPE: 524292 LEN: 0 *************************** 3. row *************************** TABLE_ID: 11 NAME: REF_NAME POS: 0 MTYPE: 1 PRTYPE: 524292 LEN: 0 3 rows in set (0.00 sec) ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CREATE EVENT CREATE EVENT ============ Syntax ------ ``` CREATE [OR REPLACE] [DEFINER = { user | CURRENT_USER | role | CURRENT_ROLE }] EVENT [IF NOT EXISTS] event_name ON SCHEDULE schedule [ON COMPLETION [NOT] PRESERVE] [ENABLE | DISABLE | DISABLE ON SLAVE] [COMMENT 'comment'] DO sql_statement; schedule: AT timestamp [+ INTERVAL interval] ... | EVERY interval [STARTS timestamp [+ INTERVAL interval] ...] [ENDS timestamp [+ INTERVAL interval] ...] interval: quantity {YEAR | QUARTER | MONTH | DAY | HOUR | MINUTE | WEEK | SECOND | YEAR_MONTH | DAY_HOUR | DAY_MINUTE | DAY_SECOND | HOUR_MINUTE | HOUR_SECOND | MINUTE_SECOND} ``` Description ----------- This statement creates and schedules a new [event](../events/index). It requires the `[EVENT](../grant/index#database-privileges)` privilege for the schema in which the event is to be created. The minimum requirements for a valid CREATE EVENT statement are as follows: * The keywords `CREATE EVENT` plus an event name, which uniquely identifies the event in the current schema. (Prior to MySQL 5.1.12, the event name needed to be unique only among events created by the same user on a given database.) * An `ON SCHEDULE` clause, which determines when and how often the event executes. * A `DO` clause, which contains the SQL statement to be executed by an event. Here is an example of a minimal `CREATE EVENT` statement: ``` CREATE EVENT myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO UPDATE myschema.mytable SET mycol = mycol + 1; ``` The previous statement creates an event named myevent. This event executes once — one hour following its creation — by running an SQL statement that increments the value of the myschema.mytable table's mycol column by 1. The event\_name must be a valid MariaDB identifier with a maximum length of 64 characters. It may be delimited using back ticks, and may be qualified with the name of a database schema. An event is associated with both a MariaDB user (the definer) and a schema, and its name must be unique among names of events within that schema. In general, the rules governing event names are the same as those for names of stored routines. See [Identifier Names](../identifier-names/index). If no schema is indicated as part of event\_name, the default (current) schema is assumed. For valid identifiers to use as event names, see [Identifier Names](../identifier-names/index). #### OR REPLACE The `OR REPLACE` clause was included in [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/). If used and the event already exists, instead of an error being returned, the existing event will be dropped and replaced by the newly defined event. #### IF NOT EXISTS If the `IF NOT EXISTS` clause is used, MariaDB will return a warning instead of an error if the event already exists. Cannot be used together with OR REPLACE. #### ON SCHEDULE The `ON SCHEDULE` clause can be used to specify when the event must be triggered. #### AT If you want to execute the event only once (one time event), you can use the `AT` keyword, followed by a timestamp. If you use `[CURRENT\_TIMESTAMP](../current_timestamp/index)`, the event acts as soon as it is created. As a convenience, you can add one or more intervals to that timestamp. You can also specify a timestamp in the past, so that the event is stored but not triggered, until you modify it via [ALTER EVENT](../alter-event/index). The following example shows how to create an event that will be triggered tomorrow at a certain time: ``` CREATE EVENT example ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 DAY + INTERVAL 3 HOUR DO something; ``` You can also specify that an event must be triggered at a regular interval (recurring event). In such cases, use the `EVERY` clause followed by the interval. If an event is recurring, you can specify when the first execution must happen via the `STARTS` clause and a maximum time for the last execution via the `ENDS` clause. `STARTS` and `ENDS` clauses are followed by a timestamp and, optionally, one or more intervals. The `ENDS` clause can specify a timestamp in the past, so that the event is stored but not executed until you modify it via [ALTER EVENT](../alter-event/index). In the following example, next month a recurring event will be triggered hourly for a week: ``` CREATE EVENT example ON SCHEDULE EVERY 1 HOUR STARTS CURRENT_TIMESTAMP + INTERVAL 1 MONTH ENDS CURRENT_TIMESTAMP + INTERVAL 1 MONTH + INTERVAL 1 WEEK DO some_task; ``` Intervals consist of a quantity and a time unit. The time units are the same used for other staments and time functions, except that you can't use microseconds for events. For simple time units, like `HOUR` or `MINUTE`, the quantity is an integer number, for example '10 MINUTE'. For composite time units, like `HOUR_MINUTE` or `HOUR_SECOND`, the quantity must be a string with all involved simple values and their separators, for example '2:30' or '2:30:30'. #### ON COMPLETION [NOT] PRESERVE The `ON COMPLETION` clause can be used to specify if the event must be deleted after its last execution (that is, after its `AT` or `ENDS` timestamp is past). By default, events are dropped when they are expired. To explicitly state that this is the desired behaviour, you can use `ON COMPLETION NOT PRESERVE`. Instead, if you want the event to be preserved, you can use `ON COMPLETION PRESERVE`. In you specify `ON COMPLETION NOT PRESERVE`, and you specify a timestamp in the past for `AT` or `ENDS` clause, the event will be immediatly dropped. In such cases, you will get a Note 1558: "Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. The event was dropped immediately after creation". #### ENABLE/DISABLE/DISABLE ON SLAVE Events are `ENABLE`d by default. If you want to stop MariaDB from executing an event, you may specify `DISABLE`. When it is ready to be activated, you may enable it using `[ALTER EVENT](../alter-event/index)`. Another option is `DISABLE ON SLAVE`, which indicates that an event was created on a master and has been replicated to the slave, which is prevented from executing the event. If `DISABLE ON SLAVE` is specifically set, the event will be disabled everywhere. It will not be executed on the mater or the slaves. #### COMMENT The `COMMENT` clause may be used to set a comment for the event. Maximum length for comments is 64 characters. The comment is a string, so it must be quoted. To see events comments, you can query the [INFORMATION\_SCHEMA.EVENTS table](../information-schema-events-table/index) (the column is named `EVENT_COMMENT`). Examples -------- Minimal `CREATE EVENT` statement: ``` CREATE EVENT myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO UPDATE myschema.mytable SET mycol = mycol + 1; ``` An event that will be triggered tomorrow at a certain time: ``` CREATE EVENT example ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 DAY + INTERVAL 3 HOUR DO something; ``` Next month a recurring event will be triggered hourly for a week: ``` CREATE EVENT example ON SCHEDULE EVERY 1 HOUR STARTS CURRENT_TIMESTAMP + INTERVAL 1 MONTH ENDS CURRENT_TIMESTAMP + INTERVAL 1 MONTH + INTERVAL 1 WEEK DO some_task; ``` OR REPLACE and IF NOT EXISTS: ``` CREATE EVENT myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO UPDATE myschema.mytable SET mycol = mycol + 1; ERROR 1537 (HY000): Event 'myevent' already exists CREATE OR REPLACE EVENT myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO UPDATE myschema.mytable SET mycol = mycol + 1;; Query OK, 0 rows affected (0.00 sec) CREATE EVENT IF NOT EXISTS myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO UPDATE myschema.mytable SET mycol = mycol + 1; Query OK, 0 rows affected, 1 warning (0.00 sec) SHOW WARNINGS; +-------+------+--------------------------------+ | Level | Code | Message | +-------+------+--------------------------------+ | Note | 1537 | Event 'myevent' already exists | +-------+------+--------------------------------+ ``` See Also -------- * [Event Limitations](../event-limitations/index) * [Identifier Names](../identifier-names/index) * [Events Overview](../events-overview/index) * [SHOW CREATE EVENT](../show-create-event/index) * [ALTER EVENT](../alter-event/index) * [DROP EVENT](../drop-event/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mariadb Command-Line Client mariadb Command-Line Client =========================== **MariaDB starting with [10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/)**From [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), `mariadb` is a symlink to `mysql`, the command-line client. See [mysql Command-Line Client](../mysql-command-line-client/index) for details. **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), `mariadb` is the name of the command-line client, with `mysql` a symlink . Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Plugin SQL Statements Plugin SQL Statements ====================== [Plugin](../plugin-overview/index) commands. | Title | Description | | --- | --- | | [SHOW PLUGINS](../show-plugins/index) | Display information about installed plugins. | | [SHOW PLUGINS SONAME](../show-plugins-soname/index) | Information about all available plugins, installed or not. | | [INSTALL PLUGIN](../install-plugin/index) | Install a plugin. | | [UNINSTALL PLUGIN](../uninstall-plugin/index) | Remove a single installed plugin. | | [INSTALL SONAME](../install-soname/index) | Installs all plugins from a given library. | | [UNINSTALL SONAME](../uninstall-soname/index) | Remove all plugins belonging to a specified library. | | [mysql\_plugin](../mysql_plugin/index) | Tool for enabling or disabling plugins. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema user_variables_by_thread Table Performance Schema user\_variables\_by\_thread Table ==================================================== **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**The `user_variables_by_thread` table was added in [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). The `user_variables_by_thread` table contains information about [user-defined variables](../user-defined-variables/index) and the threads that defined them. [TRUNCATE TABLE](../truncate-table/index) cannot be performed on the table. The table contains the following columns: | Column | Description | | --- | --- | | THREAD\_ID | The thread identifier of the session in which the variable is defined. | | VARIABLE\_NAME | The variable name, without the leading @ character. | | VARIABLE\_VALUE | The variable value | Example ------- ``` SET @var = 0; SELECT * FROM user_variables_by_thread; +-----------+---------------+----------------+ | THREAD_ID | VARIABLE_NAME | VARIABLE_VALUE | +-----------+---------------+----------------+ | 11 | var | 0 | +-----------+---------------+----------------+ ``` See Also -------- * [User-defined variables](../user-defined-variables/index) * [Information Schema USER\_VARIABLES Table](../information-schema-user_variables-table/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Enabling Core Dumps Enabling Core Dumps =================== Enabling in an Option File -------------------------- **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, core dumps are enabled by default on **Windows**, so **this step can be skipped on Windows** in those versions. See [MDEV-18439](https://jira.mariadb.org/browse/MDEV-18439) for more information. In order to enable core dumps, you need to set the `[core\_file](../server-system-variables/index#core_file)` system variable either on the command-line or in a relevant server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [mariadb] ... core_file ``` You can check your current value by executing: ``` my_print_defaults --mysqld ``` **MariaDB starting with [10.1.35](https://mariadb.com/kb/en/mariadb-10135-release-notes/)**In [MariaDB 10.1.35](https://mariadb.com/kb/en/mariadb-10135-release-notes/), [MariaDB 10.2.17](https://mariadb.com/kb/en/mariadb-10217-release-notes/), and [MariaDB 10.3.9](https://mariadb.com/kb/en/mariadb-1039-release-notes/) and later, `[core\_file](../server-system-variables/index#core_file)` has also been made into a system variable. Previously it was just an option. It's value can be checked at runtime by executing the following: ``` SHOW GLOBAL VARIABLES LIKE 'core_file'; ``` Core Files on Linux ------------------- There are some additional details related to using core files on Linux. ### Disabling Core File Size Restrictions on Linux On some systems there is a limit on the sizes of core files that can be dumped. You can check the system's current system-wide limit by executing the following: ``` ulimit -c ``` You can check the current limit of the `mysqld` process specifically by executing the following: ``` sudo cat /proc/$(pidof mysqld)/limits | grep "core file" ``` If you need to change the core size limit, the method you use depends on how you start `mysqld`. See the sections below for more details. **MariaDB starting with [10.2.24](https://mariadb.com/kb/en/mariadb-10224-release-notes/)**In [MariaDB 10.2.24](https://mariadb.com/kb/en/mariadb-10224-release-notes/), [MariaDB 10.3.15](https://mariadb.com/kb/en/mariadb-10315-release-notes/), and [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/) and later, the resource limits for the `mysqld` process are printed to the [error log](../error-log/index) when the `mysqld` process crashes. That way, users can confirm whether the process may have been allowed to dump a core file. See [MDEV-15051](https://jira.mariadb.org/browse/MDEV-15051) for more information. #### Running mysqld Using mysqld\_safe If you are starting MariaDB by running `[mysqld\_safe](../mysqld_safe/index)`, then configuring the following in the `[mysqld_safe]` option group in an option file should allow for unlimited sized core files: ``` [mysqld_safe] ... core_file_size=unlimited ``` You can check your current values by executing: ``` my_print_defaults mysqld_safe ``` See [mysqld\_safe: Configuring the Core File Size](../mysqld_safe/index#configuring-the-core-file-size) for more details. **Note:** If you are using `[mysqld\_safe](../mysqld_safe/index)` and running `mysqld` as the `root` user, then no core file is created on some systems. The solution is to run `mysqld` as another user. #### Running mysqld Manually If you are starting mysqld manually or in a custom script, then you can allow for unlimited sized core files by executing the following in the same shell or script in which mysqld is executed: ``` ulimit -c unlimited ``` #### Running mysqld Using systemd If you are starting `mysqld` using `[systemd](../systemd/index)`, then you may need to customize the MariaDB service to allow for unlimited size core files. For example, you could execute the following: Using `sudo systemctl edit mariadb.service` add the contents: ``` [Service] LimitCORE=infinity ``` See [systemd: Configuring the Core File Size](../systemd/index#configuring-the-core-file-size) for more details. #### Changing the System-Wide Limit If you want to change the system-wide limit to allow for unlimited size core files for for the `mysql` user account, then you can do so by adding the following lines to a file in `[/etc/security/limits.d/](https://linux.die.net/man/5/limits.conf)`. For example: ``` sudo tee /etc/security/limits.d/mariadb_core.conf <<EOF mysql soft core unlimited mysql hard core unlimited EOF ``` The system would have to be restarted for this change to take effect. See [Configuring Linux for MariaDB: Configuring the Core File Size](../configuring-linux-for-mariadb/index#configuring-the-core-file-size) for more details. ### Setting the Path on Linux If you are using Linux, then it can be helpful to change a few settings to alter where the core files is written and what file name is used. This is done by setting the `kernel.core_pattern` and `kernel.core_uses_pid` attributes. You can check the current values by executing the following: ``` sysctl kernel.core_pattern sysctl kernel.core_uses_pid ``` If you are using `mysql-test-run` and want to have the core as part of the test result, the optimal setting is probably the following (store cores in the current directory as `core.number-of-process-id`): ``` sudo sysctl kernel.core_pattern=core.%p kernel.core_uses_pid=0 ``` If you are using a production system, you probably want to have the core files in a specific directory, not in the data directory. They place to store cores can be temporarily altered using the `[sysctl](https://linux.die.net/man/8/sysctl)` utility, but it is often more common to alter them via the `[/proc](https://linux.die.net/man/5/proc)` file system. See the following example: ``` sudo mkdir /tmp/corefiles sudo chmod 777 /tmp/corefiles sudo echo /tmp/corefiles/core > /proc/sys/kernel/core_pattern sudo echo 1 > /proc/sys/kernel/core_uses_pid ``` The above commands will tell the system to put core files in `/tmp/corefiles`, and it also tells the system to put the process ID in the file name. If you want to make these changes permanent, then you can add the following to a file in `[/etc/sysctl.conf.d/](https://linux.die.net/man/5/sysctl.conf)`. For example: ``` sudo tee /etc/sysctl.d/mariadb_core.conf <<EOF kernel.core_pattern=/tmp/corefiles/core kernel.core_uses_pid=1 EOF ``` **MariaDB starting with [10.2.24](https://mariadb.com/kb/en/mariadb-10224-release-notes/)**In [MariaDB 10.2.24](https://mariadb.com/kb/en/mariadb-10224-release-notes/), [MariaDB 10.3.15](https://mariadb.com/kb/en/mariadb-10315-release-notes/), and [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/) and later, the value of `kernel.core_pattern` is printed to the [error log](../error-log/index) when the `mysqld` process crashes. That way, users can determine where the process may have dumped a core file. See [MDEV-15051](https://jira.mariadb.org/browse/MDEV-15051) for more information. **MariaDB until [10.2.23](https://mariadb.com/kb/en/mariadb-10223-release-notes/)**In [MariaDB 10.2.23](https://mariadb.com/kb/en/mariadb-10223-release-notes/), [MariaDB 10.3.14](https://mariadb.com/kb/en/mariadb-10314-release-notes/), and [MariaDB 10.4.4](https://mariadb.com/kb/en/mariadb-1044-release-notes/) and before, the [error log](../error-log/index) contains a message indicating that a core file would be written in the `[datadir](../server-system-variables/index#datadir)` when the `mysqld` process crashes, even if this was not true because the `kernel.core_pattern` actually configured the process to write the core file in a different directory. **Note:** Ensure that you have enough free disk space in the path pointed to by `kernel.core_pattern`. #### Extracting Linux core dumps with systemd-coredump Core dump management can be automated using `[coredumpctl](#)` utility. This is enabled per default on RedHat Enterprise Linux 8 and CentOS 8, and maybe other contemporary Linux distribution releases by now, too. It can be easily checked for by looking at the `kernel.core_pattern setting`. If it looks like this systemd-coredump is enabled: ``` # sysctl kernel.core_pattern kernel.core_pattern = |/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h %e ``` On other distributions like Ubuntu (at least up to 21.10) it is not enabled by default, but can be set up manually. To see all recent core dumps on the system you can then simply run ``` # coredumpctl list ``` Or you can check for MariaDB Server core dumps specifically with: ``` # coredumpctl list /usr/sbin/mariadbd ``` If an actual core file got stored you'll see `present` in the COREFILE column of the output, you can then extract the core file with: ``` # coredump dump -o mariadbd.core ...PID... ``` using the process id number from the PID column, or when you just want to retrieve the latest MariaDB Server related entry: ``` # coredump dump -o mariadb.core /usr/sbin/mariadbd ``` Starting with `systemd` 248 it is also possible to invoke the `gdb` debugger directly using the new `--debugger-arguments=...` option, e.g. making the extraction of all thread backtraces from the most recent MariaDB server crash a one liner without even having to extract the core dump file first (requires `gdb` to be installed): ``` # coredumpctl debug --debugger-arguments="-batch -ex 'thread apply all bt full'" /usr/sbin/mariadbd ``` So far none of the long term support Linux distribution releases have a new enough `systemd` version for this, the (as of this writing) still upcoming Ubuntu 22.04 "Jammy Jellyfish" will probably the first to support this. ### Core Dumps and setuid on Linux Since `mysqld` executes `[setuid](https://linux.die.net/man/2/setuid)`, you may have to set `fs.suid_dumpable=2` to allow core dumps on Linux. You can check the current `fs.suid_dumpable` value by using the `[sysctl](https://linux.die.net/man/8/sysctl)` utility. For example: ``` sysctl fs.suid_dumpable ``` You can temporarily set it to `2` by using the `[sysctl](https://linux.die.net/man/8/sysctl)` utility. For example: ``` sudo sysctl -w fs.suid_dumpable=2 ``` Or you can temporarily set it to `2` by writing to the `[/proc](https://linux.die.net/man/5/proc)` file system. For example: ``` sudo echo 2 > /proc/sys/fs/suid_dumpable ``` If you want to permanently set it to `2` then you can add the following to a file in `[/etc/sysctl.conf.d/](https://linux.die.net/man/5/sysctl.conf)`: ``` sudo tee /etc/sysctl.d/mariadb_fs_suid_dumpable.conf <<EOF fs.suid_dumpable=2 EOF ``` **Note:** If you don't want to change `fs.suid_dumpable`, then another solution is to start `mysqld` directly as the `mysql` user, so that the `[setuid](https://linux.die.net/man/2/setuid)` call is not needed. ### Forcing a Core File on Linux To force a core file for `mysqld` you can send the process the `sigabrt` signal, which has the signal code `6`. This is very useful to get the state of the unresponsive `mysqld` process. However, this will cause `mysqld` to crash, and crash recovery will be run on restart. You can send the signal with the `[kill](https://linux.die.net/man/1/kill)` command. For example: ``` sudo kill -6 $(pidof mysqld) ``` As an alternative to `$(pidof mysqld)`, you can find the process ID either by using the `[ps](https://linux.die.net/man/1/ps)` utility or by checking the file defined by the `[pid\_file](../server-system-variables/index#pid_file)` system variable. Core Files on Windows --------------------- In [MariaDB 10.4](../what-is-mariadb-104/index) and later, core dumps are enabled by default on Windows. See [MDEV-18439](https://jira.mariadb.org/browse/MDEV-18439) for more information. There are some additional details related to using core files on Windows. ### Minidump Files on Windows On Windows, the core file is created as a [minidump file](https://docs.microsoft.com/en-us/windows/desktop/debug/minidump-files). For details on how to configure and read the [minidump file](https://docs.microsoft.com/en-us/windows/desktop/debug/minidump-files), see [How to read the small memory dump file that is created by Windows if a crash occurs](https://support.microsoft.com/en-us/help/315263/how-to-read-the-small-memory-dump-file-that-is-created-by-windows-if-a). Core Files and Address Sanitizer (ASAN) --------------------------------------- If your `mysqld` binary is built with [Address Sanitizer (ASAN)](../how-to-compile-and-use-mariadb-with-addresssanitizer-asan/index) then it will not be able to generate a core file. What's Included in Core Files ----------------------------- Core files usually contain a dump of all memory in the process's full address space. This means that if a server has some large buffers configured (such as a large [InnoDB buffer pool](../xtradbinnodb-buffer-pool/index)), then the server's core files can get very large. However, in [MariaDB 10.3.7](https://mariadb.com/kb/en/mariadb-1037-release-notes/) and later, some large buffers have been excluded from core files on some systems as a way to reduce the size. The following buffers are excluded: * [InnoDB buffer pool](../xtradbinnodb-buffer-pool/index) * [InnoDB log buffer](../innodb-system-variables/index#innodb_log_buffer_size) * InnoDB Redo log buffer (fixed 2M) * [Query cache](../query-cache/index) The buffers are only excluded on Linux when using kernel version 3.4 and above and when using a non-debug build of `mysqld`. Some Linux kernel versions have a [bug](https://lists.launchpad.net/maria-discuss/msg05245.html) which would cause the following warning to be printed to the log: ``` Sep 25 10:41:19 srv1 mysqld: 2018-09-25 10:41:19 0 [Warning] InnoDB: Failed to set memory to DODUMP: Invalid argument ptr 0x2aaac3400000 size 33554432 ``` In those cases, the core dump may exclude some additional data. If that is not a concern, then the warning can be ignored. The problem can be fixed by upgrading to a Linux kernel version in which the bug is fixed. See Also -------- * [How to Produce a Full Stack Trace for mysqld](../how-to-produce-a-full-stack-trace-for-mysqld/index) * [HowTo: Debug Crashed Linux Application Core Files Like A Pro](http://www.cyberciti.biz/tips/linux-core-dumps.html) * [A Nice Feature in MariaDB 10.3: no InnoDB Buffer Pool in Core Dumps](https://www.percona.com/community-blog/2018/06/28/nice-feature-in-mariadb-103-no-innodb-buffer-pool-in-coredumps/) * [Getting MySQL Core file on Linux](https://www.percona.com/blog/2011/08/26/getting-mysql-core-file-on-linux/) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MASTER_POS_WAIT MASTER\_POS\_WAIT ================= Syntax ------ ``` MASTER_POS_WAIT(log_name,log_pos[,timeout,["connection_name"]]) ``` Description ----------- This function is useful in [replication](../replication/index) for controlling primary/replica synchronization. It blocks until the replica has read and applied all updates up to the specified position (`log_name,log_pos`) in the primary log. The return value is the number of log events the replica had to wait for to advance to the specified position. The function returns NULL if the replica SQL thread is not started, the replica's primary information is not initialized, the arguments are incorrect, or an error occurs. It returns -1 if the timeout has been exceeded. If the replica SQL thread stops while `MASTER_POS_WAIT()` is waiting, the function returns NULL. If the replica is past the specified position, the function returns immediately. If a `timeout` value is specified, `MASTER_POS_WAIT()` stops waiting when `timeout` seconds have elapsed. `timeout` must be greater than 0; a zero or negative `timeout` means no `timeout`. The `connection_name` is used when you are using [multi-source-replication](../multi-source-replication/index). If you don't specify it, it's set to the value of the [default\_master\_connection](../replication-and-binary-log-server-system-variables/index#default_master_connection) system variable. Statements using the MASTER\_POS\_WAIT() function are not [safe for replication](../unsafe-statements-for-replication/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CENTROID CENTROID ======== A synonym for [ST\_CENTROID](../st_centroid/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CAST CAST ==== Syntax ------ ``` CAST(expr AS type) ``` Description ----------- The `CAST()` function takes a value of one [type](../data-types/index) and produces a value of another type, similar to the [CONVERT()](../convert/index) function. The type can be one of the following values: * [BINARY](../binary/index) * [CHAR](../char/index) * [DATE](../date/index) * [DATETIME](../datetime/index) * [DECIMAL[(M[,D])](../decimal/index)] * [DOUBLE](../double/index) * [FLOAT](../float/index) (from [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/)) * [INTEGER](../int/index) + Short for `SIGNED INTEGER` * SIGNED [INTEGER] * UNSIGNED [INTEGER] * [TIME](../time/index) * [VARCHAR](../varchar/index) (in [Oracle mode](../sql_modeoracle/index), from [MariaDB 10.3](../what-is-mariadb-103/index)) The main difference between `CAST` and [CONVERT()](../convert/index) is that `[CONVERT(expr,type)](../convert/index)` is ODBC syntax while `CAST(expr as type)` and `[CONVERT(... USING ...)](../convert/index)` are SQL92 syntax. In [MariaDB 10.4](../what-is-mariadb-104/index) and later, you can use the `CAST()` function with the `INTERVAL` keyword. Until [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), `X'HHHH'`, the standard SQL syntax for binary string literals, erroneously worked in the same way as `0xHHHH`. In 5.5.31 it was intentionally changed to behave as a string in all contexts (and never as a number). This introduced an incompatibility with previous versions of MariaDB, and all versions of MySQL (see the example below). Examples -------- Simple casts: ``` SELECT CAST("abc" AS BINARY); SELECT CAST("1" AS UNSIGNED INTEGER); SELECT CAST(123 AS CHAR CHARACTER SET utf8) ``` Note that when one casts to [CHAR](../char/index) without specifying the character set, the [collation\_connection](../server-system-variables/index#collation_connection) character set collation will be used. When used with `CHAR CHARACTER SET`, the default collation for that character set will be used. ``` SELECT COLLATION(CAST(123 AS CHAR)); +------------------------------+ | COLLATION(CAST(123 AS CHAR)) | +------------------------------+ | latin1_swedish_ci | +------------------------------+ SELECT COLLATION(CAST(123 AS CHAR CHARACTER SET utf8)); +-------------------------------------------------+ | COLLATION(CAST(123 AS CHAR CHARACTER SET utf8)) | +-------------------------------------------------+ | utf8_general_ci | +-------------------------------------------------+ ``` If you also want to change the collation, you have to use the `COLLATE` operator: ``` SELECT COLLATION(CAST(123 AS CHAR CHARACTER SET utf8) COLLATE utf8_unicode_ci); +-------------------------------------------------------------------------+ | COLLATION(CAST(123 AS CHAR CHARACTER SET utf8) COLLATE utf8_unicode_ci) | +-------------------------------------------------------------------------+ | utf8_unicode_ci | +-------------------------------------------------------------------------+ ``` Using `CAST()` to order an `[ENUM](../enum/index)` field as a `[CHAR](../char/index)` rather than the internal numerical value: ``` CREATE TABLE enum_list (enum_field enum('c','a','b')); INSERT INTO enum_list (enum_field) VALUES('c'),('a'),('c'),('b'); SELECT * FROM enum_list ORDER BY enum_field; +------------+ | enum_field | +------------+ | c | | c | | a | | b | +------------+ SELECT * FROM enum_list ORDER BY CAST(enum_field AS CHAR); +------------+ | enum_field | +------------+ | a | | b | | c | | c | +------------+ ``` From [MariaDB 5.5.31](https://mariadb.com/kb/en/mariadb-5531-release-notes/), the following will trigger warnings, since `x'aa'` and `'X'aa'` no longer behave as a number. Previously, and in all versions of MySQL, no warnings are triggered since they did erroneously behave as a number: ``` SELECT CAST(0xAA AS UNSIGNED), CAST(x'aa' AS UNSIGNED), CAST(X'aa' AS UNSIGNED); +------------------------+-------------------------+-------------------------+ | CAST(0xAA AS UNSIGNED) | CAST(x'aa' AS UNSIGNED) | CAST(X'aa' AS UNSIGNED) | +------------------------+-------------------------+-------------------------+ | 170 | 0 | 0 | +------------------------+-------------------------+-------------------------+ 1 row in set, 2 warnings (0.00 sec) Warning (Code 1292): Truncated incorrect INTEGER value: '\xAA' Warning (Code 1292): Truncated incorrect INTEGER value: '\xAA' ``` Casting to intervals: ``` SELECT CAST(2019-01-04 INTERVAL AS DAY_SECOND(2)) AS "Cast"; +-------------+ | Cast | +-------------+ | 00:20:17.00 | +-------------+ ``` See Also -------- * [Supported data types](../data-types/index) * [Microseconds in MariaDB](../microseconds-in-mariadb/index) * [String literals](../string-literals/index) * [COLLATION()](../collation/index) * [CONVERT()](../convert/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb EXPLAIN Analyzer API EXPLAIN Analyzer API ==================== The online [EXPLAIN Analyzer](../explain-analyzer/index) tool has an open API to allow client applications to send it EXPLAINs. Sending EXPLAINs to the EXPLAIN Analyzer ---------------------------------------- To send an EXPLAIN to the EXPLAIN Analyzer, simply POST or GET to the following address: ``` mariadb.org/explain_analyzer/api/1/?raw_explain=EXPLAIN&client=CLIENT ``` Replace "EXPLAIN" with the output of the EXPLAIN command and "CLIENT" with the name of your client. Client Banner ------------- If you like, you can have a banner promoting your client appear at the bottom of the page. Once you've added support for the EXPLAIN Analyzer to your client application, just send a logo, the name of your client, and what you want the name and logo to link to to bryan AT montyprogram DOT com Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Table Elimination in Other Databases Table Elimination in Other Databases ==================================== In addition to MariaDB, Table Elimination is found in both Microsoft SQL Server 2005/2008 and Oracle 11g. Of the two, Microsoft SQL Server 2005/2008 seems to have the most advanced implementation. Oracle 11g has been confirmed to use table elimination but not to the same extent. To compare the two, we will look at the following query: ``` select A.colA from tableA A left outer join tableB B on B.id = A.id; ``` When using A as the left table we ensure that the query will return at least as many rows as there are in that table. For rows where the join condition (B.id = A.id) is not met the selected column (A.colA) will still contain its original value. The not seen B.\* row would contain all NULL:s. However, the result set could actually contain more rows than what is found in tableA if there are duplicates of the column B.id in tableB. If A contains a row [1, "val1"] and B the rows [1, "other1a"],[1, "other1b"] then two rows will match in the join condition. The only way to know what the result will look like is to actually touch both tables during execution. Instead, let's say tableB contains rows that make it possible to place a unique constraint on the column B.id, for example, which is often the case with a primary key. In this situation we know that we will get exactly as many rows as there are in tableA, since joining with tableB cannot introduce any duplicates. Furthermore, as in the example query, if we do not select any columns from tableB, touching that table during execution is unnecessary. We can remove the whole join operation from the execution plan. Both SQL Server 2005/2008 and Oracle 11g deploy table elimination in the case described above. Let us look at a more advanced query, where Oracle fails. ``` select A.colA from tableA A left outer join tableB B on B.id = A.id and B.fromDate = ( select max(sub.fromDate) from tableB sub where sub.id = A.id ); ``` In this example we have added another join condition, which ensures that we only pick the matching row from tableB having the latest fromDate. In this case tableB will contain duplicates of the column B.id, so in order to ensure uniqueness the primary key has to contain the fromDate column as well. In other words the primary key of tableB is (B.id, B.fromDate). Furthermore, since the subselect ensures that we only pick the latest B.fromDate for a given B.id we know that at most one row will match the join condition. We will again have the situation where joining with tableB cannot affect the number of rows in the result set. Since we do not select any columns from tableB, the whole join operation can be eliminated from the execution plan. SQL Server 2005/2008 will deploy table elimination in this situation as well. We have not found a way to make Oracle 11g use it for this type of query. Queries like these arise in two situations. Either when you have a denormalized model consisting of a fact table with several related dimension tables, or when you have a highly normalized model where each attribute is stored in its own table. The example with the subselect is common whenever you store historized/versioned data. See Also -------- * This page is based on the following blog post about table elimination: <http://s.petrunia.net/blog/?p=58> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema Tables Performance Schema Tables ========================== Tables that are part of the [MariaDB Performance Schema](../performance-schema/index), a feature for monitoring the performance of MariaDB server. | Title | Description | | --- | --- | | [List of Performance Schema Tables](../list-of-performance-schema-tables/index) | List and short description of all performance\_schema tables. | | [Performance Schema accounts Table](../performance-schema-accounts-table/index) | Account connection information. | | [Performance Schema cond\_instances Table](../performance-schema-cond_instances-table/index) | List of instrumented condition objects. | | [Performance Schema events\_stages\_current Table](../performance-schema-events_stages_current-table/index) | Current stage events. | | [Performance Schema events\_stages\_history Table](../performance-schema-events_stages_history-table/index) | Most recent stage events per thread. | | [Performance Schema events\_stages\_history\_long Table](../performance-schema-events_stages_history_long-table/index) | Most recent completed stage events. | | [Performance Schema events\_stages\_summary\_by\_account\_by\_event\_name Table](../performance-schema-events_stages_summary_by_account_by_event_name-table/index) | Stage events, summarized by account and event name. | | [Performance Schema events\_stages\_summary\_by\_host\_by\_event\_name Table](../performance-schema-events_stages_summary_by_host_by_event_name-table/index) | Stage events summarized by host and event name. | | [Performance Schema events\_stages\_summary\_by\_thread\_by\_event\_name Table](../performance-schema-events_stages_summary_by_thread_by_event_name-table/index) | Stage events summarized by thread and event name. | | [Performance Schema events\_stages\_summary\_by\_user\_by\_event\_name Table](../performance-schema-events_stages_summary_by_user_by_event_name-table/index) | Stage events summarized by user and event name. | | [Performance Schema events\_stages\_summary\_global\_by\_event\_name Table](../performance-schema-events_stages_summary_global_by_event_name-table/index) | Event summaries. | | [Performance Schema events\_statements\_current Table](../performance-schema-events_statements_current-table/index) | Current statement events. | | [Performance Schema events\_statements\_history Table](../performance-schema-events_statements_history-table/index) | Most recent statement events per thread | | [Performance Schema events\_statements\_history\_long Table](../performance-schema-events_statements_history_long-table/index) | Most recent statement events. | | [Performance Schema events\_statements\_summary\_by\_account\_by\_event\_name Table](../performance-schema-events_statements_summary_by_account_by_event_name-table/index) | Statement events summarized by account and event name. | | [Performance Schema events\_statements\_summary\_by\_digest Table](../performance-schema-events_statements_summary_by_digest-table/index) | Statement events summarized by schema and digest. | | [Performance Schema events\_statements\_summary\_by\_host\_by\_event\_name Table](../performance-schema-events_statements_summary_by_host_by_event_name-table/index) | Statement events summarized by host and event name. | | [Performance Schema events\_statements\_summary\_by\_program Table](../performance-schema-events_statements_summary_by_program-table/index) | Summarizes events for a particular stored program. | | [Performance Schema events\_statements\_summary\_by\_thread\_by\_event\_name Table](../performance-schema-events_statements_summary_by_thread_by_event_name-table/index) | Statement events summarized by thread and event name. | | [Performance Schema events\_statements\_summary\_by\_user\_by\_event\_name Table](../performance-schema-events_statements_summary_by_user_by_event_name-table/index) | Statement events summarized by user and event name. | | [Performance Schema events\_statements\_summary\_global\_by\_event\_name Table](../performance-schema-events_statements_summary_global_by_event_name-table/index) | Statement events summarized by event name. | | [Performance Schema events\_transactions\_current Table](../performance-schema-events_transactions_current-table/index) | Current transaction events for each thread. | | [Performance Schema events\_transactions\_history Table](../performance-schema-events_transactions_history-table/index) | Most recent completed transaction events for each thread. | | [Performance Schema events\_transactions\_history\_long Table](../performance-schema-events_transactions_history_long-table/index) | Most recent completed transaction events that have ended globally. | | [Performance Schema events\_transactions\_summary\_by\_account\_by\_event\_name Table](../performance-schema-tables-performance-schema-events_transactions_summary_by/index) | Transaction events aggregated by account and event name. | | [Performance Schema events\_transactions\_summary\_by\_host\_by\_event\_name Table](../performance-schema-events_transactions_summary_by_host_by_event_name-table/index) | Transaction events aggregated by host and event name. | | [Performance Schema events\_transactions\_summary\_by\_thread\_by\_event\_name Table](../performance-schema-events_transactions_summary_by_thread_by_event_name-tabl/index) | Transaction events aggregated by thread and event name. | | [Performance Schema events\_transactions\_summary\_by\_user\_by\_event\_name Table](../performance-schema-events_transactions_summary_by_user_by_event_name-table/index) | Transaction events aggregated by user and event name. | | [Performance Schema events\_transactions\_summary\_global\_by\_event\_name Table](../performance-schema-events_transactions_summary_global_by_event_name-table/index) | Transaction events aggregated by event name. | | [Performance Schema events\_waits\_current Table](../performance-schema-events_waits_current-table/index) | Current wait events | | [Performance Schema events\_waits\_history Table](../performance-schema-events_waits_history-table/index) | Most recent wait events per thread | | [Performance Schema events\_waits\_history\_long Table](../performance-schema-events_waits_history_long-table/index) | Most recent completed wait events | | [Performance Schema events\_waits\_summary\_by\_account\_by\_event\_name Table](../performance-schema-events_waits_summary_by_account_by_event_name-table/index) | Wait events summarized by account and event name. | | [Performance Schema events\_waits\_summary\_by\_host\_by\_event\_name Table](../performance-schema-events_waits_summary_by_host_by_event_name-table/index) | Wait events summarized by host and event name. | | [Performance Schema events\_waits\_summary\_by\_instance Table](../performance-schema-events_waits_summary_by_instance-table/index) | Wait events summarized by instance | | [Performance Schema events\_waits\_summary\_by\_thread\_by\_event\_name Table](../performance-schema-events_waits_summary_by_thread_by_event_name-table/index) | Wait events summarized by thread and event name. | | [Performance Schema events\_waits\_summary\_by\_user\_by\_event\_name Table](../performance-schema-events_waits_summary_by_user_by_event_name-table/index) | Wait events summarized by user and event name. | | [Performance Schema events\_waits\_summary\_global\_by\_event\_name Table](../performance-schema-events_waits_summary_global_by_event_name-table/index) | Wait events summarized by event name. | | [Performance Schema file\_instances Table](../performance-schema-file_instances-table/index) | List of file instruments. | | [Performance Schema file\_summary\_by\_event\_name Table](../performance-schema-file_summary_by_event_name-table/index) | File events summarized by event name. | | [Performance Schema file\_summary\_by\_instance Table](../performance-schema-file_summary_by_instance-table/index) | File events summarized by instance. | | [Performance Schema global\_status Table](../performance-schema-global_status-table/index) | Status variables and their global values. | | [Performance Schema hosts Table](../performance-schema-hosts-table/index) | Hosts used to connect to the server. | | [Performance Schema host\_cache Table](../performance-schema-host_cache-table/index) | Host\_cache information. | | [Performance Schema memory\_summary\_by\_account\_by\_event\_name Table](../performance-schema-memory_summary_by_account_by_event_name-table/index) | Memory usage statistics aggregated by account and event. | | [Performance Schema memory\_summary\_by\_host\_by\_event\_name Table](../performance-schema-memory_summary_by_host_by_event_name-table/index) | Memory usage statistics aggregated by host and event. | | [Performance Schema memory\_summary\_by\_thread\_by\_event\_name Table](../performance-schema-memory_summary_by_thread_by_event_name-table/index) | Memory usage statistics aggregated by thread and event. | | [Performance Schema memory\_summary\_by\_user\_by\_event\_name Table](../performance-schema-memory_summary_by_user_by_event_name-table/index) | Memory usage statistics aggregated by user and event. | | [Performance Schema memory\_summary\_global\_by\_event\_name Table](../performance-schema-memory_summary_global_by_event_name-table/index) | Memory usage statistics aggregated by event and event. | | [Performance Schema metadata\_locks Table](../performance-schema-metadata_locks-table/index) | Metadata lock information. | | [Performance Schema mutex\_instances Table](../performance-schema-mutex_instances-table/index) | Seen mutexes | | [Performance Schema objects\_summary\_global\_by\_type Table](../performance-schema-objects_summary_global_by_type-table/index) | Aggregates object wait events. | | [Performance Schema performance\_timers Table](../performance-schema-performance_timers-table/index) | Available event timers | | [Performance Schema prepared\_statements\_instances Table](../performance-schema-prepared_statements_instances-table/index) | Aggregated statistics of prepared statements. | | [Performance Schema replication\_applier\_configuration Table](../performance-schema-replication_applier_configuration-table/index) | Configuration settings affecting replica transactions. | | [Performance Schema replication\_applier\_status Table](../performance-schema-replication_applier_status-table/index) | Information about the general transaction execution status on the slave. | | [Performance Schema replication\_applier\_status\_by\_coordinator Table](../performance-schema-replication_applier_status_by_coordinator-table/index) | Coordinator thread status used in multi-threaded replicas to manage multiple workers. | | [Performance Schema replication\_applier\_status\_by\_worker Table](../performance-schema-replication_applier_status_by_worker-table/index) | Slave worker thread specific information. | | [Performance Schema replication\_connection\_configuration Table](../performance-schema-replication_connection_configuration-table/index) | Replica configuration settings used for connecting to the primary. | | [Performance Schema rwlock\_instances Table](../performance-schema-rwlock_instances-table/index) | Seen read-write locks | | [Performance Schema session\_account\_connect\_attrs Table](../performance-schema-session_account_connect_attrs-table/index) | Connection attributes for the current session. | | [Performance Schema session\_connect\_attrs Table](../performance-schema-session_connect_attrs-table/index) | Connection attributes for all sessions. | | [Performance Schema session\_status Table](../performance-schema-session_status-table/index) | Status variables and their session values. | | [Performance Schema setup\_actors Table](../performance-schema-setup_actors-table/index) | Determines whether monitoring is enabled for host/user combinations. | | [Performance Schema setup\_consumers Table](../performance-schema-setup_consumers-table/index) | Lists the types of consumers for which event information is available. | | [Performance Schema setup\_instruments Table](../performance-schema-setup_instruments-table/index) | List of instrumented object classes | | [Performance Schema setup\_objects Table](../performance-schema-setup_objects-table/index) | Which objects are monitored. | | [Performance Schema setup\_timers Table](../performance-schema-setup_timers-table/index) | Currently selected event timers | | [Performance Schema socket\_instances Table](../performance-schema-socket_instances-table/index) | Active server connections. | | [Performance Schema socket\_summary\_by\_event\_name Table](../performance-schema-socket_summary_by_event_name-table/index) | Aggregates timer and byte count statistics for all socket I/O operations by socket instrument. | | [Performance Schema socket\_summary\_by\_instance Table](../performance-schema-socket_summary_by_instance-table/index) | Aggregates timer and byte count statistics for all socket I/O operations by socket instance. | | [Performance Schema status\_by\_account Table](../performance-schema-status_by_account-table/index) | Status variable information by user/host account. | | [Performance Schema status\_by\_host Table](../performance-schema-status_by_host-table/index) | Status variable information by host. | | [Performance Schema status\_by\_thread Table](../performance-schema-status_by_thread-table/index) | Status variable information about active foreground threads. | | [Performance Schema status\_by\_user Table](../performance-schema-status_by_user-table/index) | Status variable information by user. | | [Performance Schema table\_handles Table](../performance-schema-table_handles-table/index) | Table lock information. | | [Performance Schema table\_io\_waits\_summary\_by\_index\_usage Table](../performance-schema-table_io_waits_summary_by_index_usage-table/index) | Table I/O waits by index. | | [Performance Schema table\_io\_waits\_summary\_by\_table Table](../performance-schema-table_io_waits_summary_by_table-table/index) | Table I/O waits by table. | | [Performance Schema table\_lock\_waits\_summary\_by\_table Table](../performance-schema-table_lock_waits_summary_by_table-table/index) | Table lock waits by table. | | [Performance Schema threads Table](../performance-schema-threads-table/index) | Each server thread is represented as a row in the threads table. | | [Performance Schema users Table](../performance-schema-users-table/index) | User connection information. | | [Performance Schema user\_variables\_by\_thread Table](../performance-schema-user_variables_by_thread-table/index) | User-defined variables and the threads that defined them. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb ps_is_account_enabled ps\_is\_account\_enabled ======================== Syntax ------ ``` sys.ps_is_account_enabled(host,user) ``` Description ----------- `ps_is_account_enabled` is a [stored function](../stored-functions/index) available with the [Sys Schema](../sys-schema/index). It takes *host* and *user* arguments, and returns an ENUM('YES','NO') depending on whether Performance Schema instrumentation for the given account is enabled. Examples -------- ``` SELECT sys.ps_is_account_enabled('localhost', 'root'); +------------------------------------------------+ | sys.ps_is_account_enabled('localhost', 'root') | +------------------------------------------------+ | YES | +------------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Triggers Triggers ========= A trigger is a set of statements that run when an event occurs on a table. | Title | Description | | --- | --- | | [Trigger Overview](../trigger-overview/index) | Statements run when an event occurs on a table. | | [Binary Logging of Stored Routines](../binary-logging-of-stored-routines/index) | Stored routines require extra consideration when binary logging. | | [CREATE TRIGGER](../create-trigger/index) | Create a new trigger. | | [DROP TRIGGER](../drop-trigger/index) | Drops a trigger. | | [Information Schema TRIGGERS Table](../information-schema-triggers-table/index) | Information about triggers | | [Running Triggers on the Replica for Row-based Events](../running-triggers-on-the-replica-for-row-based-events/index) | Running triggers on the replica for row-based events. | | [SHOW CREATE TRIGGER](../show-create-trigger/index) | Shows the CREATE TRIGGER statement used to create the trigger | | [SHOW TRIGGERS](../show-triggers/index) | Shows currently-defined triggers | | [Trigger Limitations](../trigger-limitations/index) | Restrictions applying to triggers. | | [Triggers and Implicit Locks](../triggers-and-implicit-locks/index) | Implicit locks due to triggers and LOCK TABLE | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Index Statistics Index Statistics ================ How Index Statistics Help the Query Optimizer --------------------------------------------- The MariaDB query optimizer decides how best to execute each query based largely on the details of the indexes involved. The index statistics help inform these decisions. Imagine yourself choosing whether to look up a number in a phone book, or in your personal address book. You'd choose the personal phone book if at all possible, as it would (usually!) contain far fewer records and be quicker to search. Now imagine getting to your personal address book and finding it has twice the number of entries as the phone book. Your search would be slower. The same process applies to the query optimizer, so having access to up-to-date and accurate statistics is critical. Value Groups ------------ The statistics are mainly based on groups of index elements of the same value. In a primary key, every index is unique, so every group size is one. In a non-unique index, you may have multiple keys with the same value. A worst-case example would be having large groups with the same value, for example an index on a boolean field. MariaDB makes heavy use of the average group size statistic. For example, if there are 100 rows, and twenty groups with the same index values, the average group size would be five. However, averages can be skewed by extremes, and the usual culprit is NULL values. The row of 100 may have 19 groups with an average size of 1, while the other 81 values are all NULL. MariaDB may think five is a good average size and choose to use that index, and then end up having to read through 81 rows with identical keys, taking longer than an alternative. Dealing with NULLs ------------------ There are three main approaches to the problem of NULLs. NULL index values can be treated as a single group (nulls\_equal). This is usually fine, but if you have large numbers of NULLs the average group size is slanted higher, and the optimizer may miss using the index for ref accesses when it would be useful. This is the default used by XtraDB/InnoDB and MyISAM. Nulls\_unequal is the opposite approach, with each NULL forming its own group of one. Conversely, the average group size is slanted lower, and the optimizer may use the index for ref accesses when not suitable. This is the default used by the Aria storage engine. A third options sees NULL's ignored altogether from index group calculations. The default approaches can be changed by setting the [aria\_stats\_method](../aria-server-system-variables/index#aria_stats_method), [myisam\_stats\_method](../myisam-server-system-variables/index#myisam_stats_method) and [innodb\_stats\_method](../xtradbinnodb-server-system-variables/index#innodb_stats_method) server variables. Null-Safe and Regular Comparisons --------------------------------- The comparison operator used plays an important role. If two values are compared with <=> (see the [null-safe-equal](../null-safe-equal/index) comparison operator), and both are null, 1 is returned. If the same values are compared with = (see the [equal](../equal/index) comparison operator) null is returned. For example: ``` SELECT 1 <=> 1, NULL <=> NULL, 1 <=> NULL; +---------+---------------+------------+ | 1 <=> 1 | NULL <=> NULL | 1 <=> NULL | +---------+---------------+------------+ | 1 | 1 | 0 | +---------+---------------+------------+ SELECT 1 = 1, NULL = NULL, 1 = NULL; +-------+-------------+----------+ | 1 = 1 | NULL = NULL | 1 = NULL | +-------+-------------+----------+ | 1 | NULL | NULL | +-------+-------------+----------+ ``` Engine-Independent Statistics ----------------------------- [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/) introduced a way to gather statistics independently of the storage engine. See [Engine-independent table statistics](../engine-independent-table-statistics/index). Histogram-Based Statistics -------------------------- [Histogram-Based Statistics](../histogram-based-statistics/index) were introduced in [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/), and are collected by default from [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/). See Also -------- * [User Statistics](../user-statistics/index). This plugin provides user, client, table and index usage statistics. * [InnoDB Persistent Statistics](../innodb-persistent-statistics/index) * [Engine-independent Statistics](../engine-independent-table-statistics/index) * [Histogram-based Statistics](../histogram-based-statistics/index) * [Ignored Indexes](../ignored-indexes/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Event Limitations Event Limitations ================= The following restrictions apply to [Events](../stored-programs-and-views-events/index). * All of the restrictions listed in [Stored Routine Limitations](../stored-routine-limitations/index). * Events cannot return a resultset. * Event names are case insensitive, so it's not possible to define two events in the same database if their case insensitive names will match. This restriction has applied since MariaDB/MySQL 5.1.8. If you are upgrading from an older version of MySQL, and have events that could clash, these events need to be renamed before the upgrade. * Events do not support dates beyond the maximum that can be represented in the Unix epoch (2038-01-19). * Events cannot be created, dropped or altered by another stored program, trigger or event. * Events cannot create, drop or alter stored programs or triggers * Event timings cannot be strictly predicted. The intervals MONTH, YEAR\_MONTH, QUARTER and YEAR are all resolved in months. All others are resolved in seconds. A delay of up to two seconds is possible in extreme cases, and events scheduled to run at the same second cannot be executed in a given order. The `LAST_EXECUTED` column in the `[INFORMATION\_SCHEMA.EVENTS](../information-schema-events-table/index)` table will however always be accurate to within a second. * A new connection is used for each execution of statements within the body of an event, so the session counts for [server status variables](../server-status-variables/index) such as Com\_delete and Com\_select will not reflect these. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Partition Management ColumnStore Partition Management ================================ Introduction ============ MariaDB ColumnStore automatically creates logical horizontal partitions across every column. For ordered or semi-ordered data fields such as an order date this will result in a highly effective partitioning scheme based on that column. This allows for increased performance of queries filtering on that column since partition elimination can be performed. It also allows for data lifecycle management as data can be disabled or dropped by partition cheaply. Caution should be used when disabling or dropping partitions as these commands are destructive. It is important to understand that a Partition in ColumnStore terms is actually 2 extents (16 million rows) and that extents & partitions are created according to the following algorithm in 1.0.x: 1. Create 4 extents in 4 files 2. When these are filled up (after 32M rows), create 4 more extents in the 4 files created in step 1. 3. When these are filled up (after 64M rows), create a new partition. Managing partitions by partition number ======================================= Displaying partition information -------------------------------- Information about all partitions for a given column can be retrieved using the *calShowPartitions* stored procedure which takes either two or three mandatory parameters: [*database\_name*], *table\_name*, and *column\_name*. If two parameters are provided the current database is assumed. For example: ``` select calShowPartitions('orders','orderdate'); +-----------------------------------------+ | calShowPartitions('orders','orderdate') | +-----------------------------------------+ | Part# Min Max Status 0.0.1 1992-01-01 1998-08-02 Enabled 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +-----------------------------------------+ 1 row in set (0.05 sec) ``` Disabling partitions -------------------- The *calDisablePartitions* stored procedure allows for disabling of one or more partitions. A disabled partition still exists on the file system (and can be enabled again at a later time) but will not participate in any query, DML or import activity. The procedure takes either two or three mandatory parameters: [*database\_name*], *table\_name*, and *partition\_numbers* separated by commas. If two parameters are provided the current database is assumed. For example: ``` select calDisablePartitions('orders','0.0.1'); +----------------------------------------+ | calDisablePartitions('orders','0.0.1') | +----------------------------------------+ | Partitions are disabled successfully. | +----------------------------------------+ 1 row in set (0.28 sec) ``` The result showing the first partition has been disabled: ``` select calShowPartitions('orders','orderdate'); +-----------------------------------------+ | calShowPartitions('orders','orderdate') | +-----------------------------------------+ | Part# Min Max Status 0.0.1 1992-01-01 1998-08-02 Disabled 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +-----------------------------------------+ 1 row in set (0.05 sec) ``` Enabling partitions ------------------- The *calEnablePartitions* stored procedure allows for enabling of one or more partitions. The procedure takes the same set of parameters as *calDisablePartitions*. For example: ``` select calEnablePartitions('orders', '0.0.1'); +----------------------------------------+ | calEnablePartitions('orders', '0.0.1') | +----------------------------------------+ | Partitions are enabled successfully. | +----------------------------------------+ 1 row in set (0.28 sec) ``` The result showing the first partition has been enabled: ``` select calShowPartitions('orders','orderdate'); +-----------------------------------------+ | calShowPartitions('orders','orderdate') | +-----------------------------------------+ | Part# Min Max Status 0.0.1 1992-01-01 1998-08-02 Enabled 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +-----------------------------------------+ 1 rows in set (0.05 sec) ``` Dropping partitions ------------------- The *calDropPartitions* stored procedure allows for dropping of one or more partitions. Dropping means that the underlying storage is deleted and the partition is completely removed. A partition can be dropped from either enabled or disabled state. The procedure takes the same set of parameters as *calDisablePartitions*. Extra caution should be used with this procedure since it is destructive and cannot be reversed. For example: ``` select calDropPartitions('orders', '0.0.1'); +--------------------------------------+ | calDropPartitions('orders', '0.0.1') | +--------------------------------------+ | Partitions are enabled successfully | +--------------------------------------+ 1 row in set (0.28 sec) ``` The result showing the first partition has been dropped: ``` select calShowPartitions('orders','orderdate'); +-----------------------------------------+ | calShowPartitions('orders','orderdate') | +-----------------------------------------+ | Part# Min Max Status 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +-----------------------------------------+ 1 row in set (0.05 sec) ``` Managing partitions by column value =================================== Displaying partition information -------------------------------- Information about a range of parititions for a given column can be retrieved using the *calShowPartitionsByValue* stored procedure. This procedure takes either four or five mandatory parameters: [*database\_name*], *table\_name*, *column\_name*, *start\_value*, and *end\_value*. If four parameters are provided the current database is assumed. Only casual partition column types ([INTEGER](../int/index), [DECIMAL](../decimal/index), [DATE](../date/index), [DATETIME](../datetime/index), [CHAR](../char/index) up to 8 bytes and [VARCHAR](../varchar/index) up to 7 bytes) are supported for this function. The function returns a list of partitions whose minimum and maximum values for the column 'col\_name' fall completely within the range of 'start\_value' and 'end\_value'. For example: ``` select calShowPartitionsByValue('orders','orderdate', '1992-01-01', '2010-07-24'); +----------------------------------------------------------------------------+ | calShowPartitionsbyvalue('orders','orderdate', '1992-01-02', '2010-07-24') | +----------------------------------------------------------------------------+ | Part# Min Max Status 0.0.1 1992-01-01 1998-08-02 Enabled 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +----------------------------------------------------------------------------+ 1 row in set (0.05 sec) ``` Disabling partitions -------------------- The *calDisablePartitionsByValue* stored procedure allows for disabling of one or more partitions by value. A disabled partition still exists on the file system (and can be enabled again at a later time) but will not participate in any query, DML or import activity. The procedure takes the same set of arguments as *calShowPartitionsByValue*. A good practice is to use *calShowPartitionsByValue* to identify the partitions to be disabled and then the same argument values used to construct the *calDisablePartitionsByValue* call. For example: ``` select calDisablePartitionsByValue('orders','orderdate', '1992-01-01', '1998-08-02'); +---------------------------------------------------------------------------------+ | caldisablepartitionsbyvalue ('orders', 'o_orderdate','1992-01-01','1998-08-02') | +---------------------------------------------------------------------------------+ | Partitions are disabled successfully | +---------------------------------------------------------------------------------+ 1 row in set (0.28 sec) ``` The result showing the first partition has been disabled: ``` select calShowPartitionsByValue('orders','orderdate', '1992-01-01', '2010-07-24'); +----------------------------------------------------------------------------+ | calShowPartitionsbyvalue('orders','orderdate', '1992-01-02','2010-07-24’ ) | +----------------------------------------------------------------------------+ | Part# Min Max Status 0.0.1 1992-01-01 1998-08-02 Disabled 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +----------------------------------------------------------------------------+ 1 row in set (0.05 sec) ``` Enabling partitions ------------------- The *calEnablePartitionsbyValue* stored procedure allows for enabling of one or more partitions by value. The procedure takes the same set of arguments as *calShowPartitionsByValue*. A good practice is to use *calShowPartitionsByValue* to identify the partitions to be enabled and then the same argument values used to construct the *calEnablePartitionsbyValue* call. For example: ``` select calEnablePartitionsByValue('orders','orderdate', '1992-01-01', '1998-08-02'); +--------------------------------------------------------------------------------+ | calenablepartitionsbyvalue ('orders', 'o_orderdate','1992-01-01','1998-08-02') | +--------------------------------------------------------------------------------+ | Partitions are enabled successfully | +--------------------------------------------------------------------------------+ 1 row in set (0.28 sec) ``` The result showing the first partition has been enabled: ``` select calShowPartitionsByValue('orders','orderdate', '1992-01-01', '2010-07-24'); +----------------------------------------------------------------------------+ | calShowPartitionsbyvalue('orders','orderdate', '1992-01-02','2010-07-24' ) | +----------------------------------------------------------------------------+ | Part# Min Max Status 0.0.1 1992-01-01 1998-08-02 Enabled 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +----------------------------------------------------------------------------+ 1 rows in set (0.05 sec) ``` Dropping partitions ------------------- The *calDropPartitionsByValue* stored procedure allows for dropping of one or more partitions by value. Dropping means that the underlying storage is deleted and the partition is completely removed. A partition can be dropped from either enabled or disabled state. The procedure takes the same set of arguments as *calShowPartitionsByValue*. A good practice is to use *calShowPartitionsByValue* to identify the partitions to be enabled and then the same argument values used to construct the *calDropPartitionsByValue* call. Extra caution should be used with this procedure since it is destructive and cannot be reversed. For example: ``` select calDropPartitionsByValue('orders','orderdate', '1992-01-01', '1998-08-02'); +------------------------------------------------------------------------------+ | caldroppartitionsbyvalue ('orders', 'o_orderdate','1992-01-01','1998-08-02') | +------------------------------------------------------------------------------+ | Partitions are enabled successfully. | +------------------------------------------------------------------------------+ 1 row in set (0.28 sec) ``` The result showing the first partition has been dropped: ``` select calShowPartitionsByValue('orders','orderdate', '1992-01-01', '2010-07-24'); +----------------------------------------------------------------------------+ | calShowPartitionsbyvalue('orders','orderdate', '1992-01-02','2010-07-24' ) | +----------------------------------------------------------------------------+ | Part# Min Max Status 0.1.2 1998-08-03 2004-05-15 Enabled 0.2.3 2004-05-16 2010-07-24 Enabled | +----------------------------------------------------------------------------+ 1 row in set (0.05 sec) ``` Dropping data not wholly within one partition ============================================= Since the partitioning scheme is system maintained the min and max values are not directly specified but influenced by the order of data loading. If the goal is to drop a specific date range then additional deletes are required to achieve this. The following cases may occur: * For semi-ordered data, there may be overlap between min and max values between partitions. * As in the example above, the partition ranged from 1992-01-01 to 1998-08-02. Potentially it may be desirable to drop the remaining 1998 rows. A bulk delete statement can be used to delete the remaining rows that do not fall exactly within partition ranges. The partition drops will be fastest, however the system optimizes bulk delete statements to delete by block internally so are still relatively fast. ``` delete from orders where orderdate <= '1998-12-31'; ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Replication and Binary Log System Variables Replication and Binary Log System Variables =========================================== The terms *master* and *slave* have historically been used in replication, but the terms terms *primary* and *replica* are now preferred. The old terms are used still used in parts of the documentation, and in MariaDB commands, although [MariaDB 10.5](../what-is-mariadb-105/index) has begun the process of renaming. The documentation process is ongoing. See [MDEV-18777](https://jira.mariadb.org/browse/MDEV-18777) to follow progress on this effort. This page lists system variables that are related to [binary logging](../binary-log/index) and [replication](../replication/index). See [Server System Variables](../server-system-variables/index) for a complete list of system variables and instructions on setting them, as well as [System variables for global transaction ID](../gtid/index#system-variables-for-global-transaction-id). Also see [mysqld replication options](../mysqld-options/index#replication-and-binary-logging-options) for related options that are not system variables (such as [binlog\_do\_db](../mysqld-options/index#-binlog-do-db) and [binlog\_ignore\_db](../mysqld-options/index#-binlog-ignore-db)). See also the [Full list of MariaDB options, system and status variables](../full-list-of-mariadb-options-system-and-status-variables/index). #### `auto_increment_increment` * **Description:** The increment for all [AUTO\_INCREMENT](../auto_increment/index) values on the server, by default `1`. Intended for use in master-to-master [replication](../replication/index). * **Commandline:** `--auto-increment-increment[=#]` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `1` to `65535` --- #### `auto_increment_offset` * **Description:** The offset for all [AUTO\_INCREMENT](../auto_increment/index) values on the server, by default `1`. Intended for use in master-to-master [replication](../replication/index). Should be smaller than `auto_increment_increment`, except when both variables are 1 (default setup). * **Commandline:** `--auto-increment-offset[=#]` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` * **Range:** `1` to `65535` --- #### `binlog_annotate_row_events` * **Description:** This option tells the master to write [annotate\_rows\_events](../annotate_rows_log_event/index) to the binary log. * **Commandline:** `--binlog-annotate-row-events[={0|1}]` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** boolean * **Default Value:** + `ON` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)) + `OFF` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) #### `binlog_cache_size` * **Description:** If the [binary log](../binary-log/index) is active, this variable determines the size in bytes, per-connection, of the cache holding a record of binary log changes during a transaction. A separate variable, [binlog\_stmt\_cache\_size](#binlog_stmt_cache_size), sets the upper limit for the statement cache. The [binlog\_cache\_disk\_use](../server-status-variables/index#binlog_cache_disk_use) and [binlog\_cache\_use](../server-status-variables/index#binlog_cache_use) [server status variables](../server-status-variables/index) will indicate whether this variable needs to be increased (you want a low ratio of binlog\_cache\_disk\_use to binlog\_cache\_use). * **Commandline:** `--binlog-cache-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `32768` * **Range - 32 bit:** `4096` to `4294967295` * **Range - 64 bit:** `4096` to `18446744073709547520` --- #### `binlog_checksum` * **Description:** Specifies the type of BINLOG\_CHECKSUM\_ALG for log events in the [binary log](../binary-log/index). * **Commandline:** + `--binlog-checksum=name` + `--binlog-checksum=[0|1]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** + `CRC32` (>= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) + `NONE` (<= [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/)) * **Valid Values:** `NONE` (`0`), `CRC32` (`1`) --- #### `binlog_commit_wait_count` * **Description:** Configures the behavior of [group commit for the binary log](../group-commit-for-the-binary-log/index), which can help increase transaction throughput and is used to enable [conservative mode of in-order parallel replication](../parallel-replication/index#conservative-mode-of-in-order-parallel-replication). With [group commit for the binary log](../group-commit-for-the-binary-log/index), the server can delay flushing a committed transaction into [binary log](../binary-log/index) until the given number of transactions are ready to be flushed as a group. The delay will however not be longer than the value set by [binlog\_commit\_wait\_usec](#binlog_commit_wait_usec). The default value of 0 means that no delay is introduced. Setting this value can reduce I/O on the binary log and give an increased opportunity for parallel apply on the replica when [conservative mode of in-order parallel replication](../parallel-replication/index#conservative-mode-of-in-order-parallel-replication) is enabled, but too high a value will decrease the transaction throughput. By monitoring the status variable [binlog\_group\_commit\_trigger\_count](../replication-and-binary-log-status-variables/index#binlog_group_commit_trigger_count) (>=[MariaDB 10.1.5](https://mariadb.com/kb/en/mariadb-1015-release-notes/)) it is possible to see how often this is occurring. * Starting with [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) and [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/): If the server detects that one of the committing transactions T1 holds an [InnoDB](../xtradb-and-innodb/index) row lock that another transaction T2 is waiting for, then the commit will complete immediately without further delay. This helps avoid losing throughput when many transactions need conflicting locks. This often makes it safe to use this option without losing throughput on a replica with [conservative mode of in-order parallel replication](../parallel-replication/index#conservative-mode-of-in-order-parallel-replication), provided the value of [slave\_parallel\_threads](#slave_parallel_threads) is sufficiently high. * **Commandline:** `--binlog-commit-wait-count=#]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `18446744073709551615` --- #### `binlog_commit_wait_usec` * **Description:** Configures the behavior of [group commit for the binary log](../group-commit-for-the-binary-log/index), which can help increase transaction throughput and is used to enable [conservative mode of in-order parallel replication](../parallel-replication/index#conservative-mode-of-in-order-parallel-replication). With [group commit for the binary log](../group-commit-for-the-binary-log/index), the server can delay flushing a committed transaction into [binary log](../binary-log/index) until the transaction has waited the configured number of microseconds. By monitoring the status variable [binlog\_group\_commit\_trigger\_timeout](../replication-and-binary-log-status-variables/index#binlog_group_commit_trigger_timeout) (>=[MariaDB 10.1.5](https://mariadb.com/kb/en/mariadb-1015-release-notes/)) it is possible to see how often group commits are made due to `binlog_commit_wait_usec`. As soon as the number of pending commits reaches [binlog\_commit\_wait\_count](#binlog_commit_wait_count), the wait will be terminated, though. Thus, this setting only takes effect if `binlog_commit_wait_count` is non-zero. * **Commandline:** `--binlog-commit-wait-usec#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `100000` * **Range:** `0` to `18446744073709551615` --- #### `binlog_direct_non_transactional_updates` * **Description:** [Replication](../replication/index) inconsistencies can occur due when a transaction updates both transactional and non-transactional tables and the updates to the non-transactional tables are visible before being written to the binary log. This is because, to preserve causality, the non-transactional statements are written to the transaction cache, which is only flushed on commit. Setting binlog\_direct\_non\_transactional\_updates to 1 (0 is default) will cause non-transactional tables to be written straight to the binary log, rather than the transaction cache. This setting has no effect when row-based binary logging is used, as it requires statement-based logging. See [binlog\_format](#binlog_format). Use with care, and only in situations where no dependencies exist between the non-transactional and transactional tables, for example INSERTing into a non-transactional table based upon the results of a SELECT from a transactional table. * **Commandline:** `--binlog-direct-non-transactional-updates[=value]` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF (0)` --- #### `binlog_expire_logs_seconds` * **Description:** If non-zero, binary logs will be purged after `binlog_expire_logs_seconds` seconds. Possible purges happen at startup and at binary log rotation. From [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/), `binlog_expire_logs_seconds` and [expire\_logs\_days](#expire_logs_days) are forms of aliases, such that changes to one automatically reflect in the other. * **Commandline:** `--binlog-expire-logs-seconds=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `4294967295` * **Introduced:** [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/) --- #### `binlog_file_cache_size` * **Description:** Size of in-memory cache that is allocated when reading [binary log](../binary-log/index) and [relay log](../relay-log/index) files. * **Commandline:** `--binlog-file-cache-size=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `16384` * **Range:** `8192` to `18446744073709551615` * **Introduced:** [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) --- #### `binlog_format` * **Description:** Determines whether [replication](../replication/index) is row-based, statement-based or mixed. Statement-based was the default until [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). Be careful of changing the binary log format when a replication environment is already running. See [Binary Log Formats](../binary-log-formats/index). Starting from [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) a replica will apply any events it gets from the primary, regardless of the binary log format. `binlog_format` only applies to normal (not replicated) updates. * **Commandline:** `--binlog-format=format` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** + `MIXED` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)) + `STATEMENT` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) * **Valid Values:** `ROW`, `STATEMENT` or `MIXED` --- #### `binlog_optimize_thread_scheduling` * **Description:** Run fast part of group commit in a single thread, to optimize kernel thread scheduling. On by default. Disable to run each transaction in group commit in its own thread, which can be slower at very high concurrency. This option is mostly for testing one algorithm versus another, and it should not normally be necessary to change it. * **Commandline:** `--binlog-optimize-thread-scheduling` or `--skip-binlog-optimize-thread-scheduling` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `ON` --- #### `binlog_row_image` * **Description:** Controls whether, in [row-based](../binary-log-formats/index#row-based) [replication](../replication/index), rows should be logged in 'FULL', 'NOBLOB' or 'MINIMAL' formats. In row-based replication (the variable has no effect with [statement-based replication](../binary-log-formats/index#statement-based)), each row change event contains an image for matching against when choosing the row to be updated, and another image containing the changes. Before the introduction of this variable, all columns were logged for both of these images. In certain circumstances, this is not necessary, and memory, disk and network resources can be saved by partial logging. Note that to safely change this setting from the default, the table being replicated to must contain identical primary key definitions, and columns must be present, in the same order, and use the same data types as the original table. If these conditions are not met, matches may not be correctly determined and updates and deletes may diverge on the replica, with no warnings or errors returned. + `FULL`: All columns in the before and after image are logged. This is the default, and the only behavior in earlier versions. + `NOBLOB`: mysqld avoids logging blob and text columns whenever possible (eg, blob column was not changed or is not part of primary key). + `MINIMAL`: A PK equivalent (PK columns or full row if there is no PK in the table) is logged in the before image, and only changed columns are logged in the after image. * **Commandline:** `--binlog-row-image=value` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** `FULL` * **Valid Values:** `FULL`, `NOBLOB` or `MINIMAL` --- #### `binlog_row_metadata` * **Description:** Controls the format used for binlog metadata logging. + `NO_LOG`: No metadata is logged (default). + `MINIMAL`: Only metadata required by a replica is logged. + `FULL`: All metadata is logged. * **Commandline:** `--binlog-row-metadata=value` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** `NO_LOG` * **Valid Values:** `NO_LOG`, `MINIMAL`, `FULL` * **Introduced:** [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/) --- #### `binlog_stmt_cache_size` * **Description:** If the [binary log](../binary-log/index) is active, this variable determines the size in bytes of the cache holding a record of binary log changes outside of a transaction. The variable [binlog\_cache\_size](#binlog_cache_size), determines the cache size for binary log statements inside a transaction. The [binlog\_stmt\_cache\_disk\_use](../server-status-variables/index#binlog_stmt_cache_disk_use) and [binlog\_stmt\_cache\_use](../server-status-variables/index#binlog_stmt_cache_use) [server status variables](../server-status-variables/index) will indicate whether this variable needs to be increased (you want a low ratio of binlog\_stmt\_cache\_disk\_use to binlog\_stmt\_cache\_use). * **Commandline:** `--binlog-stmt-cache-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `32768` * **Range - 32 bit:** `4096` to `4294967295` * **Range - 64 bit:** `4096` to `18446744073709547520` --- #### `default_master_connection` * **Description:** In [multi-source replication](../multi-source-replication/index), specifies which connection will be used for commands and variables if you don't specify a connection. * **Commandline:** None * **Scope:** Session * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `''` (empty string) --- #### `encrypt_binlog` * **Description:** Encrypt [binary logs](../binary-log/index) (including [relay logs](../relay-log/index)). See [Data at Rest Encryption](../data-at-rest-encryption/index) and [Encrypting Binary Logs](../encrypting-binary-logs/index). * **Commandline:** `--encrypt-binlog[={0|1}]` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `expire_logs_days` * **Description:** Number of days after which the [binary log](../binary-log/index) can be automatically removed. By default 0, or no automatic removal. When using [replication](../replication/index), should always be set higher than the maximum lag by any replica. Removals take place when the server starts up, when the binary log is flushed, when the next binary log is created after the previous one reaches the maximum size, or when running [PURGE BINARY LOGS](../sql-commands-purge-logs/index). Units are whole days (integer) until [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/), or 1/1000000 precision (double) from [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/). Starting from [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/), `expire_logs_days` and [binlog\_expire\_logs\_seconds](#binlog_expire_logs_seconds) are forms of aliases, such that changes to one automatically reflect in the other. * **Commandline:** `--expire-logs-days=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0.000000` (>= [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)), `0` (<= [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/)) * **Range:** `0` to `99` --- #### `init_slave` * **Description:** Similar to [init\_connect](../server-system-variables/index#init_connect), but the string contains one or more SQL statements, separated by semicolons, that will be executed by a replica server each time the SQL thread starts. These statements are only executed after the acknowledgement is sent to the replica and [START SLAVE](../start-slave/index) completes. * **Commandline:** `--init-slave=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Related variables:** `[init\_connect](../server-system-variables/index#init_connect)` --- #### `log_bin` * **Description:** Whether [binary logging](../binary-log/index) is enabled or not. If the --log-bin [option](../mysqld-options-full-list/index) is used, log\_bin will be set to ON, otherwise it will be OFF. If no `name` option is given for `--log-bin`, `datadir/'log-basename'-bin` or `'datadir'/mysql-bin` will be used (the latter if [--log-basename](../mysqld-options/index#-log-basename) is not specified). We strongly recommend you use either `--log-basename` or specify a filename to ensure that [replication](../replication/index) doesn't stop if the real hostname of the computer changes. The name option can optionally include an absolute path. If no path is specified, the log will be written to the [data directory](../server-system-variables/index#datadir). The name can optionally include the file extension; it will be stripped and only the file basename will be used. * **Commandline:** `--log-bin[=name]` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` * **Related variables:** `[sql\_log\_bin](index#sql_log_bin)` --- #### `log_bin_basename` * **Description:** The full path of the binary log file names, excluding the extension. Its value is derived from the rules specified in `log_bin` system variable. * **Commandline:** `No commandline option` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** None * **Read Only:** `Yes` --- #### `log_bin_compress` * **Description:** Whether or not the binary log can be compressed. `0` (the default) means no compression. See [Compressing Events to Reduce Size of the Binary Log](../compressing-events-to-reduce-size-of-the-binary-log/index). * **Commandline:** `--log-bin-compress` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` * **Introduced:** [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) --- #### `log_bin_compress_min_len` * **Description:** Minimum length of sql statement (in statement mode) or record (in row mode) that can be compressed. See [Compressing Events to Reduce Size of the Binary Log](../compressing-events-to-reduce-size-of-the-binary-log/index). * **Commandline:** `--log-bin-compress-min-len` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `256` * **Range: `10` to `1024`** * **Introduced:** [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) --- #### `log_bin_index` * **Description:** File that holds the names for last binlog files. * **Commandline:** `--log-bin-index=name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** None --- #### `log_bin_trust_function_creators` * **Description:** Functions and triggers can be dangerous when used with [replication](../high-availability-performance-tuning-mariadb-replication/index). Certain types of functions and triggers may have unintended consequences when the statements are applied on a replica. For that reason, there are some restrictions on the creation of functions and triggers when the [binary log](../binary-log/index) is enabled by default, such as: + When `log_bin_trust_function_creators` is `OFF` and `[log\_bin](#log_bin)` is `ON`, `[CREATE FUNCTION](../create-function/index)` and `[ALTER FUNCTION](../alter-function/index)` statements will trigger an error if the function is defined with any of the `NOT DETERMINISTIC`, `CONTAINS SQL` or `MODIFIES SQL DATA` characteristics. + This means that when `log_bin_trust_function_creators` is `OFF` and `[log\_bin](#log_bin)` is `ON`, `[CREATE FUNCTION](../create-function/index)` and `[ALTER FUNCTION](../alter-function/index)` statements will only succeed if the function is defined with any of the `DETERMINISTIC`, `NO SQL`, or `READS SQL DATA` characteristics. + When `log_bin_trust_function_creators` is `OFF` and `[log\_bin](#log_bin)` is `ON`, the `[SUPER](../grant/index#global-privileges)` privilege is also required to execute the following statements: - `[CREATE FUNCTION](../create-function/index)` - `[CREATE TRIGGER](../create-trigger/index)` - `[DROP TRIGGER](../drop-trigger/index)` + Setting `log_bin_trust_function_creators` to `ON` removes these requirements around functions characteristics and the `[SUPER](../grant/index#global-privileges)` privileges. + See [Binary Logging of Stored Routines](../binary-logging-of-stored-routines/index) for more information. * **Commandline:** `--log-bin-trust-function-creators[={0|1}]` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `log_slow_slave_statements` * **Description:** Log slow statements executed by replica thread to the [slow log](../slow-query-log/index) if it is open. Before [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/), this was only available as a mysqld option, not a server variable. * **Commandline:** `--log-slow-slave-statements` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** + `ON` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)) + `OFF` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) --- #### `log_slave_updates` * **Description:** If set to `0`, the default, updates on a replica received from a primary during [replication](../replication/index) are not logged in the replica's binary log. If set to `1`, they are. The replica's binary log needs to be enabled for this to have an effect. Set to `1` if you want to daisy-chain the replicas. * **Commandline:** `--log-slave-updates` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `master_verify_checksum` * **Description:** Verify [binlog checksums](../binlog-event-checksums/index) when reading events from the binlog on the master. * **Commandline:** `--master-verify-checksum=[0|1]` * **Scope:** Global * **Access Type:** Can be changed dynamically * **Data Type:** `bool` * **Default Value:** `OFF (0)` --- #### `max_binlog_cache_size` * **Description:** Restricts the size in bytes used to cache a multi-transactional query. If more bytes are required, a `Multi-statement transaction required more than 'max_binlog_cache_size' bytes of storage` error is generated. If the value is changed, current sessions are unaffected, only sessions started subsequently. See [max\_binlog\_stmt\_cache\_size](#max_binlog_stmt_cache_size) and [binlog\_cache\_size](#binlog_cache_size). * **Commandline:** `--max-binlog-cache-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `18446744073709547520` * **Range:** `4096` to `18446744073709547520` --- #### `max_binlog_size` * **Description:** If the [binary log](../binary-log/index) exceeds this size after a write, the server rotates it by closing it and opening a new binary log. Single transactions will always be stored in the same binary log, so the server will wait for open transactions to complete before rotating. This figure also applies to the size of [relay logs](../relay-log/index) if [max\_relay\_log\_size](#max_relay_log_size) is set to zero. * **Commandline:** `--max-binlog-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1073741824` (1GB) * **Range:** `4096 to 1073741824` (4KB to 1GB) --- #### `max_binlog_stmt_cache_size` * **Description:** Restricts the size used to cache non-transactional statements. See [max\_binlog\_cache\_size](#max_binlog_cache_size) and [binlog\_stmt\_cache\_size](#binlog_stmt_cache_size). * **Commandline:** `--max-binlog-stmt-cache-size=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `18446744073709547520` (64 bit), `4294963200` (32 bit) * **Range:** `4096` to `18446744073709547520` --- #### `max_relay_log_size` * **Description:** Replica will rotate its [relay log](../relay-log/index) if it exceeds this size after a write. If set to 0, the [max\_binlog\_size](#max_binlog_size) setting is used instead. Previously global only, since the implementation of [multi-source replication](../multi-source-replication/index), it can be set per session as well. * **Commandline:** `--max-relay-log-size=#` * **Scope:** Global, Session * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0`, or `4096 to 1073741824` (4KB to 1GB) --- #### `read_binlog_speed_limit` * **Description:** Used to restrict the speed at which a [replica](../replication/index) can read the binlog from the primary. This can be used to reduce the load on a primary if many replicas need to download large amounts of old binlog files at the same time. The network traffic will be restricted to the specified number of kilobytes per second. * **Commandline:** `--read-binlog-speed-limit=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` (no limit) * **Range:** `0` to `18446744073709551615` * **Introduced:** [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) --- #### `relay_log` * **Description:** [Relay log](../relay-log/index) basename. If not set, the basename will be hostname-relay-bin. * **Commandline:** `--relay-log=file_name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `filename` * **Default Value:** `''` (none) --- #### `relay_log_basename` * **Description:** The full path of the relay log file names, excluding the extension. Its value is derived from the [relay-log](#relay_log) variable value. * **Commandline:** `No commandline option` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** None * **Read Only:** `Yes` --- #### `relay_log_index` * **Description:** Name and location of the [relay log](../relay-log/index) index file, the file that keeps a list of the last relay logs. Defaults to *hostname*-relay-bin.index. * **Commandline:** `--relay-log-index=name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` --- #### `relay_log_info_file` * **Description:** Name and location of the file where the `RELAY_LOG_FILE` and `RELAY_LOG_POS` options (i.e. the [relay log](../relay-log/index) position) for the `[CHANGE MASTER](../change-master-to/index)` statement are written. The [replica's SQL thread](../replication-threads/index#slave-sql-thread) keeps this [relay log](../relay-log/index) position updated as it applies events. + See [CHANGE MASTER TO: Option Persistence](../change-master-to/index#option-persistence) for more information. * **Commandline:** `--relay-log-info-file=file_name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** `relay-log.info` --- #### `relay_log_purge` * **Description:** If set to `1` (the default), [relay logs](../relay-log/index) will be purged as soon as they are no longer necessary. * **Commandline:** `--relay-log-purge={0|1}` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `ON` * **Note:** In MySQL and in MariaDB before version 10.0.8 this variable was silently changed if you did [CHANGE MASTER](../change-master-to/index). --- #### `relay_log_recovery` * **Description:** If set to `1` (`0` is default), on startup the replica will drop all [relay logs](../relay-log/index) that haven't yet been processed, and retrieve relay logs from the master. Can be useful after the replica has crashed to prevent the processing of corrupt relay logs. relay\_log\_recovery should always be set together with [relay\_log\_purge](#relay_log_purge). Setting `relay-log-recovery=1` with `relay-log-purge=0` can cause the relay log to be read from files that were not purged, leading to data inconsistencies. * **Commandline:** `--relay-log-recovery` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `relay_log_space_limit` * **Description:** Specifies the maximum space to be used for the [relay logs](../relay-log/index). The IO thread will stop until the SQL thread has cleared the backlog. By default `0`, or no limit. * **Commandline:** `--relay-log-space-limit=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `0` * **Range - 32 bit:** `0` to `4294967295` * **Range - 64 bit:** `0` to `18446744073709547520` --- #### `replicate_annotate_row_events` * **Description:** Tells the replica to reproduce [annotate\_rows\_events](../annotate_rows_log_event/index) received from the primary in its own binary log. This option is sensible only when used in tandem with the [log\_slave\_updates](#log_slave_updates) option. * **Commandline:** `--replicate-annotate-row-events` * **Scope:** Global * **Dynamic:** No * **Data Type:** `boolean` * **Default Value:** + `ON` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)) + `OFF` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) --- #### `replicate_do_db` * **Description:** This system variable allows you to configure a [replica](../replication/index) to apply statements and transactions affecting databases that match a specified name. + This system variable will **not** work with cross-database updates with [statement-based logging](../binary-log-formats/index#statement-based-logging). See the [Statement-Based Logging](../replication-filters/index#statement-based-logging) section for more information. + When setting it dynamically with `[SET GLOBAL](../set/index#global-session)`, the system variable accepts a comma-separated list of filters. + When setting it on the command-line or in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), the system variable does not accept a comma-separated list. If you would like to specify multiple filters, then you need to specify the system variable multiple times. + See [Replication Filters](../replication-filters/index) for more information. * **Commandline:** `--replicate-do-db=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `''` (empty) --- #### `replicate_do_table` * **Description:** This system variable allows you to configure a [replica](../replication/index) to apply statements and transactions that affect tables that match a specified name. The table name is specified in the format: `dbname.tablename`. + This system variable will **not** work with cross-database updates with [statement-based logging](../binary-log-formats/index#statement-based-logging). See the [Statement-Based Logging](../replication-filters/index#statement-based-logging) section for more information. + When setting it dynamically with `[SET GLOBAL](../set/index#global-session)`, the system variable accepts a comma-separated list of filters. + When setting it on the command-line or in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), the system variable does not accept a comma-separated list. If you would like to specify multiple filters, then you need to specify the system variable multiple times. + See [Replication Filters](../replication-filters/index) for more information. * **Commandline:** `--replicate-do-table=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `''` (empty) --- #### `replicate_events_marked_for_skip` * **Description:** Tells the replica whether to [replicate](../replication/index) events that are marked with the `@@skip_replication` flag. See [Selectively skipping replication of binlog events](../selectively-skipping-replication-of-binlog-events/index) for more information. * **Commandline:** `--replicate-events-marked-for-skip` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `replicate` * **Valid Values:** `REPLICATE`, `FILTER_ON_SLAVE`, `FILTER_ON_MASTER` --- #### `replicate_ignore_db` * **Description:** This system variable allows you to configure a [replica](../replication/index) to ignore statements and transactions affecting databases that match a specified name. + This system variable will **not** work with cross-database updates with [statement-based logging](../binary-log-formats/index#statement-based-logging). See the [Statement-Based Logging](../replication-filters/index#statement-based-logging) section for more information. + When setting it dynamically with `[SET GLOBAL](../set/index#global-session)`, the system variable accepts a comma-separated list of filters. + When setting it on the command-line or in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), the system variable does not accept a comma-separated list. If you would like to specify multiple filters, then you need to specify the system variable multiple times. + See [Replication Filters](../replication-filters/index) for more information. * **Commandline:** `--replicate-ignore-db=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `''` (empty) --- #### `replicate_ignore_table` * **Description:** This system variable allows you to configure a [replica](../replication/index) to ignore statements and transactions that affect tables that match a specified name. The table name is specified in the format: `dbname.tablename`. + This system variable will **not** work with cross-database updates with [statement-based logging](../binary-log-formats/index#statement-based-logging). See the [Statement-Based Logging](../replication-filters/index#statement-based-logging) section for more information. + When setting it dynamically with `[SET GLOBAL](../set/index#global-session)`, the system variable accepts a comma-separated list of filters. + When setting it on the command-line or in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), the system variable does not accept a comma-separated list. If you would like to specify multiple filters, then you need to specify the system variable multiple times. + See [Replication Filters](../replication-filters/index) for more information. * **Commandline:** `--replicate-ignore-table=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `''` (empty) --- #### `replicate_rewrite_db` * **Description:** `replicate_rewrite_db` is not available as a system variable, only as a mysqld option. See [the description on that page](../mysqld-options/index#-replicate-rewrite-db). + See [Replication Filters](../replication-filters/index) for more information. --- #### `replicate_wild_do_table` * **Description:** This system variable allows you to configure a [replica](../replication/index) to apply statements and transactions that affect tables that match a specified wildcard pattern. The wildcard pattern uses the same semantics as the `[LIKE](../like/index)` operator. + This system variable will work with cross-database updates with [statement-based logging](../binary-log-formats/index#statement-based-logging). See the [Statement-Based Logging](../replication-filters/index#statement-based-logging) section for more information. + When setting it dynamically with `[SET GLOBAL](../set/index#global-session)`, the system variable accepts a comma-separated list of filters. + When setting it on the command-line or in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), the system variable does not accept a comma-separated list. If you would like to specify multiple filters, then you need to specify the system variable multiple times. + See [Replication Filters](../replication-filters/index) for more information. * **Commandline:** `--replicate-wild-do-table=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `''` (empty) --- #### `replicate_wild_ignore_table` * **Description:** This system variable allows you to configure a [replica](../replication/index) to ignore statements and transactions that affect tables that match a specified wildcard pattern. The wildcard pattern uses the same semantics as the [LIKE](../like/index) operator. + This system variable will work with cross-database updates with [statement-based logging](../binary-log-formats/index#statement-based-logging). See the [Statement-Based Logging](../replication-filters/index#statement-based-logging) section for more information. + When setting it dynamically with [SET GLOBAL](../set/index#global-session), the system variable accepts a comma-separated list of filters. + When setting it on the command-line or in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index), the system variable does not accept a comma-separated list. If you would like to specify multiple filters, then you need to specify the system variable multiple times. + See [Replication Filters](../replication-filters/index) for more information. * **Commandline:** `--replicate-wild-ignore-table=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `string` * **Default Value:** `''` (empty) --- #### `report_host` * **Description:** The host name or IP address the replica reports to the primary when it registers. If left unset, the replica will not register itself. Reported by [SHOW SLAVE HOSTS](../show-slave-hosts/index). Note that it is not sufficient for the primary to simply read the IP of the replica from the socket once the replica connects. Due to NAT and other routing issues, that IP may not be valid for connecting to the replica from the primary or other hosts. * **Commandline:** `--report-host=host_name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` --- #### `report_password` * **Description:** Replica password reported to the primary when it registers. Reported by [SHOW SLAVE HOSTS](../show-slave-hosts/index) if `--show-slave-auth-info` is set. This password has no connection with user privileges or with the [replication](../replication/index) user account password. * **Commandline:** `--report-password=password` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` --- #### `report_port` * **Description:** The commandline option sets the TCP/IP port for connecting to the replica that will be reported to the [replicating](../replication/index) primary during the replica's registration. Viewing the variable will show this value. * **Commandline:** `--report-port=#` * **Scope:** Global * **Dynamic:** No * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `65535` --- #### `report_user` * **Description:** Replica's account user name reported to the primary when it registers. Reported by [SHOW SLAVE HOSTS](../show-slave-hosts/index) if `--show-slave-auth-info` is set. This username has no connection with user privileges or with the [replication](../replication/index) user account. * **Commandline:** `--report-user=name` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` --- #### `server_id` * **Description:** This system variable is used with [MariaDB replication](../replication/index) to identify unique primary and replica servers in a topology. This system variable is also used with the [binary log](../binary-log/index) to determine which server a specific transaction originated on. + When [MariaDB replication](../replication/index) is used with standalone MariaDB Server, each server in the replication topology must have a unique `server_id` value. + When [MariaDB replication](../replication/index) is used with [MariaDB Galera Cluster](../galera/index), see [Using MariaDB Replication with MariaDB Galera Cluster: Setting server\_id on Cluster Nodes](../using-mariadb-replication-with-mariadb-galera-cluster-using-mariadb-replica/index#setting-server_id-on-cluster-nodes) for more information on how to set the `server_id` values. + In [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) and below, the default `server_id` value is `0`. If a replica's `server_id` value is `0`, then all primary's will refuse its connection attempts. If a primary's `server_id` value is `0`, then it will refuse all replica connection attempts. * **Commandline:** `--server-id =#` * **Scope:** Global, Session (>= [MariaDB 10.0.2](https://mariadb.com/kb/en/mariadb-1002-release-notes/) only - see [Global Transaction ID](../global-transaction-id/index#server_id)) * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), `0` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) * **Range:** `1` to `4294967295` (>= [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)), `0` to `4294967295` (<= [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)) --- #### `skip_parallel_replication` * **Description:** If set when a transaction is written to the binlog, parallel apply of that transaction will be avoided on a replica where [slave\_parallel\_mode](#slave_parallel_mode) is not `aggressive`. Can be used to avoid unnecessary rollback and retry for transactions that are likely to cause a conflict if replicated in parallel. See [parallel replication](../parallel-replication/index). * **Commandline:** None * **Scope:** Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `skip_replication` * **Description:** Changes are logged into the [binary log](../binary-log/index) with the @@skip\_replication flag set. Such events will not be [replicated](../replication/index) by replica that run with `--replicate-events-marked-for-skip` set different from its default of `REPLICATE`. See [Selectively skipping replication of binlog events](../selectively-skipping-replication-of-binlog-events/index) for more information. * **Commandline:** None * **Scope:** Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `OFF` --- #### `slave_compressed_protocol` * **Description:** If set to 1 (0 is the default), will use compression for the replica/primary protocol if both primary and replica support this. * **Commandline:** `--slave-compressed-protocol` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `0` --- #### `slave_ddl_exec_mode` * **Description:** Modes for how [replication](../replication/index) of DDL events should be executed. Legal values are `STRICT` and `IDEMPOTENT` (default). In `IDEMPOTENT` mode, the replica will not stop for failed DDL operations that would not cause a difference between the primary and the replica. In particular [CREATE TABLE](../create-table/index) is treated as [CREATE OR REPLACE TABLE](../create-table/index#create-or-replace) and [DROP TABLE](../drop-table/index) is treated as `DROP TABLE IF EXISTS`. * **Commandline:** `--slave-ddl-exec-mode=name` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `IDEMPOTENT` * **Valid Values:** `IDEMPOTENT`, `STRICT` --- #### `slave_domain_parallel_threads` * **Description:** When set to a non-zero value, each [replication](../replication/index) domain in one master connection can reserve at most that many worker threads at any one time, leaving the rest (up to the value of [slave\_parallel\_threads](#slave_parallel_threads)) free for other primary connections or replication domains to use in parallel. See [Parallel Replication](../parallel-replication/index#configuration-variable-slave_domain_parallel_threads) for details. * **Commandline:** `--slave-domain-parallel-threads=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Valid Values:** `0` to `16383` --- #### `slave_exec_mode` * **Description:** Determines the mode used for [replication](../replication/index) error checking and conflict resolution. STRICT mode is the default, and catches all errors and conflicts. IDEMPOTENT mode suppresses duplicate key or no key errors, which can be useful in certain replication scenarios, such as when there are multiple masters, or circular replication. * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enumeration` * **Default Value:** `IDEMPOTENT` (NDB), `STRICT` (All) * **Valid Values:** `IDEMPOTENT`, `STRICT` --- #### `slave_load_tmpdir` * **Description:** Directory where the replica stores temporary files for [replicating](../replication/index) [LOAD DATA INFILE](../load-data-infile/index) statements. If not set, the replica will use [tmpdir](../server-system-variables/index#tmpdir). Should be set to a disk-based directory that will survive restarts, or else replication may fail. * **Commandline:** `--slave-load-tmpdir=path` * **Scope:** Global * **Dynamic:** No * **Data Type:** `file name` * **Default Value:** `/tmp` --- #### `slave_max_allowed_packet` * **Description:** Maximum packet size in bytes for replica SQL and I/O threads. This value overrides [max\_allowed\_packet](#max_allowed_packet) for [replication](../replication/index) purposes. Set in multiples of 1024 (the minimum) up to 1GB * **Commandline:** `--slave-max-allowed-packet=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `1073741824` * **Range:** `1024` to `1073741824` --- #### `slave_net_timeout` * **Description:** Time in seconds for the replica to wait for more data from the master before considering the connection broken, after which it will abort the read and attempt to reconnect. The retry interval is determined by the MASTER\_CONNECT\_RETRY open for the [CHANGE MASTER](../change-master-to/index) statement, while the maximum number of reconnection attempts is set by the [master-retry-count](../mysqld-options/index#-master-retry-count) option. The first reconnect attempt takes place immediately. * **Commandline:** `--slave-net-timeout=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** + `60 (1 minute)` (>= [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)) + `3600 (1 hour)` (<= [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)) * **Range:** `1` to `31536000` --- #### `slave_parallel_max_queued` * **Description:** When [parallel\_replication](../parallel-replication/index) is used, the [SQL thread](../replication-threads/index#slave-sql-thread) will read ahead in the relay logs, queueing events in memory while looking for opportunities for executing events in parallel. This system variable sets a limit for how much memory it will use for this. + The configured value of this system variable is actually allocated for each [worker thread](../replication-threads/index#worker-threads), so the total allocation is actually equivalent to the following: - `[slave\_parallel\_max\_queued](../replication-and-binary-log-server-system-variables/index#slave_parallel_max_queued)` \* `[slave\_parallel\_threads](../replication-and-binary-log-server-system-variables/index#slave_parallel_threads)` + This system variable is only meaningful when parallel replication is configured (i.e. when `[slave\_parallel\_threads](../replication-and-binary-log-server-system-variables/index#slave_parallel_threads)` > `0`). + See [Parallel Replication: Configuring the Maximum Size of the Parallel Slave Queue](../parallel-replication/index#configuring-the-maximum-size-of-the-parallel-slave-queue) for more information. * **Commandline:** `--slave-parallel-max-queued=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `131072` * **Range:** `0` to `2147483647` --- #### `slave_parallel_mode` * **Description:** Controls what transactions are applied in parallel when using [parallel replication](../parallel-replication/index). + `optimistic`: tries to apply most transactional DML in parallel, and handles any conflicts with rollback and retry. See [optimistic mode](../parallel-replication/index#optimistic-mode-of-in-order-parallel-replication). + `conservative`: limits parallelism in an effort to avoid any conflicts. See [conservative mode](../parallel-replication/index#conservative-mode-of-in-order-parallel-replication). + `aggressive`: tries to maximize the parallelism, possibly at the cost of increased conflict rate. + `minimal`: only parallelizes the commit steps of transactions. + `none` disables parallel apply completely. * **Commandline:** None * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `enum` * **Default Value:** `optimistic` (>= [MariaDB 10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)), `conservative` (<= [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)) * **Valid Values:** `conservative`, `optimistic`, `none`, `aggressive` and `minimal` --- #### `slave_parallel_threads` * **Description:** This system variable is used to configure [parallel replication](../parallel-replication/index). + If this system variable is set to a value greater than `0`, then its value will determine how many replica [worker threads](../replication-threads/index#worker-threads) will be created to apply [binary log](../binary-log/index) events in parallel. + If this system variable is set to `0` (which is the default value), then no replica [worker threads](../replication-threads/index#worker-threads) will be created. Instead, when replication is enabled, [binary log](../binary-log/index) events are applied by the replica's [SQL thread](../replication-threads/index#slave-sql-thread). + The [replica threads](../replication-threads/index#threads-on-the-slave) must be [stopped](../stop-slave/index) in order to change this option's value dynamically. + Events that were logged with [GTIDs](../gtid/index) with different `[gtid\_domain\_id](../gtid/index#gtid_domain_id)` values can be applied in parallel in an [out-of-order](../parallel-replication/index#out-of-order-parallel-replication) manner. Each `[gtid\_domain\_id](../gtid/index#gtid_domain_id)` can use the number of threads configured by `[slave\_domain\_parallel\_threads](#slave_domain_parallel_threads)`. + Events that were [group-committed](../group-commit-for-the-binary-log/index) on the master can be applied in parallel in an [in-order](../parallel-replication/index#what-can-be-run-in-parallel) manner, and the specific behavior can be configured by setting `[slave\_parallel\_mode](#slave_parallel_mode)`. * **Commandline:** `--slave-parallel-threads=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `16383` --- #### `slave_parallel_workers` * **Description:** Alias for [slave\_parallel\_threads](#slave_parallel_threads). * **Commandline:** `--slave-parallel-workers=#` * **Introduced:** [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) --- #### `slave_run_triggers_for_rbr` * **Description:** See [Running triggers on the slave for Row-based events](../running-triggers-on-the-slave-for-row-based-events/index) for a description and use-case for this setting. * **Commandline:** `--slave-run-triggers-for-rbr=value` * **Scope:** Global * **Data Type:** `enum` * **Default Value:** `NO` * **Valid Values:** `NO`, `YES`, `LOGGING`, or `ENFORCE` (>= [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)) --- #### `slave_skip_errors` * **Description:** When an error occurs on the replica, [replication](../replication/index) usually halts. This option permits a list of [error codes](../mariadb-error-codes/index) to ignore, and for which replication will continue. This option should never be needed in normal use, and careless use could lead to replica that are out of sync with primary's. Error codes are in the format of the number from the replica error log. Using `all` as an option permits the replica the keep replicating no matter what error it encounters, an option you would never normally need in production and which could rapidly lead to data inconsistencies. A count of these is kept in [slave\_skipped\_errors](../replication-and-binary-log-status-variables/index#slave_skipped_errors). * **Commandline:** `--slave-skip-errors=[error_code1,error_code2,...|all|ddl_exist_errors]` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** `OFF` * **Valid Values:** `[list of error codes]`, `ALL`, `OFF` --- #### `slave_sql_verify_checksum` * **Description:** Verify [binlog checksums](../binlog-event-checksums/index) when the replica SQL thread reads events from the [relay log](../relay-log/index). * **Commandline:** `--slave-sql-verify-checksum=[0|1]` * **Scope:** Global * **Access Type:** Can be changed dynamically * **Data Type:** `bool` * **Default Value:** `ON (1)` --- #### `slave_transaction_retries` * **Description:** Number of times a [replication](../replication/index) replica retries to execute an SQL thread after it fails due to InnDB deadlock or by exceeding the transaction execution time limit. If after this number of tries the SQL thread has still failed to execute, the replica will stop with an error. See also the [innodb\_lock\_wait\_timeout](../xtradbinnodb-server-system-variables/index#innodb_lock_wait_timeout) system variable. * **Commandline:** `--slave-transaction-retries=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `10` * **Range - 32 bit:** `0` to `4294967295` * **Range - 64 bit:** `0` to `18446744073709547520` --- #### `slave_transaction_retry_errors` * **Description:** When an error occurs during a transaction on the replica, [replication](../replication/index) usually halts. By default, transactions that caused a deadlock or elapsed lock wait timeout will be retried. One can add other errors to the the list of errors that should be retried by adding a comma-separated list of [error numbers](../mariadb-error-codes/index) to this variable. This is particularly useful in some [Spider](../spider/index) setups. Some recommended errors to retry for Spider are 1158,1159,1160,1161,1429,2013,12701.(From [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/), these are in the default value) * **Commandline:** `--slave-transaction_retry-errors=[error_code1,error_code2,...]` * **Scope:** Global * **Dynamic:** No * **Data Type:** `string` * **Default Value:** + `1158,1159,1160,1161,1205,1213,1429,2013,12701` (>= [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/)) + `1213,1205` (>= [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)) * **Valid Values:** `comma-separated list of error codes` * **Introduced:** [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) --- #### `slave_transaction_retry_interval` * **Description:** Interval in seconds for the replica SQL thread to retry a failed transaction due to a deadlock, elapsed lock wait timeout or an error listed in [slave\_transaction\_retry\_errors](#slave_transaction_retry_errors). The interval is calculated as `max(slave_transaction_retry_interval, min(retry_count, 5))`. * **Commandline:** `--slave-transaction-retry-interval=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `3600` * **Introduced:** [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) --- #### `slave_type_conversions` * **Description:** Determines the type conversion mode on the replica when using [row-based](../binary-log-formats/index#row-based) [replication](../replication/index), including replications in MariaDB Galera cluster. Multiple options can be set, delimited by commas. If left empty, the default, type conversions are disallowed. The variable is dynamic and a change in its value takes effect immediately. This variable tells the server what to do if the table definition is different between the master and replica (for example a column is 'int' on the master and 'bigint' on the replica). + `ALL_NON_LOSSY` means that all safe conversions (no data loss) are allowed. + `ALL_LOSSY` means that all lossy conversions are allowed (for example 'bigint' to 'int'). This, however, does not imply that safe conversions (non-lossy) are allowed as well. In order to allow all conversions, one needs to allow both lossy as well as non-lossy conversions by setting this variable to ALL\_NON\_LOSSY,ALL\_LOSSY. + Empty (default) means that the server should give an error and replication should stop if the table definition is different between the master and replica. * **Commandline:** `--slave-type-conversions=set` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `set` * **Default Value:** `Empty variable` * **Valid Values:** `ALL_LOSSY`, `ALL_NON_LOSSY`, empty --- #### `sql_log_bin` * **Description:** If set to 0 (1 is the default), no logging to the [binary log](../binary-log/index) is done for the client. Only clients with the SUPER privilege can update this variable. Does not affect the replication of events in a Galera cluster. * **Scope:** Session * **Dynamic:** Yes * **Data Type:** `boolean` * **Default Value:** `1` --- #### `sql_slave_skip_counter` * **Description:** Number of events that a replica skips from the master. If this would cause the replica to begin in the middle of an event group, the replica will instead begin from the beginning of the next event group. See [SET GLOBAL sql\_slave\_skip\_counter](../set-global-sql_slave_skip_counter/index). * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` --- #### `sync_binlog` * **Description:** MariaDB will synchronize its binary log file to disk after this many events. The default is 0, in which case the operating system handles flushing the file to disk. 1 is the safest, but slowest, choice, since the file is flushed after each write. If autocommit is enabled, there is one write per statement, otherwise there's one write per transaction. If the disk has cache backed by battery, synchronization will be fast and a more conservative number can be chosen. * **Commandline:** `--sync-binlog=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `0` * **Range:** `0` to `4294967295` --- #### `sync_master_info` * **Description:** A [replication](../replication/index) replica will synchronize its master.info file to disk after this many events. If set to 0, the operating system handles flushing the file to disk. * **Commandline:** `--sync-master-info=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `10000` (>= [MariaDB 10.1.7](https://mariadb.com/kb/en/mariadb-1017-release-notes/)) --- #### `sync_relay_log` * **Description:** The MariaDB server will synchronize its [relay log](../relay-log/index) to disk after this many writes to the log. The default until [MariaDB 10.1.7](https://mariadb.com/kb/en/mariadb-1017-release-notes/) was 0, in which case the operating system handles flushing the file to disk. 1 is the safest, but slowest, choice, since the file is flushed after each write. If autocommit is enabled, there is one write per statement, otherwise there's one write per transaction. If the disk has cache backed by battery, synchronization will be fast and a more conservative number can be chosen. * **Commandline:** `--sync-relay-log=#` * **Scope:** Global * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `10000` --- #### `sync_relay_log_info` * **Description:** A [replication](../replication/index) replica will synchronize its relay-log.info file to disk after this many transactions. The default until [MariaDB 10.1.7](https://mariadb.com/kb/en/mariadb-1017-release-notes/) was 0, in which case the operating system handles flushing the file to disk. 1 is the most secure choice, because at most one event could be lost in the event of a crash, but it's also the slowest. * **Commandline:** `--sync-relay-log-info=#` * **Scope:** Global, * **Dynamic:** Yes * **Data Type:** `numeric` * **Default Value:** `10000` * **Range:** `0` to `4294967295` --- Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb CACHE INDEX CACHE INDEX =========== Syntax ------ ``` CACHE INDEX tbl_index_list [, tbl_index_list] ... IN key_cache_name tbl_index_list: tbl_name [[INDEX|KEY] (index_name[, index_name] ...)] ``` Description ----------- The `CACHE INDEX` statement assigns table indexes to a specific key cache. It is used only for [MyISAM](../myisam/index) tables. A default key cache exists and cannot be destroyed. To create more key caches, the [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) server system variable. The associations between tables indexes and key caches are lost on server restart. To recreate them automatically, it is necessary to configure caches in a [configuration file](../mysqld-configuration-files-and-groups/index) and include some `CACHE INDEX` (and optionally `[LOAD INDEX](../load-index/index)`) statements in the init file. Examples -------- The following statement assigns indexes from the tables t1, t2, and t3 to the key cache named hot\_cache: ``` CACHE INDEX t1, t2, t3 IN hot_cache; +---------+--------------------+----------+----------+ | Table | Op | Msg_type | Msg_text | +---------+--------------------+----------+----------+ | test.t1 | assign_to_keycache | status | OK | | test.t2 | assign_to_keycache | status | OK | | test.t3 | assign_to_keycache | status | OK | +---------+--------------------+----------+----------+ ``` Implementation (for MyISAM) --------------------------- Normally CACHE INDEX should not take a long time to execute. Internally it's implemented the following way: * Find the right key cache (under LOCK\_global\_system\_variables) * Open the table with a TL\_READ\_NO\_INSERT lock. * Flush the original key cache for the given file (under key cache lock) * Flush the new key cache for the given file (safety) * Move the file to the new key cache (under file share lock) The only possible long operations are getting the locks for the table and flushing the original key cache, if there were many key blocks for the file in it. We plan to also add CACHE INDEX for Aria tables if there is a need for this. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Upgrading Between Major MariaDB Versions Upgrading Between Major MariaDB Versions ======================================== MariaDB is designed to allow easy upgrades. You should be able to trivially upgrade from ANY earlier MariaDB version to the latest one (for example [MariaDB 5.5](../what-is-mariadb-55/index).x to [MariaDB 10.5](../what-is-mariadb-105/index).x), usually in a few seconds. This is also mainly true for any MySQL version < 8.0 to [MariaDB 10.4](../what-is-mariadb-104/index) and up. Upgrades are normally easy because: * All MariaDB table data files are backward compatible * The MariaDB connection protocol is backward compatible. You don't normally need to upgrade any of your old clients to be able to connect to a newer MariaDB version. * The MariaDB slave can be of any newer version than the master. MariaDB Corporation regularly runs tests to check that one can upgrade from [MariaDB 5.5](../what-is-mariadb-55/index) to the latest MariaDB version without any trouble. All older versions should work too (as long as the storage engines you were using are still around). Note that if you are using [MariaDB Galera Cluster](../galera-cluster/index), you have to follow the [Galera upgrading instructions](../upgrading-galera-cluster/index)! Requirements for Doing an Upgrade Between Major Versions -------------------------------------------------------- * Go through the individual version upgrade notes (listed below) to look for any major changes or configuration options that have changed. * Ensure that the target MariaDB version supports the storage engines you are using. For example, in 10.5 [TokuDB](../tokudb/index) is not supported. * Backup the database (just in case). At least, take a copy of the `mysql` data directory with [mysqldump --add-drop-table mysql](../mysqldump/index) as most of the upgrade changes are done there (adding new fields and new system tables etc). * Ensure that the [innodb\_fast\_shutdown](../innodb-system-variables/index#innodb_fast_shutdown) variable is not 2 (fast crash shutdown) or 3. The default of this variable is 1. The safest option for upgrades is 0, but the shutdown time may be notably larger with 0 than for 1 as there are a lot more cleanups done for 0. * [innodb\_force\_recovery](../innodb-system-variables/index#innodb_force_recovery) must be less than `3`. * Cleanly shutdown of the server. This is necessary because even if data files are compatible between versions, recovery logs may not be. Note that rpms don't support upgrading between major versions, only minor like 10.4.1 to 10.4.2. If you are using rpms, you should de-install the old MariaDB rpms and install the new MariaDB rpms before running [mysql\_upgrade](../mysql_upgrade/index). Note that when installing the new rpms, [mysql\_upgrade](../mysql_upgrade/index) may be run automatically. There is no problem with running [mysql\_upgrade](../mysql_upgrade/index) many times. Recommended Steps ----------------- * If you have a [master-slave setup](../standard-replication/index), first upgrade one slave and when you have verified that the slave works well, upgrade the rest of the slaves (if any). Then [upgrade one slave to master](../changing-a-slave-to-become-the-master/index), upgrade the master, and change the master to a slave. * If you don't have a master-slave setup, then [take a backup](../mariabackup/index), [shutdown MariaDB](../mysqladmin/index) and do the upgrade. ### Step by step instructions for upgrades * Upgrade MariaDB binaries and libraries, preferably without starting MariaDB. * If the MariaDB server process, [mysqld or mariadbd](https://mariadb.com/mysqld-options) was not started as part of the upgrade, start it by executing `mysqld --skip-grant-tables`. This may produce some warnings about some system tables not being up to date, but you can ignore these for now as [mysql\_upgrade](../mysql_upgrade/index) will fix that. * Run [mysql\_upgrade](../mysql_upgrade/index) * Restart MariaDB server. Work Done by [mysql\_upgrade](../mysql_upgrade/index) ----------------------------------------------------- The main work done when upgrading is done by running [mysql\_upgrade](../mysql_upgrade/index). The main things it does are: * Updating the system tables in the `mysql` database to the newest version. This is very quick. * [mysql\_upgrade](../mysql_upgrade/index) also runs [mysqlcheck --check-upgrade](mysql_check) to check if there have been any collation changes between the major versions. This recreates indexes in old tables that are using any of the changed collations. This can take a bit of time if there are a lot of tables or there are many tables which used the changed collation. The last time a collation changed was in MariaDB/MySQL 5.1.23. Post Upgrade Work ----------------- Check the [MariaDB error log](../error-log/index) for any problems during upgrade. If there are any warnings in the log files, do your best to get rid of them! The common warnings/errors are: * Using obsolete options. If this is the case, remove them from your [my.cnf files](../configuring-mariadb-with-option-files/index). * Check the manual for [new features](../upgrading/index) that have been added since your last MariaDB version. * Test that your application works as before. The main difference from before is that because of optimizer improvements your application should work better than before, but in some rare cases the optimizer may get something wrong. In this case, you can try to use [explain](../explain/index), [optimizer trace](../mariadb-internals-documentation-optimizer-trace/index) or [optimizer\_switch](../optimizer-switch/index) to fix the queries. If Something Goes Wrong ----------------------- * First, check the [MariaDB error log](../error-log/index) to see if you are using configure options that are not supported anymore. * Check the upgrade notices for the MariaDB release that you are upgrading to. * File an issue in the [MariaDB bug tracker](../bug-tracking/index) so that we know about the issue and can provide a fix to make upgrades even better. * Add a comment to this manual entry for how we can improve it. ### Disaster Recovery In the unlikely event something goes wrong, you can try the following: * Remove the InnoDB tables from the `mysql` data directory. They are: + gtid\_slave\_pos + innodb\_table\_stats + innodb\_index\_stats + transaction\_registry * Move the `mysql` data directory to `mysql-old` and run [mysql\_install\_db](../mysql_install_db/index) to generate a new one. * After the above, you have to add back your old users. * When done, delete the `mysql-old` data directory. Downgrading ----------- MariaDB server is not designed for downgrading. That said, in most cases, as long as you haven't run any [ALTER TABLE](../alter-table/index) or [CREATE TABLE](../create-table/index) statements and you have a [mysqldump](../mysqldump/index) of your old `mysql` database , you should be able to downgrade to your previous version by doing the following: * Do a clean shutdown. For this special case you have to set [innodb\_fast\_shutdown](../innodb-system-variables/index#innodb_fast_shutdown) to 0,before taking down the new MariaDB server, to ensure there are no redo or undo logs that need to be applied on the downgraded server. * Delete the tables in the `mysql` database (if you didn't use the option `--add-drop-table` to [mysqldump](../mysqldump/index)) * Delete the new MariaDB installation * Install the old MariaDB version * Start the server with [mysqld --skip-grant-tables](../mysqld-options/index#-skip-grant-tables) * Install the old `mysql` database * Execute in the [mysql client](../mysql-client/index) `FLUSH PRIVILEGES` See Also -------- * [Upgrading from MySQL to MariaDB](../upgrading-from-mysql-to-mariadb/index) * [Upgrading from MariaDB 10.6 to MariaDB 10.7](../upgrading-from-mariadb-106-to-mariadb-107/index) * [Upgrading from MariaDB 10.5 to MariaDB 10.6](../upgrading-from-mariadb-105-to-mariadb-106/index) * [Upgrading from MariaDB 10.4 to MariaDB 10.5](../upgrading-from-mariadb-104-to-mariadb-105/index) * [Upgrading from MariaDB 10.3 to MariaDB 10.4](../upgrading-from-mariadb-103-to-mariadb-104/index) * [Upgrading from MariaDB 10.2 to MariaDB 10.3](../upgrading-from-mariadb-102-to-mariadb-103/index) * [Upgrading from MariaDB 10.1 to MariaDB 10.2](../upgrading-from-mariadb-101-to-mariadb-102/index) * [Upgrading from MariaDB 10.0 to MariaDB 10.1](../upgrading-from-mariadb-100-to-mariadb-101/index) * [Upgrading from MariaDB 5.5 to MariaDB 10.0](../upgrading-from-mariadb-55-to-mariadb-100/index) * [Galera upgrading instructions](../upgrading-galera-cluster/index) * [innodb\_fast\_shutdown](../innodb-system-variables/index#innodb_fast_shutdown) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Secondary Functions Secondary Functions ==================== These are commonly used functions, but they are not primary functions. | Title | Description | | --- | --- | | [Bit Functions and Operators](../bit-functions-and-operators/index) | Operators for comparison and setting of values, and related functions. | | [Encryption, Hashing and Compression Functions](../encryption-hashing-and-compression-functions/index) | Functions used for encryption, hashing and compression. | | [Information Functions](../information-functions/index) | Functions which return information on the server, the user, or a given query. | | [Miscellaneous Functions](../miscellaneous-functions/index) | Functions for very singular and specific needs. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Preparing for ColumnStore Installation - 1.2.1 Preparing for ColumnStore Installation - 1.2.1 ============================================== ### Prerequisite With version 1.2.1 of MariaDB ColumnStore, there should be no version of MariaDB Server or MySQL installed on the OS before a MariaDB ColumnStore is installed on the system. If you have an installation of MariaDB Server or MySQL, uninstall it before proceeding. #### Configuration preparation Before installing MariaDB ColumnStore, there is some preparation necessary. You will need to determine the following. Please refer to the MariaDB ColumnStore Architecture Document for additional information. * How many User Modules (UMs) will your system need? * How many Performance Modules (PMs) will your system need? * How much disk space will your system need? * Would you have passwordless ssh access between PMs? * Do you want to run the install as root or an unprivileged user? #### OS information MariaDB ColumnStore is certified to run on: RHEL/CentOS v6, v7 Ubuntu 16.04 LTS, Ubuntu 18.04 LTS Debian v8, v9 SUSE 12 but it should run on any recent Linux system. Make sure all nodes are running the same OS. Make sure the locale setting on all nodes is the same. To set locale to en\_US and UTf-8, as root run: ``` # localedef -i en_US -f UTF-8 en_US.UTF-8 ``` #### System administration information Information your system administrator must provide before installing MariaDB ColumnStore: * The hostnames of each interface on each node (optional). * The IP address of each interface on each node. * The user and password ColumnStore will run as should be consistent across all nodes. MariaDB ColumnStore can be installed as root or an unprivileged user. Example for 3 PM, 1UM system, these are the steps required to configure PM-1 for password-less ssh. The equivalent steps must be repeated on every PM in the system. The equivalent steps must be repeated on every UM in the system if the MariaDB ColumnStore Data Replication feature is enabled during the install process. ``` [root@pm- 1 ~] $ ssh-keygen [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-1 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-2 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-3 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub um-1 ``` If you will be using ssh keys... * and plan to enable the Data Redundancy feature, make sure you can login to PM1 from PM1, and between all UM nodes, without an additional prompt. This is required for the Data Redundancy feature. * and plan to enable the Local Query Feature, make sure you can login between all UM nodes and all PM nodes. #### Network configuration MariaDB ColumnStore is quite flexible regarding networking. Some options are as follows: * The interconnect between UMs and PMs can be one or more private VLANs. In this case MariaDB ColumnStore will automatically trunk the individual LANs together to provide greater effective bandwidth between the UMs and PMs. * The PMs do not require a public LAN access as they only need to communicate with the UMs, unless the local query feature is desired. * The UMs most likely require at least one public interface to access the MySQL server front end from the site LAN. This interface can be a separate physical or logical connection from the PM interconnect. * You can use whatever security your site requires on the public access to the MySQL server front end on the UMs. By default it is listening on port 3306. * MariaDB ColumnStore software only requires a TCP/IP stack to be present to function. You can use any physical layer you desire. #### MariaDB ColumnStore port usage The MariaDB ColumnStore daemon uses port 3306. You must reserve the following ports to run the MariaDB ColumnStore software: 8600 - 8630, 8700, and 8800 #### Storage and Database files (DBRoots) 'DBRoot' is a term used by ColumnStore to refer to a storage unit, typically located at mariadb/columnstore/data<N>, where N is the identifier for that storage unit. You will see that term throughout the documentation. MariaDB ColumnStore supports many storage options. * Internal - Internal means you will use block storage already mounted and available on each node. The data directories (mariadb/columnstore/dataN) can be links to other locations if preferable. With Internal storage setup, there is no High Availability Performance Module Failover capability. This is one of the limitations to using Internal storage. Its also for systems that have SAN that are mounted to single Performance Module. Its not shared mounted to all Performance Modules. * External - External means the SAN devices used for the DBRoots are shared mounted to all Performance Modules configured in the system. With External storage setup, the High Availability Performance Module Failover capability is supported, because mounts can be moved quickly from one node to another. So this is the only time that 'External' storage should be configured. * Data Redundancy - MariaDB ColumnStore supports Data Redundancy for both internal and external configurations. For Data Redundancy to be an option, the user is required to install the third party GlusterFS software on all Performance Modules. This is discussed later in the Package Dependency section. With Data Redundancy configured, High Availability Performance Module Failover capabilities is supported. IMPORTANT: When using external storage, be sure that only whole DBRoots are on the external filesystem. Do not use higher level directories, which may include the ColumnStore binaries and libraries. For example, /usr/local/mariadb/columnstore/data1 (aka DBRoot 1) would be a good candidate for external storage, but /usr/local/mariadb/columnstore would not be. #### Local database files If you are using internal storage, the DBRoot directories will be created under the installation directory, for example /usr/local/mariadb/columnstore/data<N> where N is the DBRoot number. There is no performance gain from assigning more than one DBRoot to a single storage device. DBRoots can be linked to other locations with more capacity if necessary. #### SAN mounted database files If you are using a SAN for storage, the following must be taken into account: * Each DBRoot must be a separate filesystem. * Each DBRoot should have the same capacity and performance characteristics, and each Performance Module should have the same number of DBRoots assigned for best performance. * MariaDB ColumnStore performs best on filesystems with low overhead, such as the ext family, however it can use any Linux filesystem. ColumnStore writes relatively large files (up to 64MB) compared to other databases, so please take that into account when choosing and configuring your filesystems. * For the failover feature to work, all Performance Modules must be able to mount any DBRoot. * The fstab file on all Performance Modules must include all of the external mounts, all with the 'noauto' option specified. ColumnStore will manage the mounting and unmounting. These lines are an example of an installation with 2 DBRoots configured. ``` /dev/sda1 /usr/local/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto 0 0 /dev/sdd1 /usr/local/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto 0 0 ``` #### Performance optimization considerations There are optimizations that should be made when using MariaDB ColumnStore listed below. As always, please consult with your network administrator for additional optimization considerations for your specific installation needs. #### GbE NIC settings: * Modify /etc/rc.d/rc.local to include the following: ``` /sbin/ifconfig eth0 txqueuelen 10000 ``` * Modify /etc/sysctl.conf for the following: ``` # increase TCP max buffer size net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 # increase Linux autotuning TCP buffer limits # min, default, and max number of bytes to use net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 65536 16777216 # don't cache ssthresh from previous connection net.ipv4.tcp_no_metrics_save = 1 # recommended to increase this for 1000 BT or higher net.core.netdev_max_backlog = 2500 # for 10 GigE, use this net.core.netdev_max_backlog = 30000 ``` NOTE: Make sure there is only 1 setting of net.core.netdev\_max\_backlog in the /etc/sysctl.conf file. * Cache memory settings: The kernel parameter vm.vfs\_cache\_pressure can be set to a lower value than 100 to attempt to retain caches for inode and directory structures. This will help improve read performance. A value of 10 is suggested. The following commands must be run as the root user or with sudo. To check the current value: ``` cat /proc/sys/vm/vfs_cache_pressure ``` To set the current value until the next reboot: ``` sysctl -w vm.vfs_cache_pressure=10 ``` To set the value permanently across reboots, add the following to /etc/sysctl.conf: ``` vm.vfs_cache_pressure = 10 ``` #### System settings considerations ##### umask setting The default setting of 022 is what is recommended. ColumnStore requires that it not end with a 7, like 077. For example, on a root installation, mysqld runs as the mysql user, and needs to be able to read the ColumnStore configuration file, which likely is not owned by mysql. If it were, then the other ColumnStore processes could not read it. The current umask can be determined by running the 'umask' command: A value of 022 can be set in the current session or in /etc/profile with the command: ``` umask 022 ``` #### Firewall considerations The MariaDB ColumnStore uses TCP ports 3306, 8600 - 8630, 8700, and 8800. Port 3306 is the default port for clients to connect to the MariaDB server; the others are for internal communication and will need to be open between ColumnStore nodes. To disable any local firewalls and SELinux on mutli-node installations, as root do the following. CentOS 6 and systems using iptables ``` #service iptables save (Will save your existing IPTable Rules) #service iptables stop (It will disable firewall Temporary) ``` To Disable it Permanentely: ``` #chkconfig iptables off ``` CentOS 7 and systems using systemctl with firewalld ``` #systemctl status firewalld #systemctl stop firewalld #systemctl disable firewalld ``` Ubuntu and systems using ufw ``` #service ufw stop (It will disable firewall Temporary) ``` To Disable it Permanently: ``` #chkconfig ufw off ``` SUSE ``` #/sbin/rcSuSEfirewall2 status #/sbin/rcSuSEfirewall2 stop ``` To disable SELinux, edit "/etc/selinux/config" and find line: ``` SELINUX=enforcing ``` Now replace it with, ``` SELINUX=disabled ``` #### User considerations MariaDB ColumnStore can be installed in different user configurations. #### Root User installation and execution MariaDB ColumnStore is installed by root and the MariaDB ColumnStore commands are run by root. With this installation type, you have the option of install using rpm, deb or binary packages. You can install the packages with the standard tools yum, apt, or zypper. The default package installation directory is /usr/local/mariadb/columnstore The location of the temporary files created by MariaDB ColumnStore is /tmp/columnstore\_tmp. #### Unprivileged user installation and execution MariaDB ColumnStore is installed by an unprivileged user and the MariaDB ColumnStore commands are run by that user. With this installation type, you are required to install using the binary tarball, which can be downloaded from the MariaDB ColumnStore Downloads page: <https://mariadb.com/downloads/#mariadbax> The default package installation directory is the home directory of the user account. The location of the temporary files created by MariaDB ColumnStore is $HOME/.tmp #### Root user installation and unprivileged user execution MariaDB ColumnStore is installed by root user and the MariaDB ColumnStore commands are run by an unprivileged user. This document will show how to configure the system to run commands as an unprivileged user: [https://mariadb.com/kb/en/library/mariadb-columnstore-system-usage/#non-root-user-mariadb-columnstore-admin-console](../library/mariadb-columnstore-system-usage/index#non-root-user-mariadb-columnstore-admin-console) With this installation type, you have the option of install using rpm, deb or binary packages, which you can install with the standard tools yum, apt, zypper. The default package installation directory is /usr/local/mariadb/columnstore The location of the temporary files created by MariaDB ColumnStore is /tmp/columnstore\_tmp. ### Package dependencies #### Boost libraries MariaDB ColumnStore requires that the boost package of 1.53 or newer is installed. For Centos 7, Ubuntu 16, Debian 8, SUSE 12 and other newer OS's, you can just install the default boost package that comes with your distribution. ``` # yum -y install boost ``` or ``` # apt-get -y install libboost-all-dev ``` For SUSE 12, you will need to install the boost-devel package, which is part of the SLE-SDK package. ``` SUSEConnect -p sle-sdk/12.2/x86_64 zypper install boost-devel ``` For CentOS 6, you can either download and install the MariaDB Columnstore Centos 6 boost library package or build version 1.55 from source and deploy it to each ColumnStore node. To download the pre-built libraries from MariaDB, go to binaries download page and download "centos6\_boost\_1\_55.tar.gz" <https://mariadb.com/downloads/columnstore> Click All Versions - > 1.0.x -> centos -> x86\_64 Install package on each server in the cluster. ``` wget https://downloads.mariadb.com/ColumnStore/1.0.14/centos/x86_64/centos6_boost_1_55.tar.gz tar xfz centos6_boost_1_55.tar.gz -C /usr/lib ldconfig ``` Downloading and build the boost libraries from source: NOTE: This requires that the "Development Tools" group and cmake be installed prior to this. ``` yum groupinstall "Development Tools" yum install cmake ``` Here is the procedure to download and build the boost source. As root do the following: ``` cd /usr/ wget http://sourceforge.net/projects/boost/files/boost/1.55.0/boost_1_55_0.tar.gz tar zxvf boost_1_55_0.tar.gz cd boost_1_55_0 ./bootstrap.sh --with-libraries=atomic,date_time,exception,filesystem,iostreams,locale,program_options,regex,signals,system,test,thread,timer,log --prefix=/usr ./b2 install ldconfig ``` #### Other packages Additional packages are required on each ColumnStore node. ##### Centos 6/7 ``` # yum -y install expect perl perl-DBI openssl zlib file sudo libaio rsync snappy net-tools numactl-libs nmap ``` ##### Ubuntu 16/18 ``` # apt-get -y install tzdata libtcl8.6 expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1v5 net-tools libnuma1 nmap ``` ##### Debian 8 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1 net-tools libnuma1 nmap ``` ##### Debian 9 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync net-tools libsnappy1v5 libreadline5 libaio1 libnuma1 nmap ``` ##### SUSE 12 ``` zypper install expect perl perl-DBI openssl file sudo libaio1 rsync net-tools libsnappy1 libnuma1 nmap ``` #### Data Redundancy packages To enable the Data Redundancy feature, install and enable GlusterFS version 3.3.1 or higher on each Performance Module. ##### Centos 6/7 ``` # yum -y install centos-release-gluster # yum -y install glusterfs glusterfs-fuse glusterfs-server start / enable service: # systemctl enable glusterd.service # systemctl start glusterd.service ``` ##### Ubuntu 16/18 ``` # apt-get install glusterfs-server attr start / enable service: # systemctl start glusterfs-server.service # systemctl enable glusterfs-server.service ``` ##### Debian 8 ``` # apt-get -y install glusterfs-server attr start / enable service: # update-rc.d glusterfs-server defaults ``` ##### Debian 9 ``` # apt-get install glusterfs-server attr start / enable service: # systemctl start glusterfs-server.service # systemctl enable glusterfs-server.service ``` ##### SUSE 12 ``` # zypper install glusterfs start / enable service: # chkconfig glusterd on ``` #### System Logging Package MariaDB ColumnStore can use the following standard logging systems. * syslog * rsyslog * syslog-ng ### Download location The standard ColumnStore RPM and DEB packages are available at <https://mariadb.com/downloads/columnstore>. If you need to install ColumnStore without root-level permissions, you must use the binary tarball, which is available at <https://downloads.mariadb.com/ColumnStore/> Note: MariaDB ColumnStore will configure a root user with no password in the MariaDB server initially. Afterward, you may setup users and permissions within MariaDB as you normally would. ### Choosing the type of initial download/install #### Non-Distributed Installation The default MariaDB ColumnStore installation process supports a Non-Distributed installation mode for multi-node deployments. With this option, the user will need to install the ColumnStore packages manually on each node. #### Distributed Install With the Distributed option, MariaDB ColumnStore will distribute and install the packages automatically on each node. The user installs ColumnStore on Performance Module 1, then during the postConfigure step, ColumnStore will handle the rest. ### Root user installations #### Initial download/install of MariaDB ColumnStore Packages The MariaDB ColumnStore RPM and DEB Packages can be installed using yum/apt-get commands. Check here for additional Information: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) #### Initial download/install of MariaDB ColumnStore Package with the AX package The MariaDB ColumnStore RPM, DEB and binary packages can be installed along with the other packages that make up the AX package. Check here for additional Information: [https://mariadb.com/kb/en/library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/](../library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/index) #### Initial download & installation of MariaDB ColumnStore RPMs 1. Install MariaDB ColumnStore as user root: Note: MariaDB ColumnStore will configure a root user with no password in the MariaDB server initially. Afterward, you may setup users and permissions within MariaDB as you normally would. Note: The packages will be installed at /usr/local. This is required for root user installations. * Download the appropriate ColumnStore package and place in the /root directory. * Unpack the tarball, which contains multiple RPMs. * Install the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. `rpm -ivh mariadb-columnstore*release#*.rpm` #### Initial download & installation of MariaDB ColumnStore binary package The MariaDB ColumnStore binary packages can be downloaded from <https://downloads.mariadb.com/ColumnStore/>. Select version 1.2.1, then navigate to the appropriate package for your system. The binary package will have the extension '.bin.tar.gz' rather than '.rpm.tar.gz' or '.deb.tar.gz'. * Unpack the tarball in /usr/local/ `tar -zxf mariadb-columnstore-release#.x86_64.bin.tar.gz` Run the post-install script: ``` /usr/local/mariadb/columnstore/bin/post-install ``` #### Initial download & installation of MariaDB ColumnStore DEB package 1. Download the package mariadb-columnstore-release#.amd64.deb.tar.gz into the /root directory of the server where you are installing MariaDB ColumnStore. 2. Unpack the tarball, which contains multiple DEBs. `tar -zxf mariadb-columnstore-release#.amd64.deb.tar.gz` 3. Install the MariaDB ColumnStore DEBs. The MariaDB ColumnStore software will be installed in /usr/ local/. `dpkg -i mariadb-columnstore*release#*.deb` ### Unprivileged user installation MariaDB Columnstore can be installed to run as an unprivileged user using the binary package. This procedure will allow you to change the location of the installation. It will need to be run on all MariaDB ColumnStore nodes. For the purpose of these instructions, the following assumptions are: * Unprivileged user 'mysql' is used in this example * Installation directory is /home/mysql/mariadb/columnstore Tasks involved: * Create the mysql user and group of the same name (by root user) * Update sudo configuration, if needed (by root user) * Set the user file limits (by root user) * Modify fstab if using 'external' storage (by root user) * Uninstall existing MariaDB Columnstore installation if needed (by root user) * Update permissions on certain directories that MariaDB Columnstore writes (by root user) * MariaDB Columnstore Installation (by the new user user) * Enable MariaDB Columnstore to start automatically at boot time #### Creation of a new user (by root user) Before beginning the binary tar file installation you will need your system administrator to set up accounts for you on every MariaDB Columnstore node. The account name & password must be the same on every node. If you change the password on one node, you must change it on every node. The user ID must be the same on every node as well. In the examples below we will use the account name 'mysql' and the password 'mariadb'. * create new user Group ID is an example, can be different than 1000, but needs to be the same on all servers in the cluster `adduser mysql -u 1000` * create group ``` addgroup mysql moduser -g mysql mysql ``` The value for user-id must be the same for all nodes. * Assign a password to newly created user `passwd mysql` * Log in as user mysql `su - mysql` The installation directory will be the home directory of the user account. So it would be '/home/mysql/ in this example. The installation directory must be the same on every node. In the examples below we will use the path '/home/mysql/mariadb/columnstore'. #### Update sudo configuration, if needed (by root user) In the MariaDB ColumnStore 1.2.1 and later, sudo configuration is only required for certain system configurations. These would include: * Data Redundancy * External Storage * Amazon EC2 using EBS storage If your system is not configured with any of these, you can skip this section. #### sudo configuration for Data Redundancy The sudo configuration on each node will need to allow the new user to run the gluster, mount, umount, and chmod commands. Add the following lines to your /etc/sudoers file, changing the paths to those commands if necessary on your system. ``` mysql ALL=NOPASSWD: /sbin/gluster mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount mysql ALL=NOPASSWD: /usr/bin/chmod ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### sudo configuration for External Storage The sudo configuration on each node will need to allow the new user to run the chmod, chown, mount, and umount commands. Add the following lines to your /etc/sudoers file, changing the path of each command if necessary on your system. ``` mysql ALL=NOPASSWD: /usr/bin/chmod mysql ALL=NOPASSWD: /usr/bin/chown mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### sudo configuration for Amazon EC2 using EBS storage The sudo configuration on each node will need to allow the new user to run several commands. Add the following lines to your /etc/sudoers file, changing the path of each command if necessary on your system. ``` mysql ALL=NOPASSWD: /usr/sbin/mkfs.ext2 mysql ALL=NOPASSWD: /usr/bin/chmod mysql ALL=NOPASSWD: /usr/bin/chown mysql ALL=NOPASSWD: /usr/bin/sed mysql ALL=NOPASSWD: /usr/bin/mount mysql ALL=NOPASSWD: /usr/bin/umount ``` Comment the following line, which will allow the user to login without a terminal: ``` #Defaults requiretty ``` #### Set the user file limits (by root user) ColumnStore needs the open file limit to be increased for the new user. To do this edit the /etc/security/limits.conf file and make the following additions at the end of the file: ``` mysql hard nofile 65536 mysql soft nofile 65536 ``` If you are already logged in as 'mysql' you will need to logout, then login for this change to take effect. #### Modify fstab if using the external storage option (by root user) If you are using an 'external' storage configuration, you will need to allow the new user to mount and unmount those filesystems. Add the 'users' option to those filesystems in your /etc/fstab file. Example entries: /dev/sda1 /home/mysql/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto,users 0 0 /dev/sdd1 /home/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto,users 0 0 The external filesystems will need to be owned by the new user. This is an example command run as root setting the owner and group of dbroot /dev/sda1 to the mysql user: ``` mount /dev/sda1 /tmpdir chown -R mysql:mysql /tmpdir umount /tmpdir ``` #### Update permissions on directories that MariaDB Columnstore writes to (by root user) ColumnStore uses POSIX shared memory segments. On some systems, the entry point /dev/shm does not allow regular users to create new segments. If necessary, permissions on /dev/shm should be set such that the new user or group has full access. The default on most systems is 777. ``` chmod 777 /dev/shm ``` For Data Redundancy using GlusterFS configured system: ``` chmod 777 -R /var/log/glusterfs ``` To allow external storage on an Amazon EC2 instance using EBS storage: ``` chmod 644 /etc/fstab ``` #### Uninstall existing MariaDB Columnstore installation, if needed (by root user) If MariaDB Columnstore has ever before been installed on any of the planned hosts as a root user install, you must have the system administrator verify that no remnants of that installation exist. The unprivileged installation will not be successful if there are MariaDB Columnstore files owned by root on any of the hosts. * Verify the MariaDB Columnstore installation directory does not exist: The /usr/local/mariadb/columnstore directory should not exist at all unless it is your target directory, in which case it must be completely empty and owned by the new user. * Verify the /etc/fstab entries are correct for the new installation. * Verify the /etc/default/columnstore directory does not exist. * Verify the /var/lock/subsys/mysql-Columnstore file does not exist. * Verify the /tmp/StopColumnstore file does not exist. #### MariaDB Columnstore installation (by the new user) You should be familiar with the general MariaDB Columnstore installation instructions in this guide as you will be asked the same questions during installation. If performing the distributed-mode installation across multiple node, the binary package only needs to be installed on Performance Module #1 (pm1). If performing a non-distributed installation, the binary package is required to install the MariaDB ColumnStore on all the nodes in the system. * Log in as the unprivileged user (mysql, in our example) Note: Ensure you are at your home directory before proceeding to the next step * Now place the MariaDB Columnstore binary tar file in your home directory on the host you will be using as PM1. Untar the binary distribution package to the /home/mysql directory: tar -xf mariadb-columnstore-release#.x86\_64.bin.tar.gz * Run post installation: If performing the distributed-mode installation, post-install only needs to be run on Performance Module #1 (pm1). If performing non-distributed installations, post-install needs to be run on all the nodes in the system. NOTE: $HOME is the same as /home/mysql in this example ``` ./mariadb/columnstore/bin/post-install --installdir=$HOME/mariadb/columnstore ``` Here is an example of what is printed by the post-install command ``` NOTE: For non-root install, you will need to run the following commands as root user to setup the MariaDB ColumnStore System Logging export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/syslogSetup.sh --installdir=/home/mysql/mariadb/columnstore --user=mysql install The next steps are: If installing on a pm1 node using non-distributed install export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore If installing on a pm1 node using distributed install export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore -d If installing on a non-pm1 using the non-distributed option: export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib:/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/columnstore start ``` * Setup System Logging For an unprivileged user installation, you will need to run the following commands as root on all nodes after the post-install command is run to make log entries go to the right places: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/syslogSetup.sh --installdir=/home/mysql/mariadb/columnstore --user=mysql install ``` Without that, log entries will go to the main system log file, and low-severity logs may not be recorded at all. * Start MariaDB ColumnStore Service for Non-Distributed installations If performing the non-distributed installation mode, the 'columnstore' service needs to be started on all nodes in the system except Performance Module #1 (pm1). postConfigure is on pm1, which is documented in the next section. Starting the 'columnstore' service: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/columnstore start ``` * Running ColumnStore Configuration and Installation Tool, 'postConfigure' On PM1, run the 2 export commands that were printed by the post-install command, then run postConfigure, which would look like the following: ``` export COLUMNSTORE_INSTALL_DIR=/home/mysql/mariadb/columnstore export LD_LIBRARY_PATH=/home/mysql/mariadb/columnstore/lib:/home/mysql/mariadb/columnstore/mysql/lib /home/mysql/mariadb/columnstore/bin/postConfigure -i /home/mysql/mariadb/columnstore ``` #### Configure ColumnStore to run automatically at boot To configure MariaDB Columnstore unprivileged installation to start automatically at boot time, perform the following steps on each Columnstore node: * Add the following to your local startup script (/etc/rc.local or similar), modifying as necessary: ``` runuser -l mysql -c "/home/mysql/mariadb/columnstore/bin/columnstore start" ``` Note: Make sure the above entry is added to the rc.local file that gets executed at boot time. Depending on the OS installation, rc.local could be in a different location. * MariaDB Columnstore will setup and log using your current system logging application in the directory /var/log/mariadb/columnstore. ### ColumnStore Cluster Test Tool This tool can be run before installation. It will verify the setup of all servers that are going to be used in the Columnstore System. [https://mariadb.com/kb/en/mariadb/mariadb-columnstore-cluster-test-tool](../mariadb/mariadb-columnstore-cluster-test-tool) ### How to Configuration and Launch MariaDB Columnstore #### ColumnStore Quick Launch Tools There are 3 Quick Launch Tools that can be used to launch basic systems. These are 1 step command tool where you provide the number of modules or amazon instances and the tool will take care of the rest. 1. Single Server Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-single-server-columnstore-system-12x/#mariadb-columnstore-quick-installer-for-a-single-server-system](../library/installing-and-configuring-a-single-server-columnstore-system-12x/index#mariadb-columnstore-quick-installer-for-a-single-server-system) 2. Multi Server Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-multi-server-columnstore-system-12x/#mariadb-columnstore-quick-installer](../library/installing-and-configuring-a-multi-server-columnstore-system-12x/index#mariadb-columnstore-quick-installer) 3. Amazon AMI Quick Launch [https://mariadb.com/kb/en/library/installing-and-configuring-a-columnstore-system-using-the-amazon-ami/#mariadb-columnstore-one-step-quick-installer-script-quick\_installer\_amazonsh](../library/installing-and-configuring-a-columnstore-system-using-the-amazon-ami/index#mariadb-columnstore-one-step-quick-installer-script-quick_installer_amazonsh) #### ColumnStore Configuration and Installation Tool MariaDB Columnstore System Configuration and Installation tool, 'postConfigure', will Configure the MariaDB Columnstore System and will perform a Package Installation of all of the Servers within the System that is being configured. It will prompt the user to for information like IP addresses, storage types, MariaDB Server, and system features. At the end, it will start the ColumnStore system. NOTE: When prompted for password, enter the non-user account password OR just hit enter if you have configured password-less ssh keys on all nodes (Please see the “System Administration Information” section earlier in this guide for more information on ssh keys.) This tool is always run on the Performance Module #1. Example uses of this script are shown in the Single and Multi Server Installations Guides. ``` # /usr/local/mariadb/columnstore/bin/postConfigure -h This is the MariaDB ColumnStore System Configuration and Installation tool. It will Configure the MariaDB ColumnStore System based on Operator inputs and will perform a Package Installation of all of the Modules within the System that is being configured. IMPORTANT: This tool should only be run on a Performance Module Server, preferably Module #1 Instructions: Press 'enter' to accept a value in (), if available or Enter one of the options within [], if available, or Enter a new value Usage: postConfigure [-h][-c][-u][-p][-qs][-qm][-qa][-port][-i][-n][-d][-sn][-pm-ip-addrs][-um-ip-addrs][-pm-count][-um-count] -h Help -c Config File to use to extract configuration data, default is Columnstore.xml.rpmsave -u Upgrade, Install using the Config File from -c, default to Columnstore.xml.rpmsave If ssh-keys aren't setup, you should provide passwords as command line arguments -p Unix Password, used with no-prompting option -qs Quick Install - Single Server -qm Quick Install - Multi Server -port MariaDB ColumnStore Port Address -i Non-root Install directory, Only use for non-root installs -n Non-distributed install, meaning postConfigure will not install packages on remote nodes -d Distributed install, meaning postConfigure will install packages on remote nodes -sn System Name -pm-ip-addrs Performance Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx -um-ip-addrs User Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb ST_CONVEXHULL ST\_CONVEXHULL ============== **MariaDB starting with [10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/)**ST\_ConvexHull() was introduced in [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) Syntax ------ ``` ST_ConvexHull(g) ConvexHull(g) ``` Description ----------- Given a geometry, returns a geometry that is the minimum convex geometry enclosing all geometries within the set. Returns NULL if the geometry value is NULL or an empty value. ST\_ConvexHull() and ConvexHull() are synonyms. Examples -------- The ConvexHull of a single point is simply the single point: ``` SET @g = ST_GEOMFROMTEXT('Point(0 0)'); SELECT ST_ASTEXT(ST_CONVEXHULL(@g)); +------------------------------+ | ST_ASTEXT(ST_CONVEXHULL(@g)) | +------------------------------+ | POINT(0 0) | +------------------------------+ ``` ``` SET @g = ST_GEOMFROMTEXT('MultiPoint(0 0, 1 2, 2 3)'); SELECT ST_ASTEXT(ST_CONVEXHULL(@g)); +------------------------------+ | ST_ASTEXT(ST_CONVEXHULL(@g)) | +------------------------------+ | POLYGON((0 0,1 2,2 3,0 0)) | +------------------------------+ ``` ``` SET @g = ST_GEOMFROMTEXT('MultiPoint( 1 1, 2 2, 5 3, 7 2, 9 3, 8 4, 6 6, 6 9, 4 9, 1 5 )'); SELECT ST_ASTEXT(ST_CONVEXHULL(@g)); +----------------------------------------+ | ST_ASTEXT(ST_CONVEXHULL(@g)) | +----------------------------------------+ | POLYGON((1 1,1 5,4 9,6 9,9 3,7 2,1 1)) | +----------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Decimal Math and Scale ColumnStore Decimal Math and Scale ================================== MariaDB ColumnStore has the ability to change intermediate decimal mathematical results from decimal type to double. The decimal type has approximately 17-18 digits of precision, but a smaller maximum range. Whereas the double type has approximately 15-16 digits of precision, but a much larger maximum range. In typical mathematical and scientific applications, the ability to avoid overflow in intermediate results with double math is likely more beneficial than the additional two digits of precisions. In banking applications, however, it may be more appropriate to leave in the default decimal setting to ensure accuracy to the least significant digit. ### Enable/Disable decimal to double math The infinidb\_double\_for\_decimal\_math variable is used to control the data type for intermediate decimal results. This decimal for double math may be set as a default for the instance, set at the session level, or at the statement level by toggling this variable on and off. To enable/disable the use of the decimal to double math at the session level, the following command is used. Once the session has ended, any subsequent session will return to the default for the instance. ``` set infinidb_double_for_decimal_math = on ``` where n is: * off (disabled, default) * on (enabled) ### ColumnStore decimal scale ColumnStore has the ability to support varied internal precision on decimal calculations. *infinidb\_decimal\_scale* is used internally by the ColumnStore engine to control how many significant digits to the right of the decimal point are carried through in suboperations on calculated columns. If, while running a query, you receive the message ‘aggregate overflow’, try reducing *infinidb\_decimal\_scale* and running the query again. Note that,as you decrease *infinidb\_decimal\_scale*, you may see reduced accuracy in the least significant digit(s) of a returned calculated column. *infinidb\_use\_decimal\_scale* is used internally by the ColumnStore engine to turn the use of this internal precision on and off. These two system variables may be set as a default for the instance or set at the session level. #### Enable/disable decimal scale To enable/disable the use of the decimal scale at the session level, the following command is used. Once the session has ended, any subsequent session will return to the default for the instance. ``` set infinidb_use_decimal_scale = on ``` where *n* is off (disabled) or on (enabled). #### Set decimal scale level To set the decimal scale at the session level, the following command is used. Once the session has ended, any subsequent session will return to the default for the instance. ``` set infinidb_decimal_scale = n ``` where *n* is the amount of precision desired for calculations. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb STDDEV_SAMP STDDEV\_SAMP ============ Syntax ------ ``` STDDEV_SAMP(expr) ``` Description ----------- Returns the sample standard deviation of `expr` (the square root of [VAR\_SAMP()](../var_samp/index)). It is an [aggregate function](../aggregate-functions/index), and so can be used with the [GROUP BY](../group-by/index) clause. From [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/), STDDEV\_SAMP() can be used as a [window function](../window-functions/index). STDDEV\_SAMP() returns `NULL` if there were no matching rows. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Code Coverage Code Coverage ============= We are working on getting more of the MariaDB source covered by our mysql-test-run (MTR) test suite. This is an ongoing (and slow) task as there is still a lot of old code with not very good coverage. Goals for new code ------------------ For new code in MariaDB, we aim much higher: The goals are: 1. All new lines of code should ideally be tested by MTR. 2. Code which cannot reasonably be tested by MTR needs to be tested by another tool and those code lines marked with /\* purecov: tested \*/. * In this case the tool used for testing should be documented in the [worklog](../worklog/index) entry for the code or in the commit message. 3. Code that can't reasonably be tested (such as error conditions) should be marked with '/\* purecov: inspected \*/' so that a reviewer of the code can easily spot this code. 4. Code that is suspected to be deadcode should have a 'DBUG\_ASSERT(0)' or be marked with '/\* purecov: deadcode \*/' so that we have a chance to notice if the code is ever executed. The reason we are using 'purecov' to mark lines is an attribution to the [purecov](ftp://ftp.software.ibm.com/software/rational/docs/v2002/dev_tools/purecov/html/ht_intro_pc.htm) tool we originally used for code coverage in the early years of MySQL. Markers ------- The recommended markers are: `/\* purecov: tested \*/` * For code lines that are tested by something *other* than mysql-test-run: `/\* purecov: inspected \*/` * For code lines that are hard to test but for which one has read the line multiple times to ensure it is correct. A code reviewer should also inspect these lines with care as they have not been properly tested. `/\* purecov: deadcode \*/` * For code lines that one suspects will never be called. Having this marker allows us to generate a warning during mysql-test-run code coverage if this line is executed. The comment must be placed on the line/lines that are affected. For code blocks larger than 1 line one can use the block syntax: ``` /* purecov: begin tested */ .... /* purecov: end */ ``` Running mysql-test-run with gcov -------------------------------- ### Prerequisites 1. First make sure that gcov 4.9 is installed.Older versions of the gocv library (lgcov) can't handle running several instances of a program in parallel. This causes the generated .gov files to not contain all executed lines when running mysql-test-run with the --parallel option or running test that starts several mysqld servers, like replication or spider tests. 2. Compile MariaDB with BUILD/compile-pentium64-gcov (if your machine does not have a pentium CPU, hack this script, or just live with the pentium-specific stuff) ### Running mysql-test-run To be able to see the level of coverage within the current test suite, do the following: 1. In the mysql-test directory, run this command: `./mysql-test-run -gcov` 2. To see which lines are not yet covered, look at `source_file_name.gcov` in the source tree. In [MariaDB 10.1](../what-is-mariadb-101/index) or below it's in the CMakeFiles directory where the object files are stored. In [MariaDB 10.2](../what-is-mariadb-102/index) it's stored together with the source files. 3. Think hard about a test case which will cover those lines that are not tested, and write one. Tools ----- * You can use the [code-coverage-with-dgcov/dgcov tool](code-coverage-with-dgcov/dgcov_tool) to check the coverage for the new code. This is especially written and maintained for MariaDB. * For code coverage you also use the [lcov](http://fedora13.selfip.org/lcov/) tool. Code coverage in buildbot ------------------------- [buildbot](../buildbot/index), the MariaDB build system, is doing [automatic coverage testing for each push](http://buildbot.askmonty.org/buildbot/builders/kvm-dgcov-jaunty-i386). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB ColumnStore software upgrade 1.0.11 to 1.1.0 Beta MariaDB ColumnStore software upgrade 1.0.11 to 1.1.0 Beta ========================================================= MariaDB ColumnStore software upgrade 1.0.11 to 1.1.0 Beta --------------------------------------------------------- Additional Dependency Packages exist for 1.1.0, so make sure you install those based on the "Preparing for ColumnStore Installation" Guide. Note: Columnstore.xml modifications you manually made are not automatically carried forward on an upgrade. These modifications will need to be incorporated back into .XML once the upgrade has occurred. The previous configuration file will be saved as /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave. If you have specified a root database password (which is good practice), then you must configure a .my.cnf file with user credentials for the upgrade process to use. Create a .my.cnf file in the user home directory with 600 file permissions with the following content (updating PASSWORD as appropriate): ``` [mysqladmin] user = root password = PASSWORD ``` ### Choosing the type of upgrade As noted on the Preparing guide, you can installing MariaDB ColumnStore with the use of soft-links. If you have the softlinks be setup at the Data Directory Levels, like mariadb/columnstore/data and mariadb/columnstore/dataX, then your upgrade will happen without any issues. In the case where you have a softlink at the top directory, like /usr/local/mariadb, you will need to upgrade using the binary package. If you updating using the rpm package and tool, this softlink will be deleted when you perform the upgrade process and the upgrade will fail. #### Root User Installs #### Upgrading MariaDB ColumnStore using RPMs Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Download the package mariadb-columnstore-1.1.0-1-centos#.x86\_64.rpm.tar.gz to the PM1 server where you are installing MariaDB ColumnStore.** Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate a set of RPMs that will reside in the /root/ directory. ``` # tar -zxf mariadb-columnstore-1.1.0-1-centos#.x86_64.rpm.tar.gz ``` * Upgrade the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. ``` # rpm -e --nodeps $(rpm -qa | grep '^mariadb-columnstore') # rpm -ivh mariadb-columnstore-*1.1.0*rpm ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml.rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` For RPM Upgrade, the previous configuration file will be saved as: /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /usr/local directory -mariadb-columnstore-1.1.0-1.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Run pre-uninstall script ``` # /usr/local/mariadb/columnstore/bin/pre-uninstall ``` * Unpack the tarball, in the /usr/local/ directory. ``` # tar -zxvf -mariadb-columnstore-1.1.0-1.x86_64.bin.tar.gz ``` * Run post-install scripts ``` # /usr/local/mariadb/columnstore/bin/post-install ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` ### Upgrading MariaDB ColumnStore using the DEB package A DEB upgrade would be done on a system that supports DEBs like Debian or Ubuntu systems. Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /root directory mariadb-columnstore-1.1.0-1.amd64.deb.tar.gz (DEB 64-BIT) to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate DEBs. ``` # tar -zxf mariadb-columnstore-1.1.0-1.amd64.deb.tar.gz ``` * Remove, purge and install all MariaDB ColumnStore debs ``` # cd /root/ # dpkg -r $(dpkg --list | grep 'mariadb-columnstore' | awk '{print $2}') # dpkg -P $(dpkg --list | grep 'mariadb-columnstore' | awk '{print $2}') # dpkg --install mariadb-columnstore-*1.1.0-1*deb ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` #### Non-Root User Installs ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /home/'non-root-user" directory mariadb-columnstore-1.1.0-1.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Run pre-uninstall script ``` # $HOME/mariadb/columnstore/bin/pre-uninstall --installdir= /home/guest/mariadb/columnstore ``` * Unpack the tarball, which will generate the $HOME/ directory. ``` # tar -zxvf -mariadb-columnstore-1.1.0-1.x86_64.bin.tar.gz ``` * Run post-install scripts ``` # $HOME/mariadb/columnstore/bin/post-install --installdir=/home/guest/mariadb/columnstore ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` # $HOME/mariadb/columnstore/bin/postConfigure -u -i /home/guest/mariadb/columnstore ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Troubleshooting Installation Issues Troubleshooting Installation Issues ==================================== Articles relating to installation issues users might run into. | Title | Description | | --- | --- | | [Troubleshooting Connection Issues](../troubleshooting-connection-issues/index) | Common problems when trying to connect to MariaDB. | | [Installation issues on Windows](../installation-issues-on-windows/index) | Issues people have encountered when installing MariaDB on Windows | | [Troubleshooting MariaDB Installs on Red Hat/CentOS](../troubleshooting-mariadb-installs-on-red-hatcentos/index) | Issues people have encountered when installing MariaDB on Red Hat / CentOS | | [Installation issues on Debian and Ubuntu](../installation-issues-on-debian-and-ubuntu/index) | Solutions to different installation issues on Debian and Ubuntu | | [What to Do if MariaDB Doesn't Start](../what-to-do-if-mariadb-doesnt-start/index) | Troubleshooting MariaDB when it fails to start. | | [Installing on an Old Linux Version](../installing-on-an-old-linux-version/index) | Typical errors from using an incompatible MariaDB binary on a linux system | | [Error: symbol mysql\_get\_server\_name, version libmysqlclient\_16 not defined](../error-symbol-mysql_get_server_name-version-libmysqlclient_16-not-defined/index) | Error from using MariaDB's mysql command-line client with MySQL's libmysqlclient.so | | [Installation Issues with PHP5](../installation-issues-with-php5/index) | PHP5 may give an error if used with the old connect method | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb TokuDB Resources TokuDB Resources ================ TokuDB has been deprecated by its upstream maintainer. It is disabled from [MariaDB 10.5](../what-is-mariadb-105/index) and has been been removed in [MariaDB 10.6](../what-is-mariadb-106/index) - [MDEV-19780](https://jira.mariadb.org/browse/MDEV-19780). We recommend [MyRocks](../myrocks/index) as a long-term migration path. This page contains links to various online resources for [TokuDB](../tokudb/index). Website ------- Tokutek was the primary developer of TokuDB before being acquired by Percona. [Their website](https://www.percona.com/software/mysql-database/percona-tokudb). Percona's TokuDB Documentation ------------------------------ * [TokuDB Documentation](https://www.percona.com/doc/percona-tokudb/index.html) Mailing Lists ------------- There were two TokuDB specific mailing lists run by Tokutek: * [tokudb-user](https://groups.google.com/forum/#!forum/tokudb-user) - a mailing list for users of TokuDB * [tokudb-dev](https://groups.google.com/forum/#!forum/tokudb-dev) - a mailing list TokuDB contributors These were discontinued and redirected to [Percona's MySQL and MariaDB forum](https://forums.percona.com/categories/mysql-mariadb). IRC --- Tokutek has a `#tokutek` [IRC](../irc/index) channel on [Freenode](http://freenode.net). The following link will take you to the `#tokutek` channel using Freenode's web IRC client: * <http://webchat.freenode.net/?randomnick=1&channels=tokutek&prompt=1> See Also -------- The [Where to find other MariaDB users and developers](../where-to-find-other-mariadb-users-and-developers/index) page has many great MariaDB resources listed. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema GEOMETRY_COLUMNS Table Information Schema GEOMETRY\_COLUMNS Table ========================================== Description ----------- The [Information Schema](../information_schema/index) `GEOMETRY_COLUMNS` table provides support for Spatial Reference systems for GIS data. It contains the following columns: | Column | Type | Null | Description | | --- | --- | --- | --- | | `F_TABLE_CATALOG` | `VARCHAR(512)` | NO | Together with `F_TABLE_SCHEMA` and `F_TABLE_NAME`, the fully qualified name of the featured table containing the geometry column. | | `F_TABLE_SCHEMA` | `VARCHAR(64)` | NO | Together with `F_TABLE_CATALOG` and `F_TABLE_NAME`, the fully qualified name of the featured table containing the geometry column. | | `F_TABLE_NAME` | `VARCHAR(64)` | NO | Together with `F_TABLE_CATALOG` and `F_TABLE_SCHEMA`, the fully qualified name of the featured table containing the geometry column. | | `F_GEOMETRY_COLUMN` | `VARCHAR(64)` | NO | Name of the column in the featured table that is the geometry golumn. | | `G_TABLE_CATALOG` | `VARCHAR(512)` | NO | | | `G_TABLE_SCHEMA` | `VARCHAR(64)` | NO | Database name of the table implementing the geometry column. | | `G_TABLE_NAME` | `VARCHAR(64)` | NO | Table name that is implementing the geometry column. | | `G_GEOMETRY_COLUMN` | `VARCHAR(64)` | NO | | | `STORAGE_TYPE` | `TINYINT(2)` | NO | Binary geometry implementation. Always 1 in MariaDB. | | `GEOMETRY_TYPE` | `INT(7)` | NO | Integer reflecting the type of geometry stored in this column (see table below). | | `COORD_DIMENSION` | `TINYINT(2)` | NO | Number of dimensions in the spatial reference system. Always 2 in MariaDB. | | `MAX_PPR` | `TINYINT(2)` | NO | Always 0 in MariaDB. | | `SRID` | `SMALLINT(5)` | NO | ID of the Spatial Reference System used for the coordinate geometry in this table. It is a foreign key reference to the `[SPATIAL\_REF\_SYS table](../information-schema-spatial_ref_sys-table/index)`. | Storage\_type ------------- The integers in the `storage_type` field match the geometry types as follows: | Integer | Type | | --- | --- | | 0 | `GEOMETRY` | | 1 | `POINT` | | 3 | `LINESTRING` | | 5 | `POLYGON` | | 7 | `MULTIPOINT` | | 9 | `MULTILINESTRING` | | 11 | `MULTIPOLYGON` | Example ------- ``` CREATE TABLE g1(g GEOMETRY(9,4) REF_SYSTEM_ID=101); SELECT * FROM information_schema.GEOMETRY_COLUMNS\G *************************** 1. row *************************** F_TABLE_CATALOG: def F_TABLE_SCHEMA: test F_TABLE_NAME: g1 F_GEOMETRY_COLUMN: G_TABLE_CATALOG: def G_TABLE_SCHEMA: test G_TABLE_NAME: g1 G_GEOMETRY_COLUMN: g STORAGE_TYPE: 1 GEOMETRY_TYPE: 0 COORD_DIMENSION: 2 MAX_PPR: 0 SRID: 101 ``` See also -------- * The `[SPATIAL\_REF\_SYS](../information-schema-spatial_ref_sys-table/index)` table. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb About XtraDB About XtraDB ============ Percona XtraDB was an enhanced version of the InnoDB storage engine [used in MariaDB before MariaDB 10.2](../why-does-mariadb-102-use-innodb-instead-of-xtradb/index), designed to better scale on modern hardware, and it includes a variety of other features useful in high performance environments. It is fully backwards compatible, and it identifies itself to MariaDB as "`ENGINE=InnoDB`" (just like InnoDB), and so can be used as a drop-in replacement for standard InnoDB. Percona XtraDB includes all of InnoDB's robust, reliable [ACID](../acid-concurrency-control-with-transactions/index)-compliant design and advanced MVCC architecture, and builds on that solid foundation with more features, more tunability, more metrics, and more scalability. In particular, it is designed to scale better on many cores, to use memory more efficiently, and to be more convenient and useful. The new features are especially designed to alleviate some of InnoDB's limitations. We choose features and fixes based on customer requests and on our best judgment of real-world needs as a high-performance consulting company. XtraDB was also available in MariaDB for Windows. Percona XtraDB versions in MariaDB ---------------------------------- ### [MariaDB 10.1](../what-is-mariadb-101/index) * XtraDB from [Percona Server 5.6.49-89.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.49-89.0.html) in [MariaDB 10.1.46](https://mariadb.com/kb/en/mariadb-10146-release-notes/) * XtraDB from [Percona Server 5.6.46-86.2](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.46-86.2.html) in [MariaDB 10.1.44](https://mariadb.com/kb/en/mariadb-10144-release-notes/) * XtraDB from [Percona Server 5.6.43-84.3](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.43-84.3.html) in [MariaDB 10.1.39](https://mariadb.com/kb/en/mariadb-10139-release-notes/) * XtraDB from [Percona Server 5.6.41-84.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.41-84.1.html) in [MariaDB 10.1.36](https://mariadb.com/kb/en/mariadb-10136-release-notes/) * XtraDB from [Percona Server 5.6.38-83.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.38-83.0.html)[[1](#_note-0)] in [MariaDB 10.1.31](https://mariadb.com/kb/en/mariadb-10131-release-notes/) * XtraDB from [Percona Server 5.6.37-82.2](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.37-82.2.html)[[2](#_note-1)]in [MariaDB 10.1.27](https://mariadb.com/kb/en/mariadb-10127-release-notes/) * XtraDB from [Percona Server 5.6.36-82.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.36-82.1.html) in [MariaDB 10.1.26](https://mariadb.com/kb/en/mariadb-10126-release-notes/) * XtraDB from [Percona Server 5.6.36-82.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.36-82.0.html) in [MariaDB 10.1.24](https://mariadb.com/kb/en/mariadb-10124-release-notes/) * XtraDB from [Percona Server 5.6.35-80.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.35-80.0.html) in [MariaDB 10.1.22](https://mariadb.com/kb/en/mariadb-10122-release-notes/) * XtraDB from [Percona Server 5.6.34-79.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.34-79.1.html) in [MariaDB 10.1.20](https://mariadb.com/kb/en/mariadb-10120-release-notes/) * XtraDB from [Percona Server 5.6.33-79.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.33-79.0.html)[[3](#_note-2)] in [MariaDB 10.1.19](https://mariadb.com/kb/en/mariadb-10119-release-notes/) * XtraDB from [Percona Server 5.6.32-78.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.32-78.1.html) in [MariaDB 10.1.18](https://mariadb.com/kb/en/mariadb-10118-release-notes/) * XtraDB from [Percona Server 5.6.31-77.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.31-77.0.html) in [MariaDB 10.1.17](https://mariadb.com/kb/en/mariadb-10117-release-notes/) * XtraDB from [Percona Server 5.6.30-76.3](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.30-76.3.html) in [MariaDB 10.1.15](https://mariadb.com/kb/en/mariadb-10115-release-notes/) * XtraDB from [Percona Server 5.6.29-76.2](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.29-76.2.html) in [MariaDB 10.1.14](https://mariadb.com/kb/en/mariadb-10114-release-notes/) * XtraDB from [Percona Server 5.6.28-76.1](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.28-76.1.html) in [MariaDB 10.1.12](https://mariadb.com/kb/en/mariadb-10112-release-notes/) * XtraDB from [Percona Server 5.6.26-76.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.26-76.0.html) in [MariaDB 10.1.10](https://mariadb.com/kb/en/mariadb-10110-release-notes/) * XtraDB from [Percona Server 5.6.26-74.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.26-74.0.html) in [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/) * XtraDB from [Percona Server 5.6.25-73.1](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.25-73.1.html) in [MariaDB 10.1.7](https://mariadb.com/kb/en/mariadb-1017-release-notes/) * XtraDB from [Percona Server 5.6.24-72.2](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.24-72.2.html) in [MariaDB 10.1.6](https://mariadb.com/kb/en/mariadb-1016-release-notes/) * XtraDB from [Percona Server 5.6.23-72.1](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.23-72.1.html) in [MariaDB 10.1.5](https://mariadb.com/kb/en/mariadb-1015-release-notes/) * XtraDB from [Percona Server 5.6.22-72.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.22-72.0.html) in [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/) * XtraDB from [Percona Server 5.6.21-70.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.21-70.0.html) in [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) * XtraDB from [Percona Server 5.6.17-65.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.17-65.0.html) in [MariaDB 10.1.1](https://mariadb.com/kb/en/mariadb-1011-release-notes/) ### [MariaDB 10.0](../what-is-mariadb-100/index) * XtraDB from [Percona Server 5.6.42-84.2](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.42-84.2.html) in [MariaDB 10.0.38](https://mariadb.com/kb/en/mariadb-10038-release-notes/) * XtraDB from [Percona Server 5.6.41-84.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.41-84.1.html) in [MariaDB 10.0.37](https://mariadb.com/kb/en/mariadb-10037-release-notes/) * XtraDB from [Percona Server 5.6.39-83.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.39-83.1.html) in [MariaDB 10.0.35](https://mariadb.com/kb/en/mariadb-10035-release-notes/) * XtraDB from [Percona Server 5.6.38-83.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.38-83.0.html)[[4](#_note-3)]in [MariaDB 10.0.34](https://mariadb.com/kb/en/mariadb-10034-release-notes/) * XtraDB from [Percona Server 5.6.37-82.2](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.37-82.2.html)[[5](#_note-4)]in [MariaDB 10.0.33](https://mariadb.com/kb/en/mariadb-10033-release-notes/) * XtraDB from [Percona Server 5.6.36-82.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.36-82.1.html) in [MariaDB 10.0.32](https://mariadb.com/kb/en/mariadb-10032-release-notes/) * XtraDB from [Percona Server 5.6.36-82.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.36-82.0.html) in [MariaDB 10.0.31](https://mariadb.com/kb/en/mariadb-10031-release-notes/) * XtraDB from [Percona Server 5.6.35-80.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.35-80.0.html) in [MariaDB 10.0.30](https://mariadb.com/kb/en/mariadb-10030-release-notes/) * XtraDB from [Percona Server 5.6.34-79.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.34-79.1.html) in [MariaDB 10.0.29](https://mariadb.com/kb/en/mariadb-10029-release-notes/) * XtraDB from [Percona Server 5.6.33-79.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.33-79.0.html)[[6](#_note-5)] in [MariaDB 10.0.28](https://mariadb.com/kb/en/mariadb-10028-release-notes/) * XtraDB from [Percona Server 5.6.31-77.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.31-77.0.html) in [MariaDB 10.0.27](https://mariadb.com/kb/en/mariadb-10027-release-notes/) * XtraDB from [Percona Server 5.6.30-76.3](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.30-76.3.html) in [MariaDB 10.0.26](https://mariadb.com/kb/en/mariadb-10026-release-notes/) * XtraDB from [Percona Server 5.6.29-76.2](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.29-76.2.html) in [MariaDB 10.0.25](https://mariadb.com/kb/en/mariadb-10025-release-notes/) * XtraDB from [Percona Server 5.6.28-76.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.28-76.1.html) in [MariaDB 10.0.24](https://mariadb.com/kb/en/mariadb-10024-release-notes/) * XtraDB from [Percona Server 5.6.27-76.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.27-76.0.html) in [MariaDB 10.0.23](https://mariadb.com/kb/en/mariadb-10023-release-notes/) * XtraDB from [Percona Server 5.6.26-74.0](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.26-74.0.html) in [MariaDB 10.0.22](https://mariadb.com/kb/en/mariadb-10022-release-notes/) * XtraDB from [Percona Server 5.6.25-73.1](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.25-73.1.html) in [MariaDB 10.0.21](https://mariadb.com/kb/en/mariadb-10021-release-notes/) * XtraDB from [Percona Server 5.6.24-72.2](https://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.24-72.2.html) in [MariaDB 10.0.20](https://mariadb.com/kb/en/mariadb-10020-release-notes/) * XtraDB from [Percona Server 5.6.23-72.1](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.23-72.1.html) in [MariaDB 10.0.18](https://mariadb.com/kb/en/mariadb-10018-release-notes/) * XtraDB from [Percona Server 5.6.22-72.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.22-72.0.html) in [MariaDB 10.0.17](https://mariadb.com/kb/en/mariadb-10017-release-notes/) * XtraDB from [Percona Server 5.6.22-71.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.22-71.0.html) in [MariaDB 10.0.16](https://mariadb.com/kb/en/mariadb-10016-release-notes/) * XtraDB from [Percona Server 5.6.21-70.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.21-70.0.html) in [MariaDB 10.0.15](https://mariadb.com/kb/en/mariadb-10015-release-notes/) * XtraDB from [Percona Server 5.6.20-68.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.20-68.0.html) in [MariaDB 10.0.14](https://mariadb.com/kb/en/mariadb-10014-release-notes/) * XtraDB from [Percona Server 5.6.19-67.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.19-67.0.html) in [MariaDB 10.0.13](https://mariadb.com/kb/en/mariadb-10013-release-notes/) * XtraDB from [Percona Server 5.6.17-65.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.17-65.0.html) in [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/) * XtraDB from [Percona Server 5.6.14-rel62.0](http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.14-62.0.html) in [MariaDB 10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/) ### [MariaDB 5.5](../what-is-mariadb-55/index) * XtraDB from [Percona Server 5.5.61-38.13](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.61-38.13.html) in [MariaDB 5.5.62](https://mariadb.com/kb/en/mariadb-5562-release-notes/) * XtraDB from [Percona Server 5.5.59-38.11](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.59-38.11.html) in [MariaDB 5.5.60](https://mariadb.com/kb/en/mariadb-5560-release-notes/) * XtraDB from [Percona Server 5.5.58-38.10](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.58-38.10.html) in [MariaDB 5.5.59](https://mariadb.com/kb/en/mariadb-5559-release-notes/) * XtraDB from [Percona Server 5.5.55-38.9](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.55-38.9.html) in [MariaDB 5.5.58](https://mariadb.com/kb/en/mariadb-5558-release-notes/) * XtraDB from [Percona Server 5.5.55-38.8](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.55-38.8.html) in [MariaDB 5.5.57](https://mariadb.com/kb/en/mariadb-5557-release-notes/) * XtraDB from [Percona Server 5.5.52-38.3](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.52-38.3.html) in [MariaDB 5.5.53](https://mariadb.com/kb/en/mariadb-5553-release-notes/) * XtraDB from [Percona Server 5.5.50-38.0](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.50-38.0.html) in [MariaDB 5.5.51](https://mariadb.com/kb/en/mariadb-5551-release-notes/) * XtraDB from [Percona Server 5.5.49-37.9](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.49-37.9.html) in [MariaDB 5.5.50](https://mariadb.com/kb/en/mariadb-5550-release-notes/) * XtraDB from [Percona Server 5.5.48-37.8](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.48-37.8.html) in [MariaDB 5.5.49](https://mariadb.com/kb/en/mariadb-5549-release-notes/) * XtraDB from [Percona Server 5.5.46-37.7](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.46-37.7.html) in [MariaDB 5.5.48](https://mariadb.com/kb/en/mariadb-5548-release-notes/) * XtraDB from [Percona Server 5.5.46-37.6](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.46-37.6.html) in [MariaDB 5.5.47](https://mariadb.com/kb/en/mariadb-5547-release-notes/) * XtraDB from [Percona Server 5.5.45-37.4](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.45-37.4.html) in [MariaDB 5.5.46](https://mariadb.com/kb/en/mariadb-5546-release-notes/) * XtraDB from [Percona Server 5.5.44-37.3](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.44-37.3.html) in [MariaDB 5.5.45](https://mariadb.com/kb/en/mariadb-5545-release-notes/) * XtraDB from [Percona Server 5.5.42-37.2](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.42-37.2.html) in [MariaDB 5.5.44](https://mariadb.com/kb/en/mariadb-5544-release-notes/) * XtraDB from [Percona Server 5.5.42-37.1](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.42-37.1.html) in [MariaDB 5.5.43](https://mariadb.com/kb/en/mariadb-5543-release-notes/) * XtraDB from [Percona Server 5.5.40-36.1](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.40-36.1.html) in [MariaDB 5.5.40](https://mariadb.com/kb/en/mariadb-5540-release-notes/) * XtraDB from [Percona Server 5.5.38-35.2](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.38-35.2.html) in [MariaDB 5.5.39](https://mariadb.com/kb/en/mariadb-5539-release-notes/) * XtraDB from [Percona Server 5.5.37-35.0](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.37-35.0.html) in [MariaDB 5.5.38](https://mariadb.com/kb/en/mariadb-5538-release-notes/) * XtraDB from [Percona Server 5.5.36-34.0](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.36-34.0.html) in [MariaDB 5.5.37](https://mariadb.com/kb/en/mariadb-5537-release-notes/) * XtraDB from [Percona Server 5.5.35-33.0](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.35-33.0.html) in [MariaDB 5.5.35](https://mariadb.com/kb/en/mariadb-5535-release-notes/) * XtraDB from [Percona Server 5.5.34-32.0](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.34-32.0.html) in [MariaDB 5.5.34](https://mariadb.com/kb/en/mariadb-5534-release-notes/) * XtraDB from [Percona Server 5.5.33-31.1](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.33-31.1.html) in [MariaDB 5.5.33](https://mariadb.com/kb/en/mariadb-5533-release-notes/) * XtraDB from [Percona Server-5.5.32-31.0](http://www.percona.com/doc/percona-server/5.5/release-notes/Percona-Server-5.5.32-31.0.html) in [MariaDB 5.5.32](https://mariadb.com/kb/en/mariadb-5532-release-notes/) ### [MariaDB 5.2](../what-is-mariadb-52/index) and [MariaDB 5.3](../what-is-mariadb-53/index) * [MariaDB 5.2](../what-is-mariadb-52/index) and 5.3 include the latest XtraDB version from [MariaDB 5.1](../what-is-mariadb-51/index) at the time they were released. ### [MariaDB 5.1](../what-is-mariadb-51/index) * version [5.1.59-13](http://www.percona.com/doc/percona-server/5.1/release-notes/Percona-Server-5.1.59-13.0.html) in [MariaDB 5.1.60](https://mariadb.com/kb/en/mariadb-5160-release-notes/) * version 5.1.54-12.5 in [MariaDB 5.1.55](https://mariadb.com/kb/en/mariadb-5155-release-notes/) * version 5.1.52-11.6 in [MariaDB 5.2.4](https://mariadb.com/kb/en/mariadb-524-release-notes/) and [5.1.53](https://mariadb.com/kb/en/mariadb-5153-release-notes/) * version 5.1.49-12 in [MariaDB 5.1.50](https://mariadb.com/kb/en/mariadb-5150-release-notes/) * version [5.1.47-11.2](http://www.percona.com/docs/wiki/percona-server:release_notes_51#release_5147-112) in [MariaDB 5.1.49](https://mariadb.com/kb/en/mariadb-5149-release-notes/) * version 1.0.6-10 in [MariaDB 5.1.47](https://mariadb.com/kb/en/mariadb-5147-release-notes/) * version 1.0.6-9 in [MariaDB 5.1.42](https://mariadb.com/kb/en/mariadb-5142-release-notes/), [5.1.44](https://mariadb.com/kb/en/mariadb-5144-release-notes/), and [5.1.44b](https://mariadb.com/kb/en/mariadb-5144b-release-notes/). * version 1.0.4-8 in [MariaDB 5.1.41 RC](https://mariadb.com/kb/en/mariadb-5141-release-notes/) * version 1.0.3-8 in [MariaDB 5.1.39 Beta](https://mariadb.com/kb/en/mariadb-5139-release-notes/) * version 1.0.3-6 in [MariaDB 5.1.38 Beta](https://mariadb.com/kb/en/mariadb-5138-release-notes/) Notes ----- 1. [↑](#_ref-0) Misidentifies itself as 5.6.36-83.0 in [MariaDB 10.1.31](https://mariadb.com/kb/en/mariadb-10131-release-notes/) 2. [↑](#_ref-1) Misidentifies itself as 5.6.36-82.2 from [MariaDB 10.1.27](https://mariadb.com/kb/en/mariadb-10127-release-notes/) to [MariaDB 10.1.30](https://mariadb.com/kb/en/mariadb-10130-release-notes/) 3. [↑](#_ref-2) Misidentifies itself as 5.6.32-79.0 in [MariaDB 10.1.19](https://mariadb.com/kb/en/mariadb-10119-release-notes/) 4. [↑](#_ref-3) Misidentifies itself as 5.6.36-83.0 in [MariaDB 10.0.34](https://mariadb.com/kb/en/mariadb-10034-release-notes/) 5. [↑](#_ref-4) Misidentifies itself as 5.6.36-82.2 in [MariaDB 10.0.33](https://mariadb.com/kb/en/mariadb-10033-release-notes/) 6. [↑](#_ref-5) Misidentifies itself as 5.6.32-79.0 in [MariaDB 10.0.28](https://mariadb.com/kb/en/mariadb-10028-release-notes/) See Also -------- More information can be found in the [Percona documentation](https://www.percona.com/doc/percona-server/5.5/percona_xtradb.html?id=percona-xtradb:start). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb quote_identifier quote\_identifier ================= Syntax ------ ``` sys.quote_identifier(str) ``` Description ----------- `quote_identifier` is a [stored function](../stored-functions/index) available with the [Sys Schema](../sys-schema/index). It quotes a string to produce a result that can be used as an identifier in an SQL statement. The string is returned enclosed by backticks ("```") and with each instance of backtick ("```") doubled. If the argument is `NULL`, the return value is the word "`NULL`" without enclosing backticks. Examples -------- ``` SELECT sys.quote_identifier("Identifier with spaces"); +------------------------------------------------+ | sys.quote_identifier("Identifier with spaces") | +------------------------------------------------+ | `Identifier with spaces` | +------------------------------------------------+ SELECT sys.quote_identifier("Identifier` containing `backticks"); +-----------------------------------------------------------+ | sys.quote_identifier("Identifier` containing `backticks") | +-----------------------------------------------------------+ | `Identifier`` containing ``backticks` | +-----------------------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb JSON_MERGE_PRESERVE JSON\_MERGE\_PRESERVE ===================== **MariaDB starting with [10.2.25](https://mariadb.com/kb/en/mariadb-10225-release-notes/)**`JSON_MERGE_PRESERVE` was introduced in [MariaDB 10.2.25](https://mariadb.com/kb/en/mariadb-10225-release-notes/), [MariaDB 10.3.16](https://mariadb.com/kb/en/mariadb-10316-release-notes/) and [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/). Syntax ------ ``` JSON_MERGE_PRESERVE(json_doc, json_doc[, json_doc] ...) ``` Description ----------- Merges the given JSON documents, returning the merged result, or NULL if any argument is NULL. `JSON_MERGE_PRESERVE` was introduced in [MariaDB 10.2.25](https://mariadb.com/kb/en/mariadb-10225-release-notes/), [MariaDB 10.3.16](https://mariadb.com/kb/en/mariadb-10316-release-notes/) and [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/) as a synonym for [JSON\_MERGE](../json_merge/index), which has been deprecated. Example ------- ``` SET @json1 = '[1, 2]'; SET @json2 = '[2, 3]'; SELECT JSON_MERGE_PATCH(@json1,@json2),JSON_MERGE_PRESERVE(@json1,@json2); +---------------------------------+------------------------------------+ | JSON_MERGE_PATCH(@json1,@json2) | JSON_MERGE_PRESERVE(@json1,@json2) | +---------------------------------+------------------------------------+ | [2, 3] | [1, 2, 2, 3] | +---------------------------------+------------------------------------+ ``` See Also -------- * [JSON\_MERGE\_PATCH](../json_merge_patch/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_statements_current Table Performance Schema events\_statements\_current Table ==================================================== The `events_statements_current` table contains current statement events, with each row being a record of a thread and its most recent statement event. The table contains the following columns: | Column | Description | | --- | --- | | `THREAD_ID` | Thread associated with the event. Together with `EVENT_ID` uniquely identifies the row. | | `EVENT_ID` | Thread's current event number at the start of the event. Together with `THREAD_ID` uniquely identifies the row. | | `END_EVENT_ID` | `NULL` when the event starts, set to the thread's current event number at the end of the event. | | `EVENT_NAME` | Event instrument name and a `NAME` from the `setup_instruments` table | | `SOURCE` | Name and line number of the source file containing the instrumented code that produced the event. | | `TIMER_START` | Value in picoseconds when the event timing started or `NULL` if timing is not collected. | | `TIMER_END` | Value in picoseconds when the event timing ended, or `NULL` if the event has not ended or timing is not collected. | | `TIMER_WAIT` | Value in picoseconds of the event's duration or `NULL` if the event has not ended or timing is not collected. | | `LOCK_TIME` | Time in picoseconds spent waiting for locks. The time is calculated in microseconds but stored in picoseconds for compatibility with other timings. | | `SQL_TEXT` | The SQL statement, or `NULL` if the command is not associated with an SQL statement. | | `DIGEST` | [Statement digest](../performance-schema-digests/index). | | `DIGEST_TEXT` | [Statement digest](../performance-schema-digests/index) text. | | `CURRENT_SCHEMA` | Statement's default database for the statement, or `NULL` if there was none. | | `OBJECT_SCHEMA` | Reserved, currently `NULL` | | `OBJECT_NAME` | Reserved, currently `NULL` | | `OBJECT_TYPE` | Reserved, currently `NULL` | | `OBJECT_INSTANCE_BEGIN` | Address in memory of the statement object. | | `MYSQL_ERRNO` | Error code. See [MariaDB Error Codes](../mariadb-error-codes/index) for a full list. | | `RETURNED_SQLSTATE` | The [SQLSTATE](../sqlstate/index) value. | | `MESSAGE_TEXT` | Statement error message. See [MariaDB Error Codes](../mariadb-error-codes/index). | | `ERRORS` | `0` if `SQLSTATE` signifies completion (starting with 00) or warning (01), otherwise `1`. | | `WARNINGS` | Number of warnings from the diagnostics area. | | `ROWS_AFFECTED` | Number of rows affected the statement affected. | | `ROWS_SENT` | Number of rows returned. | | `ROWS_EXAMINED` | Number of rows read during the statement's execution. | | `CREATED_TMP_DISK_TABLES` | Number of on-disk temp tables created by the statement. | | `CREATED_TMP_TABLES` | Number of temp tables created by the statement. | | `SELECT_FULL_JOIN` | Number of joins performed by the statement which did not use an index. | | `SELECT_FULL_RANGE_JOIN` | Number of joins performed by the statement which used a range search of the first table. | | `SELECT_RANGE` | Number of joins performed by the statement which used a range of the first table. | | `SELECT_RANGE_CHECK` | Number of joins without keys performed by the statement that check for key usage after each row. | | `SELECT_SCAN` | Number of joins performed by the statement which used a full scan of the first table. | | `SORT_MERGE_PASSES` | Number of merge passes by the sort algorithm performed by the statement. If too high, you may need to increase the [sort\_buffer\_size](../server-system-variables/index#sort_buffer_size). | | `SORT_RANGE` | Number of sorts performed by the statement which used a range. | | `SORT_ROWS` | Number of rows sorted by the statement. | | `SORT_SCAN` | Number of sorts performed by the statement which used a full table scan. | | `NO_INDEX_USED` | `0` if the statement performed a table scan with an index, `1` if without an index. | | `NO_GOOD_INDEX_USED` | `0` if a good index was found for the statement, `1` if no good index was found. See the `Range checked for each record description` in the [EXPLAIN](../explain/index) article. | | `NESTING_EVENT_ID` | Reserved, currently `NULL`. | | `NESTING_EVENT_TYPE` | Reserved, currently `NULL`. | It is possible to empty this table with a `TRUNCATE TABLE` statement. The related tables, [events\_statements\_history](../performance-schema-events_statements_history-table/index) and [events\_statements\_history\_long](../performance-schema-events_statements_history_long-table/index) derive their values from the current events table. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Buildbot Development Buildbot Development ==================== Developing on the Buildbot code ------------------------------- Buildbot has all of the right ideas for solving the problem of maintaining a complex codebase like MariaDB at a high level of quality. However, there are some smaller fixes and extensions we need to develop on the Buildbot code. Here I describe how I set up an environment for hacking on the buildbot code. Readers beware, I am a Perl guy, so this may not reflect how a Python person would choose to do things. First I installed the virtualenv Python package: ``` tar zxf virtualenv-1.3.3.tar.gz cd virtualenv-1.3.3/ mkdir -p /home/knielsen/python/lib/python/ PYTHONPATH="$HOME/python/lib/python" python setup.py install --home="$HOME/python" cd .. PYTHONPATH="$HOME/python/lib/python" ~/python/bin/virtualenv sandbox ``` Then I cloned the latest BuildBot tree from the Git repository: ``` git clone git://github.com/djmitche/buildbot.git cd buildbot/ ``` Install the BuildBot code in the virtualenv sandbox in development mode and run the test suite. (The virtualenv stuff has a script sandbox/bin/activate that is the recommended way to use things. However, I really dislike keeping that kind of state in the shell, since it means shell commands (for example copy-pasted from history) will behave differently depending on when and where they are run. That is the reason for passing the PYTHONPATH directly on the command line.) ``` PYTHONPATH="$HOME/python/lib/python" ~/devel/buildbot/sandbox/bin/python setup.py develop PYTHONPATH="$HOME/python/lib/python" ~/devel/buildbot/sandbox/bin/python /usr/bin/trial buildbot.test ``` *[I get the error "error: Could not find suitable distribution for Requirement.parse('Twisted==2.5.0')" on the first of these commands, but things seem to work ok anyway (I installed all buildbot dependencies via Ubuntu apt-get packages).]* Once that works, one can install a master and a slave and start them running each in their own terminal window for easy access to log: ``` cd .. PYTHONPATH="$HOME/python/lib/python" sandbox/bin/buildbot create-master master cp buildbot/contrib/bzr_buildbot.py master/ # Edit master/master.cfg as appropriate cd master PYTHONPATH="$HOME/python/lib/python" ../sandbox/bin/python /usr/bin/twistd --nodaemon --no_save -y buildbot.tac cd .. PYTHONPATH="$HOME/python/lib/python" sandbox/bin/buildbot create-slave slave localhost:9989 test testpass # Edit slave/info/* as appropriate cd slave PYTHONPATH="$HOME/python/lib/python" ../sandbox/bin/python /usr/bin/twistd --nodaemon --no_save -y buildbot.tac ``` With this I was able to hack away at the code and just restart the master and slave to test stuff. The web status pages will be on <http://localhost:8010/> See also -------- * [BuildBot ToDo](../buildbot-todo/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb IGNORE IGNORE ====== The `IGNORE` option tells the server to ignore some common errors. `IGNORE` can be used with the following statements: * [DELETE](../delete/index) * [INSERT](../insert/index) (see also [INSERT IGNORE](../insert-ignore/index)) * [LOAD DATA INFILE](../load-data-infile/index) * [UPDATE](../update/index) * [ALTER TABLE](../alter-table/index) * [CREATE TABLE ... SELECT](../create-table/index#create-select) * [INSERT ... SELECT](../insert-select/index) The logic used: * Variables out of ranges are replaced with the maximum/minimum value. * [SQL\_MODEs](../sql_mode/index) `STRICT_TRANS_TABLES`, `STRICT_ALL_TABLES`, `NO_ZERO_IN_DATE`, `NO_ZERO_DATE` are ignored. * Inserting `NULL` in a `NOT NULL` field will insert 0 ( in a numerical field), 0000-00-00 ( in a date field) or an empty string ( in a character field). * Rows that cause a duplicate key error or break a foreign key constraint are not inserted, updated, or deleted. The following errors are ignored: | Error number | Symbolic error name | Description | | --- | --- | --- | | `1022` | `ER_DUP_KEY` | Can't write; duplicate key in table '%s' | | `1048` | `ER_BAD_NULL_ERROR` | Column '%s' cannot be null | | `1062` | `ER_DUP_ENTRY` | Duplicate entry '%s' for key %d | | `1242` | `ER_SUBQUERY_NO_1_ROW` | Subquery returns more than 1 row | | `1264` | `ER_WARN_DATA_OUT_OF_RANGE` | Out of range value for column '%s' at row %ld | | `1265` | `WARN_DATA_TRUNCATED` | Data truncated for column '%s' at row %ld | | `1292` | `ER_TRUNCATED_WRONG_VALUE` | Truncated incorrect %s value: '%s' | | `1366` | `ER_TRUNCATED_WRONG_VALUE_FOR_FIELD` | Incorrect integer value | | `1369` | `ER_VIEW_CHECK_FAILED` | `CHECK OPTION failed '%s.%s'` | | `1451` | `ER_ROW_IS_REFERENCED_2` | Cannot delete or update a parent row | | `1452` | `ER_NO_REFERENCED_ROW_2` | Cannot add or update a child row: a foreign key constraint fails (%s) | | `1526` | `ER_NO_PARTITION_FOR_GIVEN_VALUE` | Table has no partition for value %s | | `1586` | `ER_DUP_ENTRY_WITH_KEY_NAME` | Duplicate entry '%s' for key '%s' | | `1591` | `ER_NO_PARTITION_FOR_GIVEN_VALUE_SILENT` | Table has no partition for some existing values | | `1748` | `ER_ROW_DOES_NOT_MATCH_GIVEN_PARTITION_SET` | Found a row not matching the given partition set | Ignored errors normally generate a warning. A property of the `IGNORE` clause consists in causing transactional engines and non-transactional engines (like XtraDB and Aria) to behave the same way. For example, normally a multi-row insert which tries to violate a `UNIQUE` contraint is completely rolled back on XtraDB/InnoDB, but might be partially executed on Aria. With the `IGNORE` clause, the statement will be partially executed in both engines. Duplicate key errors also generate warnings. The [OLD\_MODE](../old_mode/index) server variable can be used to prevent this. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SHOW TABLE STATUS SHOW TABLE STATUS ================= Syntax ------ ``` SHOW TABLE STATUS [{FROM | IN} db_name] [LIKE 'pattern' | WHERE expr] ``` Description ----------- `SHOW TABLE STATUS` works like `[SHOW TABLES](../show-tables/index)`, but provides more extensive information about each non-`TEMPORARY` table. The `LIKE` clause, if present on its own, indicates which table names to match. The `WHERE` and `LIKE` clauses can be given to select rows using more general conditions, as discussed in [Extended SHOW](../extended-show/index). The following information is returned: | Column | Description | | --- | --- | | Name | Table name. | | Engine | Table [storage engine](../storage-engines/index). | | Version | Version number from the table's .frm file. | | Row\_format | Row format (see [InnoDB](../xtradbinnodb-storage-formats/index), [Aria](../aria-storage-formats/index) and [MyISAM](../myisam-storage-formats/index) row formats). | | Rows | Number of rows in the table. Some engines, such as [XtraDB and InnoDB](../innodb/index) may store an estimate. | | Avg\_row\_length | Average row length in the table. | | Data\_length | For [InnoDB/XtraDB](../innodb/index), the index size, in pages, multiplied by the page size. For [Aria](../aria/index) and [MyISAM](../myisam/index), length of the data file, in bytes. For [MEMORY](../memory-storage-engine/index), the approximate allocated memory. | | Max\_data\_length | Maximum length of the data file, ie the total number of bytes that could be stored in the table. Not used in [XtraDB and InnoDB](../innodb/index). | | Index\_length | Length of the index file. | | Data\_free | Bytes allocated but unused. For InnoDB tables in a shared tablespace, the free space of the shared tablespace with small safety margin. An estimate in the case of partitioned tables - see the `[PARTITIONS](../information-schema-partitions-table/index)` table. | | Auto\_increment | Next `[AUTO\_INCREMENT](../auto_increment/index)` value. | | Create\_time | Time the table was created. Some engines just return the ctime information from the file system layer here, in that case the value is not necessarily the table creation time but rather the time the file system metadata for it had last changed. | | Update\_time | Time the table was last updated. On Windows, the timestamp is not updated on update, so MyISAM values will be inaccurate. In [InnoDB](../innodb/index), if shared tablespaces are used, will be `NULL`, while buffering can also delay the update, so the value will differ from the actual time of the last `UPDATE`, `INSERT` or `DELETE`. | | Check\_time | Time the table was last checked. Not kept by all storage engines, in which case will be `NULL`. | | Collation | [Character set and collation](../data-types-character-sets-and-collations/index). | | Checksum | Live checksum value, if any. | | Create\_options | Extra `[CREATE TABLE](../create-table/index)` options. | | Comment | Table comment provided when MariaDB created the table. | | Max\_index\_length | Maximum index length (supported by MyISAM and Aria tables). Added in [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/). | | Temporary | Placeholder to signal that a table is a temporary table. Currently always "N", except "Y" for generated information\_schema tables and NULL for [views](../views/index). Added in [MariaDB 10.3.5](https://mariadb.com/kb/en/mariadb-1035-release-notes/). | Similar information can be found in the `[information\_schema.TABLES](../information-schema-tables-table/index)` table as well as by using `[mysqlshow](../mysqlshow/index)`: ``` mysqlshow --status db_name ``` Views ----- For views, all columns in `SHOW TABLE STATUS` are `NULL` except 'Name' and 'Comment' Example ------- ``` show table status\G *************************** 1. row *************************** Name: bus_routes Engine: InnoDB Version: 10 Row_format: Dynamic Rows: 5 Avg_row_length: 3276 Data_length: 16384 Max_data_length: 0 Index_length: 0 Data_free: 0 Auto_increment: NULL Create_time: 2017-05-24 11:17:46 Update_time: NULL Check_time: NULL Collation: latin1_swedish_ci Checksum: NULL Create_options: Comment: ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DbSchema DbSchema ======== Powerful, yet easy-to-use, DbSchema helps you design, document and manage databases without having to be a SQL pro. Easily design new tables, generate HTML5 documentation, explore and edit the database data, compare and synchronize the schema over multiple databases, edit and execute SQL, generate random data. DbSchema is compatible with all relational and few No-SQL databases. It works on all major operating systems, including Windows, Linux and Mac. You can download and evaluate DbSchema 15 days for free. [DBSchema Webpage](https://www.dbschema.com/index.html) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SHOW QUERY_RESPONSE_TIME SHOW QUERY\_RESPONSE\_TIME ========================== It is possible to use `SHOW QUERY_RESPONSE_TIME` as an alternative for retrieving information from the [QUERY\_RESPONSE\_TIME](../query_response_time-plugin/index) plugin. This was introduced as part of the [Information Schema plugin extension](../information-schema-plugins-show-and-flush-statements/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Replication as a Backup Solution Replication as a Backup Solution ================================ [Replication](../replication/index) can be used to support the [backup](../backing-up-and-restoring/index) strategy. Replication alone is *not* sufficient for backup. It assists in protecting against hardware failure on the master server, but does not protect against data loss. An accidental or malicious `DROP DATABASE` or `TRUNCATE TABLE` statement will be replicated onto the slaves as well. Care needs to be taken to prevent data getting out of sync between the master and the slave. The terms *master* and *slave* have historically been used in replication, but the terms terms *primary* and *replica* are now preferred. The old terms are used still used in parts of the documentation, and in MariaDB commands, although [MariaDB 10.5](../what-is-mariadb-105/index) has begun the process of renaming. The documentation process is ongoing. See [MDEV-18777](https://jira.mariadb.org/browse/MDEV-18777) to follow progress on this effort. Replication is most commonly used to support backups as follows: * A master server replicates to a slave server * Backups are then run off the slave without any impact on the master. Backups can have a significant effect on a server, and a high-availability master may not be able to be stopped, locked or simply handle the extra load of a backup. Running the backup from a slave has the advantage of being able to shutdown or lock the slave and perform a backup without any impact on the primary server. Note that when backing up off a slave server, it is important to ensure that the servers keep the data in sync. See for example [Replication and Foreign Keys](../replication-and-foreign-keys/index) for a situation when identical statements can result in different data on a slave and a master. See Also -------- * [Replication](../replication/index) * [Replication Compatibility](../mariadb-vs-mysql-compatibility/index#replication-compatibility) * [Backing Up and Restoring](../backing-up-and-restoring/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Buildbot Setup for Windows Buildbot Setup for Windows ========================== This is the recipe for setting up a MariaDB Buildbot slave on Windows: 1. Prepare the [development environment](../building_mariadb_on_windows/index) 2. Install [Python](http://www.python.org/download/), 32 bit. Twisted does not work on 64 bit and builtbot hasn't been tested properly with Python version 3. *Note: As of June 2016, there is no fresh Twistd for 32-bit Python, so a 64-bit version has to be installed. Installed 2.7.11 64-bit, it seems to work.* 3. Install [pywin32](http://sourceforge.net/projects/pywin32/files). Make sure the version matches your Python version perfectly, and get the .exe file, not the zip file. *Note: As of June 2016, used `pywin32-220.win-amd64-py2.7.exe`, it seems to work.* 4. Install [Twisted](http://twistedmatrix.com/trac/wiki/Downloads) *Note: As of June 2016, used `Twisted 16.2.0 for Python 2.7 64 bits`* 5. Install [buildbot](http://buildbot.net): Get the zip file and unpack it. In an administrator shell, cd to the buildbot dir and run "python setup.py install". After that, the unpacked buildbot directory is no longer needed. *Note: As of June 2016, used `buildbot 0.8.12`.* When this has been done, you run these commands: ``` cd <somewhere> mkdir buildbot cd buildbot bzr init-repo . C:\buildbot\buildbot-slave-0.8.3\build\scripts-2.7\buildslave.bat create-slave --usepty=0 <slavedir> hasky.askmonty.org:9989 <slavename> <passwd> ``` Adjust paths in the last command according to the location of your unpacked buildbot. You get <slavename> and <passwd> from one of the MariaDB Corporation or MariaDB Foundation people handling the buildbot system. <slavedir> can be whatever you want - <slavename> is a good choice. Please edit the files <slavedir>\info\admin and <slavedir>\info\host with your information. The host information should include your Windows version, 32 or 64 bit, and your Visual Studio version. You can test the buildbot slave with this command: ``` C:\buildbot\buildbot-slave-0.8.3\build\scripts-2.7\buildslave.bat start <somewhere>\buildbot\<slavedir> ``` When buildbot starts, you should confgure it as a service instead of manually. See the instructions [here](http://buildbot.net/trac/wiki/RunningBuildbotOnWindows). It's under the section "Windows Buildbot service setup". This document also has the generic Windows Buildbot installation documentation. Why buildbot should run as service ---------------------------------- When buildbot is running in user session, and application that is started by buildbot crashes, you'll get a crash popup. There are popups that are generated by post-mortem debugging and there are popups that are generated by Windows Error reporting. It is hard (or impossible for those who did not try this before) to get rid of all popups. Thus, do run buildbot as service. There are no popups in services. Common Windows Buildbot Failures -------------------------------- ### Test hangs after trying to call cdb to print a backtrace. MTR attempts to call `cdb` via the Perl backticks operator, when mysqld.exe crashes. On the first run, cdb is downloading public Windows symbols from msdl.microsoft.com/download/symbols. The symbols are cached in C:\cdb\_symbols, and following runs will be faster, however crashdump analysis on very first crash will typically take some time. If you find this bothering, start the test with `--mysqld=--gdb` which will cause no crashdump files to be created and thus will prevent `cdb` from being called. ### Buildbot exception `The process cannot access the file because it is being used by another process` This is due to the fact that buildbot does not clean up any processes left over from a previous run, and those processes may hold locks on files that are needed for a new build to start. Current workaround is to use windows job objects that allow to terminate entire process trees. We use special "process launcher" utility called "`dojob` . This will also require changing buildbot configuration for the builder. Download [dojob.cpp](http://bazaar.launchpad.net/~maria-captains/mariadb-tools/trunk/view/head:/buildbot/dojob.cpp), and compile it with ``` cl dojob.cpp ``` Then, put dojob.exe into a directory in the PATH [environment variable](../mariadb-environment-variables/index). Then, change buildbot configuration to use "dojob" for every command, as a replacement for "cmd /c", e.g ``` factory.addStep(Compile( name = "cmake", command=["dojob", WithProperties("cd c:\\buildbot\\%(buildername)s\\build && cmake .")] )); ``` ### Buildbot exception `ShellCommand.failed: command failed: SIGKILL failed to kill process` (Seen very seldom?). This usually happens after retrying multiple failing tests multiple times. It appears that MTR's `--retries=` option is not safe to use on Windows. The solution is to run the test with no `--retries`. ### Buildbot exception `Connection to the other side was lost in a non-clean fashion.` This is a sympthom of intermittent network issues, which cause Buildbot to abort the current build altogether. The following workarounds are possible: * In your `buildbot.tac` file, specify a higher `keepalive` value, such as 60000. *Note: For the current versions (as of June 2016), the opposite solution worked: keepalive = 60. KeepAliveTime in the Windows registry has been set to 60000 as suggested below, but there is no proof it made any difference.* * If you are running the Windows host inside VMWare, substitute the `e1000` network adapter with `vmxnet3` * If your build host is behind a firewall, makes sure that the firewall does not time out any idle connections quickly. Configure at least a 24-hour timeout. * If your build host is behind a firewall, consider disabling the built-in Windows Firewall in order to avoid one potential point of failure. * Modify the Windows `KeepAliveTime` registry setting to a lower value, such as 60000 (equal to 60 seconds). For more information, see [TechNet](http://technet.microsoft.com/en-us/library/cc957549.aspx) * Make sure the buildbot master does not experience prolonged bouts of 100% CPU activity, as this may prevent keepalives from working. If the buildbot master `twisted.log` says that data is frequently being loaded from on-disk pickles, increase the `buildCacheSize` in the master configuration file to be more than the number of builds per builder that the log file reports are being loaded. Alternative Windows Buildbot setup (experimental) ================================================= In case the default Windows buildbot setup is not sufficiently reliable due to "connection lost in a non-clean fashion" errors, the following setup can be used instead. It runs the buildbot deamon on a linux host while doing the builds on Windows, thus working around Twisted issues on Windows. **Note that the procedure below \_significantly\_ degrades the overall security of your Windows host. It is strongly recommended that a properly-firewalled, standalone virtual machine is used.** * Set the Windows server to auto-login with the user the builds will run as. This will prevent any issues relating to running things as a service and the privilege considerations associated with services; * Install FreeSSHd on Windows. The OpenSSHd/Cygwin combo is not likely to work. + Do not run FreeSSHd it as a service, but rather as a startup console application for the user you are running the builds under. This allows FreeSSHd UI to properly operate; + Generate a private/public key pair using PuTTYGen and place the public part in a properly named file in the key directory specified in the FreeSSHd GUI + Using the FreeSSHd GUI, create a new user and set it to use key authentication; + Set the SFTP home path to the directory where builds will take place. * Disable UAC (User Access Control) (or set to lowest level) by using the Users Control Panel. Add your buildbot user to the Administrators group. * Export the private key from PuTTYGen and copy it to a Linux host. * Install buildbot on the Linux host * The buildbot configuration file will then look something like: ``` f_win2008r2_i386_release.addStep(ShellCommand( command=["ssh", "-i", "/home/buildbot/keys/id_rsa", "buildbot@win2008r2-build", "cmd", "/C", "whoami"] )); ``` The following buildbot considerations apply under this setup: * buildbot will not perform a proper cleanup of the build directory on the Windows host before each build (it will only clean up things on the linux side). So, a directory cleanup via rmdir must be placed as as an explicit first step in the build sequence; * Bzr() can not be used to check out BZR trees, as it expects that the bzr checkout command will run locally. Instead, an explicit call to bzr checkout via a SSH command must be used; Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb 10.1.36 Release Upgrade Tests 10.1.36 Release Upgrade Tests ============================= ### Tested revision 38e5dc0f772daecca1d2681885d3d85414eb6826 ### Test date 2018-10-03 11:54:43 ### Summary Tests passed ### Details | type | pagesize | OLD version | file format | encrypted | compressed | | NEW version | file format | encrypted | compressed | readonly | result | notes | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | recovery | 16 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 16 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | recovery | 4 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 4 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | recovery | 32 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | recovery | 32 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 64 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 64 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | recovery | 8 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | recovery | 8 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | recovery | 16 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 16 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 4 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 4 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 32 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 32 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 64 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 64 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | recovery | 8 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | recovery | 8 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 16 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 4 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 32 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 64 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 8 | 10.1.36 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | undo-recovery | 16 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 4 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 32 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 64 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 8 | 10.1.36 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo-recovery | 16 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 4 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 32 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 64 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 8 | 10.1.36 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo-recovery | 16 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 4 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 32 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 64 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo-recovery | 8 | 10.1.36 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 16 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 16 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 4 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 4 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 32 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 64 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 8 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | normal | 8 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 16 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 16 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 4 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 4 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 32 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 64 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | normal | 8 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | normal | 8 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 16 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 16 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | crash | 4 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 4 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | crash | 32 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | crash | 32 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 64 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | crash | 8 | 10.1.35 (inbuilt) | Barracuda | on | - | => | 10.1.36 (inbuilt) | Barracuda | on | - | - | OK | | | crash | 8 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | crash | 16 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 16 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 4 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 4 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 32 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 64 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | crash | 8 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | crash | 8 | 10.1.35 (inbuilt) | Barracuda | - | zlib | => | 10.1.36 (inbuilt) | Barracuda | - | zlib | - | OK | | | undo | 16 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 4 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 32 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 64 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 8 | 10.1.35 (inbuilt) | Barracuda | - | - | => | 10.1.36 (inbuilt) | Barracuda | - | - | - | OK | | | undo | 16 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 4 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 32 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 64 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | undo | 8 | 10.1.35 (inbuilt) | Barracuda | on | zlib | => | 10.1.36 (inbuilt) | Barracuda | on | zlib | - | OK | | | normal | 4 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | normal | 8 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | normal | 16 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | normal | 16 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | on | - | - | OK | | | normal | 4 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | on | - | - | OK | | | normal | 8 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | on | - | - | OK | | | crash | 4 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | crash | 8 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | crash | 16 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | crash | 16 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | on | - | - | OK | | | crash | 4 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | on | - | - | OK | | | crash | 8 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | on | - | - | OK | | | undo | 16 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | undo | 4 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | | undo | 8 | 10.0.36 (inbuilt) | | - | - | => | 10.1.36 (inbuilt) | | - | - | - | OK | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Getting Started with Indexes Getting Started with Indexes ============================ For a very basic overview, see [The Essentials of an Index](../the-essentials-of-an-index/index). There are four main kinds of indexes; primary keys (unique and not null), unique indexes (unique and can be null), plain indexes (not necessarily unique) and full-text indexes (for full-text searching). The terms 'KEY' and 'INDEX' are generally used interchangeably, and statements should work with either keyword. Primary Key ----------- A primary key is unique and can never be null. It will always identify only one record, and each record must be represented. Each table can only have one primary key. In [InnoDB](../innodb/index) tables, all indexes contain the primary key as a suffix. Thus, when using this storage engine, keeping the primary key as small as possible is particularly important. If a primary key does not exist and there are no UNIQUE indexes, InnoDB creates a 6-bytes clustered index which is invisible to the user. Many tables use a numeric ID field as a primary key. The [AUTO\_INCREMENT](../auto_increment/index) attribute can be used to generate a unique identity for new rows, and is commonly-used with primary keys. Primary keys are usually added when the table is created with the [CREATE TABLE](../create-table/index#indexes) statement. For example, the following creates a primary key on the ID field. Note that the ID field had to be defined as NOT NULL, otherwise the index could not have been created. ``` CREATE TABLE `Employees` ( `ID` TINYINT(3) UNSIGNED NOT NULL AUTO_INCREMENT, `First_Name` VARCHAR(25) NOT NULL, `Last_Name` VARCHAR(25) NOT NULL, `Position` VARCHAR(25) NOT NULL, `Home_Address` VARCHAR(50) NOT NULL, `Home_Phone` VARCHAR(12) NOT NULL, PRIMARY KEY (`ID`) ) ENGINE=Aria; ``` You cannot create a primary key with the [CREATE INDEX](../create-index/index) command. If you do want to add one after the table has already been created, use [ALTER TABLE](../alter-table/index), for example: ``` ALTER TABLE Employees ADD PRIMARY KEY(ID); ``` ### Finding Tables Without Primary Keys Tables in the `[information\_schema](../information-schema-tables/index)` database can be queried to find tables that do not have primary keys. For example, here is a query using the [TABLES](../information-schema-tables-table/index) and [KEY\_COLUMN\_USAGE](../information-schema-key_column_usage-table/index) tables that can be used: ``` SELECT t.TABLE_SCHEMA, t.TABLE_NAME FROM information_schema.TABLES AS t LEFT JOIN information_schema.KEY_COLUMN_USAGE AS c ON t.TABLE_SCHEMA = c.CONSTRAINT_SCHEMA AND t.TABLE_NAME = c.TABLE_NAME AND c.CONSTRAINT_NAME = 'PRIMARY' WHERE t.TABLE_SCHEMA != 'information_schema' AND t.TABLE_SCHEMA != 'performance_schema' AND t.TABLE_SCHEMA != 'mysql' AND c.CONSTRAINT_NAME IS NULL; ``` Unique Index ------------ A Unique Index must be unique, but it can be null. So each key value identifies only one record, but not each record needs to be represented. For example, to create a unique key on the Employee\_Code field, as well as a primary key, use: ``` CREATE TABLE `Employees` ( `ID` TINYINT(3) UNSIGNED NOT NULL, `First_Name` VARCHAR(25) NOT NULL, `Last_Name` VARCHAR(25) NOT NULL, `Position` VARCHAR(25) NOT NULL, `Home_Address` VARCHAR(50) NOT NULL, `Home_Phone` VARCHAR(12) NOT NULL, `Employee_Code` VARCHAR(25) NOT NULL, PRIMARY KEY (`ID`), UNIQUE KEY (`Employee_Code`) ) ENGINE=Aria; ``` Unique keys can also be added after the table is created with the [CREATE INDEX](../create-index/index) command, or with the [ALTER TABLE](../alter-table/index) command, for example: ``` ALTER TABLE Employees ADD UNIQUE `EmpCode`(`Employee_Code`); ``` and ``` CREATE UNIQUE INDEX HomePhone ON Employees(Home_Phone); ``` Indexes can contain more than one column. MariaDB is able to use one or more columns on the leftmost part of the index, if it cannot use the whole index. Take another example: ``` CREATE TABLE t1 (a INT NOT NULL, b INT, UNIQUE (a,b)); INSERT INTO t1 values (1,1), (2,2); SELECT * FROM t1; +---+------+ | a | b | +---+------+ | 1 | 1 | | 2 | 2 | +---+------+ ``` Since the index is defined as unique over both columns *a* and *b*, the following row is valid, as while neither *a* nor *b* are unique on their own, the combination is unique: ``` INSERT INTO t1 values (2,1); SELECT * FROM t1; +---+------+ | a | b | +---+------+ | 1 | 1 | | 2 | 1 | | 2 | 2 | +---+------+ ``` The fact that a `UNIQUE` constraint can be `NULL` is often overlooked. In SQL any `NULL` is never equal to anything, not even to another `NULL`. Consequently, a `UNIQUE` constraint will not prevent one from storing duplicate rows if they contain null values: ``` INSERT INTO t1 values (3,NULL), (3, NULL); SELECT * FROM t1; +---+------+ | a | b | +---+------+ | 1 | 1 | | 2 | 1 | | 2 | 2 | | 3 | NULL | | 3 | NULL | +---+------+ ``` Indeed, in SQL two last rows, even if identical, are not equal to each other: ``` SELECT (3, NULL) = (3, NULL); +---------------------- + | (3, NULL) = (3, NULL) | +---------------------- + | 0 | +---------------------- + ``` In MariaDB you can combine this with [virtual columns](../virtual-columns/index) to enforce uniqueness over a subset of rows in a table: ``` create table Table_1 ( user_name varchar(10), status enum('Active', 'On-Hold', 'Deleted'), del char(0) as (if(status in ('Active', 'On-Hold'),'', NULL)) persistent, unique(user_name,del) ) ``` This table structure ensures that all *active* or *on-hold* users have distinct names, but as soon as a user is *deleted*, his name is no longer part of the uniqueness constraint, and another user may get the same name. If a unique index consists of a column where trailing pad characters are stripped or ignored, inserts into that column where values differ only by the number of trailing pad characters will result in a duplicate-key error. Plain Indexes ------------- Indexes do not necessarily need to be unique. For example: ``` CREATE TABLE t2 (a INT NOT NULL, b INT, INDEX (a,b)); INSERT INTO t2 values (1,1), (2,2), (2,2); SELECT * FROM t2; +---+------+ | a | b | +---+------+ | 1 | 1 | | 2 | 2 | | 2 | 2 | +---+------+ ``` Full-Text Indexes ----------------- Full-text indexes support full-text indexing and searching. See the [Full-Text Indexes](../full-text-indexes/index) section. Choosing Indexes ---------------- In general you should only add indexes to match the queries your application uses. Any extra will waste resources. In an application with very small tables, indexes will not make much difference but as soon as your tables are larger than your buffer sizes the indexes will start to speed things up dramatically. Using the [EXPLAIN](../explain/index) statement on your queries can help you decide which columns need indexing. If you query contains something like `LIKE '%word%'`, without a fulltext index you are using a full table scan every time, which is very slow. If your table has a large number of reads and writes, consider using delayed writes. This uses the db engine in a "batch" write mode, which cuts down on disk io, therefore increasing performance. Use the [CREATE INDEX](../create-index/index) command to create an index. If you are building a large table then for best performance add the index after the table is populated with data. This is to increase the insert performance and remove the index overhead during inserts. Viewing Indexes --------------- You can view which indexes are present on a table, as well as details about them, with the [SHOW INDEX](../show-index/index) statement. If you want to know how to re-create an index, run `[SHOW CREATE TABLE](../show-create-table/index)`. When to Remove an Index ----------------------- If an index is rarely used (or not used at all) then remove it to increase INSERT, and UPDATE performance. If [user statistics](../user-statistics/index) are enabled, the [Information Schema](../information-schema/index) [INDEX\_STATISTICS](../information-schema-index_statistics-table/index) table stores the index usage. If the [slow query log](../slow-query-log/index) is enabled and the `[log\_queries\_not\_using\_indexes](../server-system-variables/index#log_queries_not_using_indexes)` server system variable is `ON`, the queries which do not use indexes are logged. *The initial version of this article was copied, with permission, from <http://hashmysql.org/wiki/Proper_Indexing_Strategy> on 2012-10-30.* See Also -------- * [AUTO\_INCREMENT](../auto_increment/index) * [The Essentials of an Index](../the-essentials-of-an-index/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Creating & Using Views Creating & Using Views ====================== A Tutorial Introduction ----------------------- **Up-front warning:** This is the beginning of a very basic tutorial on views, based on my experimentation with them. This tutorial assumes that you've read the appropriate tutorials up to and including [More Advanced Joins](more_advanced_joins) (or that you understand the concepts behind them). This page is intended to give you a general idea of how views work and what they do, as well as some examples of when you could use them. ### Requirements for This Tutorial In order to perform the SQL statements in this tutorial, you will need access to a database hosted on a MySQL 5.x server, and you will need the CREATE TABLE and CREATE VIEW privileges on this table. The Employee Database --------------------- First, we need some data we can perform our optimizations on, so we'll recreate the tables from the [More Advanced Joins](../more-advanced-joins/index) tutorial, to provide us with a starting point. If you have already completed that tutorial and have this database already, you can skip ahead. First, we create the table that will hold all of the employees and their contact information: ``` CREATE TABLE `Employees` ( `ID` TINYINT(3) UNSIGNED NOT NULL AUTO_INCREMENT, `First_Name` VARCHAR(25) NOT NULL, `Last_Name` VARCHAR(25) NOT NULL, `Position` VARCHAR(25) NOT NULL, `Home_Address` VARCHAR(50) NOT NULL, `Home_Phone` VARCHAR(12) NOT NULL, PRIMARY KEY (`ID`) ) ENGINE=MyISAM; ``` Next, we add a few employees to the table: ``` INSERT INTO `Employees` (`First_Name`, `Last_Name`, `Position`, `Home_Address`, `Home_Phone`) VALUES ('Mustapha', 'Mond', 'Chief Executive Officer', '692 Promiscuous Plaza', '326-555-3492'), ('Henry', 'Foster', 'Store Manager', '314 Savage Circle', '326-555-3847'), ('Bernard', 'Marx', 'Cashier', '1240 Ambient Avenue', '326-555-8456'), ('Lenina', 'Crowne', 'Cashier', '281 Bumblepuppy Boulevard', '328-555-2349'), ('Fanny', 'Crowne', 'Restocker', '1023 Bokanovsky Lane', '326-555-6329'), ('Helmholtz', 'Watson', 'Janitor', '944 Soma Court', '329-555-2478'); ``` Now, we create a second table, containing the hours which each employee clocked in and out during the week: ``` CREATE TABLE `Hours` ( `ID` TINYINT(3) UNSIGNED NOT NULL, `Clock_In` DATETIME NOT NULL, `Clock_Out` DATETIME NOT NULL ) ENGINE=MyISAM; ``` Finally, although it is a lot of information, we add a full week of hours for each of the employees into the second table that we created: ``` INSERT INTO `Hours` VALUES ('1', '2005-08-08 07:00:42', '2005-08-08 17:01:36'), ('1', '2005-08-09 07:01:34', '2005-08-09 17:10:11'), ('1', '2005-08-10 06:59:56', '2005-08-10 17:09:29'), ('1', '2005-08-11 07:00:17', '2005-08-11 17:00:47'), ('1', '2005-08-12 07:02:29', '2005-08-12 16:59:12'), ('2', '2005-08-08 07:00:25', '2005-08-08 17:03:13'), ('2', '2005-08-09 07:00:57', '2005-08-09 17:05:09'), ('2', '2005-08-10 06:58:43', '2005-08-10 16:58:24'), ('2', '2005-08-11 07:01:58', '2005-08-11 17:00:45'), ('2', '2005-08-12 07:02:12', '2005-08-12 16:58:57'), ('3', '2005-08-08 07:00:12', '2005-08-08 17:01:32'), ('3', '2005-08-09 07:01:10', '2005-08-09 17:00:26'), ('3', '2005-08-10 06:59:53', '2005-08-10 17:02:53'), ('3', '2005-08-11 07:01:15', '2005-08-11 17:04:23'), ('3', '2005-08-12 07:00:51', '2005-08-12 16:57:52'), ('4', '2005-08-08 06:54:37', '2005-08-08 17:01:23'), ('4', '2005-08-09 06:58:23', '2005-08-09 17:00:54'), ('4', '2005-08-10 06:59:14', '2005-08-10 17:00:12'), ('4', '2005-08-11 07:00:49', '2005-08-11 17:00:34'), ('4', '2005-08-12 07:01:09', '2005-08-12 16:58:29'), ('5', '2005-08-08 07:00:04', '2005-08-08 17:01:43'), ('5', '2005-08-09 07:02:12', '2005-08-09 17:02:13'), ('5', '2005-08-10 06:59:39', '2005-08-10 17:03:37'), ('5', '2005-08-11 07:01:26', '2005-08-11 17:00:03'), ('5', '2005-08-12 07:02:15', '2005-08-12 16:59:02'), ('6', '2005-08-08 07:00:12', '2005-08-08 17:01:02'), ('6', '2005-08-09 07:03:44', '2005-08-09 17:00:00'), ('6', '2005-08-10 06:54:19', '2005-08-10 17:03:31'), ('6', '2005-08-11 07:00:05', '2005-08-11 17:02:57'), ('6', '2005-08-12 07:02:07', '2005-08-12 16:58:23'); ``` Working with the Employee Database ---------------------------------- In this example, we are going to assist Human Resources by simplifying the queries that their applications need to perform. At the same time, it's going to enable us to abstract their queries from the database, which allows us more flexibility in maintaining it. ### Filtering by Name, Date and Time In the previous tutorial, we looked at a JOIN query that displayed all of the lateness instances for a particular employee. In this tutorial, we are going to abstract that query somewhat to provide us with all lateness occurrences for all employees, and then standardize that query by making it into a view. Our previous query looked like this: ``` SELECT `Employees`.`First_Name`, `Employees`.`Last_Name`, `Hours`.`Clock_In`, `Hours`.`Clock_Out` FROM `Employees` INNER JOIN `Hours` ON `Employees`.`ID` = `Hours`.`ID` WHERE `Employees`.`First_Name` = 'Helmholtz' AND DATE_FORMAT(`Hours`.`Clock_In`, '%Y-%m-%d') >= '2005-08-08' AND DATE_FORMAT(`Hours`.`Clock_In`, '%Y-%m-%d') <= '2005-08-12' AND DATE_FORMAT(`Hours`.`Clock_In`, '%H:%i:%S') > '07:00:59'; ``` The result: ``` +------------+-----------+---------------------+---------------------+ | First_Name | Last_Name | Clock_In | Clock_Out | +------------+-----------+---------------------+---------------------+ | Helmholtz | Watson | 2005-08-09 07:03:44 | 2005-08-09 17:00:00 | | Helmholtz | Watson | 2005-08-12 07:02:07 | 2005-08-12 16:58:23 | +------------+-----------+---------------------+---------------------+ ``` ### Refining Our Query The previous example displays to us all of Heimholtz's punch-in times that were after seven AM. We can see here that Heimholz has been late twice within this reporting period, and we can also see that in both instances, he either left exactly on time or he left early. Our company policy, however, dictates that late instances must be made up at the end of one's shift, so we want to exclude from our report anyone whose clock-out time was greater than 10 hours and one minute after their clock-in time. ``` SELECT `Employees`.`First_Name`, `Employees`.`Last_Name`, `Hours`.`Clock_In`, `Hours`.`Clock_Out`, (TIMESTAMPDIFF(MINUTE,`Hours`.`Clock_Out`,`Hours`.`Clock_In`) + 601) as Difference FROM `Employees` INNER JOIN `Hours` USING (`ID`) WHERE DATE_FORMAT(`Hours`.`Clock_In`, '%Y-%m-%d') >= '2005-08-08' AND DATE_FORMAT(`Hours`.`Clock_In`, '%Y-%m-%d') <= '2005-08-12' AND DATE_FORMAT(`Hours`.`Clock_In`, '%H:%i:%S') > '07:00:59' AND TIMESTAMPDIFF(MINUTE,`Hours`.`Clock_Out`,`Hours`.`Clock_In`) > -601; ``` This gives us the following list of people who have violated our attendance policy: ``` +------------+-----------+---------------------+---------------------+------------+ | First_Name | Last_Name | Clock_In | Clock_Out | Difference | +------------+-----------+---------------------+---------------------+------------+ | Mustapha | Mond | 2005-08-12 07:02:29 | 2005-08-12 16:59:12 | 4 | | Henry | Foster | 2005-08-11 07:01:58 | 2005-08-11 17:00:45 | 2 | | Henry | Foster | 2005-08-12 07:02:12 | 2005-08-12 16:58:57 | 4 | | Bernard | Marx | 2005-08-09 07:01:10 | 2005-08-09 17:00:26 | 1 | | Lenina | Crowne | 2005-08-12 07:01:09 | 2005-08-12 16:58:29 | 3 | | Fanny | Crowne | 2005-08-11 07:01:26 | 2005-08-11 17:00:03 | 2 | | Fanny | Crowne | 2005-08-12 07:02:15 | 2005-08-12 16:59:02 | 4 | | Helmholtz | Watson | 2005-08-09 07:03:44 | 2005-08-09 17:00:00 | 4 | | Helmholtz | Watson | 2005-08-12 07:02:07 | 2005-08-12 16:58:23 | 4 | +------------+-----------+---------------------+---------------------+------------+ ``` The Utility of Views -------------------- We can see in the previous example that there have been several instances of employees coming in late and leaving early. Unfortunately, we can also see that this query is getting needlessly complex. Having all of this SQL in our application not only creates more complex application code, but also means that if we ever change the structure of this table we're going to have to change what is becoming a somewhat messy query. This is where views begin to show their usefulness. ### Creating the Employee Tardiness View Creating a view is almost exactly the same as creating a SELECT statement, so we can use our previous SELECT statement in the creation of our new view: ``` CREATE SQL SECURITY INVOKER VIEW Employee_Tardiness AS SELECT `Employees`.`First_Name`, `Employees`.`Last_Name`, `Hours`.`Clock_In`, `Hours`.`Clock_Out`, (TIMESTAMPDIFF(MINUTE,`Hours`.`Clock_Out`,`Hours`.`Clock_In`) + 601) as Difference FROM `Employees` INNER JOIN `Hours` USING (`ID`) WHERE DATE_FORMAT(`Hours`.`Clock_In`, '%Y-%m-%d') >= '2005-08-08' AND DATE_FORMAT(`Hours`.`Clock_In`, '%Y-%m-%d') <= '2005-08-12' AND DATE_FORMAT(`Hours`.`Clock_In`, '%H:%i:%S') > '07:00:59' AND TIMESTAMPDIFF(MINUTE,`Hours`.`Clock_Out`,`Hours`.`Clock_In`) > -601; ``` Note that the first line of our query contains the statement 'SQL SECURITY INVOKER' - this means that when the view is accessed, it runs with the same privileges that the person accessing the view has. Thus, if someone without access to our Employees table tries to access this view, they will get an error. Other than the security parameter, the rest of the query is fairly self explanatory. We simply run 'CREATE VIEW <view-name> AS' and then append any valid SELECT statement, and our view is created. Now if we do a SELECT from the view, we can see we get the same results as before, with much less SQL: ``` SELECT * FROM Employee_Tardiness; ``` ``` +------------+-----------+---------------------+---------------------+------------+ | First_Name | Last_Name | Clock_In | Clock_Out | Difference | +------------+-----------+---------------------+---------------------+------------+ | Mustapha | Mond | 2005-08-12 07:02:29 | 2005-08-12 16:59:12 | 5 | | Henry | Foster | 2005-08-11 07:01:58 | 2005-08-11 17:00:45 | 3 | | Henry | Foster | 2005-08-12 07:02:12 | 2005-08-12 16:58:57 | 5 | | Bernard | Marx | 2005-08-09 07:01:10 | 2005-08-09 17:00:26 | 2 | | Lenina | Crowne | 2005-08-12 07:01:09 | 2005-08-12 16:58:29 | 4 | | Fanny | Crowne | 2005-08-09 07:02:12 | 2005-08-09 17:02:13 | 1 | | Fanny | Crowne | 2005-08-11 07:01:26 | 2005-08-11 17:00:03 | 3 | | Fanny | Crowne | 2005-08-12 07:02:15 | 2005-08-12 16:59:02 | 5 | | Helmholtz | Watson | 2005-08-09 07:03:44 | 2005-08-09 17:00:00 | 5 | | Helmholtz | Watson | 2005-08-12 07:02:07 | 2005-08-12 16:58:23 | 5 | +------------+-----------+---------------------+---------------------+------------+ ``` Now we can even perform operations on the table, such as limiting our results to just those with a Difference of at least five minutes: ``` SELECT * FROM Employee_Tardiness WHERE Difference >=5; ``` ``` +------------+-----------+---------------------+---------------------+------------+ | First_Name | Last_Name | Clock_In | Clock_Out | Difference | +------------+-----------+---------------------+---------------------+------------+ | Mustapha | Mond | 2005-08-12 07:02:29 | 2005-08-12 16:59:12 | 5 | | Henry | Foster | 2005-08-12 07:02:12 | 2005-08-12 16:58:57 | 5 | | Fanny | Crowne | 2005-08-12 07:02:15 | 2005-08-12 16:59:02 | 5 | | Helmholtz | Watson | 2005-08-09 07:03:44 | 2005-08-09 17:00:00 | 5 | | Helmholtz | Watson | 2005-08-12 07:02:07 | 2005-08-12 16:58:23 | 5 | +------------+-----------+---------------------+---------------------+------------+ ``` ### Other Uses of Views Aside from just simplifying our application's SQL queries, there are also other benefits that views can provide, some of which are only possible by using views. #### Restricting Data Access For example, even though our Employees database contains fields for Position, Home Address, and Home Phone, our query does not allow for these fields to be shown. This means that in the case of a security issue in the application (for example, an SQL injection attack, or even a malicious programmer), there is no risk of disclosing an employee's personal information. #### Row-level Security We can also define separate views to include a specific WHERE clause for security; for example, if we wanted to restrict a department head's access to only the staff that report to him, we could specify his identity in the view's CREATE statement, and he would then be unable to see any other department's employees, despite them all being in the same table. If this view is writeable and it is defined with the CASCADE clause, this restriction will also apply to writes. This is actually the only way to implement row-level security in MySQL, so views play an important part in that area as well. #### Pre-emptive Optimization We can also define our views in such a way as to force the use of indexes, so that other, less-experienced developers don't run the risk of running un-optimized queries or JOINs that result in full-table scans and extended locks. Expensive queries, queries that SELECT \*, and poorly thought-out JOINs can not only slow down the database entirely, but can cause inserts to fail, clients to time out, and reports to error out. By creating a view that is already optimized and letting users perform their queries on that, you can ensure that they won't cause a significant performance hit unnecessarily. #### Abstracting Tables When we re-engineer our application, we sometimes need to change the database to optimize or accommodate new or removed features. We may, for example, want to [normalize](../database-normalization/index) our tables when they start getting too large and queries start taking too long. Alternately, we may be installing a new application with different requirements alongside a legacy application. Unfortunately, database redesign will tend to break backwards-compatibility with previous applications, which can cause obvious problems. Using views, we can change the format of the underlying tables while still presenting the same table format to the legacy application. Thus, an application which demands username, hostname, and access time in string format can access the same data as an application which requires firstname, lastname, user@host, and access time in Unix timestamp format. Summary ------- Views are an SQL feature that can provide a lot of versatility in larger applications, and can even simplify smaller applications further. Just as stored procedures can help us abstract out our database logic, views can simplify the way we access data in the database, and can help un-complicate our queries to make application debugging easier and more efficient. *The initial version of this article was copied, with permission, from <http://hashmysql.org/wiki/Views_(Basic>) on 2012-10-05.* Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Unsafe Statements for Statement-based Replication Unsafe Statements for Statement-based Replication ================================================= A safe statement is generally deterministic; in other words the statement will always produce the same result. For example, an INSERT statement producing a random number will most likely produce a different result on the primary than on the replica, and so cannot be replicated safely. When an unsafe statement is run, the current binary logging format determines how the server responds. * If the binary logging format is [statement-based](../binary-log-formats/index#statement-based-logging) (the default until [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)), unsafe statements generate a warning and are logged normally. * If the binary logging format is [mixed](../binary-log-formats/index#mixed-logging) (the default from [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/)), unsafe statements are logged using the row-based format, while safe statements use the statement-based format. * If the binary logging format is [row-based](../binary-log-formats/index#row-based-logging), all statements are logged normally, and the distinction between safe and unsafe is not made. MariaDB tries to detect unsafe statements. When an unsafe statement is issued, a warning similar to the following is produced: ``` Note (Code 1592): Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. The statement is unsafe because it uses a LIMIT clause. This is unsafe because the set of rows included cannot be predicted. ``` MariaDB also issues this warning for some classes of statements that are safe. Unsafe Statements ----------------- The following statements are regarded as unsafe: * [INSERT ... ON DUPLICATE KEY UPDATE](../insert-on-duplicate-key-update/index) statements upon tables with multiple primary or unique keys, as the order that the keys are checked in, and which affect the rows chosen to update, is not deterministic. Before [MariaDB 5.5.24](https://mariadb.com/kb/en/mariadb-5524-release-notes/), these statements were not regarded as unsafe. In [MariaDB 10.0](../what-is-mariadb-100/index) this warning has been removed as we always check keys in the same order on the primary and replica if the primary and replica are using the same storage engine. * [INSERT-DELAYED](../insert-delayed/index). These statements are inserted in an indeterminate order. * [INSERT's](../insert/index) on tables with a composite primary key that has an [AUTO\_INCREMENT](../auto_increment/index) column that isn't the first column of the composite key. * When a table has an [AUTO\_INCREMENT](../auto_increment/index) column and a [trigger](../triggers/index) or [stored procedure](../stored-programs-and-views/index) executes an [UPDATE](../update/index) statement against the table. Before [MariaDB 5.5](../what-is-mariadb-55/index), all updates on tables with an AUTO\_INCREMENT column were considered unsafe, as the order that the rows were updated could differ across servers. * [UPDATE](../update/index) statements that use [LIMIT](../select/index#limit), since the order of the returned rows is unspecified. This applies even to statements using an ORDER BY clause, which are deterministic (a known bug). However, since [MariaDB 10.0.11](https://mariadb.com/kb/en/mariadb-10011-release-notes/), `LIMIT 0` is an exception to this rule (see [MDEV-6170](https://jira.mariadb.org/browse/MDEV-6170)), and these statements are safe for replication. * When using a [user-defined function](../user-defined-functions/index). * Statements using using any of the following functions, which can return different results on the replica: + [CURRENT\_ROLE()](../current_role/index) + [CURRENT\_USER()](../current_user/index) + [FOUND\_ROWS()](../found_rows/index) + [GET\_LOCK()](../get_lock/index) + [IS\_FREE\_LOCK()](../is_free_lock/index) + [IS\_USED\_LOCK()](../is_used_lock/index) + [JSON\_TABLE()](../json_table/index) + [LOAD\_FILE()](../load_file/index) + [MASTER\_POS\_WAIT()](../master_pos_wait/index) + [RAND()](../rand/index) + [RANDOM\_BYTES()](../random_bytes/index) + [RELEASE\_ALL\_LOCKS()](../release_all_locks/index) + [RELEASE\_LOCK()](../release_lock/index) + [ROW\_COUNT()](../row_count/index) + [SESSION\_USER()](../session_user/index) + [SLEEP()](../sleep/index) + [SYSDATE()](../sysdate/index) + [SYSTEM\_USER()](../system_user/index) + [USER()](../user/index) + [UUID()](../uuid/index) + [UUID\_SHORT()](../uuid_short/index). * Statements which refer to log tables, since these may differ across servers. * Statements which refer to self-logging tables. Statements following a read or write to a self-logging table within a transaction are also considered unsafe. * Statements which refer to [system variables](../server-system-variables/index) (there are a few exceptions). * [LOAD DATA INFILE](../load-data-infile/index) statements (since [MariaDB 5.5](../what-is-mariadb-55/index)). * Non-transactional reads or writes that execute after transactional reads within a transaction. * If row-based logging is used for a statement, and the session executing the statement has any temporary tables, row-based logging is used for the remaining statements until the temporary table is dropped. This is because temporary tables can't use row-based logging, so if it is used due to one of the above conditions, all subsequent statements using that table are unsafe. The server deals with this situation by treating all statements in the session as unsafe for statement-based logging until the temporary table is dropped. Safe Statements --------------- The following statements are not deterministic, but are considered safe for binary logging and replication: * [CONNECTION\_ID()](../connection_id/index) * [CURDATE()](../curdate/index) * [CURRENT\_DATE()](../current_date/index) * [CURRENT\_TIME()](../current_time/index) * [CURRENT\_TIMESTAMP()](../current_timestamp/index) * [CURTIME()](../curtime/index) * [LAST\_INSERT\_ID()](../last_insert_id/index) * [LOCALTIME()](../localtime/index) * [LOCALTIMESTAMP()](../localtimestamp/index) * [NOW()](../now/index) * [UNIX\_TIMESTAMP()](../unix_timestamp/index) * [UTC\_DATE()](../utc_date/index) * [UTC\_TIME()](../utc_time/index) * [UTC\_TIMESTAMP()](../utc_timestamp/index) Isolation Levels ---------------- Even when using safe statements, not all [transaction isolation levels](../set-transaction/index#isolation-levels) are safe with statement-based or mixed binary logging. The REPEATABLE READ and SERIALIZABLE isolation levels can only be used with the row-based format. This restriction does not apply if only non-transactional storage engines are used. See Also -------- * [Replication and Foreign Keys](../replication-and-foreign-keys/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Preparing for ColumnStore Installation - 1.1.X Preparing for ColumnStore Installation - 1.1.X ============================================== ### Prerequisite With the 1.1.X version of MariaDB ColumnStore, there should be no versions of MariaDB Server or MySQL pre-installed on the OS before a MariaDB ColumnStore binary or RPM is installed on the system. If you have an installation of MariaDB server, uninstall it before proceeding. #### Configuration preparation Before installing MariaDB ColumnStore, there is some preparation necessary. You will need to determine the following, refer the MariaDB ColumnStore Architecture Document for additional information. * How many User Modules (UMs) will your system need? * How many Performance Modules (PMs) will your system need? * How much disk space will your system need? * Would have passwordless ssh access between PMs? * Do you want to run the install as root or noon-root? ##### OS information MariaDB ColumnStore is certified to run on: RHEL/CentOS v6, v7 Ubuntu 16.04 LTS Debian v8, v9 SUSE 12 but it should run on any recent Linux system. Make sure the same OS is installed on all the servers for a multi-node system. Make sure the locale setting on all servers are all the same. To set locale to en\_US and UTf-8, run: ``` # localedef -i en_US -f UTF-8 en_US.UTF-8 ``` ##### System administration information Information your system administrator must provide you before you start installing MariaDB ColumnStore: * The hostnames of each interface on each node (optional). * The IP address of each interface on each node. * The root/non-root password for the nodes (all nodes must have the same root/non-root password or root/non-root ssh keys must be set up between servers). MariaDB ColumnStore can be installed as root or a non-root user. Example for 3 PM, 1UM system, these are the steps required to configure PM-1 for passwordless ssh. The equivalent steps must be repeated on every PM in the system. The equivalent steps must be repeated on every UM in the system if the MariaDB ColumnStore Data Replication feature is enabled during the install process. ``` [root@pm- 1 ~] $ ssh-keygen [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-1 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-2 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub pm-3 [root@pm- 1 ~] $ ssh-copy-id -i ~/.ssh/id_rsa.pub um-1 ``` If utilizing ssh-keys and will be utilizing the MariaDB ColumnStore Data Redundancy feature, make sure you setup an ssh-key on the PM1 node to itself. This is required for Data Redundancy feature. If utilizing ssh-keys and will be utilizing the MariaDB ColumnStore Data Replication feature, make sure you setup an ssh-key between all UM nodes. And if you enabled the Local Query Feature, will also need between all UM nodes and all PM nodes. ##### Network configuration MariaDB ColumnStore is quite flexible regarding networking. Some options are as follows: * The interconnect between UMs and PMs can be one or more private VLANs. In this case MariaDB ColumnStore will automatically trunk the individual LANs together to provide greater effective bandwidth between the UMs and PMs. * The PMs do not require a public LAN access as they only need to communicate with the UMs. * The UMs most likely require at least one public interface to access the MySQL server front end from the site LAN. This interface can be a separate physical or logical connection from the PM interconnect. * You can use whatever security your site requires on the public access to the MySQL server front end on the UMs. By default it is listening on port 3306. * MariaDB ColumnStore software only requires a TCP/IP stack to be present to function. You can use any physical layer you desire. #### MariaDB ColumnStore port usage The MariaDB ColumnStore daemon utilizes port 3306. You must reserve the following ports to run the MariaDB ColumnStore software: 8600 - 8630, 8700, and 8800 #### Storage and Database files (DBRoots) MariaDB ColumnStore supports being able to configure with different Storage options. * Internal - Meaning you will be utilize the local root level storage on the server. Also with the Internal storage option, you can use softlinks to map the root level data directory to a SAN storage device. With Internal storage setup, there is no High/Availability Performance Module Failover capabilities. This is one of the limitations to using Internal (local) storage. * External - Meaning to can map the root level data directory to EXTx SAN storage devices and have all of the Data directories (DBRoot) configured in the Fstab to have shared mounting to all Performance Modules in the system. With External storage setup, there is High/Availability Performance Module Failover capabilities supported. Meaning if a Performance Module was to go down, another Performance Module would automatically mount to the DBRoots that were previously mounted to the downed Performance Module. Then the system functionality would still be working since the system has access to all the of data on the DBRoots. * Data Redundancy - This feature is support in 1.1 versions and later. MariaDB ColumnStore supports Data Redundancy on both internal root level data directories or if you have them monuted with EXTx SAN devices. For Data Redundancy to be an option, the user is required to install the Third Party GlusterFS software on all Performance Module. This is discussed later the the Package Dependency section. With Data Redundancy storage setup, there is High/Availability Performance Module Failover capabilities supported. Meaning if a Performance Module was to go down, another Performance Module will have a copy of the DBRoots that were on the downed Performance Module. Then the system functionality would still be working since the system has access to all the of data on the DBRoots. DBRoots are the MariaDB ColumnStore Datafile containers or directories. For example on a root install, they are /usr/local/mariadb/columnstore/data<N> where N is the dbroot number. IMPORTANT: When using Storage (extX, NFS, etc), setup to have the MariaDB front-end data and the DBRoots back-end data files mounted. Don't setup a mount where the actually MariaDB Columnstore package as a whole is mounted, i.e. /usr/local/mariadb or /usr/local/mariadb/columnstore. This would included mounts for: * /usr/local/mariadb/columnstore/mysql/db # optional for the front-end schemas and non-Columnstore data * /usr/local/mariadb/columnstore/dataX # DBroots, Columnstore data ##### Local database files If you are using local disk to store the database files, the DBRoot directories will be created under the installation directory, for example /usr/local/mariadb/columnstore/data<N> where N is the DBRoot number. You should setup to have 1 DBRoot per Performance Module when configuring the system. Use of soft-links for the Data. If you want to setup an install where the Data is stored out in a separate directory in the case you have limit amount local storage, this can be done. It is recommended that the softlinks be setup at the Data Directory Levels, like mariadb/columnstore/data and mariadb/columnstore/dataX. With this setup, you can perform upgrades using any of the package types, rpm, debian, or binary. In the case where you prefer OR have to set a softlink at the top directory, like /usr/local/mariadb, you will need to install using the binary package. If you install using the rpm package and tool, this softlink will be deleted when you perform the upgrade process and the upgrade will fail. ##### SAN mounted database files If you are using a SAN to store the database files, the following must be taken into account: * Each of these DBRoots must be a separate, mountable partition/directory * You might have more than 1 DBRoot assigned to a Performance Module and you can have different number of DBroots per Performance Module, but its recommend to have the same number and same physical size of the storage device on each Performance Module. Here is an example: If you setup 1 Performance Module and you have 2 separate devices that aren't stripped, then you would configure 2 DBRoots to this 1 Performance Module and setup the /etc/fstab with 2 mounts. * MariaDB ColumnStore will run on most Linux filesystems, but we test most heavily with EXT2. You should have no problems with EXT3 or EXT4, but the journaling in these filesystems can be expensive for a database application. You should carefully evaluate the write characteristics of your chosen filesystem to make sure they meet your specific business needs. In any event, MariaDB ColumnStore writes relatively few, very large (64MB) files. You should consult with your Linux system administrator to see if configuring a larger bytes-per-inode setting than the default is available in your chosen filesystem. * MariaDB ColumnStore supports High Availability failover in the case where a Performance Module was to go down when you are using SAN storage devices. To setup a system to support this, all of the SAN devices would need to be mountable to all of the Performance Modules. So in a system that had 2 Performance Modules and each one had 1 SAN device. If 1 of the Performance Modules was to go offline, the system would automatically detect this and would remount the SAN device from the downed module to the 1 active Performance Module. And the system would be able to continue to perform while the module remain offline. * The fstab file must be set up (/etc/fstab). These entries would need to be added to each PM pointing to the all the dbroot(s) being used on all PMs. The 'noauto' option indicates that all dbroots will be associated to every PM but will not be automatically mounted at server startup. The associated dbroots that are assigned to each PM will be specifically mounted to that PM at Columnstore startup. The following example shows an /etc/fstab setup for 2 dbroots total for all PMs, but they can setup any disk type they want: ``` /dev/sda1 /usr/local/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto 0 0 /dev/sdd1 /usr/local/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto 0 0 ``` #### Performance optimization considerations There are optimizations that should be made when using MariaDB ColumnStore listed below. As always, please consult with your network administrator for additional optimization considerations for your specific installation needs. ##### GbE NIC settings: * Modify /etc/rc.d/rc.local to include the following: ``` /sbin/ifconfig eth0 txqueuelen 10000 ``` * Modify /etc/sysctl.conf for the following: ``` # increase TCP max buffer size net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 # increase Linux autotuning TCP buffer limits # min, default, and max number of bytes to use net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 65536 16777216 # don't cache ssthresh from previous connection net.ipv4.tcp_no_metrics_save = 1 # recommended to increase this for 1000 BT or higher net.core.netdev_max_backlog = 2500 # for 10 GigE, use this net.core.netdev_max_backlog = 30000 NOTE: Make sure there is only 1 setting of net.core.netdev_max_backlog in the /etc/sysctl.conf file. ``` * Cache memory settings: To optimize Linux to cache directories and inodes the vm.vfs\_cache\_pressure can be set to a lower value than 100 to attempt to retain caches for inode and directory structures. This will help improve read performance. A value of 10 is suggested. The following commands must all be run as the root user or with sudo. To check the current value: ``` cat /proc/sys/vm/vfs_cache_pressure ``` To set the current value until the next reboot: ``` sysctl -w vm.vfs_cache_pressure=10 ``` To set the value permanently across reboots, add the following to /etc/sysctl.conf: ``` vm.vfs_cache_pressure = 10 ``` #### System settings considerations ##### umask setting The default setting of 022 in /etc/profile is what is recommended. It it required that it the setting doesn't end with a 7, like 077. Example, on a root install, mysqld that runs as 'mysql' user needs to be able to read the MariaDB ColumnStore configuration file, Columnstore.xml. So a last digit of 7 would prevent this and cause the install to fail. The current umask can be determined: ``` umask ``` A value of 022 can be set in the current session or in /etc/profile as follows: ``` umask 022 ``` #### Firewall considerations The MariaDB ColumnStore utilizes these ports 3306, 8600 - 8630, 8700, and 8800. So on multi-node installs, these ports will need to be accessible between the servers. So if there is any firewall software running on the system that could block these ports, either that firewall would need to be disabled as shown below or the ports listed above will need to be configured to allow both input and output on all servers within the firewall software. You will also want to allow these ports to be passed though on any routers that might be connected between the servers. To disable any local firewalls and SELinux on mutli-node installs You must be a Root user. CentOS 6 and systems using iptables ``` #service iptables save (Will save your existing IPTable Rules) #service iptables stop (It will disable firewall Temporarly) ``` To Disable it Permanentely: ``` #chkconfig iptables off ``` CentOS 7 and systems using systemctl with firewalld installed ``` #systemctl status firewalld #systemctl stop firewalld #systemctl disable firewalld ``` Ubuntu and systems using ufw ``` #service ufw stop (It will disable firewall Temporary) ``` To Disable it Permanentely: ``` #chkconfig ufw off ``` SUSE ``` #/sbin/rcSuSEfirewall2 status #/sbin/rcSuSEfirewall2 stop ``` To disable SELinux, ``` edit file "/etc/selinux/config" and find line; SELINUX=enforcing Now replace it with, SELINUX=disabled ``` ### Package dependencies #### Boost libraries MariaDB ColumnStore requires that the boost package of 1.53 or newer is installed. For Centos 7, Ubuntu 16, Debian 8, SUSE 12 and other newer OS's, you can just install the boost packages via yum or apt-get. ``` # yum -y install boost ``` or ``` # apt-get -y install libboost-all-dev ``` For CentOS 6, you can either download and install the MariaDB Columnstore Centos 6 boost library package or install the boost source of 1.55 and build it to generate the required libraries. That means both the build and the install machines require this. How to download, go to binaries download page and download "centos6\_boost\_1\_55.tar.gz" <https://mariadb.com/downloads/columnstore> Click All Versions - > 1.0.x -> centos -> x86\_64 Install package on each server in the cluster ``` wget https://downloads.mariadb.com/ColumnStore/1.0.14/centos/x86_64/centos6_boost_1_55.tar.gz tar xfz centos6_boost_1_55.tar.gz -C /usr/lib ldconfig ``` Downloading and build the boost libraries: NOTE: This means that the "Development Tools" group install be done prior to this. ``` yum groupinstall "Development Tools" yum install cmake ``` Here is the procedure to download and build the boost source: ``` cd /usr/ wget http://sourceforge.net/projects/boost/files/boost/1.55.0/boost_1_55_0.tar.gz tar zxvf boost_1_55_0.tar.gz cd boost_1_55_0 ./bootstrap.sh --with-libraries=atomic,date_time,exception,filesystem,iostreams,locale,program_options,regex,signals,system,test,thread,timer,log --prefix=/usr ./b2 install ldconfig ``` For SUSE 12, you will need to install the boost-devel package, which is part of the SLE-SDK package. ``` SUSEConnect -p sle-sdk/12.2/x86_64 zypper install boost-devel ``` #### Other packages Make sure these packages are installed on the nodes where the MariaDB ColumnStore packages will be installed: ##### Centos 6/7 ``` # yum -y install expect perl perl-DBI openssl zlib file sudo libaio rsync snappy net-tools numactl-libs nmap jemalloc ``` ##### Ubuntu 16/18 ``` # apt-get -y install tzdata libtcl8.6 expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1v5 snappy net-tools libnuma1 nmap libjemalloc1 ``` ##### Debian 8 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync libsnappy1 net-tools libnuma1 nmap libjemalloc1 ``` ##### Debian 9 ``` # apt-get install expect perl openssl file sudo libdbi-perl libboost-all-dev libreadline-dev rsync net-tools libsnappy1v5 libreadline5 libaio1 libnuma1 nmap libjemalloc1 ``` ##### SUSE 12 ``` zypper install expect perl perl-DBI openssl file sudo libaio1 rsync net-tools libsnappy1 libnuma1 nmap jemalloc ``` #### Data Redundancy packages In 1.1.0 and later, MariaDB ColumnStore supports Data Redundancy by utilize the third party software GlusterFS. So if you wanted to utilize the Data Redundancy feature, you would need to install the the GlusterFS package on all nodes that will be used as Performance Modules. Requires 3.3.1 version or later. ##### Centos 6/7 ``` # yum -y install centos-release-gluster # yum -y install glusterfs glusterfs-fuse glusterfs-server start / enable service: # systemctl enable glusterd.service # systemctl start glusterd.service ``` ##### Ubuntu 16/18 ``` # sudo apt-get install glusterfs-server attr start / enable service: # sudo systemctl start glusterfs-server.service # sudo systemctl enable glusterfs-server.service ``` ##### Debian 8 ``` # apt-get -y install glusterfs-server attr start / enable service: # update-rc.d glusterfs-server defaults ``` ##### Debian 9 ``` # sudo apt-get install glusterfs-server attr start / enable service: # sudo systemctl start glusterfs-server.service # sudo systemctl enable glusterfs-server.service ``` ##### SUSE 12 ``` # zypper install glusterfs start / enable service: # chkconfig glusterd on ``` #### System Logging Package MariaDB ColumnStore utilizes the System Logging applications for generating logs. So one of the below system logging applications should be install on all servers in the ColumnStore system: * syslog * rsyslog * syslog-ng ### Choosing the type of initial download/install Installing MariaDB ColumnStore with the use of soft-links. If you want to setup an install where the Data is stored out in a separate directory in the case you have limit amount local storage, this can be done. It is requied that the softlinks be setup at the Data Directory Levels, like mariadb/columnstore/data and mariadb/columnstore/dataX. With this setup, you can perform upgrades using any of the package types, rpm, debian, or binary. Dont set a softlink at the top directory, like /usr/local/mariadb or /usr/local/mariadb/columnstore. IMPORTANT: Make sure there are no other version of MariaDB server install. If so, these will need to be uninstalled before installing MariaDB ColumnStore. #### Where to Install The default MariaDB ColumnStore installation process supports a Distributed installation functionality for Multi-Node installs. With Distributed,the MariaDB ColumnStore packages only needed to be installed on the Performance Module #1 node. MariaDB ColumnStore would distributed the packages across to the other nodes in the system and will install them automatically. In the 1.1 version and later, MariaDB ColumnStore supports a Non-Distributed option for Multi-Node installs. With this option, the user is required to install the MariaDB ColumnStore on all the nodes in the system. ### Root user installs #### Initial download/install of MariaDB ColumnStore Package Repositories The MariaDB ColumnStore RPM and DEB Packages can be installed using yum/apt-get commands. Check here for additional Information: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) #### Initial download/install of MariaDB ColumnStore Package with the AX package The MariaDB ColumnStore RPM, DEB and binary Packages can be installed along with all of the other packages that make up the AX package. Check here for additional Information: [https://mariadb.com/kb/en/library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/](../library/columnstore-getting-started-installing-mariadb-ax-from-the-mariadb-download/index) #### Initial download/install of MariaDB ColumnStore RPMs 1. Install MariaDB ColumnStore as user root (use 'su -' to establish a login shell if you access the box using another account): Note: MariaDB ColumnStore installation will install with a single MariaDB userid of root with no password. You may setup users and permissions for a MariaDB ColumnStore-Mysql account just as you would in MySQL. Note: The packages will be installed into /usr/local. This is required for root user installs **Download the package mariadb-columnstore-release#.x86\_64.tar.gz (RHEL5 64-BIT) to the server where you are installing MariaDB ColumnStore and place in the /root directory.** Unpack the tarball, which will generate multiple RPMs that will reside in the /root/ directory. `tar -zxf mariadb-columnstore-release#.x86_64.tar` **Install the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. `rpm -ivh mariadb-columnstore*release#*.rpm`** #### Initial download/install of MariaDB ColumnStore binary package The MariaDB ColumnStore binary package can be installed from the MariaDB Downloads page. <CLICK> on the "all versions" link and then step down into the OS version to the bottom level directory where you will see 2 packages, one for rpm/deb and the bother for the binary. Select the binary package to download. Install MariaDB ColumnStore as user root on the server designated as PM1: Note: You may setup users and permissions for an MariaDB ColumnStore account just as you would in MariaDB. **For root user installs, MariaDB Columnstore needs to run in /usr/local. You can either install directly into /usr/local or install elsewhere and then setup a softlink to /usr/local. Here is an example of setting up a soft-link if you install the binary package in /mnt/mariadb** ``` # ln -s /mnt/mariadb /usr/local ``` * Download the package into the /root/ and copy to /usr/local directory to the server where you are installing MariaDB ColumnStore. ``` cp /root/mariadb-columnstore-release#.x86_64.bin.tar.gz /usr/local/ mariadb-columnstore-release#.x86_64.bin.tar.gz ``` * Unpack the tarball, which will generate the /usr/local/ directory. `tar -zxvf mariadb-columnstore-release#.x86_64.bin.tar.gz` Run the post-install script: ``` /usr/local/mariadb/columnstore/bin/post-install ``` #### Initial download/install of MariaDB ColumnStore DEB package DEB package installs are not supported in the current version, but there is an Ubuntu 16.04 binary package that you can use to install. Just follow the binary package instructions above Install MariaDB ColumnStore on a Debian or Ubuntu OS as user root: Note: You may setup users and permissions for an MariaDB ColumnStore account just as you would in MariaDB. 1. Download the package mariadb-columnstore-release#.amd64.deb.tar.gz (DEB 64- BIT) into the /root directory of the server where you are installing MariaDB ColumnStore. 2. Unpack the tarball, which will generate DEBs. `tar -zxf mariadb-columnstore-release#.amd64.deb.tar.gz` 3. Install the MariaDB ColumnStore DEBs. The MariaDB ColumnStore software will be installed in /usr/ local/. `dpkg -i mariadb-columnstore*release#*.deb` ### Non-root user installs MariaDB Columnstore can be installed to run as a non-root user using the binary tar file installation. These procedures will also allow you to change the installation from the default install directory into a user-specified directory. These procedures will need to be run on all the MariaDB ColumnStore Servers. Non-root user, since the MariaDB Server runs under the user mysql, you can also install the MariaDB ColumnStore package and run as the mysql user. So below where it shows 'guest' as the user, you can substitute 'mysql'. For the purpose of these instructions, the following assumptions are: * Non-root user "guest" is used in this example * Installation directory is /home/guest/mariadb/columnstore Tasks involved: * Create the non-root user and group of the same name (by root user) * Update sudo configuration (by root user) * Set the user file limits (by root user) * Modify fstab if using SAN Mounted files (by root user) * Uninstall existing MariaDB Columnstore installation if needed (by root user) * Update permissions on certain directories that MariaDB Columnstore writes (by root user) * MariaDB Columnstore Installation (by non-root user) * Enable MariaDB Columnstore to start automatically at boot time #### Creation of the non-root user (by root user) Before beginning the binary tar file installation you will need your system administrator to set up accounts for you on every MariaDB Columnstore node. The account name must be the same on every node. The password used must be the same on every node. If you subsequently change the password on one node, you must change it on every node. The user-id must be the same on every node as well. In the examples below we will use the account name 'guest' and the password 'mariadb'. Additionally, every node must have a basic Linux server package setup and additionally have expect (and all its dependencies) installed. * create new user Group ID is an example, can be different than 1000, but needs to be the same on all servers in the cluster `adduser guest -u 1000` * create group ``` addgroup guest moduser -g guest guest ``` The value for user-id must be the same for all nodes. * Assign password to newly created user `passwd guest` * Log in as user guest `su - guest` * Choose an installation directory in which the non-root user has full read-write access. The installation directory must be the same on every node. In the examples below we will use the path '/home/guest/mariadb/columnstore'. On each host, the following will be in a /etc/profile.d/columnstore.sh This file is setup during install. ``` export COLUMNSTORE_INSTALL_DIR=$HOME/mariadb/columnstore export PATH=$COLUMNSTORE_INSTALL_DIR/bin:$COLUMNSTORE_INSTALL_DIR/mysql/bin:/usr/sbin:$PATH export LD_LIBRARY_PATH=$COLUMNSTORE_INSTALL_DIR/lib:$COLUMNSTORE_INSTALL_DIR/mysql/lib ``` #### Update sudo configuration (by root user) The sudo configuration file on each node will need to be modified to add in the non-root user. The recommended way is to use the Unix command, visudo. The following example will add the ‘guest’ user: visudo * Add the following line for the non-root user: ``` guest ALL=(ALL) NOPASSWD: ALL ``` * Comment out the following line, which will allow the user to login without 'tty': ``` #Defaults requiretty ``` #### Set the user file limits (by root user) ColumnStore needs the open file limit to be increased for the specified user. To do this edit the /etc/security/limits.conf file and make the following additions at the end of the file: ``` guest hard nofile 65536 guest soft nofile 65536 ``` If you are already logged in as 'guest' you will need to log out and back in again for this change to take effect. #### Modify fstab if using SAN Mounted Database Files (by root user) If you are using a SAN to store the database files, an ‘users‘ option will need to be added to the fstab entries (by the root user). For more information, please see the “SAN Mounted Database Files” section earlier in this guide. Example entries: /dev/sda1 /home/guest/mariadb/columnstore/data1 ext2 noatime,nodiratime,noauto,users 0 0 /dev/sdd1 /home/mariadb/columnstore/data2 ext2 noatime,nodiratime,noauto,users 0 0 The disk device being used will need to have its user permissions set to the non-root user name. This is an example command run as 'root' user setting the user ownership of dbroot /dev/sda1 to non-root user of 'guest': ``` mke2fs dbroot (i.e., /dev/sda1) mount /dev/sda1 /tmpdir chown -R infinidb.infinidb /tmpdir umount /tmpdir ``` #### Uninstall existing MariaDB Columnstore installation, if needed (by root user) If MariaDB Columnstore has ever before been installed on any of the planned hosts as a root user install, you must have the system administrator verify that no remnants of that installation exist. The non-root installation will not be successful if there are MariaDB Columnstore files owned by root on any of the hosts. * Verify the MariaDB Columnstore installation directory does not exist: The /usr/local/mariadb/columnstore directory should not exist at all unless it is your target directory, in which case it must be completely empty and owned by the non-root user. * Verify the /etc/fstab entries are correct for the new installation. * Verify the /etc/default/columnstore directory does not exist. * Verify the /var/lock/subsys/mysql-Columnstore file does not exist. * Verify the /tmp/StopColumnstore file does not exist. There should not be any files or directories owned by root in the /tmp directory #### Update permissions on certain directories that MariaDB Columnstore writes (by root user) These directories are writing to by the MariaDB Columnstore applications and the permissions need to be set to allow them to create files. So the permissions of them need to be set to the following by root user. ``` chmod 777 /tmp chmod 777 /dev/shm ``` #### MariaDB Columnstore installation (by non-root user) You should be familiar with the general MariaDB Columnstore installation instructions in this guide as you will be asked the same questions during installation. If performing the MariaDB ColumnStore Multi-node Distributed Installation, the binary package only needs to be installed on Performance Module #1 (pm1). If performing Non-Distributed installs, the binary package is required to install the MariaDB ColumnStore on all the nodes in the system. * Log in as non-root user ( guest , in our example) Note: Ensure you are at your home directory before proceeding to the next step * Now place the MariaDB Columnstore binary tar file in your home directory on the host you will be using as PM1. Untar the binary distribution package to the /home/guest directory: tar -xf mariadb-columnstore-release#.x86\_64.bin.tar.gz * Run post installation: If performing the MariaDB ColumnStore Multi-node Distributed Installation, the post-install only needs to be run on Performance Module #1 (pm1). If performing Non-Distributed installs, the post-install needs to be run the MariaDB ColumnStore on all the nodes in the system. ``` ./mariadb/columnstore/bin/post-install --installdir=$HOME/mariadb/columnstore ``` * Run the 2 export command lines that were outputted by the previous post-install command, which would look like the following. See the “MariaDB Columnstore Configuration” in this guide for more information: ``` export COLUMNSTORE_INSTALL_DIR=/home/guest/mariadb/columnstore export LD_LIBRARY_PATH=/home/guest/mariadb/columnstore/lib:/home/guest/mariadb/columnstore/mysql/lib /home/guest/mariadb/columnstore/bin/postConfigure -i /home/guest/mariadb/columnstore ``` * Start MariaDB ColumnStore Service for Non-Distributed installs If performing the MariaDB ColumnStore Multi-node Non-Distributed installs, the 'columnstore' service needs to be started on all the nodes in the system except Performance Module #1 (pm1). postConfigure is run from pm1, which is documented in the next section Starting the 'columnstore' service: ``` ./mariadb/columnstore/bin/columnstore start ``` #### Post-installation (by root user) Optional items to assist in MariaDB Columnstore auto-start and logging: * To configure MariaDB Columnstore to start automatically at boot time, perform the following steps in each Columnstore server: * Add the following to the /etc/rc.local or /etc/rc.d/rc.local (centos7) file: su - guest -l -c "/home/guest/mariadb/columnstore/bin/columnstore start" or sudo runuser -l mariadb-user -c "/home/mariadb-user/mariadb/columnstore/bin/columnstore start" Note: Make sure the above entry is added to the rc.local file that gets executed at boot time. Depending on the OS installation, rc.local could be in a different location. * MariaDB Columnstore will setup and log using your current system logging application in the directory /var/log/mariadb/columnstore. ### ColumnStore Cluster Test Tool This tool can be running before doing installation on a single-server or multi-node installs. It will verify the setup of all servers that are going to be used in the Columnstore System. [https://mariadb.com/kb/en/mariadb/mariadb-columnstore-cluster-test-tool](../mariadb/mariadb-columnstore-cluster-test-tool) The next step would be to run the install script postConfigure, check the Single Server Or Multi-Server Install guide. ### ColumnStore Configuration and Installation Tool MariaDB Columnstore System Configuration and Installation tool, 'postConfigure', will Configure the MariaDB Columnstore System and will perform a Package Installation of all of the Servers within the System that is being configured. It will prompt the user to configuration information like server, storage, MariaDB Server, and system features. It updates the MariaDB Columnstore System Configuration File, Columnstore.xml. At the end, it will start up the ColumnStore system. NOTE: When prompted for password, enter the non-user account password OR just hit enter if you have setup the non-root user with password-less ssh keys on all nodes (Please see the “System Administration Information” section earlier in this guide for more information on ssh keys.) This tool is always run on the Performance Module #1. Example uses of this script are shown in the Single and Multi Server Installations Guides. ``` # /usr/local/mariadb/columnstore/bin/postConfigure -h This is the MariaDB ColumnStore System Configuration and Installation tool. It will Configure the MariaDB ColumnStore System based on Operator inputs and will perform a Package Installation of all of the Modules within the System that is being configured. IMPORTANT: This tool should only be run on a Performance Module Server, preferably Module #1 Instructions: Press 'enter' to accept a value in (), if available or Enter one of the options within [], if available, or Enter a new value Usage: postConfigure [-h][-c][-u][-p][-qs][-qm][-qa][-port][-i][-n][-d][-sn][-pm-ip-addrs][-um-ip-addrs][-pm-count][-um-count] -h Help -c Config File to use to extract configuration data, default is Columnstore.xml.rpmsave -u Upgrade, Install using the Config File from -c, default to Columnstore.xml.rpmsave If ssh-keys aren't setup, you should provide passwords as command line arguments -p Unix Password, used with no-prompting option -qs Quick Install - Single Server -qm Quick Install - Multi Server -port MariaDB ColumnStore Port Address -i Non-root Install directory, Only use for non-root installs -n Non-distributed install, meaning postConfigure will not install packages on remote nodes -d Distributed install, meaning postConfigure will install packages on remote nodes -sn System Name -pm-ip-addrs Performance Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx -um-ip-addrs User Module IP Addresses xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SOUNDS LIKE SOUNDS LIKE =========== Syntax ------ ``` expr1 SOUNDS LIKE expr2 ``` Description ----------- This is the same as `[SOUNDEX](../soundex/index)(expr1) = SOUNDEX(expr2)`. Example ------- ``` SELECT givenname, surname FROM users WHERE givenname SOUNDS LIKE "robert"; +-----------+---------+ | givenname | surname | +-----------+---------+ | Roberto | Castro | +-----------+---------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Setting Up MariaDB for Testing for SQL Server Users Setting Up MariaDB for Testing for SQL Server Users =================================================== This page contains links and hints to setup MariaDB for testing. The page is designed for SQL Server users, assuming that they are mostly familiar with Windows and they are not familiar with MariaDB. Choosing a MariaDB Version -------------------------- As a general rule, for new installations it's better to choose the [latest Generally Available (GA) version](../download-latest-releases/index). If you need a feature that is only present in a version that is not yet production-ready, and the project will surely not go to production before that version is GA, it could make sense to use a non-GA version. In this case however, keep in mind that you are using a version that is only suitable for testing. If you need to work with an existing production instance, you should of course use the same version in testing. However, deprecated versions should not be used in production, because they could be exposed to vulnerabilities that will never be fixed. See [deprecation policies](../deprecation-policy/index) if you are not sure about the version you are using. Setting up MariaDB on Windows ----------------------------- There are two different ways to use MariaDB on Windows natively: using Zip packages or MSI packages. In both cases, 32-bit platforms are still supported. Check the page [Installation issues on Windows](../installation-issues-on-windows/index) to verify if current versions of MariaDB have troubles on Windows. More generally, it is a good idea to check the [Troubleshooting Installation Issues](../troubleshooting-installation-issues/index) category. ### ZIP Packages Windows users don't necessarily need to install MariaDB to use it. They can download ready-to-use ZIP packages to avoid any change in the system (except for downloading MariaDB and writing databases on the disk). This is very useful for testing without risking some undesired side effect on the machine in use. And it avoids the hassle of installing Docker or virtual machines. **MariaDB starting with [10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/)**Starting with [MariaDB 10.4.3](https://mariadb.com/kb/en/mariadb-1043-release-notes/), it is necessary to run [mysql\_install\_db.exe](../mysql_install_dbexe/index) to install the data directory. The drawback is that MariaDB will need to be started and stopped from the command line. See [Installing MariaDB Windows ZIP Packages](../installing-mariadb-windows-zip-packages/index). ### MSI Packages MSI packages provide a friendly graphical interface to install MariaDB. The installation process is easy but flexible. For example, the user can decide which components to install, whether to install it as a service or not, and if networking should be enabled. An interface to uninstall MariaDB is also provided. See [Installing MariaDB MSI Packages on Windows](../installing-mariadb-msi-packages-on-windows/index). Installing MariaDB on Docker ---------------------------- Docker is a container platform that runs natively on Linux. A Docker image is a representation of a basic Linux system, which usually runs a single process - in our case, that process is MariaDB. A container is an instance of an image, which can be created or destroyed instantaneously. Once a container is started, it can be used just like a normal system. Docker runs on all major operating systems. On Windows and MacOS it runs on a Linux virtual machine, but this additional complexity is transparent for the end user. Docker's characteristics makes it optimal to test MariaDB functionalities without wasting time on installation and without making changes to the host system. However, it is not ideal to test MariaDB performance. See [Installing and Using MariaDB via Docker](../installing-and-using-mariadb-via-docker/index). Reinitializing MariaDB Data Directory ------------------------------------- While experimenting with MariaDB, you could end up with an unusable installation. This occurs for example if you deliberately delete files that you shouldn't delete. If it happens, there is no need to uninstall and reinstall MariaDB. Instead, you can simply delete the contents of the data directory and run [mysql\_install\_db](../mysql_install_db/index). The program will recreate your system tables and the essential files. To know where your data directory is, check the [datadir](../server-system-variables/index#datadir) system variable. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb TablePlus TablePlus ========= [TablePlus](https://tableplus.com/) is a modern, native app with a clean user interface that allows developers to simultaneously manage databases in a very fast and secure way. TablePlus supports most of the popular databases such as MySQL, Postgres, SQL Server, SQLite, Microsoft SQL Server, Redis, Redshift, Oracle, and many more. ![table](https://mariadb.com/kb/en/tableplus/+image/table "table") TablePlus is compatible with all versions of MariaDB. It is available for macOS, Windows, iOS, and Linux at the moment. Some notable features: * Native build * Convenient query editor * Multi Tabs & Code Review * Can connect to multiples databases simultaneously. TablePlus is available for free, but users can purchase a license to remove some limitations and customize the tool for higher needs on [TablePlus website](https://tableplus.com/pricing). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.spider_link_failed_log Table mysql.spider\_link\_failed\_log Table ===================================== The `mysql.spider_link_failed_log` table is installed by the [Spider storage engine](../spider/index). **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this table uses the [Aria](../aria/index) storage engine. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. It contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | db\_name | char(64) | NO | | | | | table\_name | char(199) | NO | | | | | link\_id | char(64) | NO | | | | | failed\_time | timestamp | NO | | current\_timestamp() | | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Database Design: Overview Database Design: Overview ========================= Databases exist because of the need to change data into information. Data are the raw and unprocessed facts. Information is obtained by processing the data into something useful. For example, millions of names and telephone numbers in a phone book are data. Information is the telephone number of the fire department when your house is burning down. A database is a large repository of facts, designed in such a way that processing the facts into information is easy. If the phone book was structured in a less convenient way, such as with names and numbers placed in chronological order according to when the numbers were issued, converting the data into information would be much more difficult. Not knowing when the fire department was issued their latest number, you could search for days, and by the time you find the number your house would be a charred pile of ash. So, it's a good thing the phone book was designed as it was. A database is much more flexible; a similar set of data to what's in a phone book could be ordered by MariaDB according to name, telephone number, address as well as chronologically. But databases are of course more complex, containing many different kinds of information. People, job titles and a company's products can all mingle to provide complex information. But this complexity makes the design of databases more complex as well. Poor design could make for slow queries, or it could even make certain kinds of information impossible to reach. This section of the Knowledge Base features articles about good database design, specifically: * The database lifecycle * Entity-relationship modeling * Common mistakes in database design * Real-world example: creating a publishing tracking system * Concurrency control with transactions Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Select Random Ranges and Select Random Point Select Random Ranges and Select Random Point ============================================ * `select_random_ranges` (select 10 ranges with a delta as parameter) * `select_random_points` (select 100 random points) Findings: --------- `select_random_ranges` * A delta of 100 for the ranges gives 3 - 6% performance gain * A delta of 50 for the ranges gives 3 - 15% performance gain * A delta of 5 for the ranges gives up to 70% performance gain * A delta of 1 million shows no difference at all. `select_random_points` * We see up to 150% performance gain fetching index only * We see up to 50% performance gain fetching index and data The absolute numbers are highly RAM depended * We see an up to 250% performance difference on a 2GB system compared to a 4GB system. MariaDB and MySQL were compiled with ``` BUILD/compile-amd64-max ``` MariaDB revision was: ``` revno: 2742 committer: Igor Babaev <[email protected]> branch nick: maria-5.2-keycache timestamp: Tue 2010-02-16 08:41:11 -0800 message: WL#86: Partitioned key cache for MyISAM. This is the base patch for the task. ``` sysbench was run with the following parameters: ``` --oltp-table-size=20000000 \ # 20 million rows. --max-requests=0 \ --mysql-table-engine=MyISAM \ --mysql-user=root \ --mysql-engine-trx=no \ --myisam-max-rows=50000000 \ --rand-seed=303 ``` and the following variable parameters ``` --num-threads=$THREADS --test=${TEST_DIR}/${SYSBENCH_TEST} ``` Configuration used for MariDB: ``` --no-defaults \ --datadir=/mnt/data/sysbench/data \ --language=./sql/share/english \ --key_buffer_size=512M \ --key_cache_partitions=32 \ # Off | 32 | 64 --max_connections=256 \ --query_cache_size=0 \ --query_cache_type=0 \ --skip-grant-tables \ --socket=/tmp/mysql.sock \ --table_open_cache=512 \ --thread_cache=512 \ --tmpdir=/mnt/data/sysbench ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Aria Disabling Encryption Aria Disabling Encryption ========================= The process involved in safely disabling data-at-rest encryption for your Aria tables is very similar to that of enabling encryption. To disable, you need to set the relevant system variables and then rebuild each table into an unencrypted state. Don't remove the [Encryption Key Management](key-management-encryption-plugins) plugin from your configuration file until you have unencrypted all tables in your database. MariaDB cannot read encrypted tables without the relevant encryption key. Disabling Encryption on User-created Tables ------------------------------------------- With tables that the user creates, you can disable encryption by setting the `[aria\_encrypt\_tables](../aria-system-variables/index#aria_encrypt_tables)` system variable to `OFF`. Once this is set, MariaDB no longer encrypts new tables created with the Aria storage engine. ``` SET GLOBAL aria_encrypt_tables = OFF; ``` Unlike [InnoDB](../innodb-encryption/index), Aria does not currently use background encryption threads. Before removing the [Encryption Key Management](key-management-encryption-plugins) plugin from the configuration file, you first need to manually rebuild each table to an unencrypted state. To find the encrypted tables, query the Information Schema, filtering the `[TABLES](information_schema-tables-table)` table for those that use the Aria storage engine and the `PAGE` `[ROW\_FORMAT](../create-table/index#row_format)`. ``` SELECT TABLE_SCHEMA, TABLE_NAME FROM information_schema.TABLES WHERE ENGINE = 'Aria' AND ROW_FORMAT = 'PAGE' AND TABLE_SCHEMA != 'information_schema'; ``` Each table in the result-set was potentially written to disk in an encrypted state. Before removing the configuration for the encryption keys, you need to rebuild each of these to an unencrypted state. This can be done with an `[ALTER TABLE](../alter-table/index)` statement. ``` ALTER TABLE test.aria_table ENGINE = Aria ROW_FORMAT = PAGE; ``` Once all of the Aria tables are rebuilt, they're safely unencrypted. Disabling Encryption for Internal On-disk Temporary Tables ---------------------------------------------------------- MariaDB routinely creates internal temporary tables. When these temporary tables are written to disk and the `[aria\_used\_for\_temp\_tables](../aria-system-variables/index#aria_used_for_temp_tables)` system variable is set to `ON`, MariaDB uses the Aria storage engine. To decrypt these tables, set the `[encrypt\_tmp\_disk\_tables](../server-system-variables/index#encrypt_tmp_disk_tables)` to `OFF`. Once set, all internal temporary tables that are created from that point on are written unencrypted to disk. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb BACKUP TABLE (removed) BACKUP TABLE (removed) ====================== **MariaDB until [5.3](../what-is-mariadb-53/index)**BACKUP TABLE was removed in [MariaDB 5.5](../what-is-mariadb-55/index). Syntax ------ ``` BACKUP TABLE tbl_name [, tbl_name] ... TO '/path/to/backup/directory' ``` Description ----------- **Note:** Like [RESTORE TABLE](../restore-table/index), this command was not reliable and has been removed in current versions of MariaDB. For doing a backup of MariaDB use [mysqldump](../mysqldump/index) or [MariaDB Backup](../mariadb-backup/index). See [Backing Up and Restoring](../backing-up-and-restoring/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SRID SRID ==== A synonym for [ST\_SRID](../st_srid/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_SYS_TABLESPACES Table Information Schema INNODB\_SYS\_TABLESPACES Table ================================================= The [Information Schema](../information_schema/index) `INNODB_SYS_TABLESPACES` table contains information about InnoDB tablespaces. Until [MariaDB 10.5](../what-is-mariadb-105/index) it was based on the internal `SYS_TABLESPACES` table. This internal table was removed in [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/), so this Information Schema table has been repurposed to directly reflect the filesystem (fil\_system.space\_list). The `PROCESS` [privilege](../grant/index) is required to view the table. It has the following columns: | Column | Description | | --- | --- | | `SPACE` | Unique InnoDB tablespace identifier. | | `NAME` | Database and table name separated by a backslash, or the uppercase InnoDB system table name. | | `FLAG` | `1` if a `DATA DIRECTORY` option has been specified in `[CREATE TABLE](../create-table/index)`, otherwise `0`. | | `FILE_FORMAT` | [InnoDB file format](../innodb-file-format/index). Removed in [MariaDB 10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/) | | `ROW_FORMAT` | [InnoDB storage format](../innodb-storage-formats/index) used for this tablespace. If the [Antelope](../innodb-file-format/index#antelope) file format is used, this value is always `Compact or Redundant`. | | `PAGE_SIZE` | Page size in bytes for this tablespace. Until [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/), this was the value of the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) variable. From [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/), contains the physical page size of a page (previously `ZIP_PAGE_SIZE`). | | `ZIP_PAGE_SIZE` | Zip page size for this tablespace. Removed in [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/). | | `SPACE_TYPE` | Tablespace type. Can be `General` for general tablespaces or `Single` for file-per-table tablespaces. Introduced [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). Removed [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/). | | `FS_BLOCK_SIZE` | File system block size. Introduced [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). | | `FILE_SIZE` | Maximum size of the file, uncompressed. Introduced [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). | | `ALLOCATED_SIZE` | Actual size of the file as per space allocated on disk. Introduced [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/). | | `FILENAME` | Tablespace datafile path, previously part of the [INNODB\_SYS\_DATAFILES table](../information-schema-innodb_sys_datafiles-table/index). Added in [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/). | Examples -------- [MariaDB 10.4](../what-is-mariadb-104/index): ``` DESC information_schema.innodb_sys_tablespaces; +----------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------------+---------------------+------+-----+---------+-------+ | SPACE | int(11) unsigned | NO | | 0 | | | NAME | varchar(655) | NO | | | | | FLAG | int(11) unsigned | NO | | 0 | | | ROW_FORMAT | varchar(22) | YES | | NULL | | | PAGE_SIZE | int(11) unsigned | NO | | 0 | | | ZIP_PAGE_SIZE | int(11) unsigned | NO | | 0 | | | SPACE_TYPE | varchar(10) | YES | | NULL | | | FS_BLOCK_SIZE | int(11) unsigned | NO | | 0 | | | FILE_SIZE | bigint(21) unsigned | NO | | 0 | | | ALLOCATED_SIZE | bigint(21) unsigned | NO | | 0 | | +----------------+---------------------+------+-----+---------+-------+ ``` From [MariaDB 10.4](../what-is-mariadb-104/index): ``` SELECT * FROM information_schema.INNODB_SYS_TABLESPACES LIMIT 2\G *************************** 1. row *************************** SPACE: 2 NAME: mysql/innodb_table_stats FLAG: 33 ROW_FORMAT: Dynamic PAGE_SIZE: 16384 ZIP_PAGE_SIZE: 0 SPACE_TYPE: Single FS_BLOCK_SIZE: 4096 FILE_SIZE: 98304 ALLOCATED_SIZE: 98304 *************************** 2. row *************************** SPACE: 3 NAME: mysql/innodb_index_stats FLAG: 33 ROW_FORMAT: Dynamic PAGE_SIZE: 16384 ZIP_PAGE_SIZE: 0 SPACE_TYPE: Single FS_BLOCK_SIZE: 4096 FILE_SIZE: 98304 ALLOCATED_SIZE: 98304 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Database Design Phase 1: Analysis Database Design Phase 1: Analysis ================================= This article follows on from [Database Lifecycle](../database-lifecycle/index). Your existing system can no longer cope. It's time to move on. Perhaps the existing paper system is generating too many errors, or the old Perl script based on flat files can no longer handle the load. Or perhaps an existing news database is struggling under its own popularity and needs an upgrade. This is the stage where the existing system is reviewed. Depending on the size of the project, the designer may be an individual, responsible for the database implementation and coding, or may be a whole team of analysts. For now, the term *designer* will represent all these possibilities. The following are the steps in the Analysis Phase. 1. Analyze the organization 2. Define any problems, possibilities or constraints 3. Define the objectives 4. Agree on the scope When reviewing a system, the designer needs to look at the bigger picture - not just the hardware or existing table structures, but the whole situation of the organization calling for the redesign. For example, a large bank with centralized management would have a different structure and a different way of operating from a decentralized media organization, where anyone can post news onto a website. This may seem trivial, but understanding the organization you're building the database for is vital. to designing a good database for it. The same demands in the bank and media organizations should lead to different designs because the organizations are different. In other words, a solution that was constructed for the bank cannot be unthinkingly implemented for the media organization, even when the situation seems similar. A culture of central control at the bank may mean that news posted on the bank website has to be moderated and authorized by central management, or may require the designer to keep detailed audit trails of who modified what and when. On the flip-side, the media organization may be more laissez-faire and will be happy with news being modified by any authorized editor. Understanding an organization's culture helps the designers ask the right questions. The bank may not ask for an audit trail, it may simply expect it; and when the time comes to roll out the implementation, the audit trail would need to be patched on, requiring more time and resources. Once you understand the organization structure, you can question the users of any existing system as to what their problems and needs are, as well as what constraints will exist then. You need to question different role players, as each can add new understanding as to what the database may need. For example, the media organization's marketing department may need detailed statistics about the times of day certain articles are read. You may also be alerted to possible future requirements. Perhaps the editorial department is planning to expand the website, which will give them the staff to cross-link web articles. Keeping this future requirement in mind could make it easier to add the cross-linking feature when the time comes. Constraints can include hardware ("We have to use our existing database server") or people ("We only have one data capturer on shift at any one time"). Constraints also refer to the limitations on values. For example, a student's grade in a university database may not be able to go beyond 100 percent, or the three categories of seats in a theatre database are small, medium and large. It is rarely sufficient to rely on one level of management, or an individual, to supply objectives and current problems, except in the smallest of organizations. Top management may be paying for the database design, but lower levels will need to use it, and their input is probably even more important for a successful design. Of course, although anything is possible given infinite time and money, this is (usually) never forthcoming. Determining scope, and formalizing it, is an important part of the project. If the budget is for one month's work but the ideal solution requires three, the designer must make clear these constraints and agree with the project owners on which facets are not going to be implemented. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb JSON_MERGE JSON\_MERGE =========== **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**JSON functions were added in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). Syntax ------ ``` JSON_MERGE(json_doc, json_doc[, json_doc] ...) ``` Description ----------- Merges the given JSON documents. Returns the merged result,or NULL if any argument is NULL. An error occurs if any of the arguments are not valid JSON documents. `JSON_MERGE` has been deprecated since [MariaDB 10.2.25](https://mariadb.com/kb/en/mariadb-10225-release-notes/), [MariaDB 10.3.16](https://mariadb.com/kb/en/mariadb-10316-release-notes/) and [MariaDB 10.4.5](https://mariadb.com/kb/en/mariadb-1045-release-notes/). [JSON\_MERGE\_PATCH](../json_merge_patch/index) is an RFC 7396-compliant replacement, and [JSON\_MERGE\_PRESERVE](../json_merge_preserve/index) is a synonym. Example ------- ``` SET @json1 = '[1, 2]'; SET @json2 = '[3, 4]'; SELECT JSON_MERGE(@json1,@json2); +---------------------------+ | JSON_MERGE(@json1,@json2) | +---------------------------+ | [1, 2, 3, 4] | +---------------------------+ ``` See Also -------- * [JSON\_MERGE\_PATCH](../json_merge_patch/index) * [JSON\_MERGE\_PRESERVE](../json_merge_preserve/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Package Repository Setup and Usage MariaDB Package Repository Setup and Usage ========================================== If you are looking to set up MariaDB Server, it is often easiest to use a repository. The MariaDB Foundation has a repository configuration tool at <https://mariadb.org/download/> and MariaDB Corporation provides a convenient shell script to configure access to their MariaDB Package Repositories. It is available at: * <https://r.mariadb.com/downloads/mariadb_repo_setup> The script by default sets up 3 different repositories in a single repository configuration file. The repositories are * MariaDB Server Repository * MariaDB MaxScale Repository * MariaDB Tools Repository The script can be executed in the following way: ``` curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash ``` For the script to work, the `curl` and `ca-certificates` packages need to be installed on your system. Additionally on Debian and Ubuntu the `apt-transport-https` package needs to be installed. The script will check if these are installed and let you know before it attempts to create the repository configuration on your system. Repositories ------------ The script will will set up 2 different repositories in a single repository configuration file. ### MariaDB Repository The **MariaDB Repository** contains software packages related to MariaDB Server, including the server itself, [clients and utilities](../clients-utilities/index), [client libraries](../client-libraries/index), [plugins](../plugins/index), and [Mariabackup](../mariabackup/index). The binaries in MariaDB Corporation's **MariaDB Repository** are currently identical to the binaries in MariaDB Foundation's MariaDB Repository that is configured with the [MariaDB Repository Configuration Tool](https://mariadb.org/download/?t=repo-config). By default, the script will configure your system to install from the repository of the latest GA version of MariaDB. That is currently [MariaDB 10.7](../what-is-mariadb-107/index). If a new major GA release occurs and you would like to upgrade to it, then you will need to either manually edit the repository configuration file to point to the new version, or run the MariaDB Package Repository setup script again. The script can also configure your system to install from the repository of a different version of MariaDB if you use the `[--mariadb-server-version](#-mariadb-server-version)` option. If you would not like to configure the **MariaDB Repository** on your system, then you can use the `--skip-server` option to prevent the MariaDB Package Repository setup script from configuring it. ### MariaDB MaxScale Repository The **MariaDB MaxScale Repository** contains software packages related to [MariaDB MaxScale](../maxscale/index). By default, the script will configure your system to install from the repository of the *latest* GA version of MariaDB MaxScale. When a new major GA release occurs, the repository will automatically switch to the new version. If instead you would like to stay on a particular version you will need to manually edit the repository configuration file and change '`latest`' to the version you want (e.g. '`6.1`') or run the MariaDB Package Repository setup script again, specifying the particular version or series you want. Older versions of the MariaDB Package Repository setup script would configure a specific MariaDB MaxScale series in the repository (i.e. '`2.4`'), so if you used the script in the past to set up your repository and want MariaDB MaxScale to automatically use the latest GA version then change '`2.4`' or '`2.3`' in the repository configuration to '`latest`'. Or download the current version of the script and re-run it to set up the repository again. The script can configure your system to install from the repository of an older version of MariaDB MaxScale if you use the `[--mariadb-maxscale-version](#-mariadb-maxscale-version)` option. For example, `--mariadb-maxscale-version=2.4` if you want the latest release in the MariaDB MaxScale 2.4.x series. If you do not want to configure the **MariaDB MaxScale Repository** on your system, then you can use the `--skip-maxscale` option to prevent the MariaDB Package Repository setup script from configuring it. MariaDB MaxScale is licensed under the [Business Source License 1.1](https://mariadb.com/bsl11/), so it is not entirely free to use for organizations who do not have a subscription with MariaDB Corporation. If you would like more information, see the information at [MariaDB Business Source License (BSL): Frequently Asked Questions](https://mariadb.com/bsl-faq-mariadb/). If you would like to know how much a subscription to use MariaDB MaxScale would cost, see [MariaDB Corporation's subscription pricing](https://mariadb.com/pricing/). Supported Distributions ----------------------- The script supports Linux distributions that are officially supported by MariaDB Corporation's [MariaDB TX subscription](https://mariadb.com/products/mariadb-platform-transactional/). However, a MariaDB TX subscription with MariaDB Corporation is not required to use the MariaDB Package Repository. The distributions currently supported by the script include: * Red Hat Enterprise Linux (RHEL) 7 and 8 * CentOS 7 * Debian 9 (Stretch), 10 (Buster), 11 (Bullseye) * Ubuntu 18.04 LTS (Bionic), and 20.04 LTS (Focal) * SUSE Linux Enterprise Server (SLES) 12 and 15 To install MariaDB on distributions not supported by the MariaDB Package Repository setup script, please consider using MariaDB Foundation's [MariaDB Repository Configuration Tool](https://mariadb.org/download/?t=repo-config). Some Linux distributions also include MariaDB [in their own repositories](../distributions-which-include-mariadb/index). Using the MariaDB Package Repository Setup Script ------------------------------------------------- The script can be executed in the following way: ``` curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash ``` The script will have to set up package repository configuration files, so it will need to be executed as root. The script will also install the GPG public keys used to verify the signature of MariaDB software packages. If you want to avoid that, then you can use the `--skip-key-import` option. If the script tries to create the repository configuration file and one with that name already exists, then the script will rename the existing file with an extension in the format ".old\_[0-9]+", which would make the OS's package manager ignore the file. You can safely remove those files after you have confirmed that the updated repository configuration file works.. If you want to see the repository configuration file that would be created without actually doing so, then you can use the `[--write-to-stdout](#-write-to-stdout)` option. This also prevents the need to run the script as root, If you want to download the script, rather than executing it, then you can do so in the following way: ``` curl -LO https://r.mariadb.com/downloads/mariadb_repo_setup ``` ### Options To provide options to the script, you must tell bash to expect them by executing bash with the options `-s --`, for example: ``` curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash -s -- --help ``` | Option | Description | | --- | --- | | `--help` | Display a usage message and exit. | | `--mariadb-server-version=<version>` | Override the default MariaDB Server version. By default, the script will use 'mariadb-10.5'. | | `--mariadb-maxscale-version=<version>` | Override the default MariaDB MaxScale version. By default, the script will use 'latest'. | | `--os-type=<type>` | Override detection of OS type. Acceptable values include `debian`, `ubuntu`, `rhel`, and `sles`. | | `--os-version=<version>` | Override detection of OS version. Acceptable values depend on the OS type you specify. | | `--skip-key-import` | Skip importing GPG signing keys. | | `--skip-maxscale` | Skip the 'MaxScale' repository. | | `--skip-server` | Skip the 'MariaDB Server' repository. | | `--skip-tools` | Skip the 'Tools' repository. | | `--skip-check-installed` | Skip tests for required prerequisites for this script. | | `--write-to-stdout` | Write output to stdout instead of to the OS's repository configuration file. This will also skip importing GPG public keys and updating the package cache on platforms where that behavior exists. | #### `--mariadb-server-version` By default, the script will configure your system to install from the repository of the latest GA version of MariaDB. That is currently [MariaDB 10.5](../what-is-mariadb-105/index). If a new major GA release occurs and you would like to upgrade to it, then you will need to either manually edit the repository configuration file to point to the new version, or run the MariaDB Package Repository setup script again. The script can also configure your system to install from the repository of a different version of MariaDB if you use the `--mariadb-server-version` option. The string `mariadb-` has to be prepended to the version number. For example, to configure your system to install from the repository of [MariaDB 10.3](../what-is-mariadb-103/index), that would be: ``` curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash -s -- --mariadb-server-version="mariadb-10.6" ``` The following MariaDB versions are currently supported: * `mariadb-10.2` * `mariadb-10.3` * `mariadb-10.4` * `mariadb-10.5` * `mariadb-10.6` * `mariadb-10.7` If you want to pin the repository of a specific minor release, such as [MariaDB 10.3.9](https://mariadb.com/kb/en/mariadb-1039-release-notes/), then you can also specify the minor release. For example, `mariadb-10.6.4`. This may be helpful if you want to avoid upgrades. However, avoiding upgrades is not recommended, since minor releases can contain important bug fixes and fixes for security vulnerabilities. #### `--mariadb-maxscale-version` By default, the script will configure your system to install from the repository of the latest GA version of MariaDB MaxScale. If you would like to pin the repository to a specific version of MariaDB MaxScale then you will need to either manually edit the repository configuration file to point to the desired version, or use the `--mariadb-maxscale-version` option. For example, to configure your system to install from the repository of MariaDB MaxScale 6.1, that would be: ``` curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash -s -- --mariadb-maxscale-version="6.1" ``` The following MariaDB MaxScale versions are currently supported: * MaxScale 1.4 * MaxScale 2.0 * MaxScale 2.1 * MaxScale 2.2 * MaxScale 2.3 * MaxScale 2.4 * MaxScale 2.5 * MaxScale 6.1 * MaxScale 6.2 The special identifiers `latest` (for the latest GA release) and `beta` (for the latest beta release) are also supported. By default the `mariadb_repo_setup` script uses `latest` as the version. #### `--os-type` and `--os-version` If you want to run this script on an unsupported OS that you believe to be package-compatible with an OS that is supported, then you can use the `--os-type` and `--os-version` options to override the script's OS detection. If you use either option, then you must use both options. The supported values for `--os-type` are: * `rhel` * `debian` * `ubuntu` * `sles` If you use a non-supported value, then the script will fail, just as it would fail if you ran the script on an unsupported OS. The supported values for `--os-version` are entirely dependent on the OS type. For Red Hat Enterprise Linux (RHEL) and CentOS, `7` and `8` are valid options. For Debian and Ubuntu, the version must be specified as the codename of the specific release. For example, Debian 9 must be specified as `stretch`, and Ubuntu 18.04 must be specified as `bionic`. These options can be useful if your distribution is a fork of another distribution. As an example, Linux Mint 8.1 is based on and is fully compatible with Ubuntu 16.04 LTS (Xenial). Therefore, If you are using Linux Mint 8.1, then you can configure your system to install from the repository of Ubuntu 16.04 LTS (Xenial). If you would like to do that, then you can do so by specifying `--os-type=ubuntu` and `--os-version=xenial` to the MariaDB Package Repository setup script. For example, to manually set the `--os-type` and `--os-version` to RHEL 8 you could do: ``` curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash -s -- --os-type=rhel --os-version=8 ``` #### `--write-to-stdout` The `--write-to-stdout` option will prevent the script from modifying anything on the system. The repository configuration will not be written to the repository configuration file. Instead, it will be printed to standard output. That allows the configuration to be reviewed, redirected elsewhere, consumed by another script, or used in some other way. The `--write-to-stdout` option automatically enables `--skip-key-import`. For example: ``` curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash -s -- --write-to-stdout ``` ### Platform-Specific Behavior #### Platform-Specific Behavior on RHEL and CentOS On Red Hat Enterprise Linux (RHEL) and CentOS, the MariaDB Package Repository setup script performs the following tasks: 1. Creates a repository configuration file at `/etc/yum.repos.d/mariadb.repo`. 2. Imports the GPG public key used to verify the signature of MariaDB software packages with `rpm --import` from `downloads.mariadb.com`. #### Platform-Specific Behavior on Debian and Ubuntu On Debian and Ubuntu, the MariaDB Package Repository setup script performs the following tasks: 1. Creates a repository configuration file at `/etc/apt/sources.list.d/mariadb.list`. 2. Creates a package preferences file at `/etc/apt/preferences.d/mariadb-enterprise.pref`, which gives packages from MariaDB repositories a higher priority than packages from OS and other repositories, which can help avoid conflicts. It looks like the following: ``` Package: * Pin: origin downloads.mariadb.com Pin-Priority: 1000 ``` 3. Imports the GPG public key used to verify the signature of MariaDB software package with `apt-key` from the `keyserver.ubuntu.com` key server. 4. Updates the package cache with package definitions from the MariaDB Package Repository with `apt-get update`. #### Platform-Specific Behavior on SLES On SUSE Linux Enterprise Server (SLES), the MariaDB Package Repository setup script performs the following tasks: 1. Creates a repository configuration file at `/etc/zypp/repos.d/mariadb.repo`. 2. Imports the GPG public key used to verify the signature of MariaDB software packages with `rpm --import` from `downloads.mariadb.com`. Installing Packages with the MariaDB Package Repository ------------------------------------------------------- After setting up the MariaDB Package Repository, you can install the software packages in the supported repositories. ### Installing Packages on RHEL and CentOS To install MariaDB on Red Hat Enterprise Linux (RHEL) and CentOS, see the instructions at [Installing MariaDB Packages with YUM](../yum/index#installing-mariadb-packages-with-yum). For example: ``` sudo yum install MariaDB-server MariaDB-client MariaDB-backup ``` To install MariaDB MaxScale on Red Hat Enterprise Linux (RHEL) and CentOS, see the instructions at [MariaDB MaxScale Installation Guide](../mariadb-maxscale-23-mariadb-maxscale-installation-guide/index). For example: ``` sudo yum install maxscale ``` ### Installing Packages on Debian and Ubuntu To install MariaDB on Debian and Ubuntu, see the instructions at [Installing MariaDB Packages with APT](../installing-mariadb-deb-files/index#installing-mariadb-packages-with-apt). For example: ``` sudo apt-get install mariadb-server mariadb-client mariadb-backup ``` To install MariaDB MaxScale on Debian and Ubuntu, see the instructions at [MariaDB MaxScale Installation Guide](../mariadb-maxscale-23-mariadb-maxscale-installation-guide/index). For example: ``` sudo apt-get install maxscale ``` ### Installing Packages on SLES To install MariaDB on SUSE Linux Enterprise Server (SLES), see the instructions at [Installing MariaDB Packages with ZYpp](../installing-mariadb-with-zypper/index#installing-mariadb-packages-with-zypp). For example: ``` sudo zypper install MariaDB-server MariaDB-client MariaDB-backup ``` To install MariaDB MaxScale on SUSE Linux Enterprise Server (SLES), see the instructions at [MariaDB MaxScale Installation Guide](../mariadb-maxscale-23-mariadb-maxscale-installation-guide/index). For example: ``` sudo zypper install maxscale ``` Versions -------- | Version | sha256sum | | --- | --- | | 2022-08-22 | `733cf126b03f73050e242102592658913d10829a5bf056ab77e7f864b3f8de1f` | | 2022-08-15 | `f99e1d560bd72a3a23f64eaede8982d5494407cafa8f995de45fb9a7274ebc5c` | | 2022-06-14 | `d4e4635eeb79b0e96483bd70703209c63da55a236eadd7397f769ee434d92ca8` | | 2022-02-08 | `b9e90cde27affc2a44f9fc60e302ccfcacf71f4ae02071f30d570e6048c28597` | | 2022-01-18 | `c330d2755e18e48c3bba300a2898b0fc8ad2d3326d50b64e02fe65c67b454599` | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Buffers, Caches and Threads Buffers, Caches and Threads ============================ MariaDB makes use of a number of buffering, caching and threading techniques to improve performance. | Title | Description | | --- | --- | | [Thread Pool](../thread-pool/index) | MariaDB thread pool | | [Thread States](../thread-states/index) | Descriptions of the various thread states | | [InnoDB Buffer Pool](../innodb-buffer-pool/index) | The most important memory buffer used by InnoDB. | | [InnoDB Change Buffering](../innodb-change-buffering/index) | Buffering INSERT, UPDATE and DELETE statements for greater efficiency. | | [Query Cache](../query-cache/index) | Caching SELECT queries for better performance. | | [Segmented Key Cache](../segmented-key-cache/index) | Collection of structures for regular MyISAM key caches | | [Subquery Cache](../subquery-cache/index) | Subquery cache for optimizing the evaluation of correlated subqueries. | | [Thread Command Values](../thread-command-values/index) | Thread command values from SHOW PROCESSLIST or Information Schema PROCESSLIST Table | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Aria Encryption Aria Encryption ================ Configuration and use of data-at-rest encryption with the Aria storage engine. | Title | Description | | --- | --- | | [Aria Encryption Overview](../aria-encryption-overview/index) | Data-at-rest encryption for user-created tables and internal on-disk tempor... | | [Aria Enabling Encryption](../aria-enabling-encryption/index) | In order to enable data-at-rest encryption for tables using the Aria stora... | | [Aria Disabling Encryption](../aria-disabling-encryption/index) | The process involved in safely disabling data-at-rest encryption for your ... | | [Aria Encryption Keys](../aria-encryption-keys/index) | As with other storage engines that support data-at-rest encryption, Aria r... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb systemd systemd ======= `systemd` is a `[sysVinit](../sysvinit/index)` replacement that is the default service manager on the following Linux distributions: * RHEL 7 and above * CentOS 7 and above * Fedora 15 and above * Debian 8 and above * Ubuntu 15.04 and above * SLES 12 and above * OpenSUSE 12.2 and above MariaDB's `systemd` unit file is included in the server packages for [RPMs](../rpm/index) and [DEBs](../installing-mariadb-deb-files/index). It is also included in certain [binary tarballs](../installing-mariadb-binary-tarballs/index). The service name is `mariadb.service`. Aliases to `mysql.service` and `mysqld.service` are also installed for convenience. When MariaDB is started with the `systemd` unit file, it directly starts the `[mysqld](../mysqld-options/index)` process as the `mysql` user. Unlike with `[sysVinit](../sysvinit/index)`, the `[mysqld](../mysqld-options/index)` process is not started with `[mysqld\_safe](../mysqld_safe/index)`. As a consequence, options will not be read from the `[mysqld_safe]` [option group](../configuring-mariadb-with-option-files/index#option-groups) from [option files](../configuring-mariadb-with-option-files/index). Locating the MariaDB Service's Unit File ---------------------------------------- By default, the unit file for the service will be installed in a directory defined at build time by the `INSTALL_SYSTEMD_UNITDIR` option provided to `[cmake](../generic-build-instructions/index#using-cmake)`. For example, on RHEL, CentOS, Fedora, and other similar Linux distributions, `INSTALL_SYSTEMD_UNITDIR` is defined as `/usr/lib/systemd/system/`, so it will be installed to: * `/usr/lib/systemd/system/mariadb.service` And on Debian, Ubuntu, and other similar Linux distributions, `INSTALL_SYSTEMD_UNITDIR` is defined as `/lib/systemd/system/`, so it will be installed to: * `/lib/systemd/system/mariadb.service` Interacting with the MariaDB Server Process ------------------------------------------- The service can be interacted with by using the `[systemctl](https://www.freedesktop.org/software/systemd/man/systemctl.html)` command. ### Starting the MariaDB Server Process on Boot MariaDB's `systemd` service can be configured to start at boot by executing the following: ``` sudo systemctl enable mariadb.service ``` ### Starting the MariaDB Server Process MariaDB's `systemd` service can be started by executing the following: ``` sudo systemctl start mariadb.service ``` MariaDB's `systemd` unit file has a default startup timeout of about 90 seconds on most systems. If certain startup tasks, such as crash recovery, take longer than this default startup timeout, then `systemd` will assume that `mysqld` has failed to startup, which causes `systemd` to kill the `mysqld` process. To work around this, you can reconfigure the MariaDB `systemd` unit to have an [infinite timeout](#configuring-the-systemd-service-timeout). Note that [systemd 236 added the `EXTEND_TIMEOUT_USEC` environment variable](https://lists.freedesktop.org/archives/systemd-devel/2017-December/039996.html) that allows services to extend the startup timeout during long-running processes. Starting with [MariaDB 10.1.33](https://mariadb.com/kb/en/mariadb-10133-release-notes/), [MariaDB 10.2.15](https://mariadb.com/kb/en/mariadb-10215-release-notes/), and [MariaDB 10.3.6](https://mariadb.com/kb/en/mariadb-1036-release-notes/), on systems with systemd versions that support it, MariaDB uses this feature to extend the startup timeout during certain startup processes that can run long. Therefore, if you are using `systemd` 236 or later, then you should not need to manually override `TimeoutStartSec`, even if your startup tasks, such as crash recovery, run for longer than the configured value. See [MDEV-14705](https://jira.mariadb.org/browse/MDEV-14705) for more information. ### Stopping the MariaDB Server Process MariaDB's `systemd` service can be stopped by executing the following: ``` sudo systemctl stop mariadb.service ``` ### Restarting the MariaDB Server Process MariaDB's `systemd` service can be restarted by executing the following: ``` sudo systemctl restart mariadb.service ``` ### Checking the Status of the MariaDB Server Process The status of MariaDB's `systemd` service can be obtained by executing the following: ``` sudo systemctl status mariadb.service ``` ### Interacting with Multiple MariaDB Server Processes A `systemd` [template unit file](https://www.freedesktop.org/software/systemd/man/systemd.unit.html) with the name `[email protected]` is installed in `INSTALL_SYSTEMD_UNITDIR` on some systems. See [Locating the MariaDB Service's Unit File](#locating-the-mariadb-services-unit-file) to see what directory that refers to on each distribution. This template unit file allows you to interact with multiple MariaDB instances on the same system using the same template unit file. When you interact with a MariaDB instance using this template unit file, you have to provide an instance name as a suffix. For example, the following command tries to start a MariaDB instance with the name `node1`: ``` sudo systemctl start [email protected] ``` MariaDB's build system cannot include the `[email protected]` template unit file in [RPM](../rpm/index) packages on platforms that have `[cmake](../generic-build-instructions/index#using-cmake)` versions older than 3.3.0, because these `[cmake](../generic-build-instructions/index#using-cmake)` versions have a [bug](https://public.kitware.com/Bug/view.php?id=14782) that causes it to encounter errors when packaging a file in RPMs if the file name contains the `@` character. MariaDB's RHEL 7 and CentOS 7 RPM build hosts only got a new enough `[cmake](../generic-build-instructions/index#using-cmake)` version starting with [MariaDB 10.1.39](https://mariadb.com/kb/en/mariadb-10139-release-notes/), [MariaDB 10.2.23](https://mariadb.com/kb/en/mariadb-10223-release-notes/), and [MariaDB 10.3.14](https://mariadb.com/kb/en/mariadb-10314-release-notes/). To use this functionality on a MariaDB version that does not have the file, you can copy the file from a package that does have the file. #### Default configuration of Multiple Instances in 10.4 and Later `systemd` will also look for an [option file](../configuring-mariadb-with-option-files/index) for a specific MariaDB instance based on the instance name. It will use the `.%I` as the [custom option group suffix](../configuring-mariadb-with-option-files/index#custom-option-group-suffixes) that is appended to any [server option group](../configuring-mariadb-with-option-files/index#server-option-groups), in any configuration file included by default. In all distributions, the `%I` is the MariaDB instance name. In the above `node1` case, it would use the [option file](../configuring-mariadb-with-option-files/index) at the path`/etc/mynode1.cnf`. When using multiple instances, each instance will of course also need their own `[datadir](../server-system-variables/index#datadir)`, `[socket](../server-system-variables/index#socket)` and , `[port](../server-system-variables/index#port)` (unless `[skip\_networking](../server-system-variables/index#skip_networking) is specified). As [mysql\_install\_db#option-groups](../mysql_install_db/index#option-groups) reads the same sections as the server, and` ExecStartPre= `run [mysql\_install\_db](../mysql_install_db/index) within the service, the instances are autocreated if there is sufficient priviledges.` To use a 10.3 configuration in 10.4 or later and the following customisation in the editor after running `sudo systemctl edit [email protected]`: ``` [Unit] ConditionPathExists= [Service] Environment='MYSQLD_MULTI_INSTANCE=--defaults-file=/etc/my%I.cnf' ``` #### Custom configuration of Multiple Instances in 10.4 and Later Because users may want to do many various things with their multiple instances, we've provided a way to let the user define how they wish their multiple instances to run. The systemd environment variable `MYSQLD_MULTI_INSTANCE` can be set to anything that [mysqld](../mariadbd/index) and [mysql\_install\_db](../mysql_install_db/index) will recognise. A hosting environment where each user has their own instance may look like (with `sudo systemctl edit [email protected]`): ``` [Service] ProtectHome=false Environment='MYSQLD_MULTI_INSTANCE=--defaults-file=/home/%I/my.cnf \ --user=%I \ --socket=/home/%I.sock \ --datadir=/home/%I/mariadb_data \ --skip-networking' ``` Here the instance name is the unix user of the service. #### Configuring Multiple Instances in 10.3 and Earlier `systemd` will also look for an [option file](../configuring-mariadb-with-option-files/index) for a specific MariaDB instance based on the instance name. By default, it will look for the option file in a directory defined at build time by the `INSTALL_SYSCONF2DIR` option provided to `[cmake](../generic-build-instructions/index#using-cmake)`. For example, on RHEL, CentOS, Fedora, and other similar Linux distributions, `INSTALL_SYSCONF2DIR` is defined as `/etc/my.cnf.d/`, so it will look for an option file that matches the format: * `/etc/my.cnf.d/my%I.cnf` And on Debian, Ubuntu, and other similar Linux distributions, `INSTALL_SYSCONF2DIR` is defined as `/etc/mysql/conf.d//`, so it will look for an option file that matches the format: * `/etc/mysql/conf.d/my%I.cnf` In all distributions, the `%I` is the MariaDB instance name. In the above `node1` case, it would use the [option file](../configuring-mariadb-with-option-files/index) at the path`/etc/my.cnf.d/mynode1.cnf` for RHEL-like distributions and `/etc/mysql/conf.d/mynode1.cnf` for Debian-like distributions. When using multiple instances, each instance will of course also need their own `[datadir](../server-system-variables/index#datadir)`. See [mysql\_install\_db](../mysql_install_db/index) for information on how to initialize the `[datadir](../server-system-variables/index#datadir)` for additional MariaDB instances. Systemd and Galera Cluster -------------------------- ### Bootstrapping a New Cluster When using [Galera Cluster](../galera/index) with systemd, the first node in a cluster has to be started with `galera_new_cluster`. See [Getting Started with MariaDB Galera Cluster: Bootstrapping a New Cluster](../getting-started-with-mariadb-galera-cluster/index#bootstrapping-a-new-cluster) for more information. ### Recovering a Node's Cluster Position When using [Galera Cluster](../galera/index) with systemd, a node's position in the cluster can be recovered with `galera_recovery`. See [Getting Started with MariaDB Galera Cluster: Determining the Most Advanced Node](../getting-started-with-mariadb-galera-cluster/index#determining-the-most-advanced-node) for more information. ### SSTs and Systemd MariaDB's `systemd` unit file has a default startup timeout of about 90 seconds on most systems. If an SST takes longer than this default startup timeout on a joiner node, then `systemd` will assume that `mysqld` has failed to startup, which causes `systemd` to kill the `mysqld` process on the joiner node. To work around this, you can reconfigure the MariaDB `systemd` unit to have an [infinite timeout](#configuring-the-systemd-service-timeout). See [Introduction to State Snapshot Transfers (SSTs): SSTs and Systemd](../introduction-to-state-snapshot-transfers-ssts/index#ssts-and-systemd) for more information. Note that [systemd 236 added the `EXTEND_TIMEOUT_USEC` environment variable](https://lists.freedesktop.org/archives/systemd-devel/2017-December/039996.html) that allows services to extend the startup timeout during long-running processes. Starting with [MariaDB 10.1.35](https://mariadb.com/kb/en/mariadb-10135-release-notes/), [MariaDB 10.2.17](https://mariadb.com/kb/en/mariadb-10217-release-notes/), and [MariaDB 10.3.8](https://mariadb.com/kb/en/mariadb-1038-release-notes/), on systems with systemd versions that support it, MariaDB uses this feature to extend the startup timeout during long SSTs. Therefore, if you are using `systemd` 236 or later, then you should not need to manually override `TimeoutStartSec`, even if your SSTs run for longer than the configured value. See [MDEV-15607](https://jira.mariadb.org/browse/MDEV-15607) for more information. Configuring the Systemd Service ------------------------------- You can configure MariaDB's `systemd` service by creating a "drop-in" configuration file for the `systemd` service. On most systems, the `systemd` service's directory for "drop-in" configuration files is `/etc/systemd/system/mariadb.service.d/`. You can confirm the directory and see what "drop-in" configuration files are currently loaded by executing: ``` $ sudo systemctl status mariadb.service ● mariadb.service - MariaDB 10.1.37 database server Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled) Drop-In: /etc/systemd/system/mariadb.service.d └─migrated-from-my.cnf-settings.conf, timeoutstartsec.conf ... ``` If you want to configure the `systemd` service, then you can create a file with the `.conf` extension in that directory. The configuration option(s) that you would like to change would need to be placed in an appropriate section within the file, usually `[Service]`. If a `systemd` option is a list, then you may need to set the option to empty before you set the replacement values. For example: ``` [Service] ExecStart= ExecStart=/usr/bin/numactl --interleave=all /usr/sbin/mysqld $MYSQLD_OPTS $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION ``` After any configuration change, you will need to execute the following for the change to go into effect: ``` sudo systemctl daemon-reload ``` ### Useful Systemd Options Useful `systemd` options are listed below. If an option is equivalent to a common `[mysqld\_safe](../mysqld_safe/index)` option, then that is also listed. | mysqld\_safe option | systemd option | Comments | | --- | --- | --- | | no option | `[ProtectHome=false](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#ProtectHome=)` | If any MariaDB files are in /home/ | | no option | `[PrivateDevices=false](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#PrivateDevices=)` | If any MariaDB storage references raw block devices | | no option | `[ProtectSystem=](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#ProtectSystem=)` | If any MariaDB write any files to anywhere under /boot, /usr or /etc | | no option | `[TimeoutStartSec={time}](https://www.freedesktop.org/software/systemd/man/systemd.service.html#TimeoutStartSec=)` | Service startup timeout. See [Configuring the Systemd Service Timeout](#configuring-the-systemd-service-timeout). | | no option (see [MDEV-9264](https://jira.mariadb.org/browse/MDEV-9264)) | `[OOMScoreAdjust={priority}](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#OOMScoreAdjust=)` | e.g. -600 to lower priority of OOM killer for mysqld | | `[open-files-limit](../mysqld_safe/index#mysqld_safe-options)` | `[LimitNOFILE={limit}](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#LimitCPU=)` | Limit on number of open files. See [Configuring the Open Files Limit](#configuring-the-open-files-limit). | | `[core-file-size](../mysqld_safe/index#mysqld_safe-options)` | `[LimitCORE={size}](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#LimitCPU=)` | Limit on core file size. Useful when [enabling core dumps](../enabling-core-dumps/index). See [Configuring the Core File Size](#configuring-the-core-file-size). | | | `[LimitMEMLOCK={size}](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#LimitCPU=)` or `infinity` | Limit on how much can be locked in memory. Useful when [large-pages](../server-system-variables/index#large_pages) or [memlock](../mysqld-options/index#-memlock) is used | | `[nice](../mysqld_safe/index#mysqld_safe-options)` | `[Nice={nice value}](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#Nice=)` | | | `[syslog](../mysqld_safe/index#mysqld_safe-options)` | `[StandardOutput=syslog](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#StandardOutput=)` | See [Configuring MariaDB to Write the Error Log to Syslog](#configuring-mariadb-to-write-the-error-log-to-syslog). | | | `[StandardError=syslog](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#StandardError=)` | | | | `[SyslogFacility=daemon](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#SyslogFacility=)` | | | | `[SyslogLevel=err](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#SyslogLevel=)` | | | `[syslog-tag](../mysqld_safe/index#mysqld_safe-options)` | `[SyslogIdentifier](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#SyslogIdentifier=)` | | | `[flush-caches](../mysqld_safe/index#mysqld_safe-options)` | ExecStartPre=/usr/bin/sync | | | | ExecStartPre=/usr/sbin/sysctl -q -w vm.drop\_caches=3 | | | `[malloc-lib](../mysqld_safe/index#mysqld_safe-options)` | `[Environment=LD\_PRELOAD=/path/to/library](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#Environment=)` | | | `[numa-interleave](../mysqld_safe/index#mysqld_safe-options)` | `[NUMAPolicy=interleave](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#NUMAPolicy=)` | from systemd v243 onwards | | | or: `ExecStart=/usr/bin/numactl --interleave=all /usr/sbin/mysqld $MYSQLD_OPTS $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION` | prepending `ExecStart=/usr/bin/numactl --interleave=all` to existing `ExecStart` setting | | `[no-auto-restart](../mysqld_safe/index#mysqld_safe-options)` | Restart={exit-status} | | Note: the `[systemd](http://www.freedesktop.org/software/systemd/man/systemd.service.html)` manual contains the official meanings for these options. The manual also lists considerably more options than the ones listed above. There are other options and the `mariadb-service-convert` script will attempt to convert these as accurately as possible. ### Configuring the Systemd Service Timeout MariaDB's `[systemd](index)` unit file has a default startup timeout of about 90 seconds on most systems. If a service startup takes longer than this default startup timeout, then `systemd` will assume that `mysqld` has failed to startup, which causes `systemd` to kill the `mysqld` process. To work around this, it can be changed by configuring the `[TimeoutStartSec](https://www.freedesktop.org/software/systemd/man/systemd.service.html#TimeoutStartSec=)` option for the `systemd` service. A similar problem can happen when stopping the MariaDB service. Therefore, it may also be a good idea to set `[TimeoutStopSec](https://www.freedesktop.org/software/systemd/man/systemd.service.html#TimeoutStopSec=)`. For example, you can reconfigure the MariaDB `systemd` service to have an infinite timeout by executing one of the following commands: If you are using `systemd` 228 or older, then you can execute the following to set an infinite timeout: ``` sudo tee /etc/systemd/system/mariadb.service.d/timeoutsec.conf <<EOF [Service] TimeoutStartSec=0 TimeoutStopSec=0 EOF sudo systemctl daemon-reload ``` [Systemd 229 added the infinity option](https://lists.freedesktop.org/archives/systemd-devel/2016-February/035748.html), so if you are using `systemd` 229 or later, then you can execute the following to set an infinite timeout: ``` sudo tee /etc/systemd/system/mariadb.service.d/timeoutsec.conf <<EOF [Service] TimeoutStartSec=infinity TimeoutStopSec=infinity EOF sudo systemctl daemon-reload ``` Note that [systemd 236 added the EXTEND\_TIMEOUT\_USEC environment variable](https://lists.freedesktop.org/archives/systemd-devel/2017-December/039996.html) that allows services to extend the startup timeout during long-running processes. On systems with systemd versions that support it, MariaDB uses this feature to extend the startup timeout during certain startup processes that can run long. ### Configuring the Open Files Limit When using `systemd`, rather than setting the open files limit by setting the `[open-files-limit](../mysqld_safe/index#mysqld_safe-options)` option for `mysqld_safe` or the `[open\_files\_limit](../server-system-variables/index#open_files_limit)` system variable, the limit can be changed by configuring the `[LimitNOFILE](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#LimitCPU=)` option for the MariaDB `systemd` service. The default is set to `LimitNOFILE=16364` in `mariadb.service`. For example, you can reconfigure the MariaDB `systemd` service to have a larger limit for open files by executing the following commands: ``` sudo tee /etc/systemd/system/mariadb.service.d/limitnofile.conf <<EOF [Service] LimitNOFILE=infinity EOF sudo systemctl daemon-reload ``` An important note is that setting `LimitNOFILE=infinity` doesn't actually set the open file limit to *infinite*. In `systemd` 234 and later, setting `LimitNOFILE=infinity` actually sets the open file limit to the value of the kernel's `fs.nr_open` parameter. Therefore, in these `systemd` versions, you may have to change this parameter's value. The value of the `fs.nr_open` parameter can be changed permanently by setting the value in `[/etc/sysctl.conf](https://linux.die.net/man/5/sysctl.conf)` and restarting the server. The value of the `fs.nr_open` parameter can be changed temporarily by executing the `[sysctl](https://linux.die.net/man/8/sysctl)` utility. For example: ``` sudo sysctl -w fs.nr_open=1048576‬ ``` In `systemd` 233 and before, setting `LimitNOFILE=infinity` actually sets the open file limit to `65536`. See [systemd issue #6559](https://github.com/systemd/systemd/issues/6559) for more information. Therefore, in these `systemd` versions, it is not generally recommended to set `LimitNOFILE=infinity`. Instead, it is generally better to set `LimitNOFILE` to a very large integer. For example: ``` sudo tee /etc/systemd/system/mariadb.service.d/limitnofile.conf <<EOF [Service] LimitNOFILE=1048576 EOF sudo systemctl daemon-reload ``` ### Configuring the Core File Size When using `systemd`, if you would like to [enable core dumps](../enabling-core-dumps/index), rather than setting the core file size by setting the `[core-file-size](../mysqld_safe/index#mysqld_safe-options)` option for `mysqld_safe`, the limit can be changed by configuring the `[LimitCORE](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#LimitCPU=)` option for the MariaDB `systemd` service. For example, you can reconfigure the MariaDB `systemd` service to have an infinite size for core files by executing the following commands: ``` sudo tee /etc/systemd/system/mariadb.service.d/limitcore.conf <<EOF [Service] LimitCORE=infinity EOF sudo systemctl daemon-reload ``` ### Configuring MariaDB to Write the Error Log to Syslog When using `systemd`, if you would like to redirect the [error log](../error-log/index) to the [syslog](https://linux.die.net/man/8/rsyslogd), then that can easily be done by doing the following: * Ensure that `[log\_error](../server-system-variables/index#log_error)` system variable is **not** set. * Set `[StandardOutput=syslog](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#StandardOutput=)`. * Set `[StandardError=syslog](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#StandardError=)`. * Set `[SyslogFacility=daemon](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#SyslogFacility=)`. * Set `[SysLogLevel=err](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#SyslogLevel=)`. For example: ``` sudo tee /etc/systemd/system/mariadb.service.d/syslog.conf <<EOF [Service] StandardOutput=syslog StandardError=syslog SyslogFacility=daemon SysLogLevel=err EOF sudo systemctl daemon-reload ``` If you have multiple instances of MariaDB, then you may also want to set `[SyslogIdentifier](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#SyslogIdentifier=)` with a different tag for each instance. ### Configuring LimitMEMLOCK If using [--memlock](../mysqld-options/index#-memlock) or the iouring in InnoDB in [MariaDB 10.6](../what-is-mariadb-106/index), you will need to raise the LimitMEMLOCK limit. ``` sudo tee /etc/systemd/system/mariadb.service.d/limitcore.conf <<EOF [Service] LimitMEMLOCK=2M EOF sudo systemctl daemon-reload ``` Note: Prior to [MariaDB 10.1.10](https://mariadb.com/kb/en/mariadb-10110-release-notes/), the [--memlock](../mysqld-options/index#-memlock) option could not be used with the MariaDB `systemd` service. ### Configuring Access to Home Directories MariaDB's [systemd](index) unit file restricts access to `/home`, `/root`, and `/run/user` by default. This restriction can be overridden by setting the [ProtectHome](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#ProtectHome=) option to `false` for the MariaDB `systemd` service. This is done by creating a "drop-in" directory `/etc/systemd/system/mariadb.service.d/` and in it a file with a `.conf` suffix that contains the `ProtectHome=false` directive. You can reconfigure the MariaDB `systemd` service to allow access to `/home` by executing the following commands: ``` sudo mkdir /etc/systemd/system/mariadb.service.d sudo tee /etc/systemd/system/mariadb.service.d/dontprotecthome.conf <<EOF [Service] ProtectHome=false EOF sudo systemctl daemon-reload ``` ### Configuring the umask When using `systemd`, the default file permissions of `mysqld` can be set by setting the `UMASK` and `UMASK_DIR` environment variables for the `systemd` service. For example, you can configure the MariaDB `systemd` service's umask by executing the following commands: ``` sudo tee /etc/systemd/system/mariadb.service.d/umask.conf <<EOF [Service] Environment="UMASK=0750" Environment="UMASK_DIR=0750" EOF sudo systemctl daemon-reload ``` These environment variables do not set the umask. They set the default file system permissions. See [MDEV-23058](https://jira.mariadb.org/browse/MDEV-23058) for more information. Keep in mind that configuring the umask this way will only affect the permissions of files created by the `mysqld` process that is managed by `systemd`. The permissions of files created by components that are not managed by `systemd`, such as `[mysql\_install\_db](../mysql_install_db/index)`, will not be effected. See [Specifying Permissions for Schema (Data) Directories and Tables](../specifying-permissions-for-schema-data-directories-and-tables/index) for more information. ### Configuring the data directory When doing a standard binary tarball install the datadir will be under /usr/local/data. The systemd service file makes the whole /usr directory tree write protected via ``` # Prevent writes to /usr, /boot, and /etc ProtectSystem=full ``` though. So when just copying the distributed service file a tarball install will not start up, complaining e.g. about ``` [Warning] Can't create test file /usr/local/.../data/ubuntu-focal.lower-test [ERROR] mariadbd: File '/usr/local/.../data/aria_log_control' not found (Errcode: 30 "Read-only file system") [ERROR] mariadbd: Got error 'Can't open file' when trying to use aria control file '/usr/local/.../data/aria_log_control' ``` So when using a data directory under /usr/local that specific directory needs to be made writable for the service using the ReadWritePaths setting: ``` sudo tee /etc/systemd/system/mariadb.service.d/datadir.conf <<EOF [Service] ReadWritePaths=/usr/local/mysql/data EOF sudo systemctl daemon-reload ``` Systemd Socket Activation ------------------------- **MariaDB starting with [10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/)**MariaDB can use systemd's socket activation. This is an on-demand service for MariaDB that will activate when required. Systemd socket activation uses a `mariadb.socket` definition file to define a set of UNIX and TCP sockets. Systemd will listen on these sockets, and when they are connected to, systemd will start the `mariadb.service` and hand over the socket file descriptors for MariaDB to process the connection. MariaDB remains running at this point and will have all sockets available and process connections exactly like it did before 10.6. When MariaDB is shut down, the systemd `mariadb.socket` remains active, and a new connection will restart the `mariadb.service`. ### Using Systemd Socket Activation To use MariaDB systemd socket activation, instead of enabling/starting `mariadb.service`, `mariadb.socket` is used instead. So the following commands work exactly like the `mariadb.service` equivalents. ``` systemctl start mariadb.socket systemctl enable mariadb.socket ``` These files alone only contain the UNIX and TCP sockets and basic network connection information to which will be listening for connections. `@mariadb` is a UNIX abstract socket, which means it doesn't appear on the filesystem. Connectors based on MariaDB Connector/C will be able to connect with these by using the socket name directly, provided the higher level implementation doesn't try to test for the file's existence first. Some connectors like PHP use mysqlnd that is a pure PHP implementation and as such will only be able to connect to on filesystem UNIX sockets. With systemd activated sockets there is only a file descriptor limit on the number of listening sockets that can be created. ### When to Use Systemd Socket Activation A common use case for systemd socket activated MariaDB is when there needs to be a quick boot up time. MariaDB needs to be ready to run, but it doesn't need to be running. The ideal use case for systemd socket activation for MariaDB is for infrastructure providers running many multiple instances of MariaDB, where each instance is dedicated for a user. ### Downsides to Using Systemd Socket Activiation From the time the connection occurs, the client is going to be waiting until MariaDB has fully initialized before MariaDB can process the awaiting connection. If MariaDB was previously hard shutdown and needs to perform an extensive InnoDB rollback, then the activation time may be larger than the desired wait time of the client connection. ### Configuring Systemd Socket Activation When MariaDB is run under systemd socket activation, the usual [socket](../server-system-variables/index#socket) , [port](../server-system-variables/index#port), and [backlog](../server-system-variables/index#backlog) system variables are ignored, as these settings are contained within the systemd socket definition file. There is no configuration required in MariaDB to use MariaDB under socket activation. The systemd options available are from the `[systemd documentation](https://www.freedesktop.org/software/systemd/man/systemd.socket.html)`, however `[ListenStream](https://www.freedesktop.org/software/systemd/man/systemd.socket.html#ListenStream=)` and `[BackLog](https://www.freedesktop.org/software/systemd/man/systemd.socket.html#Backlog=)` would be the most common configuration options. As MariaDB isn't creating these sockets, the sockets don't need to be created with a `mysql` user. The sockets MariaDB may end up listening to under systemd socket activation, it may have not had the privileges to create itself. Changes to the default `mariadb.socket` can be made in the same way as services, `systemctl edit mariadb.socket`, or using `/etc/systemd/system/mariadb.socket.d/someconfig.conf` files. ### Extra Port A systemd socket can be configured as an `[extra\_port](../thread-pool-system-status-variables/index#extra_port), by using the` [FileDescriptorName=extra](https://www.freedesktop.org/software/systemd/man/systemd.socket.html#FileDescriptorName=) `in the` .socket `file.` The `mariadb-extra.socket` is already packaged and ready for use. ### Multi-instance socket activation `[email protected]` is MariaDB's packaged multi-instance defination. It creates multiple UNIX sockets based on the socket file started. Starting `[email protected]` will use the `[email protected]` defination with `%I` within the defination replaced with "bob". When something connects to a socket defined there, the `[email protected]` will be started. Systemd Socket Activation for Hosting Service Providers ------------------------------------------------------- A systemd socket activation service with multi-instance can provide an on-demand per user access to a hosting service provider's dedicated database. "User", in this case, refers to the customer of the hosting service provider. ### End User Benefits This provides the following benefits for the user: * Each user has their own dedicated instance with the following benefits: + The instance is free from the database contention of neighbors on MariaDB shared resources (table cache, connections, etc) + The user is free to change their own configuration of MariaDB, within the limits and permissions of the service provider. + Database service level backups, like mariabackup, are now directly available. + A user can install their own plugins. + The user can run a different database version to their neighbors. + If a user's neighbor triggers a fault in the server, the uder's instance isn't affected. * The database runs as their unix user in the server facilitating: + User can directly migrate their MariaDB data directory to a different provider. + The user's data is protected from other users on a kernel level. ### Hosting Service Provider Benefits In addition to providing user benefits as a sales item, the following are additional benefits for the hosting service provider compared to a monolith service: * Without passwords for the database, while still having security, support may be easier. * When a user's database isn't active, there is no resource usage, only listening file descriptors by systemd. * The socket activation transparently, with a minor startup time, starts the service as required. * When the user's database hasn't had any activity after a time, it will deactivate ([MDEV-25282](https://jira.mariadb.org/browse/MDEV-25282)). * Planned enhancements in InnoDB provide: + an on-demand consumption of memory ([MDEV-25340](https://jira.mariadb.org/browse/MDEV-25340) . + a proactive reduction in memory ([MDEV-25341](https://jira.mariadb.org/browse/MDEV-25341)). + a memory resource pressure reduction in memory use ([MDEV-24670](https://jira.mariadb.org/browse/MDEV-24670)). * The service provider can still cap the user's database memory usage in a ulimit way that a user cannot override in settings. * The service provider may choose a CPU/memory/IO based billing to the user on Linux cgroup accounting rather than the available comprared to the rather limited options in `[CREATE USER](../create-user/index#resource-limit-options)`. * Because a user's database will shutdown when inactive, a database upgrade on the server will not take effect for the user until it passively shuts down, restarts, and then gets reactivated hence reducing user downtime.. ### Downsides to the Hosting Service Provider The extra memory used by more instances. This is mitigated by the on-demand activation. The deactivation when idle, and improved InnoDB memory management. With plenty of medium size database servers running, the Linux OOM kill has the opportunity to kill off only a small number of database servers running rather than everyones. ### Example on configuration Items for a per user, systemd socket activitated multi-instance service From a server pespective the operation would be as follows; To make the socket ready to connect and systemd will be listening to the socket: ``` # systemctl start [email protected] # systemctl start [email protected] ``` To enable this on reboot (the same way as a systemd service): ``` # systemctl enable [email protected] # systemctl enable [email protected] ``` #### A MariaDB Template File A global template file. Once installed as a user's `$HOME/.my.cnf` file, it will becomes the default for many applications, and the MariaDB server itself. ``` # cat /etc/my.cnf.templ [client] socket=/home/USER/mariadb.sock [client-server] user=USER [mariadbd] datadir=/home/USER/mariadb-datadir ``` #### Custom Configuration for the Multiinstance Service This extends/modifies the MariaDB multi-instance service. The feature of this extension are: * that it will autocreate configuration file for user applications * It will install the database on first service start * `auth-root-*` in [mariadb-install-db](../mariadb-install-db/index) means that the user is their own privileged user with unix socket authentication active. This means non-that user cannot access another users service, even with access to the unix socket(s). For more information see #[unix socket authentication security](../authentication-plugin-unix-socket/index#security)`.` * If the MariaDB version was upgrade, the upgrade changes are made automaticly * `LimitData` places a hard upper limit so the user doesn't exceed a portion of the server resources ``` # cat /etc/systemd/system/[email protected]/user.conf [Service] User=%I ProtectHome=false Environment=MYSQLD_MULTI_INSTANCE="--defaults-file=/home/%I/.my.cnf" ExecStartPre= ExecStartPre=/bin/sh -c "[ -f /home/%I/.my.cnf ] || sed -e \"s/USER/%I/g\" /etc/my.cnf.templ > /home/%I/.my.cnf" ExecStartPre=mkdir -p /home/%I/mariadb-datadir ExecStartPre=/usr/bin/mariadb-install-db $MYSQLD_MULTI_INSTANCE --rpm \ --auth-root-authentication-method=socket --auth-root-socket-user=%I ExecStartPost=/usr/bin/mariadb-upgrade $MYSQLD_MULTI_INSTANCE # To limit user based tuning LimitData=768M # For io_uring use by innodb on < 5.12 kernels LimitMEMLOCK=1M ``` #### Custom Configuration for the Multi-instance Socket This extends/modifies the MariaDB socket defination to be per user. Create sockets based on the user of the istance (`%I`). Permissions are only necessary in the sense that the user can connect to them. It won't matter to the server. Access control is enforced within the server, however if the user web services are run as the user, `Mode=777` can be reduced. `@mariadb-%I` is a abstract unix socket not on the filesystem. It may help if a user is in a chroot. Not all applications can connect to abstract sockets. ``` # cat /etc/systemd/system/[email protected]/user.conf [Socket] SocketUser=%I SocketMode=777 ListenSteam= ListenStream=@mariadb-%I ListenStream=/home/%I/mariadb.sock ``` The extra socket provides the user the ability to access the server when all max-connections are used: ``` # cat /etc/systemd/system/[email protected]/user.conf [Socket] SocketUser=%I SocketMode=777 ListenSteam= ListenStream=@mariadb-extra-%I ListenStream=/home/%I/mariadb-extra.sock ``` Systemd Journal --------------- `systemd` has its own logging system called the `systemd` journal. The `systemd` journal contains information about the service startup process. It is a good place to look when a failure has occurred. The MariaDB `systemd` service's journal can be queried by using the `[journalctl](https://www.freedesktop.org/software/systemd/man/journalctl.html)` command. For example: ``` $ sudo journalctl n 20 -u mariadb.service -- Logs begin at Fri 2019-01-25 13:49:04 EST, end at Fri 2019-01-25 18:07:02 EST. -- Jan 25 13:49:15 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: Starting MariaDB 10.1.37 database server... Jan 25 13:49:16 ip-172-30-0-249.us-west-2.compute.internal mysqld[2364]: 2019-01-25 13:49:16 140547528317120 [Note] /usr/sbin/mysqld (mysqld 10.1.37-MariaDB) starting as process 2364 ... Jan 25 13:49:17 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: Started MariaDB 10.1.37 database server. Jan 25 18:06:42 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: Stopping MariaDB 10.1.37 database server... Jan 25 18:06:44 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: Stopped MariaDB 10.1.37 database server. Jan 25 18:06:57 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: Starting MariaDB 10.1.37 database server... Jan 25 18:08:32 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: mariadb.service start-pre operation timed out. Terminating. Jan 25 18:08:32 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: Failed to start MariaDB 10.1.37 database server. Jan 25 18:08:32 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: Unit mariadb.service entered failed state. Jan 25 18:08:32 ip-172-30-0-249.us-west-2.compute.internal systemd[1]: mariadb.service failed. ``` Converting mysqld\_safe Options to Systemd Options -------------------------------------------------- `mariadb-service-convert` is a script included in many MariaDB packages that is used by the package manager to convert `[mysqld\_safe](../mysqld_safe/index#mysqld_safe-options)` options to `systemd` options. It reads any explicit settings in the `[mysqld_safe]` [option group](../configuring-mariadb-with-option-files/index#option-groups) from [option files](../configuring-mariadb-with-option-files/index), and its output is directed to `/etc/systemd/system/mariadb.service.d/migrated-from-my.cnf-settings.conf`. This helps to keep the configuration the same when upgrading from a version of MariaDB that does not use `systemd` to one that does. Implicitly high defaults of `[open-files-limit](../mysqld_safe/index#mysqld_safe-options)` may be missed by the conversion script and require explicit configuration. See [Configuring the Open Files Limit](#configuring-the-open-files-limit). Known Issues ------------ Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Information Schema INNODB_FT_DELETED Table Information Schema INNODB\_FT\_DELETED Table ============================================ The [Information Schema](../information_schema/index) `INNODB_FT_DELETED` table contains rows that have been deleted from an InnoDB [fulltext index](../full-text-indexes/index). This information is then used to filter results on subsequent searches, removing the need to expensively reorganise the index each time a row is deleted. The fulltext index is then only reorganized when an [OPTIMIZE TABLE](../optimize-table/index) statement is underway. The related [INNODB\_FT\_BEING\_DELETED](../information-schema-innodb_ft_being_deleted-table/index) table contains rows being deleted while an `OPTIMIZE TABLE` is in the process of running. The `SUPER` [privilege](../grant/index) is required to view the table, and it also requires the [innodb\_ft\_aux\_table](../innodb-system-variables/index#innodb_ft_aux_table) system variable to be set. It has the following column: | Column | Description | | --- | --- | | `DOC_ID` | Document ID of the deleted row deleted. Either an underlying ID value, or a sequence value generated by InnoDB if no usable option exists. | Example ------- ``` SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_DELETED; +--------+ | DOC_ID | +--------+ | 2 | +--------+ DELETE FROM test.ft_innodb LIMIT 1; SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_DELETED; +--------+ | DOC_ID | +--------+ | 2 | | 3 | +--------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SEC_TO_TIME SEC\_TO\_TIME ============= Syntax ------ ``` SEC_TO_TIME(seconds) ``` Description ----------- Returns the seconds argument, converted to hours, minutes, and seconds, as a TIME value. The range of the result is constrained to that of the [TIME data type](../time/index). A warning occurs if the argument corresponds to a value outside that range. The time will be returned in the format `hh:mm:ss`, or `hhmmss` if used in a numeric calculation. Examples -------- ``` SELECT SEC_TO_TIME(12414); +--------------------+ | SEC_TO_TIME(12414) | +--------------------+ | 03:26:54 | +--------------------+ SELECT SEC_TO_TIME(12414)+0; +----------------------+ | SEC_TO_TIME(12414)+0 | +----------------------+ | 32654 | +----------------------+ SELECT SEC_TO_TIME(9999999); +----------------------+ | SEC_TO_TIME(9999999) | +----------------------+ | 838:59:59 | +----------------------+ 1 row in set, 1 warning (0.00 sec) SHOW WARNINGS; +---------+------+-------------------------------------------+ | Level | Code | Message | +---------+------+-------------------------------------------+ | Warning | 1292 | Truncated incorrect time value: '9999999' | +---------+------+-------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Switching Between Different Installed MariaDB Versions Switching Between Different Installed MariaDB Versions ====================================================== This article is about managing many different installed MariaDB versions and running them one at a time. This is useful when doing benchmarking, testing, or for when developing different MariaDB versions. This is most easily done using the tar files from [downloads.askmonty.org](http://downloads.askmonty.org/mariadb/). Stopping a pre-installed MySQL/MariaDB from interfering with your tests ----------------------------------------------------------------------- If MySQL/MariaDB is already installed and running, you have two options: 1. Use test MariaDB servers with a different port & socket. * In this case you are probably best off creating a specific section for MariaDB in your `~/.my.cnf` file. 2. Stop mysqld with `/etc/rc.d/mysql stop` or `mysqladmin shutdown`. Note that you don't have to uninstall or otherwise remove MySQL! How to create a binary distribution (tar file) ---------------------------------------------- Here is a short description of how to generate a tar file from a source distribution. If you have [downloaded](http://downloads.askmonty.org/mariadb/) a binary tar file, you can skip this section. The steps to create a binary tar file are: * Decide where to put the source. A good place is under `/usr/local/src/mariadb-5.#`. * [Get the source](../source-getting-the-mariadb-source-code/index) * [Compile the source](../compiling-mariadb-from-source/index) * [Create the binary tar ball](../creating-the-mariadb-binary-tarball/index). You will then be left with a tar file named something like: `mariadb-5.3.2-MariaDB-beta-linux-x86_64.tar.gz` Creating a directory structure for the different installations -------------------------------------------------------------- Install the binary tar files under `/usr/local/` with the following directory names (one for each MariaDB version you want to use): * `mariadb-5.1` * `mariadb-5.2` * `mariadb-5.3` * `mariadb-5.5` * `mariadb-10.0` The above assumes you are just testing major versions of MariaDB. If you are testing specific versions, use directory names like `mariadb-5.3.2` With the directories in place, create a sym-link named `mariadb` which points at the `mariadb-XXX` directory you are currently testing. When you want to switch to testing a different version, just update the sym-link. Example: ``` cd /usr/local tar xfz /tmp/mariadb-5.3.2-MariaDB-beta-linux-x86_64.tar.gz mv -vi mariadb-5.3.2-MariaDB-beta-linux-x86_64 mariadb-5.3 ln -vs mariadb-5.3 mariadb ``` Setting up the data directory ----------------------------- When setting up the data directory, you have the option of either using a shared database directory or creating a unique database directory for each server version. For testing, a common directory is probably easiest. Note that you can only have one `mysqld` server running against one data directory. ### Setting up a common data directory The steps are: 1. Create the `mysql` system user if you don't have it already! (On Linux you do it with the `useradd` command). 2. Create the directory (we call it `mariadb-data` in the example below) or add a symlink to a directory which is in some other place. 3. Create the `mysql` permission tables with `mysql_install_db` ``` cd /usr/local/ mkdir mariadb-data cd mariadb ./bin/mysql_install_db --no-defaults --datadir=/usr/local/mariadb-data chown -R mysql mariadb-data mariadb-data/* ``` The reason to use `--no-defaults` is to ensure that we don't inherit incorrect options from some old my.cnf. ### Setting up different data directories To create a different `data` directories for each installation: ``` cd mariadb ./scripts/mysql_install_db --no-defaults chown -R mysql mariadb-data mariadb-data/* ``` This will create a directory `data` inside the current directory. If you want to use another disk you should do: ``` cd mariadb ln -s path-to-empty-directory-for-data data ./scripts/mysql_install_db --no-defaults --datadir=./data chown -R mysql mariadb-data mariadb-data/* ``` Running a MariaDB server ------------------------ The normal steps are: ``` rm mariadb ln -s mariadb-5.# mariadb cd mariadb ./bin/mysqld_safe --no-defaults --datadir=/usr/local/mariadb-data & ``` Setting up a .my.cnf file for running multiple MariaDB main versions -------------------------------------------------------------------- If you are going to start/stop MariaDB a lot of times, you should create a `~/.my.cnf` file for the common options you are using. The following example shows how to use a non-standard TCP-port and socket (to not interfere with a main MySQL/MariaDB server) and how to setup different options for each main server: ``` [client-server] socket=/tmp/mysql.sock port=3306 [mysqld] datadir=/usr/local/mariadb-data [mariadb-5.2] # Options for MariaDB 5.2 [mariadb-5.3] # Options for MariaDB 5.3 ``` If you create an `~/.my.cnf` file, you should start `mysqld` with `--defaults-file=~/.my.cnf` instead of `--no-defaults` in the examples above. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Replication Overview for SQL Server Users MariaDB Replication Overview for SQL Server Users ================================================= MariaDB supports the following types of replication: * Asynchronous replication. * Semi-synchronous replication. * Galera Cluster. **MariaDB starting with [10.5.1](https://mariadb.com/kb/en/mariadb-1051-release-notes/)**Note: in the snippets in this page, several SQL statements use the keyword `SLAVE`. This word is considered inappropriate by some persons or cultures, so from [MariaDB 10.5](../what-is-mariadb-105/index) it is possible to use the `REPLICA` keyword, as a synonym. Similar synonyms will be created in the future for status variables and system variables. See [MDEV-18777](https://jira.mariadb.org/browse/MDEV-18777) to track the status of these changes. Asynchronous Replication ------------------------ The original MariaDB replication system is asynchronous master-slave replication. A master needs to have the [binary log](../binary-log/index) enabled. The master logs all data changes in the binary log. Every *event* (a binary log entry) is sent to all the slaves. For a high-level description of the binary log for SQL Server users, see [Understanding MariaDB Architecture](../understanding-mariadb-architecture/index#the-binary-log). The events can be written in two formats: as an SQL statement (*statement-based replication*, or SBR), or as a binary representation of the change (*row-based replication*, or RBR). The former is generally slower, because the statement needs to be re-executed by the slaves. It is also less reliable, because some SQL statements are [not deterministic](../unsafe-statements-for-statement-based-replication/index), so they could produce different results on the slaves. On the other hand row-based replication could make the binary log much bigger, and require more network traffic. For this reason, DML statements are always logged in statement format. For more details on replication formats, see [binary log formats](../binary-log-formats/index). The slaves have an [I/O thread](../replication-threads/index#slave-io-thread) that receives the binary log events and writes them to the [relay log](../relay-log/index). These events are then read by the [SQL thread](../replication-threads/index#slave-sql-thread). This thread could directly apply the changes to the local databases, and this was the only option before [MariaDB 10.0.5](https://mariadb.com/kb/en/mariadb-1005-release-notes/). If [parallel replication](#parallel-replication-and-group-commit) is enabled, the SQL thread hands the events to the worker thread, that apply them to the databases. The latter method is recommended for performance reasons. When a slave cannot apply an event to the local data, the SQL thread stops. This happens, for example, if the event is a row deletion but that row doesn't exist on the slave. There can be several reasons for this, for example non-deterministic statements, or a user deleted the row in the slave. To reduce the risk, it is recommended to set [read\_only](../server-system-variables/index#read_only) to 1 in the slaves. [SHOW SLAVE STATUS](../show-slave-status/index) has columns named `Slave_SQL_State` and `Slave_IO_State` that show, respectively, if the SQL thread and the IO thread are running. If they are not, the column `Last_IO_Errno` and `Last_IO_Error` (for the IO thread) or `Last_SQL_Errno` and `Last_SQL_Error` (for the SQL thread) show what the problem is. In a replication chain, every server must have a unique [server\_id](../replication-and-binary-log-system-variables/index#server_id). For more information on replication, see [standard replication](../standard-replication/index). ### Binary Log Coordinates, Relay Log Coordinates and GTID The binary log coordinates provide a way to identify a certain data change made by a server. Coordinates consist of a file name and the position of the latest event, expressed as an integer. The last event coordinates can be seen with the [SHOW MASTER STATUS](../show-master-status/index) columns `File` and `Position`. [mysqldump](../mysqldump/index) includes them in a dump if the `--master-data` option is used. A slave uses master binary log coordinates to identify the last event it read. This can be seen with the [SHOW SLAVE STATUS](../show-slave-status/index),columns `Master_Log_File` and `Read_Master_Log_Pos`. The columns `Relay_Master_Log_File` and `Exec_Master_Log_Pos` identify the master event that corresponds to the last event applied by the SQL thread. The slave relay log also has coordinates. The coordinates of the last applied event can be seen with the `SHOW SLAVE STATUS` columns `Relay_Log_File` and `Relay_Log_Pos`. To easily find out how far the slave is lagging behind the master, we can look at `Seconds_Behind_Master`. Coordinates represented in this way have a problem: they are different on each server. Each server can use files with different (or the same) names, depending on its configuration. And files can be rotated at different times, including when a user runs [FLUSH LOGS](../flush/index). By enabling the GTID (global transaction id) an event will have the same id on the master and on all the slaves. When [GTID](../gtid/index) is enabled, `SHOW SLAVE STATUS` shows two GTIDs: `Gtid_IO_Pos` is the last event written into the relay log, and `Gtid_Slave_Pos` is the last event applied by the SQL thread. There is no need for a column identifying the same event in the master, because the id is the same. ### Provisioning a Slave MariaDB does not have an equivalent to SQL Server's snapshot replication. To setup a slave, it is necessary to manually provision it. It can be provisioned from the master in this way: * A backup from the master must be restored on the new slave; * The binary log coordinates at the moment of the backup should be set as replication coordinates in the slave, via [CHANGE MASTER TO](../change-master-to/index). However, if there is at least one existing slave, it is better to use it to provision the new slave: * A backup from the existing slave must be restored in the new slave; * The backup should include the system tables. In this way it will not be necessary to set the correct coordinates manually. For more information see [Setting Up Replication](../setting-up-replication/index) and [Setting up a Replication Slave with Mariabackup](../setting-up-a-replication-slave-with-mariabackup/index). ### Replication and Permissions A slave connects to a master using its credentials. See [CHANGE MASTER TO](../change-master-to/index). The appropriate account must be created in the master, and it needs to have the `REPLICATION SLAVE` permission. See [Setting Up Replication](../setting-up-replication/index) for more information. ### Parallel Replication and Group Commit MariaDB uses [group commit](../group-commit-for-the-binary-log/index), which means that a group of events are physically written in the binary log altogether. This reduces the number of IOPS (input/output operations per second). Group commit cannot be disabled, but it can be tuned with variables like [binlog\_commit\_wait\_count](../replication-and-binary-log-system-variables/index#binlog_commit_wait_count) and [binlog\_commit\_wait\_usec](../replication-and-binary-log-system-variables/index#binlog_commit_wait_usec). Slaves can apply the changes using multiple threads. This is known as [parallel replication](../parallel-replication/index). Before [MariaDB 10.0.5](https://mariadb.com/kb/en/mariadb-1005-release-notes/) only one thread was used to apply changes. Since a master can use many threads to write data, mono-thread replication is a well-known bottleneck. Parallel replication is not enabled by default. To use it, set the [slave\_parallel\_threads](../replication-and-binary-log-system-variables/index#slave_parallel_threads) variable to a number greater than 1. If replication is running, the slave threads must be stopped in order to change this value: ``` STOP SLAVE SQL_THREAD; SET GLOBAL slave_parallel_threads = 4; START SLAVE SQL_THREAD; ``` There are different parallel replication styles available: in-order and out-of-order. The exact mode in use is determined by the [slave\_parallel\_mode](../replication-and-binary-log-system-variables/index#slave_parallel_mode) system variable. In parallel replication, the events are not replicated exactly in the same order as they occurred in the master. But with an in-order replication mode the commit phase is always applied simultaneously. In this way data in the slave always reflect data as they have been in the master at a certain point in time. Out-of-order replication is faster because there is less queuing, but it's not completely consistent with the master. If two transactions modified different sets of rows in the master, they could become visible in the slave in a different order. `conservative` relies on master group commit: events in different groups are executed in a parallel way. `optimistic` does not try to find out which transaction can be executed in a parallel way - except for transactions that conflicted on the master. Instead, it always tries to apply many events together, and rolls transactions back when there is a conflict. `aggressive` is similar to optimistic, but it does not take into account which transactions conflicted in the master. `minimal` applies commits together, but all other events are applied in order. Out-of-order replication cannot be enabled automatically by changing a variable in the slave. Instead, it must be enabled by the applications that run transactions in the master. They can do this if the GTID is enabled. They can set different values for the [gtid\_domain\_id](../replication-and-binary-log-system-variables/index#gtid_domain_id) variable in different transactions. This shifts a lot of responsibility to the application layer; however, if the application is aware of which transactions are not going to conflict and this information allows one to sensibly increase the parallelism, and using out-of-order replication can be a good idea. Even if out-of-order replication is not normally used, it can be a good idea to use it for long running transactions or [ALTER TABLEs](../alter-table/index), so they can be applied at the same time as normal operations that are not conflicting. The impact of the number of threads and mode on performance can be partly seen with [SHOW PROCESSLIST](../show-processlist/index), which shows the state of all threads. This includes the replication worker threads, and shows if they are blocking each other. ### Differences Between the Master and the Slaves As a general rule, we want the master and the slaves to contain exactly the same data. In this way, no conflicts are possible. Conflicts are the most likely cause of replication outages. To reduce the possible causes of conflicts, the following best practices are recommended: * Users must not change data in the slaves directly. Set [read\_only](../server-system-variables/index#read_only) to 1. Note that this won't prevent root from making changes. * Use the same table definitions in the master and in the slave. * Use `ROW` binary log format on the master. Another cause of inconsistencies include MariaDB bugs and failover in case the master crashes. An open source third party tool is available to check if the master and a slave are consistent. It is called pt-table-checksum. Another tool, pt-table-sync, can be used to eliminate the differences. Both are part of Percona Toolkit. The advice is to run pt-table-checksum periodically, and use pt-table-sync if inconsistencies are found. If a replication outage occurs because an inconsistency is found, sometimes we want to quickly bring the slave up again as quickly as possible, and solve the core problem later. If GTID is not used, a way to do this is to run [SET GLOBAL SQL\_SLAVE\_SKIP\_COUNTER = 1](../set-global-sql_slave_skip_counter/index), which skips the problematic replication event. If GTID is used, the [gtid\_slave\_pos](../gtid/index#gtid_slave_pos) variable can be used instead. See the link for an explanation of how it works. There are ways to have different data on the slaves. For example: * Multi-source replication is possible. In this way, a slave will replicate data from multiple masters. This feature is described below. * [Replication filters](../replication-filters/index) are supported. This allows one to exclude or include in replication specific tables, entire databases, or tables whose name matches a certain pattern. This allows one to avoid replicating data that is present in the master but can always be rebuilt. * [Differences in table definitions](../replication-when-the-master-and-slave-have-different-table-definitions/index) are also possible. For example, a slave could have [more columns or less columns](../replication-when-the-master-and-slave-have-different-table-definitions/index#different-number-or-order-of-columns) compared to the master. In this way we can avoid replicating columns whose values can be rebuilt. Or we can add columns for analytics purposes, without having them in the master. Be sure to understand the limitations and risks of this technique. ### Delayed Replication **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**Delayed replication was introduced in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). MariaDB supports delayed replication. This is the equivalent of setting a `pollinginterval` in SQL Server. To delay replication in a MariaDB slave, use [CHANGE MASTER TO](../change-master-to/index) to specify a delay in seconds. For more information, see [Delayed Replication](../delayed-replication/index). ### Multi-Source Replication [Multi-source replication](../multi-source-replication/index) is an equivalent to peer-to-peer replication, available in SQL Server Enterprise Edition. A MariaDB slave can replicate from any number of masters. It is very important that different masters don't have the same tables. Otherwise there could be conflicts between data changes made on different masters, and this will result in a replication outage. In multi-source replication different channels exist, one for each master. This changed the way [SQL replication statements](../replication-commands/index) work. [SHOW PROCESSLIST](../show-processlist/index) returns a different row for each channel. Several statements, like [CHANGE MASTER TO](../change-master-to/index), [START SLAVE](../start-slave/index) or [STOP SLAVE](../stop-slave/index). accept a parameter which specifies which replication channel they should affect. For example, to stop a channel called `wp1`: ``` STOP SLAVE "wp1"; ``` Furthermore, variables that affect parallel replication can be prefixed with a channel name. This allow one to only use parallel replication for certain channels, or to tune it differently for each channel. For example, to enable parallel replication on a channel called `wp1`: ``` SET GLOBAL wp1.slave_parallel_threads = 4; ``` ### Dual Master It is possible to configure two servers in a way that each of them acts as a master for the other server. In this way, data could theoretically be inserted into any of these servers, and will then be replicated to the other server. However, in such a configuration conflicts are very likely. So it is impractical to use this technique to scale writes. A dual master (or master-master) configuration however can be useful for failover. In this case we talk about an *active master* that receives reads and writes from the clients, and a *passive master* that is not used until the active master crashes. Several problems should be considered in this scenario: * If the active master crashes, it is very possible that the passive master did not receive all events yet, because replication is asynchronous. If the master data are lost (for example because the disk is damaged), some data are also lost. * If data is not lost, when we bring the master up again, the latest events will be replicated by the other server. There could be conflicts that will break replication. * When is the active master considered down? Even if a server cannot reach it, the active master could be running and it could be able to communicate with the passive master. Switching the clients to the passive master could lead to unnecessary problems. It is a good idea to always check `SHOW SLAVE STATUS` to be sure that the two masters are not communicating. * If we want to have more slaves, we should attach some of them to the active master, and some of them to the passive master. The reason is that when a server crashes, its slaves stop receiving any data. Failover is still possible, but it's better to have some servers that will not need any failover. A safe master-master configuration where both servers accept writes, however, is possible. This is the case is data never conflicts. For example, the two servers could accept writes on different databases. We will have to decide what should happens in case of a server crash: * Writes can be stopped until the server is up again. Reads can be sent to the other server, but keep in mind that the most recently written data could be missing. * Both writes and reads can failover to the other server. All the problems mentioned above may apply to this situation. See Sveta Smirnova's slides at MariaDB Day 2020: "[How Safe is Asynchronous Master-Master Setup?](https://www.slideshare.net/SvetaSmirnova/how-safe-is-asynchronous-mastermaster-setup)". Semi-Synchronous Replication ---------------------------- **MariaDB starting with [10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/)**Semi-synchronous replication was initially implemented as a plugin, in MySQL. Two different plugins needed to be used, one on the master and the other on the slaves. Starting from [MariaDB 10.3.3](https://mariadb.com/kb/en/mariadb-1033-release-notes/) it is built-in, which improved its performance. The problem with standard replication is that there is no guarantee that it will not lag, even by long amounts of time. [Semi-synchronous replication](../semisynchronous-replication/index) reduces this problem, at the cost of reducing the speed of the master. In semi-synchronous replication, when a transaction is committed on the master, the master does not immediately return control to the client. Instead, it sends the event to the slaves. After one slave reported that the commit was executed with success, the master reports success to the client. Semi-synchronous replication is useful for failover, therefore a dual master setup is not needed in this case. If the master crashes, the most up-to-date slave can be promoted to master without losing any data. ### Enabling Semi-Synchronous Replication Semi-synchronous replication can be enabled at runtime in this way on the master: ``` SET GLOBAL rpl_semi_sync_master_enabled = ON; ``` Semi-synchronous replication is not used until it has been enabled on the slaves also. If the slaves are already replicating, the io\_thread needs to be stopped and restarted. This can be done as follows: ``` SET GLOBAL rpl_semi_sync_slave_enabled = ON; STOP SLAVE IO_THREAD; START SLAVE IO_THREAD; ``` ### Tuning the Wait Point and the Master Timeout The most important aspects to tune are the wait point and the master timeout. When the binary log is enabled, transactions must be committed both in the [storage engine](../understanding-mariadb-architecture/index#storage-engines) (usually [InnoDB](../innodb/index)) and in the [binary log](../understanding-mariadb-architecture/index#the-binary-log). Semi-synchronous replication requires that the transaction is also acknowledged by at least one slave before the master can report success to the client. The wait point determines at which point the master must stop and wait for a confirmation from a slave. This is an important decision from disaster recovery standpoint, in case the master crashes when a transaction is not fully committed. The [rpl\_semi\_sync\_master\_wait\_point](../semisynchronous-replication/index#rpl_semi_sync_master_wait_point) is used to set the wait point, Its allowed values are: * `AFTER_SYNC`: After committing the transaction in the binary log, but before committing it to the storage engine. After a crash, a transaction may be present in the binary log even if it was not committed. * `AFTER_COMMIT`. After committing a transaction both in the binary log and in the storage engine. In case of a crash, a transaction could possibly be committed in the master but not replicated in the slaves. This is the default. Master timeout is meant to avoid that a master remains stuck for a long time, or virtually forever, because no slave acknowledges a transaction. If master timeout is reached, the master switches to asynchronous replication. Before doing that, the master writes an error in the [error log](../error-log/index) and increments the [Rpl\_semi\_sync\_master\_no\_times](../semisynchronous-replication-plugin-status-variables/index#rpl_semi_sync_master_no_times) status variable. The timeout is set via the [rpl\_semi\_sync\_master\_timeout](../semisynchronous-replication/index#rpl_semi_sync_master_timeout) variable. Galera Cluster -------------- [Galera](../galera-cluster/index) is a technology that implements virtually synchronous, master-master replication for a cluster of MariaDB servers. ### Raft and the Primary Cluster Nodes of the cluster communicate using the Raft protocol. In case the cluster is partitioned or some nodes crash, a cluster knows that it's still the *primary cluster* if it has the *quorum*: half of the nodes + 1. Only the primary cluster accepts reads and writes. For this reason a cluster should consist of an odd number of nodes. Imagine for example that a cluster consists of two nodes: if one of them crashes of the connection between them is interrupted, there will be no primary cluster. ### Transaction Certification A transaction can be executed against any node. The node will use a 2-phase commit. After running the transaction locally, the node will ask other nodes to *certify* it. This means that other nodes will receive it, and will try to apply it, and will report success or a failure. The node that received the transaction will not wait for an answer from all the nodes. Once it succeeded on more than half of the nodes (the quorum) the node will run the final commit and data becomes visible. It is desirable to write data on only one node (unless it fails), or write different databases on different nodes. This will minimize the risk of conflicts. ### Galera Cache and SST Data changes applied are recorded for some time in the *Galera cache*. This is an on-disk cache, written in a circularly written file. The size of Galera cache can be tuned using the [wsrep\_provider\_options](../wsrep_provider_options/index) system variable, which contains many flags. We need to tune [gcache.size](../wsrep_provider_options/index#gcachesize). To tune it, add a line similar to the following to a configuration file: ``` wsrep_provider_options = 'gcache.size=2G'; ``` If a single transaction is bigger than half of the Galera cache, it needs to be written in a separate file, as *on-demand pages*. On-demand pages are regularly replaced. Whether a new page replaces an old one depends on another wsrep\_provider\_options flag: `wsrep_provider_options#gcachekeep_pages_size|gcache.keep_pages_size`, which limits the total size of on-demand pages. When a node is restarted (after a crash or for maintenance reasons), it will need to receive all the changes that were written by other nodes since the moment it was unreachable. A node is therefore chosen as a donor, possibly using the [gcssync\_donor](../wsrep_provider_options/index#gcssync_donor) wsrep\_provider\_options flag. If possible, the donor will send all the recent changes, reading them from the Galera cache and on-demand pages. However, sometimes the Galera cache is not big enough to contain all the needed changes, or the on-demand pages have been overwritten because `gcache.keep_pages_size` is not big enough. In these cases, a [State Snapshot Transfer (SST)](../state-snapshot-transfers-ssts-in-galera-cluster/index) needs to be sent. This means that the donor will send the whole dataset to the restarted node. Most commonly, this happens using the [mariabackup method](../mariabackup-sst-method/index). ### Flow Control While transaction certification is synchronous, certified transactions are applied locally in asynchronous fashion. However, a node should never lag too much behind others. To avoid that, a node may occasionally trigger a mechanism called *flow control* to ask other nodes to stop replication until its situation improves. Several [wsrep\_provider\_options](../wsrep_provider_options/index) flags affect flow control. [gcs.fc\_master\_slave](../wsrep_provider_options/index#gcsfc_master_slave) should normally be set to 1 if all writes are sent to a single node. [gcs.fc\_limit](../wsrep_provider_options/index#gcsfc_limit) is tuned automatically, unless [gcs.fc\_master\_slave](../wsrep_provider_options/index#gcsfc_master_slave) is set to 0. The *receive queue* (the transactions received and not yet applied) should not exceed this limit. When this happens, flow control is triggered by the node to pause other node's replication. Once flow control is activated, [gcs.fc\_factor](../wsrep_provider_options/index#gcsfc_factor) determines when it is released. It is a number from 0 to 1, and it represents a fraction. When the receive queue is below this fraction, the flow control is released. Flow control and the receive queue can and should be monitored. The most useful metrics are: * [wsrep\_flow\_control\_paused](../galera-cluster-status-variables/index#wsrep_flow_control_paused) indicates how many times the replication has been paused as requested by other nodes, since the last `FLUSH STATUS`. * [wsrep\_flow\_control\_sent](../galera-cluster-status-variables/index#wsrep_flow_control_sent) indicates how many times this node requested other nodes to pause replication. * [wsrep\_local\_recv\_queue](../galera-cluster-status-variables/index#wsrep_local_recv_queue) is the size of the receive queue. ### Configuration Galera is implemented as a plugin. Starting from version 10.1, MariaDB comes with Galera pre-installed, but not in use by default. To enable it one has to set the [wsrep\_on](../galera-cluster-system-variables/index#wsrep_on) system variable. Like asynchronous replication, Galera uses the binary log. It also requires that data changes are logged in the `ROW` format. For other required settings, see [Mandatory Options](../configuring-mariadb-galera-cluster/index#mandatory-options). Galera Limitations ------------------ Galera is not suitable for all databases and workloads. * Galera only replicates [InnoDB](../innodb/index) tables. Other storage engines should not be used. * For performance reasons, it is highly desirable that all tables have a primary key. * Long transactions will damage performance. * Some applications use an integer [AUTO\_INCREMENT](../auto_increment/index) primary key. In case of failover from a crashed node to another, Galera does not guarantee that `AUTO_INCREMENT` follows a chronological order. Therere, applications should use [TIMESTAMP](../timestamp/index) columns for chronological order instead. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb mysql.proxies_priv Table mysql.proxies\_priv Table ========================= The `mysql.proxies_priv` table contains information about proxy privileges. The table can be queried and although it is possible to directly update it, it is best to use [GRANT](../grant/index) for setting privileges. **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this table uses the [Aria](../aria/index) storage engine. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. The `mysql.proxies_priv` table contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | `Host` | `char(60)` | NO | PRI | | | | `User` | `char(80)` | NO | PRI | | | | `Proxied_host` | `char(60)` | NO | PRI | | | | `Proxied_user` | `char(80)` | NO | PRI | | | | `With_grant` | `tinyint(1)` | NO | | 0 | | | `Grantor` | `char(141)` | NO | MUL | | | | `Timestamp` | `timestamp` | NO | | `CURRENT_TIMESTAMP` | | The [Acl\_proxy\_users](../server-status-variables/index#acl_proxy_users) status variable, added in [MariaDB 10.1.4](https://mariadb.com/kb/en/mariadb-1014-release-notes/), indicates how many rows the `mysql.proxies_priv` table contains. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Generated (Virtual and Persistent/Stored) Columns Generated (Virtual and Persistent/Stored) Columns ================================================= Syntax ------ ``` <type> [GENERATED ALWAYS] AS ( <expression> ) [VIRTUAL | PERSISTENT | STORED] [UNIQUE] [UNIQUE KEY] [COMMENT <text>] ``` MariaDB's generated columns syntax is designed to be similar to the syntax for [Microsoft SQL Server's computed columns](https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2017) and [Oracle Database's virtual columns](https://oracle-base.com/articles/11g/virtual-columns-11gr1). In [MariaDB 10.2](../what-is-mariadb-102/index) and later, the syntax is also compatible with the syntax for [MySQL's generated columns](https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html). Description ----------- A generated column is a column in a table that cannot explicitly be set to a specific value in a [DML query](../data-manipulation/index). Instead, its value is automatically generated based on an expression. This expression might generate the value based on the values of other columns in the table, or it might generate the value by calling [built-in functions](../built-in-functions/index) or [user-defined functions (UDFs)](../user-defined-functions/index). There are two types of generated columns: * `PERSISTENT` (a.k.a. `STORED`): This type's value is actually stored in the table. * `VIRTUAL`: This type's value is not stored at all. Instead, the value is generated dynamically when the table is queried. This type is the default. Generated columns are also sometimes called computed columns or virtual columns. Supported Features ------------------ ### Storage Engine Support * Generated columns can only be used with storage engines which support them. If you try to use a storage engine that does not support them, then you will see an error similar to the following: ``` ERROR 1910 (HY000): TokuDB storage engine does not support computed columns ``` * [InnoDB](../innodb/index), [Aria](../aria/index), [MyISAM](../myisam/index) and [CONNECT](../using-connect-virtual-and-special-columns/index) support generated columns. * A column in a [MERGE](../merge/index) table can be built on a `PERSISTENT` generated column. + However, a column in a MERGE table can **not** be defined as a `VIRTUAL` and `PERSISTENT` generated column. ### Data Type Support * All data types are supported when defining generated columns. * Using the [ZEROFILL](../create-table/index#zerofill-column-option) column option is supported when defining generated columns. **MariaDB starting with [10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/)**In [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/) and later, the following statements apply to data types for generated columns: * Using the [AUTO\_INCREMENT](../auto_increment/index) column option is **not** supported when defining generated columns. Previously, it was supported, but this support was removed, because it would not work correctly. See [MDEV-11117](https://jira.mariadb.org/browse/MDEV-11117). ### Index Support * Using a generated column as a table's primary key is **not** supported. See [MDEV-5590](https://jira.mariadb.org/browse/MDEV-5590) for more information. If you try to use one as a primary key, then you will see an error similar to the following: ``` ERROR 1903 (HY000): Primary key cannot be defined upon a computed column ``` * Using `PERSISTENT` generated columns as part of a [foreign key](../foreign-keys/index) is supported. * Referencing `PERSISTENT` generated columns as part of a [foreign key](../foreign-keys/index) is also supported. + However, using the `ON UPDATE CASCADE`, `ON UPDATE SET NULL`, or `ON DELETE SET NULL` clauses is **not** supported. If you try to use an unsupported clause, then you will see an error similar to the following: ``` ERROR 1905 (HY000): Cannot define foreign key with ON UPDATE SET NULL clause on a computed column ``` **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**In [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/) and later, the following statements apply to indexes for generated columns: * Defining indexes on both `VIRTUAL` and `PERSISTENT` generated columns is supported. + If an index is defined on a generated column, then the optimizer considers using it in the same way as indexes based on "real" columns. **MariaDB until [10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/)**In [MariaDB 10.2.2](https://mariadb.com/kb/en/mariadb-1022-release-notes/) and before, the following statements apply to indexes for generated columns: * Defining indexes on `VIRTUAL` generated columns is **not** supported. * Defining indexes on `PERSISTENT` generated columns is supported. + If an index is defined on a generated column, then the optimizer considers using it in the same way as indexes based on "real" columns. ### Statement Support * Generated columns are used in [DML queries](../data-manipulation/index) just as if they were "real" columns. + However, `VIRTUAL` and `PERSISTENT` generated columns differ in how their data is stored. - Values for `PERSISTENT` generated columns are generated whenever a [DML queries](../data-manipulation/index) inserts or updates the row with the special `DEFAULT` value. This generates the columns value, and it is stored in the table like the other "real" columns. This value can be read by other [DML queries](../data-manipulation/index) just like the other "real" columns. - Values for `VIRTUAL` generated columns are not stored in the table. Instead, the value is generated dynamically whenever the column is queried. If other columns in a row are queried, but the `VIRTUAL` generated column is not one of the queried columns, then the column's value is not generated. * The [SELECT](../select/index) statement supports generated columns. * Generated columns can be referenced in the [INSERT](../insert/index), [UPDATE](../update/index), and [DELETE](../delete/index) statements. + However, `VIRTUAL` or `PERSISTENT` generated columns cannot be explicitly set to any other values than `NULL` or [DEFAULT](../default/index). If a generated column is explicitly set to any other value, then the outcome depends on whether [strict mode](../sql-mode/index#strict-mode) is enabled in [sql\_mode](../sql-mode/index). If it is not enabled, then a warning will be raised and the default generated value will be used instead. If it is enabled, then an error will be raised instead. * The [CREATE TABLE](../create-table/index) statement has limited support for generated columns. + It supports defining generated columns in a new table. + It supports using generated columns to [partition tables](../partitioning-tables/index). + It does **not** support using the [versioning clauses](../system-versioned-tables/index) with generated columns. * The [ALTER TABLE](../alter-table/index) statement has limited support for generated columns. + It supports the `MODIFY` and `CHANGE` clauses for `PERSISTENT` generated columns. + It does **not** support the `MODIFY` clause for `VIRTUAL` generated columns if [ALGORITHM](../alter-table/index#algorithm) is not set to `COPY`. See [MDEV-15476](https://jira.mariadb.org/browse/MDEV-15476) for more information. + It does **not** support the `CHANGE` clause for `VIRTUAL` generated columns if [ALGORITHM](../alter-table/index#algorithm) is not set to `COPY`. See [MDEV-17035](https://jira.mariadb.org/browse/MDEV-17035) for more information. + It does **not** support altering a table if [ALGORITHM](../alter-table/index#algorithm) is not set to `COPY` if the table has a `VIRTUAL` generated column that is indexed. See [MDEV-14046](https://jira.mariadb.org/browse/MDEV-14046) for more information. + It does **not** support adding a `VIRTUAL` generated column with the `ADD` clause if the same statement is also adding other columns if [ALGORITHM](../alter-table/index#algorithm) is not set to `COPY`. See [MDEV-17468](https://jira.mariadb.org/browse/MDEV-17468) for more information. + It also does **not** support altering an existing column into a `VIRTUAL` generated column. + It supports using generated columns to [partition tables](../partitioning-tables/index). + It does **not** support using the [versioning clauses](../system-versioned-tables/index) with generated columns. * The [SHOW CREATE TABLE](../show-create-table/index) statement supports generated columns. * The [DESCRIBE](../describe/index) statement can be used to check whether a table has generated columns. + You can tell which columns are generated by looking for the ones where the `Extra` column is set to either `VIRTUAL` or `PERSISTENT`. For example: ``` DESCRIBE table1; +-------+-------------+------+-----+---------+------------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+------------+ | a | int(11) | NO | | NULL | | | b | varchar(32) | YES | | NULL | | | c | int(11) | YES | | NULL | VIRTUAL | | d | varchar(5) | YES | | NULL | PERSISTENT | +-------+-------------+------+-----+---------+------------+ ``` * Generated columns can be properly referenced in the `NEW` and `OLD` rows in [triggers](../triggers/index). * [Stored procedures](../stored-procedures/index) support generated columns. * The [HANDLER](../handler-commands/index) statement supports generated columns. ### Expression Support * Most legal, deterministic expressions which can be calculated are supported in expressions for generated columns. * Most [built-in functions](../built-in-functions/index) are supported in expressions for generated columns. + However, some [built-in functions](../built-in-functions/index) can't be supported for technical reasons. For example, If you try to use an unsupported function in an expression, an error is generated similar to the following: ``` ERROR 1901 (HY000): Function or expression 'dayname()' cannot be used in the GENERATED ALWAYS AS clause of `v` ``` * [Subqueries](../subqueries/index) are **not** supported in expressions for generated columns because the underlying data can change. * Using anything that depends on data outside the row is **not** supported in expressions for generated columns. * [Stored functions](../stored-functions/index) are **not** supported in expressions for generated columns. See [MDEV-17587](https://jira.mariadb.org/browse/MDEV-17587) for more information. **MariaDB starting with [10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)**In [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) and later, the following statements apply to expressions for generated columns: * Non-deterministic [built-in functions](../built-in-functions/index) are supported in expressions for not indexed `VIRTUAL` generated columns. * Non-deterministic [built-in functions](../built-in-functions/index) are **not** supported in expressions for `PERSISTENT` or indexed `VIRTUAL` generated columns. * [User-defined functions (UDFs)](../user-defined-functions/index) are supported in expressions for generated columns. + However, MariaDB can't check whether a UDF is deterministic, so it is up to the user to be sure that they do not use non-deterministic UDFs with `VIRTUAL` generated columns. * Defining a generated column based on other generated columns defined before it in the table definition is supported. For example: ``` CREATE TABLE t1 (a int as (1), b int as (a)); ``` * However, defining a generated column based on other generated columns defined after in the table definition is **not** supported in expressions for generation columns because generated columns are calculated in the order they are defined. * Using an expression that exceeds 255 characters in length is supported in expressions for generated columns. The new limit for the entire table definition, including all expressions for generated columns, is 65,535 bytes. * Using constant expressions is supported in expressions for generated columns. For example: ``` CREATE TABLE t1 (a int as (1)); ``` **MariaDB until [10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/)**In [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) and before, the following statements apply to expressions for generated columns: * Non-deterministic [built-in functions](../built-in-functions/index) are **not** supported in expressions for generated columns. * [User-defined functions (UDFs)](../user-defined-functions/index) are **not** supported in expressions for generated columns. * Defining a generated column based on other generated columns defined in the table is **not** supported. Otherwise, it would generate errors like this: ``` ERROR 1900 (HY000): A computed column cannot be based on a computed column ``` * Using an expression that exceeds 255 characters in length is **not** supported in expressions for generated columns. * Using constant expressions is **not** supported in expressions for generated columns. Otherwise, it would generate errors like this: ``` ERROR 1908 (HY000): Constant expression in computed column function is not allowed ``` ### Making Stored Values Consistent When a generated column is `PERSISTENT` or indexed, the value of the expression needs to be consistent regardless of the [SQL Mode](../sql-mode/index) flags in the current session. If it is not, then the table will be seen as corrupted when the value that should actually be returned by the computed expression and the value that was previously stored and/or indexed using a different [sql\_mode](../sql-mode/index) setting disagree. There are currently two affected classes of inconsistencies: character padding and unsigned subtraction: * For a `VARCHAR` or `TEXT` generated column the length of the value returned can vary depending on the PAD\_CHAR\_TO\_FULL\_LENGTH [sql\_mode](../sql-mode/index) flag. To make the value consistent, create the generated column using an RTRIM() or RPAD() function. Alternately, create the generated column as a `CHAR` column so that its data is always fully padded. * If a `SIGNED` generated column is based on the subtraction of an `UNSIGNED` value, the resulting value can vary depending on how large the value is and the NO\_UNSIGNED\_SUBTRACTION [sql\_mode](../sql-mode/index) flag. To make the value consistent, use [CAST()](../cast/index) to ensure that each `UNSIGNED` operand is `SIGNED` before the subtraction. **MariaDB starting with [10.5](../what-is-mariadb-105/index)**Beginning in [MariaDB 10.5](../what-is-mariadb-105/index), there is a fatal error generated when trying to create a generated column whose value can change depending on the [SQL Mode](../sql-mode/index) when its data is `PERSISTENT` or indexed. For an existing generated column that has a potentially inconsistent value, a warning about a bad expression is generated the first time it is used (if warnings are enabled). Beginning in [MariaDB 10.4.8](https://mariadb.com/kb/en/mariadb-1048-release-notes/), [MariaDB 10.3.18](https://mariadb.com/kb/en/mariadb-10318-release-notes/), and [MariaDB 10.2.27](https://mariadb.com/kb/en/mariadb-10227-release-notes/) a potentially inconsistent generated column outputs a warning when created or first used (without restricting their creation). Here is an example of two tables that would be rejected in [MariaDB 10.5](../what-is-mariadb-105/index) and warned about in the other listed versions: ``` CREATE TABLE bad_pad ( txt CHAR(5), -- CHAR -> VARCHAR or CHAR -> TEXT can't be persistent or indexed: vtxt VARCHAR(5) AS (txt) PERSISTENT ); CREATE TABLE bad_sub ( num1 BIGINT UNSIGNED, num2 BIGINT UNSIGNED, -- The resulting value can vary for some large values vnum BIGINT AS (num1 - num2) VIRTUAL, KEY(vnum) ); ``` The warnings for the above tables look like this: ``` Warning (Code 1901): Function or expression '`txt`' cannot be used in the GENERATED ALWAYS AS clause of `vtxt` Warning (Code 1105): Expression depends on the @@sql_mode value PAD_CHAR_TO_FULL_LENGTH Warning (Code 1901): Function or expression '`num1` - `num2`' cannot be used in the GENERATED ALWAYS AS clause of `vnum` Warning (Code 1105): Expression depends on the @@sql_mode value NO_UNSIGNED_SUBTRACTION ``` To work around the issue, force the padding or type to make the generated column's expression return a consistent value. For example: ``` CREATE TABLE good_pad ( txt CHAR(5), -- Using RTRIM() or RPAD() makes the value consistent: vtxt VARCHAR(5) AS (RTRIM(txt)) PERSISTENT, -- When not persistent or indexed, it is OK for the value to vary by mode: vtxt2 VARCHAR(5) AS (txt) VIRTUAL, -- CHAR -> CHAR is always OK: txt2 CHAR(5) AS (txt) PERSISTENT ); CREATE TABLE good_sub ( num1 BIGINT UNSIGNED, num2 BIGINT UNSIGNED, -- The indexed value will always be consistent in this expression: vnum BIGINT AS (CAST(num1 AS SIGNED) - CAST(num2 AS SIGNED)) VIRTUAL, KEY(vnum) ); ``` ### MySQL Compatibility Support **MariaDB starting with [10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/)**In [MariaDB 10.2.1](https://mariadb.com/kb/en/mariadb-1021-release-notes/) and later, the following statements apply to MySQL compatibility for generated columns: * The `STORED` keyword is supported as an alias for the `PERSISTENT` keyword. * Tables created with MySQL 5.7 or later that contain [MySQL's generated columns](https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html) can be imported into MariaDB without a dump and restore. **MariaDB until [10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/)**In [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) and before, the following statements apply to MySQL compatibility for generated columns: * The `STORED` keyword is **not** supported as an alias for the `PERSISTENT` keyword. * Tables created with MySQL 5.7 or later that contain [MySQL's generated columns](https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html) can **not** be imported into MariaDB without a dump and restore. Implementation Differences -------------------------- Generated columns are subject to various constraints in other DBMSs that are not present in MariaDB's implementation. Generated columns may also be called computed columns or virtual columns in different implementations. The various details for a specific implementation can be found in the documentation for each specific DBMS. ### Implementation Differences Compared to Microsoft SQL Server MariaDB's generated columns implementation does not enforce the following restrictions that are present in [Microsoft SQL Server's computed columns](https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2017) implementation: * MariaDB allows [server variables](../system-variables/index) in generated column expressions, including those that change dynamically, such as [warning\_count](../server-system-variables/index#warning_count). * MariaDB allows the [CONVERT\_TZ()](../convert_tz/index) function to be called with a named [time zone](../time-zones/index) as an argument, even though time zone names and time offsets are configurable. * MariaDB allows the [CAST()](../cast/index) function to be used with non-unicode [character sets](../data-types-character-sets-and-collations/index), even though character sets are configurable and differ between binaries/versions. * MariaDB allows [FLOAT](../float/index) expressions to be used in generated columns. Microsoft SQL Server considers these expressions to be "imprecise" due to potential cross-platform differences in floating-point implementations and precision. * Microsoft SQL Server requires the [ARITHABORT](https://docs.microsoft.com/en-us/sql/t-sql/statements/set-arithabort-transact-sql?view=sql-server-2017) mode to be set, so that division by zero returns an error, and not a NULL. * Microsoft SQL Server requires `QUOTED_IDENTIFIER` to be set in [sql\_mode](../sql-mode/index). In MariaDB, if data is inserted without `ANSI_QUOTES` set in [sql\_mode](../sql-mode/index), then it will be processed and stored differently in a generated column that contains quoted identifiers. * In [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/) and before, it does not allow [user-defined functions (UDFs)](../user-defined-functions/index) to be used in expressions for generated columns. Microsoft SQL Server enforces the above restrictions by doing one of the following things: * Refusing to create computed columns. * Refusing to allow updates to a table containing them. * Refusing to use an index over such a column if it can not be guaranteed that the expression is fully deterministic. In MariaDB, as long as the [sql\_mode](../sql-mode/index), language, and other settings that were in effect during the CREATE TABLE remain unchanged, the generated column expression will always be evaluated the same. If any of these things change, then please be aware that the generated column expression might not be evaluated the same way as it previously was. In [MariaDB 5.2](../what-is-mariadb-52/index), you will get a warning if you try to update a virtual column. In [MariaDB 5.3](../what-is-mariadb-53/index) and later, this warning will be converted to an error if [strict mode](../sql-mode/index#strict-mode) is enabled in [sql\_mode](../sql-mode/index). Development History ------------------- Generated columns was originally developed by Andrey Zhakov. It was then modified by Sanja Byelkin and Igor Babaev at Monty Program for inclusion in MariaDB. Monty did the work on [MariaDB 10.2](../what-is-mariadb-102/index) to lift a some of the old limitations. Examples -------- Here is an example table that uses both `VIRTUAL` and `PERSISTENT` virtual columns: ``` USE TEST; CREATE TABLE table1 ( a INT NOT NULL, b VARCHAR(32), c INT AS (a mod 10) VIRTUAL, d VARCHAR(5) AS (left(b,5)) PERSISTENT); ``` If you describe the table, you can easily see which columns are virtual by looking in the "Extra" column: ``` DESCRIBE table1; +-------+-------------+------+-----+---------+------------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+------------+ | a | int(11) | NO | | NULL | | | b | varchar(32) | YES | | NULL | | | c | int(11) | YES | | NULL | VIRTUAL | | d | varchar(5) | YES | | NULL | PERSISTENT | +-------+-------------+------+-----+---------+------------+ ``` To find out what function(s) generate the value of the virtual column you can use `SHOW CREATE TABLE`: ``` SHOW CREATE TABLE table1; | table1 | CREATE TABLE `table1` ( `a` int(11) NOT NULL, `b` varchar(32) DEFAULT NULL, `c` int(11) AS (a mod 10) VIRTUAL, `d` varchar(5) AS (left(b,5)) PERSISTENT ) ENGINE=MyISAM DEFAULT CHARSET=latin1 | ``` If you try to insert non-default values into a virtual column, you will receive a warning and what you tried to insert will be ignored and the derived value inserted instead: ``` WARNINGS; Show warnings enabled. INSERT INTO table1 VALUES (1, 'some text',default,default); Query OK, 1 row affected (0.00 sec) INSERT INTO table1 VALUES (2, 'more text',5,default); Query OK, 1 row affected, 1 warning (0.00 sec) Warning (Code 1645): The value specified for computed column 'c' in table 'table1' has been ignored. INSERT INTO table1 VALUES (123, 'even more text',default,'something'); Query OK, 1 row affected, 2 warnings (0.00 sec) Warning (Code 1645): The value specified for computed column 'd' in table 'table1' has been ignored. Warning (Code 1265): Data truncated for column 'd' at row 1 SELECT * FROM table1; +-----+----------------+------+-------+ | a | b | c | d | +-----+----------------+------+-------+ | 1 | some text | 1 | some | | 2 | more text | 2 | more | | 123 | even more text | 3 | even | +-----+----------------+------+-------+ 3 rows in set (0.00 sec) ``` If the `ZEROFILL` clause is specified, it should be placed directly after the type definition, before the `AS (<expression>)`: ``` CREATE TABLE table2 (a INT, b INT ZEROFILL AS (a*2) VIRTUAL); INSERT INTO table2 (a) VALUES (1); SELECT * FROM table2; +------+------------+ | a | b | +------+------------+ | 1 | 0000000002 | +------+------------+ 1 row in set (0.00 sec) ``` You can also use virtual columns to implement a "poor man's partial index". See example at the end of [Unique Index](../getting-started-with-indexes/index#unique-index). See Also -------- * [Putting Virtual Columns to good use](https://mariadb.com/blog/putting-virtual-columns-good-use) on the mariadb.com blog. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Performance Schema session_account_connect_attrs Table Performance Schema session\_account\_connect\_attrs Table ========================================================= Description ----------- The `session_account_connect_attrs` table shows connection attributes for the current session. Applications can pass key/value connection attributes to the server when a connection is made. The [session\_connect\_attrs](../performance-schema-session_connect_attrs-table/index) and `session_account_connect_attrs` tables provide access to this information, for all sessions and the current session respectively. The C API functions [mysql\_options()](../mysql_options/index) and [mysql\_optionsv()](../mysql_optionsv/index) are used for passing connection attributes to the server. `session_account_connect_attrs` contains the following columns: | Column | Description | | --- | --- | | `PROCESSLIST_ID` | Session connection identifier. | | `ATTR_NAME` | Attribute name. | | `ATTR_VALUE` | Attribute value. | | `ORDINAL_POSITION` | Order in which attribute was added to the connection attributes. | Example ------- ``` SELECT * FROM performance_schema.session_account_connect_attrs; +----------------+-----------------+------------------+------------------+ | PROCESSLIST_ID | ATTR_NAME | ATTR_VALUE | ORDINAL_POSITION | +----------------+-----------------+------------------+------------------+ | 45 | _os | debian-linux-gnu | 0 | | 45 | _client_name | libmysql | 1 | | 45 | _pid | 7711 | 2 | | 45 | _client_version | 10.0.5 | 3 | | 45 | _platform | x86_64 | 4 | | 45 | program_name | mysql | 5 | +----------------+-----------------+------------------+------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Docker Environment Variables MariaDB Docker Environment Variables ==================================== When you start the %%IMAGE%% image, you can adjust the initialization of the MariaDB instance by passing one or more environment variables on the docker run command line. Do note that none of the variables below will have any effect if you start the container with a data directory that already contains a database: any pre-existing database will always be left untouched on container startup. From tag 10.2.38, 10.3.29, 10.4.19, 10.5.10 onwards, and all 10.6 and later tags, the MARIADB\_\* equivalent variables are provided. MARIADB\_\* variants will always be used in preference to MYSQL\_\* variants. One of MARIADB\_ROOT\_PASSWORD, MARIADB\_ALLOW\_EMPTY\_ROOT\_PASSWORD, or MARIADB\_RANDOM\_ROOT\_PASSWORD (or equivalents, including \*\_FILE), is required. The other environment variables are optional. ### MARIADB\_ROOT\_PASSWORD / MYSQL\_ROOT\_PASSWORD This specifies the password that will be set for the MariaDB root superuser account. In the above example, it was set to my-secret-pw. ### MARIADB\_ALLOW\_EMPTY\_ROOT\_PASSWORD / MYSQL\_ALLOW\_EMPTY\_PASSWORD Set to a non-empty value, like yes, to allow the container to be started with a blank password for the root user. NOTE: Setting this variable to yes is not recommended unless you really know what you are doing, since this will leave your MariaDB instance completely unprotected, allowing anyone to gain complete superuser access. ### MARIADB\_RANDOM\_ROOT\_PASSWORD / MYSQL\_RANDOM\_ROOT\_PASSWORD Set to a non-empty value, like yes, to generate a random initial password for the root user. The generated root password will be printed to stdout (GENERATED ROOT PASSWORD: .....). ### MARIADB\_ROOT\_HOST / MYSQL\_ROOT\_HOST This is the hostname part of the root user created. By default this is %, however it can be set to any default MariaDB allowed hostname component. Setting this to localhost will prevent any root user being accessible except via the unix socket. ### MARIADB\_MYSQL\_LOCALHOST\_USER / MARIADB\_MYSQL\_LOCALHOST\_GRANTS Set MARIADB\_MYSQL\_LOCALHOST\_USER to a non-empty value to create the mysql@locahost database user. This user is especially useful for a variety of health checks and backup scripts. The mysql@localhost user gets USAGE privileges by default. If more access is required, additional global privileges in the form of a comma separated list can be provided. If you are sharing a volume containing MariaDB's unix socket (/var/run/mysqld by default), privileges beyond USAGE can result in confidentiality, integrity and availability risks, so use a minimal set. See the example below on using Mariabackup. The healthcheck.sh script also documents the required privileges for each health check test. ### MARIADB\_DATABASE / MYSQL\_DATABASE This variable allows you to specify the name of a database to be created on image startup. MARIADB\_USER / MYSQL\_USER, MARIADB\_PASSWORD / MYSQL\_PASSWORD These are used in conjunction to create a new user and to set that user's password. Both user and password variables are required for a user to be created. This user will be granted all access (corresponding to GRANT ALL) to the MARIADB\_DATABASE database. Do note that there is no need to use this mechanism to create the root superuser, that user gets created by default with the password specified by the MARIADB\_ROOT\_PASSWORD / MYSQL\_ROOT\_PASSWORD variable. ### MARIADB\_INITDB\_SKIP\_TZINFO / MYSQL\_INITDB\_SKIP\_TZINFO By default, the entrypoint script automatically loads the timezone data needed for the CONVERT\_TZ() function. If it is not needed, any non-empty value disables timezone loading. MARIADB\_AUTO\_UPGRADE / MARIADB\_DISABLE\_UPGRADE\_BACKUP Set MARIADB\_AUTO\_UPGRADE to a non-empty value to have the entrypoint check whether mysql\_upgrade/mariadb-upgrade needs to run, and if so, run the upgrade before starting the MariaDB server. Before the upgrade, a backup of the system database is created in the top of the datadir with the name system\_mysql\_backup\_\*.sql.zst. This backup process can be disabled with by setting MARIADB\_DISABLE\_UPGRADE\_BACKUP to a non-empty value. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mroonga_normalize mroonga\_normalize ================== Syntax ------ ``` mroonga_normalize(string[, normalizer_name]) ``` Description ----------- `mroonga_normalize` is a [user-defined function](../user-defined-functions/index) (UDF) included with the [Mroonga storage engine](../mroonga/index). It uses Groonga's normalizer to normalize text. See [Creating Mroonga User-Defined Functions](../creating-mroonga-user-defined-functions/index) for details on creating this UDF if required. Given a string, returns the normalized text. See the [Groonga Normalizer Reference](http://groonga.org/docs/reference/normalizers.html) for details on the Groonga normalizers. The default if no normalizer is provided is `NormalizerAuto`. Examples -------- ``` SELECT mroonga_normalize("ABぃ㍑"); +-------------------------------+ | mroonga_normalize("ABぃ㍑") | +-------------------------------+ | abぃリットル | +-------------------------------+ ``` See Also -------- * [Creating Mroonga User-Defined Functions](../creating-mroonga-user-defined-functions/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Using CONNECT - Importing File Data Into MariaDB Tables Using CONNECT - Importing File Data Into MariaDB Tables ======================================================= Directly using external (file) data has many advantages, such as to work on “fresh” data produced for instance by cash registers, telephone switches, or scientific apparatus. However, you may want in some case to import external data into your MariaDB database. This is extremely simple and flexible using the CONNECT handler. For instance, let us suppose you want to import the data of the xsample.xml XML file previously given in example into a [MyISAM](../myisam/index) table called *biblio* belonging to the connect database. All you have to do is to create it by: ``` create table biblio engine=myisam select * from xsampall2; ``` This last statement creates the [MyISAM](../myisam/index) table and inserts the original XML data, translated to tabular format by the *xsampall2* CONNECT table, into the MariaDB *biblio* table. Note that further transformation on the data could have been achieved by using a more elaborate Select statement in the Create statement, for instance using filters, alias or applying functions to the data. However, because the Create Table process copies table data, later modifications of the *xsample.xml* file will not change the *biblio* table and changes to the *biblio* table will not modify the *xsample.xml* file. All these can be combined or transformed by further SQL operations. This makes working with CONNECT much more flexible than just using the [LOAD](../load/index) statement. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Clients & Utilities Clients & Utilities ==================== | Title | Description | | --- | --- | | [mysql Client](../mysql-client/index) | The mysql command-line client. | | [Aria Clients and Utilities](../aria-clients-and-utilities/index) | Clients and utilities for working with Aria tables | | [Backup, Restore and Import Clients](../backup-restore-and-import-clients/index) | Clients for taking backups or importing/restoring data | | [Graphical and Enhanced Clients](../graphical-and-enhanced-clients/index) | Incomplete list of graphical clients | | [MyISAM Clients and Utilities](../myisam-clients-and-utilities/index) | Clients and utilities for working with MyISAM tables | | [dbdeployer](../dbdeployer/index) | Installing and testing multiple MariaDB versions in isolation. | | [dbForge Studio for MySQL/MariaDB](../dbforge-studio-for-mysqlmariadb/index) | IDE for the development, management, and administration of MariaDB & MySQL databases. | | [EXPLAIN Analyzer](../explain-analyzer/index) | The EXPLAIN Analyzer is an online tool for analyzing and optionally sharing... | | [EXPLAIN Analyzer API](../explain-analyzer-api/index) | The online EXPLAIN Analyzer tool has an open API to allow client applicatio... | | [innochecksum](../innochecksum/index) | Tool for printing checksums for InnoDB files. | | [msql2mysql](../msql2mysql/index) | Description Initially, the MySQL C API was developed to be very similar to ... | | [my\_print\_defaults](../my_print_defaults/index) | Displays the options from option groups of option files | | [mysqladmin](../mysqladmin/index) | Admin tool for monitoring, creating/dropping databases, stopping mysqld etc. | | [mysqlaccess](../mysqlaccess/index) | Tool for checking access privileges. | | [mysqlbinlog](../mysqlbinlog/index) | mysqlbinlog utility for processing binary log files. | | [mysqlcheck](../mysqlcheck/index) | Tool for checking, repairing, analyzing and optimizing tables. | | [mysql\_convert\_table\_format](../mysql_convert_table_format/index) | Convert tables to use a particular storage engine by default. | | [mysqldumpslow](../mysqldumpslow/index) | Display data from the slow query log. | | [mysql\_embedded](../mysql_embedded/index) | mysql client statically linked to libmysqld, the embedded server. | | [mysql\_find\_rows](../mysql_find_rows/index) | Read files containing SQL statements and extract statements that match a pattern. | | [mysql\_fix\_extensions](../mysql_fix_extensions/index) | Converts the extensions for MyISAM (or ISAM) table files to their canonical forms. | | [mysql\_install\_db](../mysql_install_db/index) | Tool for creating the system tables in the mysql database. | | [mysql\_plugin](../mysql_plugin/index) | Tool for enabling or disabling plugins. | | [mysqlreport](../mysqlreport/index) | Creates a friendly report of important MariaDB status values. | | [MySQL Sandbox](../mysql-sandbox/index) | Installing multiple MariaDB versions in isolation. | | [mysql\_secure\_installation](../mysql_secure_installation/index) | Improve the security of a MariaDB installation. | | [mysql\_setpermission](../mysql_setpermission/index) | Helps add users or databases or change passwords in MariaDB. | | [mysqlshow](../mysqlshow/index) | Shows database structure. | | [mysqlslap](../mysqlslap/index) | Tool for load-testing MariaDB. | | [mysql-stress-test](../mysql-stress-test/index) | Perl script that performs stress-testing of the MariaDB server | | [mysql-test](../mysqltest/index) | Testing utility | | [mysql\_tzinfo\_to\_sql](../mysql_tzinfo_to_sql/index) | Load time zones to the mysql time zone tables. | | [mysql\_upgrade](../mysql_upgrade/index) | Update to the latest version. | | [mysql\_waitpid](../mysql_waitpid/index) | Terminate processes. | | [mysql\_zap](../mysql_zap/index) | Kill processes that match a pattern. | | [perror](../perror/index) | Display descriptions for system or storage engine error codes | | [replace Utility](../replace-utility/index) | The replace utility program changes strings in place infiles or on the standard input | | [resolveip](../resolveip/index) | Resolves IP addresses to host names and vice versa | | [resolve\_stack\_dump](../resolve_stack_dump/index) | Resolve numeric stack strace dump into symbols | | [xtstat](../xtstat/index) | Used to monitor all internal activity of PBXT | | [mariadb-access](../mariadb-access/index) | Symlink or new name for mysqlaccess. | | [mariadb-admin](../mariadb-admin/index) | Symlink or new name for mysqladmin. | | [mariadb-check](../mariadb-check/index) | Symlink or new name for mysqlcheck. | | [mariadb-conv](../mariadb-conv/index) | Character set conversion utility for MariaDB. | | [mariadb-convert-table-format](../mariadb-convert-table-format/index) | Symlink or new name for mysql\_convert\_table\_format. | | [mariadb-dumpslow](../mariadb-dumpslow/index) | Symlink or new name for mysqldumpslow. | | [mariadb-embedded](../mariadb-embedded/index) | Symlink or new name for mysql\_embedded. | | [mariadb-find-rows](../mariadb-find-rows/index) | Symlink or new name for mysql\_find\_rows. | | [mariadb-fix-extensions](../mariadb-fix-extensions/index) | Symlink or new name for mysql\_fix\_extensions. | | [mariadb-install-db](../mariadb-install-db/index) | Symlink to mysql\_install\_db. | | [mariadb-plugin](../mariadb-plugin/index) | Symlink or new name for mysql\_plugin. | | [mariadb-report](../mariadb-report/index) | Symlink or new name for mysqlreport. | | [mariadb-secure-installation](../mariadb-secure-installation/index) | Symlink or new name for mysql\_secure\_installation. | | [mariadb-setpermission](../mariadb-setpermission/index) | Symlink or new name for mysql\_setpermission. | | [mariadb-show](../mariadb-show/index) | Symlink or new name for mysqlshow. | | [mariadb-slap](../mariadb-slap/index) | Symlink or new name for mysqlslap. | | [mariadb-tzinfo-to-sql](../mariadb-tzinfo-to-sql/index) | Symlink or new name for mysql\_tzinfo\_to\_sql. | | [mariadb-upgrade](../mariadb-upgrade/index) | Symlink or new name for mysql\_upgrade. | | [mariadb-waitpid](../mariadb-waitpid/index) | Symlink or new name for mysql\_waitpid. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Encryption Plugin API Encryption Plugin API ===================== MariaDB's [data-at-rest encryption](../data-at-rest-encryption/index) requires the use of a [key management and encryption plugin](../encryption-key-management/index). These plugins are responsible both for the management of encryption keys and for the actual encryption and decryption of data. MariaDB supports the use of [multiple encryption keys](../encryption-key-management/index#using-multiple-encryption-keys). Each encryption key uses a 32-bit integer as a key identifier. If the specific plugin supports [key rotation](../encryption-key-management/index#rotating-keys), then encryption keys can also be rotated, which creates a new version of the encryption key. See [Data at Rest Encryption](../data-at-rest-encryption/index) and [Encryption Key Management](../encryption-key-management/index) for more information. Encryption Plugin API --------------------- The Encryption plugin API was created to allow a plugin to: * implement key management, provide encryption keys to the server on request and change them according to internal policies. * implement actual data encryption and decryption with the algorithm defined by the plugin. This is how the API reflects that: ``` /* Returned from get_latest_key_version() */ #define ENCRYPTION_KEY_VERSION_INVALID (~(unsigned int)0) #define ENCRYPTION_KEY_NOT_ENCRYPTED (0) #define ENCRYPTION_KEY_SYSTEM_DATA 1 #define ENCRYPTION_KEY_TEMPORARY_DATA 2 /* Returned from get_key() */ #define ENCRYPTION_KEY_BUFFER_TOO_SMALL (100) #define ENCRYPTION_FLAG_DECRYPT 0 #define ENCRYPTION_FLAG_ENCRYPT 1 #define ENCRYPTION_FLAG_NOPAD 2 struct st_mariadb_encryption { int interface_version; /**< version plugin uses */ /********************* KEY MANAGEMENT ***********************************/ /** Function returning latest key version for a given key id. @return A version or ENCRYPTION_KEY_VERSION_INVALID to indicate an error. */ unsigned int (*get_latest_key_version)(unsigned int key_id); /** Function returning a key for a key version @param key_id The requested key id @param version The requested key version @param key The key will be stored there. Can be NULL - in which case no key will be returned @param key_length in: key buffer size out: the actual length of the key This method can be used to query the key length - the required buffer size - by passing key==NULL. If the buffer size is less than the key length the content of the key buffer is undefined (the plugin is free to partially fill it with the key data or leave it untouched). @return 0 on success, or ENCRYPTION_KEY_VERSION_INVALID, ENCRYPTION_KEY_BUFFER_TOO_SMALL or any other non-zero number for errors */ unsigned int (*get_key)(unsigned int key_id, unsigned int version, unsigned char *key, unsigned int *key_length); /********************* ENCRYPTION **************************************/ /* The caller uses encryption as follows: 1. Create the encryption context object of the crypt_ctx_size() bytes. 2. Initialize it with crypt_ctx_init(). 3. Repeat crypt_ctx_update() until there are no more data to encrypt. 4. Write the remaining output bytes and destroy the context object with crypt_ctx_finish(). */ /** Returns the size of the encryption context object in bytes */ unsigned int (*crypt_ctx_size)(unsigned int key_id, unsigned int key_version); /** Initializes the encryption context object. */ int (*crypt_ctx_init)(void *ctx, const unsigned char *key, unsigned int klen, const unsigned char *iv, unsigned int ivlen, int flags, unsigned int key_id, unsigned int key_version); /** Processes (encrypts or decrypts) a chunk of data Writes the output to th dst buffer. note that it might write more bytes that were in the input. or less. or none at all. */ int (*crypt_ctx_update)(void *ctx, const unsigned char *src, unsigned int slen, unsigned char *dst, unsigned int *dlen); /** Writes the remaining output bytes and destroys the encryption context crypt_ctx_update might've cached part of the output in the context, this method will flush these data out. */ int (*crypt_ctx_finish)(void *ctx, unsigned char *dst, unsigned int *dlen); /** Returns the length of the encrypted data It returns the exact length, given only the source length. Which means, this API only supports encryption algorithms where the length of the encrypted data only depends on the length of the input (a.k.a. compression is not supported). */ unsigned int (*encrypted_length)(unsigned int slen, unsigned int key_id, unsigned int key_version); }; ``` The first method is used for key rotation. A plugin that doesn't support key rotation — for example, **file\_key\_management** — can return a fixed version for any valid key id. Note that it still has to return an error for an invalid key id. The version `ENCRYPTION_KEY_NOT_ENCRYPTED` means that the data should not be encrypted. The second method is used for key management, the server uses it to retrieve the key corresponding to a specific key identifier and a specific key version. The last five methods deal with encryption. Note that they take the key to use and key identifier and version. This is needed because the server can derive a session-specific, user-specific, or a tablespace-specific key from the original encryption key as returned by `get_key()`, so the `key` argument doesn't have to match the encryption key as the plugin knows it. On the other hand, the encryption algorithm may depend on the key identifier and version (and in the **example\_key\_management** plugin it does) so the plugin needs to know them to be able to encrypt the data. Encryption methods are optional — if unset (as in the **debug\_key\_management** plugin), the server will fall back to AES\_CBC. Current Encryption Plugins -------------------------- The MariaDB source tree has four encryption plugins. All these plugins are fairly simple and can serve as good examples of the Encryption plugin API. ### file\_key\_management It reads encryption keys from a plain-text file. It supports two different encryption algorithms. It supports multiple encryption keys. It does not support key rotation. See the [File Key Management Plugin](../file-key-management-encryption-plugin/index) article for more details. #### Versions | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Stable | [MariaDB 10.1.18](https://mariadb.com/kb/en/mariadb-10118-release-notes/) | | 1.0 | Gamma | [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/) | | 1.0 | Alpha | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | ### aws\_key\_management The AWS Key Management plugin uses the [Amazon Web Services (AWS) Key Management Service (KMS)](https://aws.amazon.com/kms/) to generate and store AES keys on disk, in encrypted form, using the Customer Master Key (CMK) kept in AWS KMS. When MariaDB Server starts, the plugin will decrypt the encrypted keys, using the AWS KMS "Decrypt" API function. MariaDB data will then be encrypted and decrypted using the AES key. It supports multiple encryption keys. It supports key rotation. See the [AWS Key Management Plugin](../aws-key-management-encryption-plugin/index) article for more details. #### Versions | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Stable | [MariaDB 10.2.6](https://mariadb.com/kb/en/mariadb-1026-release-notes/), [MariaDB 10.1.24](https://mariadb.com/kb/en/mariadb-10124-release-notes/) | | 1.0 | Beta | [MariaDB 10.1.18](https://mariadb.com/kb/en/mariadb-10118-release-notes/) | | 1.0 | Experimental | [MariaDB 10.1.13](https://mariadb.com/kb/en/mariadb-10113-release-notes/) | ### example\_key\_management Uses random time-based generated keys, ignores key identifiers, supports key versions and key rotation. Uses AES\_ECB and AES\_CBC as encryption algorithms and changes them automatically together with key versions. #### Versions | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Experimental | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | ### debug\_key\_management Key is generated from the version, user manually controls key rotation. Only supports key identifier 1, uses only AES\_CBC. #### Versions | Version | Status | Introduced | | --- | --- | --- | | 1.0 | Experimental | [MariaDB 10.1.3](https://mariadb.com/kb/en/mariadb-1013-release-notes/) | Encryption Service ------------------ Encryption is generally needed on the very low level **inside the storage engine**. That is, the storage engine needs to support encryption and have access to the encryption and key management functionality. The usual way for a plugin to access some functionality in the server is via a *service*. In this case the server provides the Encryption Service for storage engines (and other interested plugins) to use. These service functions are directly hooked into encryption plugin methods (described above). Service functions are declared as follows: ``` unsigned int encryption_key_get_latest_version(unsigned int key_id); unsigned int encryption_key_get(unsigned int key_id, unsigned int key_version, unsigned char *buffer, unsigned int *length); unsigned int encryption_ctx_size(unsigned int key_id, unsigned int key_version); int encryption_ctx_init(void *ctx, const unsigned char *key, unsigned int klen, const unsigned char *iv, unsigned int ivlen, int flags, unsigned int key_id, unsigned int key_version); int encryption_ctx_update(void *ctx, const unsigned char *src, unsigned int slen, unsigned char *dst, unsigned int *dlen); int encryption_ctx_finish(void *ctx, unsigned char *dst, unsigned int *dlen); unsigned int encryption_encrypted_length(unsigned int slen, unsigned int key_id, unsigned int key_version); ``` There are also convenience helpers to check for a key or key version existence and to encrypt or decrypt a block of data with one function call. ``` unsigned int encryption_key_id_exists(unsigned int id); unsigned int encryption_key_version_exists(unsigned int id, unsigned int version); int encryption_crypt(const unsigned char *src, unsigned int slen, unsigned char *dst, unsigned int *dlen, const unsigned char *key, unsigned int klen, const unsigned char *iv, unsigned int ivlen, int flags, unsigned int key_id, unsigned int key_version); ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb IN IN == Syntax ------ ``` expr IN (value,...) ``` Description ----------- Returns 1 if *`expr`* is equal to any of the values in the IN list, else returns 0. If all values are constants, they are evaluated according to the type of *`expr`* and sorted. The search for the item then is done using a binary search. This means IN is very quick if the IN value list consists entirely of constants. Otherwise, type conversion takes place according to the rules described at [Type Conversion](../type-conversion/index), but applied to all the arguments. If *`expr`* is NULL, IN always returns NULL. If at least one of the values in the list is NULL, and one of the comparisons is true, the result is 1. If at least one of the values in the list is NULL and none of the comparisons is true, the result is NULL. Examples -------- ``` SELECT 2 IN (0,3,5,7); +----------------+ | 2 IN (0,3,5,7) | +----------------+ | 0 | +----------------+ ``` ``` SELECT 'wefwf' IN ('wee','wefwf','weg'); +----------------------------------+ | 'wefwf' IN ('wee','wefwf','weg') | +----------------------------------+ | 1 | +----------------------------------+ ``` Type conversion: ``` SELECT 1 IN ('1', '2', '3'); +----------------------+ | 1 IN ('1', '2', '3') | +----------------------+ | 1 | +----------------------+ ``` ``` SELECT NULL IN (1, 2, 3); +-------------------+ | NULL IN (1, 2, 3) | +-------------------+ | NULL | +-------------------+ SELECT 1 IN (1, 2, NULL); +-------------------+ | 1 IN (1, 2, NULL) | +-------------------+ | 1 | +-------------------+ SELECT 5 IN (1, 2, NULL); +-------------------+ | 5 IN (1, 2, NULL) | +-------------------+ | NULL | +-------------------+ ``` See Also -------- * [Conversion of Big IN Predicates Into Subqueries](../conversion-of-big-in-predicates-into-subqueries/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Installation Issues with PHP5 Installation Issues with PHP5 ============================= PHP5 may give an error if used with the old connect method: ``` 'mysql_connect(): Headers and client library minor version mismatch. Headers:50156 Library:50206' ``` This is because the library wrongly checks and expects that the client library must be the exact same version as PHP was compiled with. You would get the same error if you tried to upgrade just the MySQL client library without upgrading PHP at the same time. See also [How to match API version for php5\_mysql and mariadb client](1079). Ways to fix this issue: 1. Switch to using the [mysqlnd driver](http://dev.mysql.com/downloads/connector/php-mysqlnd/) in PHP (Recommended solution). 2. Run with a lower [error reporting level](http://php.net/error-reporting): ``` $err_level = error_reporting(0); $conn = mysql_connect('params'); error_reporting($err_level); ``` 3. Recompile PHP with the MariaDB client libraries. 4. Use your original MySQL client library with the MariaDB. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb How to match API version for php5_mysql and mariadb client? How to match API version for php5\_mysql and mariadb client? ============================================================ Hello! I have recent php5 and php5\_mysql installed from Ubuntu repos. When i'm running scripts connecting to DB i get "mysql\_connect(): Headers and client library minor version mismatch. Headers:50149 Library:50203". I suppose i could suppress errors but it isn't my way. But what is the correct way to fix it? Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb JSON_EQUALS JSON\_EQUALS ============ **MariaDB starting with [10.7.0](https://mariadb.com/kb/en/mariadb-1070-release-notes/)**JSON\_EQUALS was added in [MariaDB 10.7.0](https://mariadb.com/kb/en/mariadb-1070-release-notes/) Syntax ------ ``` JSON_EQUALS(json1, json2) ``` Description ----------- Checks if there is equality between two json objects. Returns `1` if it there is, `0` if not, or NULL if any of the arguments are null. Examples -------- ``` SELECT JSON_EQUALS('{"a" :[1, 2, 3],"b":[4]}', '{"b":[4],"a":[1, 2, 3.0]}'); +------------------------------------------------------------------------+ | JSON_EQUALS('{"a" :[1, 2, 3],"b":[4]}', '{"b":[4],"a":[1, 2, 3.0]}') | +------------------------------------------------------------------------+ | 1 | +------------------------------------------------------------------------+ SELECT JSON_EQUALS('{"a":[1, 2, 3]}', '{"a":[1, 2, 3.01]}'); +------------------------------------------------------+ | JSON_EQUALS('{"a":[1, 2, 3]}', '{"a":[1, 2, 3.01]}') | +------------------------------------------------------+ | 0 | +------------------------------------------------------+ ``` See Also -------- * [JSON\_NORMALIZE](../json_normalize/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Replication and Foreign Keys Replication and Foreign Keys ============================ The terms *master* and *slave* have historically been used in replication, but the terms terms *primary* and *replica* are now preferred. The old terms are used still used in parts of the documentation, and in MariaDB commands, although [MariaDB 10.5](../what-is-mariadb-105/index) has begun the process of renaming. The documentation process is ongoing. See [MDEV-18777](https://jira.mariadb.org/browse/MDEV-18777) to follow progress on this effort. Replication is based upon the [binary log](../binary-log/index). However, cascading deletes or updates based on foreign key relations are an internal mechanism, and are not written to the binary log. Because of this, an identical statement run on the master and the slave may result in different outcomes if the foreign key relations are not identical on both master and slave This could be the case if the storage engine on one supports cascading deletes (e.g. InnoDB) and the storage engine on the other does not (e.g. MyISAM), or the one has specified a foreign key relation, and the other hasn't. Take the following example: ``` CREATE TABLE employees ( x INT PRIMARY KEY, name VARCHAR(10) ) ENGINE = InnoDB; CREATE TABLE children ( y INT PRIMARY KEY, f INT, name VARCHAR(10), FOREIGN KEY fk (f) REFERENCES employees (x) ON DELETE CASCADE ) ENGINE = InnoDB; ``` The slave, however, has been set up without InnoDB support, and defaults to MyISAM, so the foreign key restrictions are not in place. ``` INSERT INTO employees VALUES (1, 'Yaser'), (2, 'Prune'); INSERT INTO children VALUES (1, 1, 'Haruna'), (2, 1, 'Hera'), (3, 2, 'Eva'); ``` At this point, the slave and the master are in sync: ``` SELECT * FROM employees; +---+-------+ | x | name | +---+-------+ | 1 | Yaser | | 2 | Prune | +---+-------+ 2 rows in set (0.00 sec) SELECT * FROM children; +---+------+--------+ | y | f | name | +---+------+--------+ | 1 | 1 | Haruna | | 2 | 1 | Hera | | 3 | 2 | Eva | +---+------+--------+ ``` However, after: ``` DELETE FROM employees WHERE x=1; ``` there are different outcomes on the slave and the master. On the master, the cascading deletes have taken effect: ``` SELECT * FROM children; +---+------+------+ | y | f | name | +---+------+------+ | 3 | 2 | Eva | +---+------+------+ ``` On the slave, the cascading deletes did not take effect: ``` SELECT * FROM children; +---+------+--------+ | y | f | name | +---+------+--------+ | 1 | 1 | Haruna | | 2 | 1 | Hera | | 3 | 2 | Eva | +---+------+--------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_stages_summary_by_account_by_event_name Table Performance Schema events\_stages\_summary\_by\_account\_by\_event\_name Table ============================================================================== The table lists stage events, summarized by account and event name. It contains the following columns: | Column | Description | | --- | --- | | `USER` | User. Used together with `HOST` and `EVENT_NAME` for grouping events. | | `HOST` | Host. Used together with `USER` and `EVENT_NAME` for grouping events. | | `EVENT_NAME` | Event name. Used together with `USER` and `HOST` for grouping events. | | `COUNT_STAR` | Number of summarized events, which includes all timed and untimed events. | | `SUM_TIMER_WAIT` | Total wait time of the timed summarized events. | | `MIN_TIMER_WAIT` | Minimum wait time of the timed summarized events. | | `AVG_TIMER_WAIT` | Average wait time of the timed summarized events. | | `MAX_TIMER_WAIT` | Maximum wait time of the timed summarized events. | Example ------- ``` SELECT * FROM events_stages_summary_by_account_by_event_name\G ... *************************** 325. row *************************** USER: NULL HOST: NULL EVENT_NAME: stage/sql/Waiting for event metadata lock COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 *************************** 326. row *************************** USER: NULL HOST: NULL EVENT_NAME: stage/sql/Waiting for commit lock COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 *************************** 327. row *************************** USER: NULL HOST: NULL EVENT_NAME: stage/aria/Waiting for a resource COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DBeaver DBeaver ======= [DBeaver](http://dbeaver.jkiss.org/) is a free multi-platform database tool for developers, SQL programmers, database administrators and analysts. It supports all popular relational databases: MySQL, MariaDB, PostgreSQL, SQLite, Oracle, DB2, SQL Server, Sybase, Teradata, Netezza, etc. Also, it supports NoSQL databases: MongoDB, Cassandra, Redis, Apache Hive, etc. in the Enterprise Edition version. A brief list of basic features can be found below: * Data viewer and editor: sorting, filtering, image displaying, export of selected data and much more. * Metadata browser: possibility to view and edit existing tables, views, columns, indexes, procedures, triggers, storage entities (tablespaces, partitions, etc), security entities (users, roles, etc). * Data transfer: export and import for files in various formats (CSV, HTML, XML, XLS, XLSX). * ER diagrams: possibility to automatically generate ER diagrams for a database/schema (diagram will contain all schema tables) or for a single table and export the diagram in a suitable format. * SQL editor: possibility to organize all your scripts in folders, reassign database connections for particular scripts. * Data and metadata search: full-text data search using against all chosen tables/views. * Database structure comparing: possibility to perform objects structure compare. DBeaver is actively developed and maintained. Usability is the main goal of this project, so program UI is carefully designed and implemented. Every user can send bug report and feature request on the [GitHub page](https://github.com/serge-rider/dbeaver). ![screen1](https://mariadb.com/kb/en/graphical-and-enhanced-clients-dbeaver/+image/screen1 "screen1") ![screen2](https://mariadb.com/kb/en/graphical-and-enhanced-clients-dbeaver/+image/screen2 "screen2") Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Foreign Keys Foreign Keys ============ Overview -------- A foreign key is a constraint which can be used to enforce data integrity. It is composed by a column (or a set of columns) in a table called the child table, which references to a column (or a set of columns) in a table called the parent table. If foreign keys are used, MariaDB performs some checks to enforce that some integrity rules are always enforced. For a more exhaustive explanation, see [Relational databases: Foreign Keys](../relational-databases-foreign-keys/index). Foreign keys can only be used with storage engines that support them. The default [InnoDB](../innodb/index) and the obsolete [PBXT](../pbxt/index) support foreign keys. [Partitioned tables](../managing-mariadb-partitioning/index) cannot contain foreign keys, and cannot be referenced by a foreign key. Syntax ------ **Note:** Until [MariaDB 10.4](../what-is-mariadb-104/index), MariaDB accepts the shortcut format with a REFERENCES clause only in ALTER TABLE and CREATE TABLE statements, but that syntax does nothing. For example: ``` CREATE TABLE b(for_key INT REFERENCES a(not_key)); ``` MariaDB simply parses it without returning any error or warning, for compatibility with other DBMS's. However, only the syntax described below creates foreign keys. From [MariaDB 10.5](../what-is-mariadb-105/index), MariaDB will attempt to apply the constraint. See the [Examples](#references) below. Foreign keys are created with [CREATE TABLE](../create-table/index) or [ALTER TABLE](../alter-table/index). The definition must follow this syntax: ``` [CONSTRAINT [symbol]] FOREIGN KEY [index_name] (index_col_name, ...) REFERENCES tbl_name (index_col_name,...) [ON DELETE reference_option] [ON UPDATE reference_option] reference_option: RESTRICT | CASCADE | SET NULL | NO ACTION | SET DEFAULT ``` The `symbol` clause, if specified, is used in error messages and must be unique in the database. The columns in the child table must be an index, or the leftmost part of an index. Index prefixes are not supported (thus, [TEXT](../text/index) and [BLOB](../blob/index) columns cannot be used as foreign keys). If MariaDB automatically creates an index for the foreign key (because it does not exist and is not explicitly created), its name will be `index_name`. The referenced columns in the parent table must be a an index or a prefix of an index. The foreign key columns and the referenced columns must be of the same type, or similar types. For integer types, the size and sign must also be the same. Both the foreign key columns and the referenced columns can be [PERSISTENT](../virtual-columns/index) columns. However, the ON UPDATE CASCADE, ON UPDATE SET NULL, ON DELETE SET NULL clauses are not allowed in this case. The parent and the child table must use the same storage engine, and must not be `TEMPORARY` or partitioned tables. They can be the same table. Constraints ----------- If a foreign keys exists, each row in the child table must match a row in the parent table. Multiple child rows can match the same parent row. A child row *matches* a parent row if all its foreign key values are identical to a parent row's values in the parent table. However, if at least one of the foreign key values is `NULL`, the row has no parents, but it is still allowed. MariaDB performs certain checks to guarantee that the data integrity is enforced: * Trying to insert non-matching rows (or update matching rows in a way that makes them non-matching rows) in the child table produces a 1452 error ([SQLSTATE](../sqlstate/index) '23000'). * When a row in the parent table is deleted and at least one child row exists, MariaDB performs an action which depends on the `ON DELETE` clause of the foreign key. * When a value in the column referenced by a foreign key changes and at least one child row exists, MariaDB performs an action which depends on the `ON UPDATE` clause of the foreign key. * Trying to drop a table that is referenced by a foreign key produces a 1217 error ([SQLSTATE](../sqlstate/index) '23000'). * A [TRUNCATE TABLE](../truncate-table/index) against a table containing one or more foreign keys is executed as a [DELETE](../delete/index) without WHERE, so that the foreign keys are enforced for each row. The allowed actions for `ON DELETE` and `ON UPDATE` are: * `RESTRICT`: The change on the parent table is prevented. The statement terminates with a 1451 error ([SQLSTATE](../sqlstate/index) '2300'). This is the default behavior for both `ON DELETE` and `ON UPDATE`. * `NO ACTION`: Synonym for `RESTRICT`. * `CASCADE`: The change is allowed and propagates on the child table. For example, if a parent row is deleted, the child row is also deleted; if a parent row's ID changes, the child row's ID will also change. * `SET NULL`: The change is allowed, and the child row's foreign key columns are set to `NULL`. * `SET DEFAULT`: Only worked with PBXT. Similar to `SET NULL`, but the foreign key columns were set to their default values. If default values do not exist, an error is produced. The delete or update operations triggered by foreign keys do not activate [triggers](../triggers/index) and are not counted in the [Com\_delete](../server-status-variables/index#com_delete) and [Com\_update](../server-status-variables/index#com_update) status variables. Foreign key constraints can be disabled by setting the [foreign\_key\_checks](../server-system-variables/index#foreign_key_checks) server system variable to 0. This speeds up the insertion of large quantities of data. Metadata -------- The [Information Schema](../information_schema/index) `[REFERENTIAL\_CONSTRAINTS](../information-schema-referential_constraints-table/index)` table contains information about foreign keys. The individual columns are listed in the `[KEY\_COLUMN\_USAGE](../information-schema-key_column_usage-table/index)` table. The InnoDB-specific Information Schema tables also contain information about the InnoDB foreign keys. The foreign key information is stored in the `[INNODB\_SYS\_FOREIGN](../information-schema-innodb_sys_foreign-table/index)`. Data about the individual columns are stored in `[INNODB\_SYS\_FOREIGN\_COLS](../information-schema-innodb_sys_foreign_cols-table/index)`. The most human-readable way to get information about a table's foreign keys sometimes is the `[SHOW CREATE TABLE](../show-create-table/index)` statement. Limitations ----------- Foreign keys have the following limitations in MariaDB: * Currently, foreign keys are only supported by InnoDB. * Cannot be used with views. * The `SET DEFAULT` action is not supported. * Foreign keys actions do not activate [triggers](../triggers/index). * If ON UPDATE CASCADE recurses to update the same table it has previously updated during the cascade, it acts like RESTRICT. Examples -------- Let's see an example. We will create an `author` table and a `book` table. Both tables have a primary key called `id`. `book` also has a foreign key composed by a field called `author_id`, which refers to the `author` primary key. The foreign key constraint name is optional, but we'll specify it because we want it to appear in error messages: `fk_book_author`. ``` CREATE TABLE author ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(100) NOT NULL ) ENGINE = InnoDB; CREATE TABLE book ( id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, title VARCHAR(200) NOT NULL, author_id SMALLINT UNSIGNED NOT NULL, CONSTRAINT `fk_book_author` FOREIGN KEY (author_id) REFERENCES author (id) ON DELETE CASCADE ON UPDATE RESTRICT ) ENGINE = InnoDB; ``` Now, if we try to insert a book with a non-existing author, we will get an error: ``` INSERT INTO book (title, author_id) VALUES ('Necronomicon', 1); ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`test`.`book`, CONSTRAINT `fk_book_author` FOREIGN KEY (`author_id`) REFERENCES `author` (`id`) ON DELETE CASCADE) ``` The error is very descriptive. Now, let's try to properly insert two authors and their books: ``` INSERT INTO author (name) VALUES ('Abdul Alhazred'); INSERT INTO book (title, author_id) VALUES ('Necronomicon', LAST_INSERT_ID()); INSERT INTO author (name) VALUES ('H.P. Lovecraft'); INSERT INTO book (title, author_id) VALUES ('The call of Cthulhu', LAST_INSERT_ID()), ('The colour out of space', LAST_INSERT_ID()); ``` It worked! Now, let's delete the second author. When we created the foreign key, we specified `ON DELETE CASCADE`. This should propagate the deletion, and make the deleted author's books disappear: ``` DELETE FROM author WHERE name = 'H.P. Lovecraft'; SELECT * FROM book; +----+--------------+-----------+ | id | title | author_id | +----+--------------+-----------+ | 3 | Necronomicon | 1 | +----+--------------+-----------+ ``` We also specified `ON UPDATE RESTRICT`. This should prevent us from modifying an author's `id` (the column referenced by the foreign key) if a child row exists: ``` UPDATE author SET id = 10 WHERE id = 1; ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails (`test`.`book`, CONSTRAINT `fk_book_author` FOREIGN KEY (`author_id`) REFERENCES `author` (`id`) ON DELETE CASCADE) ``` ### REFERENCES Until [MariaDB 10.4](../what-is-mariadb-104/index) ``` CREATE TABLE a(a_key INT primary key, not_key INT); CREATE TABLE b(for_key INT REFERENCES a(not_key)); SHOW CREATE TABLE b; +-------+----------------------------------------------------------------------------------+ | Table | Create Table | +-------+----------------------------------------------------------------------------------+ | b | CREATE TABLE `b` ( `for_key` int(11) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1 | +-------+----------------------------------------------------------------------------------+ INSERT INTO a VALUES (1,10); Query OK, 1 row affected (0.005 sec) INSERT INTO b VALUES (10); Query OK, 1 row affected (0.004 sec) INSERT INTO b VALUES (1); Query OK, 1 row affected (0.004 sec) SELECT * FROM b; +---------+ | for_key | +---------+ | 10 | | 1 | +---------+ ``` From [MariaDB 10.5](../what-is-mariadb-105/index) ``` CREATE TABLE a(a_key INT primary key, not_key INT); CREATE TABLE b(for_key INT REFERENCES a(not_key)); ERROR 1005 (HY000): Can't create table `test`.`b` (errno: 150 "Foreign key constraint is incorrectly formed") CREATE TABLE c(for_key INT REFERENCES a(a_key)); SHOW CREATE TABLE c; +-------+----------------------------------------------------------------------------------+ | Table | Create Table | +-------+----------------------------------------------------------------------------------+ | c | CREATE TABLE `c` ( `for_key` int(11) DEFAULT NULL, KEY `for_key` (`for_key`), CONSTRAINT `c_ibfk_1` FOREIGN KEY (`for_key`) REFERENCES `a` (`a_key`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 | +-------+----------------------------------------------------------------------------------+ INSERT INTO a VALUES (1,10); Query OK, 1 row affected (0.004 sec) INSERT INTO c VALUES (10); ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`test`.`c`, CONSTRAINT `c_ibfk_1` FOREIGN KEY (`for_key`) REFERENCES `a` (`a_key`)) INSERT INTO c VALUES (1); Query OK, 1 row affected (0.004 sec) SELECT * FROM c; +---------+ | for_key | +---------+ | 1 | +---------+ ``` See Also -------- * [MariaDB: InnoDB foreign key constraint errors](https://blog.mariadb.org/mariadb-innodb-foreign-key-constraint-errors/), a post in the MariaDB blog Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Manual SST of Galera Cluster Node With Mariabackup Manual SST of Galera Cluster Node With Mariabackup ================================================== Sometimes it can be helpful to perform a "manual SST" when Galera's [normal SSTs](../introduction-to-state-snapshot-transfers-ssts/index) fail. This can be especially useful when the cluster's `[datadir](../server-system-variables/index#datadir)` is very large, since a normal SST can take a long time to fail in that case. A manual SST essentially consists of taking a backup of the donor, loading the backup on the joiner, and then manually editing the cluster state on the joiner node. This page will show how to perform this process with [Mariabackup](../mariabackup/index). Process ------- * Check that the donor and joiner nodes have the same Mariabackup version. ``` mariabackup --version ``` * Create backup directory on donor. ``` MYSQL_BACKUP_DIR=/mysql_backup mkdir $MYSQL_BACKUP_DIR ``` * Take a [full backup](../full-backup-and-restore-with-mariabackup/index) the of the donor node with `mariabackup`. The `[--galera-info](../mariabackup-options/index#-galera-info)` option should also be provided, so that the node's cluster state is also backed up. ``` DB_USER=sstuser DB_USER_PASS=password mariabackup --backup --galera-info \ --target-dir=$MYSQL_BACKUP_DIR \ --user=$DB_USER \ --password=$DB_USER_PASS ``` * Verify that the MariaDB Server process is stopped on the joiner node. This will depend on your [service manager](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index). For example, on [systemd](../systemd/index) systems, you can execute:: ``` systemctl status mariadb ``` * Create the backup directory on the joiner node. ``` MYSQL_BACKUP_DIR=/mysql_backup mkdir $MYSQL_BACKUP_DIR ``` * Copy the backup from the donor node to the joiner node. ``` OS_USER=dba JOINER_HOST=dbserver2.mariadb.com rsync -av $MYSQL_BACKUP_DIR/* ${OS_USER}@${JOINER_HOST}:${MYSQL_BACKUP_DIR} ``` * [Prepare the backup](../full-backup-and-restore-with-mariabackup/index#preparing-the-backup) on the joiner node. ``` mariabackup --prepare \ --target-dir=$MYSQL_BACKUP_DIR ``` * Get the Galera Cluster version ID from the donor node's `grastate.dat` file. ``` MYSQL_DATADIR=/var/lib/mysql cat $MYSQL_DATADIR/grastate.dat | grep version ``` For example, a very common version number is "2.1". * Get the node's cluster state from the `[xtrabackup\_galera\_info](../mariabackup-options/index#-galera-info)` file in the backup that was copied to the joiner node. ``` cat $MYSQL_BACKUP_DIR/xtrabackup_galera_info ``` The file contains the values of the `[wsrep\_local\_state\_uuid](../galera-cluster-status-variables/index#wsrep_local_state_uuid)` and `[wsrep\_last\_committed](../galera-cluster-status-variables/index#wsrep_last_committed)` status variables. The values are written in the following format: ``` wsrep_local_state_uuid:wsrep_last_committed ``` For example: ``` d38587ce-246c-11e5-bcce-6bbd0831cc0f:1352215 ``` * Create a `grastate.dat` file in the backup directory of the joiner node. The Galera Cluster version ID, the cluster uuid, and the seqno from previous steps will be used to fill in the relevant fields. For example, with the example values from the last two steps, we could do: ``` sudo tee $MYSQL_BACKUP_DIR/grastate.dat <<EOF # GALERA saved state version: 2.1 uuid: d38587ce-246c-11e5-bcce-6bbd0831cc0f seqno: 1352215 safe_to_bootstrap: 0 EOF ``` * Remove the existing contents of the `[datadir](../server-system-variables/index#datadir)` on the joiner node. ``` MYSQL_DATADIR=/var/lib/mysql rm -Rf $MYSQL_DATADIR/* ``` * Copy the contents of the backup directory to the `[datadir](../server-system-variables/index#datadir)` the on joiner node. ``` mariabackup --copy-back \ --target-dir=$MYSQL_BACKUP_DIR ``` * Make sure the permissions of the `[datadir](../server-system-variables/index#datadir)` are correct on the joiner node. ``` chown -R mysql:mysql $MYSQL_DATADIR/ ``` * Start the MariaDB Server process on the joiner node. This will depend on your [service manager](../starting-and-stopping-mariadb-starting-and-stopping-mariadb/index). For example, on [systemd](../systemd/index) systems, you can execute:: ``` systemctl start mariadb ``` * Watch the MariaDB [error log](../error-log/index) on the joiner node and verify that the node does not need to perform a [normal SSTs](../introduction-to-state-snapshot-transfers-ssts/index) due to the manual SST. ``` tail -f /var/log/mysql/mysqld.log ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb XtraDB option --innodb-release-locks-early XtraDB option --innodb-release-locks-early ========================================== The --innodb-release-locks-early feature ([MWL#163](http://askmonty.org/worklog/?tid=163)) was included in the [5.2 replication preview](../mariadb-52-replication-feature-preview/index). However, it was omitted from [MariaDB 5.3](../what-is-mariadb-53/index) due to the bug [lp:798213](https://bugs.launchpad.net/maria/+bug/798213). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_GeomFromText ST\_GeomFromText ================ Syntax ------ ``` ST_GeomFromText(wkt[,srid]) ST_GeometryFromText(wkt[,srid]) GeomFromText(wkt[,srid]) GeometryFromText(wkt[,srid]) ``` Description ----------- Constructs a geometry value of any type using its [WKT](../wkt-definition/index) representation and [SRID](../srid/index). `GeomFromText()`, `GeometryFromText()`, `ST_GeomFromText()` and `ST_GeometryFromText()` are all synonyms. Example ------- ``` SET @g = ST_GEOMFROMTEXT('POLYGON((1 1,1 5,4 9,6 9,9 3,7 2,1 1))'); ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb SYS_GUID SYS\_GUID ========= **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**The SYS\_GUID function was introduced in [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/) to enhance Oracle compatibility. Similar functionality can be achieved with the [UUID](../uuid/index) function. Syntax ------ ``` SYS_GUID() ``` Description ----------- Returns a 16-byte globally unique identifier (GUID), similar to the [UUID](../uuid/index) function, but without the `-` character. Example ------- ``` SELECT SYS_GUID(); +----------------------------------+ | SYS_GUID() | +----------------------------------+ | 2C574E45BA2811EBB265F859713E4BE4 | +----------------------------------+ ``` See Also -------- * [UUID](../uuid/index) * [UUID\_SHORT](../uuid_short/index) * [UUID data type](../uuid-data-type/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_METRICS Table Information Schema INNODB\_METRICS Table ======================================== The [Information Schema](../information_schema/index) `INNODB_METRICS` table contains a list of useful InnoDB performance metrics. Each row in the table represents an instrumented counter that can be stopped, started and reset, and which can be grouped together by module. The `PROCESS` [privilege](../grant/index) is required to view the table. It has the following columns: | Column | Description | | --- | --- | | `NAME` | Unique counter name. | | `SUBSYSTEM` | InnoDB subsystem. See below for the matching module to use to enable/disable monitoring this subsytem with the [innodb\_monitor\_enable](../innodb-system-variables/index#innodb_monitor_enable) and [innodb\_monitor\_disable](../innodb-system-variables/index#innodb_monitor_disable) system variables. | | `COUNT` | Count since being enabled. | | `MAX_COUNT` | Maximum value since being enabled. | | `MIN_COUNT` | Minimum value since being enabled. | | `AVG_COUNT` | Average value since being enabled. | | `COUNT_RESET` | Count since last being reset. | | `MAX_COUNT_RESET` | Maximum value since last being reset. | | `MIN_COUNT_RESET` | Minimum value since last being reset. | | `AVG_COUNT_RESET` | Average value since last being reset. | | `TIME_ENABLED` | Time last enabled. | | `TIME_DISABLED` | Time last disabled | | `TIME_ELAPSED` | Time since enabled | | `TIME_RESET` | Time last reset. | | `STATUS` | Whether the counter is currently enabled to disabled. | | `TYPE` | Item type; one of `counter`, `value`, `status_counter`, `set_owner`, `set_member`. | | `COMMENT` | Counter description. | Enabling and Disabling Counters ------------------------------- Most of the counters are disabled by default. To enable them, use the [innodb\_monitor\_enable](../innodb-system-variables/index#innodb_monitor_enable) system variable. You can either enable a variable by its name, for example: ``` SET GLOBAL innodb_monitor_enable = icp_match; ``` or enable a number of counters grouped by module. The `SUBSYSTEM` field indicates which counters are grouped together, but the following module names need to be used: | Module Name | Subsytem Field | | --- | --- | | `module_metadata` | `metadata` | | `module_lock` | `lock` | | `module_buffer` | `buffer` | | `module_buf_page` | `buffer_page_io` | | `module_os` | `os` | | `module_trx` | `transaction` | | `module_purge` | `purge` | | `module_compress` | `compression` | | `module_file` | `file_system` | | `module_index` | `index` | | `module_adaptive_hash` | `adaptive_hash_index` From [MariaDB 10.6.2](https://mariadb.com/kb/en/mariadb-1062-release-notes/), if [innodb\_adaptive\_hash\_index](../innodb-system-variables/index#innodb_adaptive_hash_index) is disabled (the default), `adaptive_hash_index` will not be updated. | | `module_ibuf_system` | `change_buffer` | | `module_srv` | `server` | | `module_ddl` | `ddl` | | `module_dml` | `dml` | | `module_log` | `recovery` | | `module_icp` | `icp` | There are four counters in the `icp` subsystem: ``` SELECT NAME, SUBSYSTEM FROM INNODB_METRICS WHERE SUBSYSTEM='icp'; +------------------+-----------+ | NAME | SUBSYSTEM | +------------------+-----------+ | icp_attempts | icp | | icp_no_match | icp | | icp_out_of_range | icp | | icp_match | icp | +------------------+-----------+ ``` To enable them all, use the associated module name from the table above, `module_icp`. ``` SET GLOBAL innodb_monitor_enable = module_icp; ``` The `%` wildcard, used to represent any number of characters, can also be used when naming counters, for example: ``` SET GLOBAL innodb_monitor_enable = 'buffer%' ``` To disable counters, use the [innodb\_monitor\_disable](../innodb-system-variables/index#innodb_monitor_disable) system variable, using the same naming rules as described above for enabling. Counter status is not persistent, and will be reset when the server restarts. It is possible to use the options on the command line, or the `innodb_monitor_enable` option only in a configuration file. Resetting Counters ------------------ Counters can also be reset. Resetting sets all the `*_COUNT_RESET` values to zero, while leaving the `*_COUNT` values, which perform counts since the counter was enabled, untouched. Resetting is performed with the [innodb\_monitor\_reset](../innodb-system-variables/index#innodb_monitor_reset) (for individual counters) and [innodb\_monitor\_reset\_all](../innodb-system-variables/index#innodb_monitor_reset_all) (for all counters) system variables. Simplifying from [MariaDB 10.6](../what-is-mariadb-106/index) ------------------------------------------------------------- **MariaDB starting with [10.6](../what-is-mariadb-106/index)**From [MariaDB 10.6](../what-is-mariadb-106/index), the interface was simplified by removing the following: * buffer\_LRU\_batches\_flush * buffer\_LRU\_batch\_flush\_pages * buffer\_LRU\_batches\_evict * buffer\_LRU\_batch\_evict\_pages and by making the following reflect the status variables: * buffer\_LRU\_batch\_flush\_total\_pages: [innodb\_buffer\_pool\_pages\_LRU\_flushed](../innodb-status-variables/index#innodb_buffer_pool_pages_lru_flushed) * buffer\_LRU\_batch\_evict\_total\_pages: [innodb\_buffer\_pool\_pages\_LRU\_freed](../innodb-status-variables/index#innodb_buffer_pool_pages_lru_freed) The intention is to eventually remove the interface entirely (see [MDEV-15706](https://jira.mariadb.org/browse/MDEV-15706)). Examples -------- [MariaDB 10.8](../what-is-mariadb-108/index): ``` SELECT name,subsystem,type,comment FROM INFORMATION_SCHEMA.INNODB_METRICS\G *************************** 1. row *************************** name: metadata_table_handles_opened subsystem: metadata type: counter comment: Number of table handles opened *************************** 2. row *************************** name: lock_deadlocks subsystem: lock type: value comment: Number of deadlocks *************************** 3. row *************************** name: lock_timeouts subsystem: lock type: value comment: Number of lock timeouts *************************** 4. row *************************** name: lock_rec_lock_waits subsystem: lock type: counter comment: Number of times enqueued into record lock wait queue *************************** 5. row *************************** name: lock_table_lock_waits subsystem: lock type: counter comment: Number of times enqueued into table lock wait queue *************************** 6. row *************************** name: lock_rec_lock_requests subsystem: lock type: counter comment: Number of record locks requested *************************** 7. row *************************** name: lock_rec_lock_created subsystem: lock type: counter comment: Number of record locks created *************************** 8. row *************************** name: lock_rec_lock_removed subsystem: lock type: counter comment: Number of record locks removed from the lock queue *************************** 9. row *************************** name: lock_rec_locks subsystem: lock type: counter comment: Current number of record locks on tables *************************** 10. row *************************** name: lock_table_lock_created subsystem: lock type: counter comment: Number of table locks created ... *************************** 207. row *************************** name: icp_attempts subsystem: icp type: counter comment: Number of attempts for index push-down condition checks *************************** 208. row *************************** name: icp_no_match subsystem: icp type: counter comment: Index push-down condition does not match *************************** 209. row *************************** name: icp_out_of_range subsystem: icp type: counter comment: Index push-down condition out of range *************************** 210. row *************************** name: icp_match subsystem: icp type: counter comment: Index push-down condition matches ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Table Elimination in MariaDB Table Elimination in MariaDB ============================ The first thing the MariaDB optimizer does is to merge the `VIEW` definition into the query to obtain: ``` select ACRAT_rating from ac_anchor left join ac_name on ac_anchor.AC_ID=ac_name.AC_ID left join ac_dob on ac_anchor.AC_ID=ac_dob.AC_ID left join ac_rating on (ac_anchor.AC_ID=ac_rating.AC_ID and ac_rating.ACRAT_fromdate = (select max(sub.ACRAT_fromdate) from ac_rating sub where sub.AC_ID = ac_rating.AC_ID)) where ACNAM_name='Gary Oldman' ``` It's important to realize that the obtained query has a useless part: * `left join ac_dob on ac_dob.AC_ID=...` will produce exactly one matching record: + `primary key(ac_dob.AC_ID)` guarantees that there will be at most one match for any value of `ac_anchor.AC_ID`, + and if there won't be a match, `LEFT JOIN` will generate a NULL-complemented “row” * and we don't care what the matching record is, as table `ac_dob` is not used anywhere else in the query. This means that the `left join ac_dob on ...` part can be removed from the query and this is what Table Elimination module does. The detection logic is rather smart, for example it would be able to remove the `left join ac_rating on ...` part as well, together with the subquery (in the above example it won't be removed because ac\_rating used in the selection list of the query). The Table Elimination module can also handle nested outer joins and multi-table outer joins. See Also -------- * This page is based on the following blog post about table elimination: <http://s.petrunia.net/blog/?p=58> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb IS_IPV4_MAPPED IS\_IPV4\_MAPPED ================ Syntax ------ ``` IS_IPV4_MAPPED(expr) ``` Description ----------- Returns 1 if a given a numeric binary string IPv6 address, such as returned by [INET6\_ATON()](../inet6_aton/index), is a valid IPv4-mapped address, otherwise returns 0. **MariaDB starting with [10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)**From [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/), when the argument is not [INET6](../inet6/index), automatic implicit [CAST](../cast/index) to INET6 is applied. As a consequence, `IS_IPV4_MAPPED` now understands arguments in both text representation and binary(16) representation. Before [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/), the function understood only binary(16) representation. Examples -------- ``` SELECT IS_IPV4_MAPPED(INET6_ATON('::10.0.1.1')); +------------------------------------------+ | IS_IPV4_MAPPED(INET6_ATON('::10.0.1.1')) | +------------------------------------------+ | 0 | +------------------------------------------+ SELECT IS_IPV4_MAPPED(INET6_ATON('::ffff:10.0.1.1')); +-----------------------------------------------+ | IS_IPV4_MAPPED(INET6_ATON('::ffff:10.0.1.1')) | +-----------------------------------------------+ | 1 | +-----------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb phpMyAdmin phpMyAdmin ========== phpMyAdmin is a web-based tool for administering MariaDB and MySQL. It requires a web server, PHP, and a browser. Read more at <http://phpmyadmin.net> Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb REGEXP_REPLACE REGEXP\_REPLACE =============== Syntax ------ ``` REGEXP_REPLACE(subject, pattern, replace) ``` Description ----------- `REGEXP_REPLACE` returns the string `subject` with all occurrences of the regular expression `pattern` replaced by the string `replace`. If no occurrences are found, then `subject` is returned as is. The replace string can have backreferences to the subexpressions in the form \N, where N is a number from 1 to 9. The function follows the case sensitivity rules of the effective [collation](../data-types-character-sets-and-collations/index). Matching is performed case insensitively for case insensitive collations, and case sensitively for case sensitive collations and for binary data. The collation case sensitivity can be overwritten using the (?i) and (?-i) PCRE flags. MariaDB uses the [PCRE regular expression](../pcre-regular-expressions/index) library for enhanced regular expression performance, and `REGEXP_REPLACE` was introduced as part of this enhancement. The [default\_regex\_flags](../server-system-variables/index#default_regex_flags) variable addresses the remaining compatibilities between PCRE and the old regex library. Examples -------- ``` SELECT REGEXP_REPLACE('ab12cd','[0-9]','') AS remove_digits; -> abcd SELECT REGEXP_REPLACE('<html><head><title>title</title><body>body</body></htm>', '<.+?>',' ') AS strip_html; -> title body ``` Backreferences to the subexpressions in the form `\N`, where N is a number from 1 to 9: ``` SELECT REGEXP_REPLACE('James Bond','^(.*) (.*)$','\\2, \\1') AS reorder_name; -> Bond, James ``` Case insensitive and case sensitive matches: ``` SELECT REGEXP_REPLACE('ABC','b','-') AS case_insensitive; -> A-C SELECT REGEXP_REPLACE('ABC' COLLATE utf8_bin,'b','-') AS case_sensitive; -> ABC SELECT REGEXP_REPLACE(BINARY 'ABC','b','-') AS binary_data; -> ABC ``` Overwriting the collation case sensitivity using the (?i) and (?-i) PCRE flags. ``` SELECT REGEXP_REPLACE('ABC','(?-i)b','-') AS force_case_sensitive; -> ABC SELECT REGEXP_REPLACE(BINARY 'ABC','(?i)b','-') AS force_case_insensitive; -> A-C ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysqld_multi mysqld\_multi ============= **MariaDB starting with [10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/)**From [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), `mariadbd-multi` is a symlink to `mysqld_multi`. **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), `mariadbd-multi` is the name of the server, with `mysqld_multi` a symlink . Before using mysqld\_multi be sure that you understand the meanings of the options that are passed to the mysqld servers and why you would want to have separate mysqld processes. Beware of the dangers of using multiple mysqld servers with the same data directory. Use separate data directories, unless you know what you are doing. Starting multiple servers with the same data directory does not give you extra performance in a threaded system. The `mysqld_multi` startup script is in MariaDB distributions on Linux and Unix. It is a wrapper that is designed to manage several `mysqld` processes running on the same host. In order for multiple `mysqld` processes to work on the same host, these processes must: * Use different Unix socket files for local connections. * Use different TCP/IP ports for network connections. * Use different data directories. * Use different process ID files (specified by the `--pid-file` option) if using `[mysqld\_safe](../mysqld_safe/index)` to start `mysqld`. `mysqld_multi` can start or stop servers, or report their current status. Using mysqld\_multi ------------------- The command to use `mysqld_multi` and the general syntax is: ``` mysqld_multi [options] {start|stop|report} [GNR[,GNR] ...] ``` `start`, `stop`, and `report` indicate which operation to perform. You can specify which servers to perform the operation on by providing one or more `GNR` values. `GNR` refers to an option group number, and it is explained more in the [option groups](#option-groups) section below. If there is no `GNR` list, then `mysqld_multi` performs the operation for all `GNR` values found in its option files. Multiple `GNR` values can be specified as a comma-separated list. `GNR` values can also be specified as a range by separating the numbers by a dash. There must not be any whitespace characters in the `GNR` list. For example: This command starts a single server using option group `[mysqld17]`: ``` mysqld_multi start 17 ``` This command stops several servers, using option groups `[mysqld8]` and `[mysqld10]` through `[mysqld13]`: ``` mysqld_multi stop 8,10-13 ``` ### Options `mysqld_multi` supports the following options: | Option | Description | | --- | --- | | `--example` | Give an example of a config file with extra information. | | `--help` | Display help and exit. | | `--log=filename` | Specify the path and name of the log file. If the file exists, log output is appended to it. | | `--mysqladmin=prog_name` | The [mysqladmin](../mysqladmin/index) binary to be used to stop servers. Can be given within groups `[mysqld#]`. | | `--mysqld=prog_name` | The mysqld binary to be used. Note that you can also specify [mysqld\_safe](../mysqld_safe/index) as the value for this option. If you use mysqld\_safe to start the server, you can include the `mysqld` or `ledir` options in the corresponding `[mysqldN]` option group. These options indicate the name of the server that mysqld\_safe should start and the path name of the directory where the server is located. Example:`[mysqld38]``mysqld = mysqld-debug``ledir = /opt/local/mysql/libexec`. | | `--no-log` | Print to stdout instead of the log file. By default the log file is turned on. | | `--password=password` | The password of the MariaDB account to use when invoking [mysqladmin](../mysqladmin/index). Note that the password value is not optional for this option, unlike for other MariaDB programs. | | `--silent` | Silent mode; disable warnings. | | `--tcp-ip` | Connect to the MariaDB server(s) via the TCP/IP port instead of the UNIX socket. This affects stopping and reporting. If a socket file is missing, the server may still be running, but can be accessed only via the TCP/IP port. By default connecting is done via the UNIX socket. This option affects stop and report operations. | | `--user=username` | The user name of the MariaDB account to use when invoking [mysqladmin](../mysqladmin/index). | | `--verbose` | Be more verbose. | | `--version` | Display version information and exit. | | `--wsrep-new-cluster` | Bootstrap a cluster. Added in [MariaDB 10.1.15](https://mariadb.com/kb/en/mariadb-10115-release-notes/). | ### Option Files In addition to reading options from the command-line, `mysqld_multi` can also read options from [option files](../configuring-mariadb-with-option-files/index). If an unknown option is provided to `mysqld_multi` in an option file, then it is ignored. The following options relate to how MariaDB command-line tools handles option files. They must be given as the first argument on the command-line: | Option | Description | | --- | --- | | `--print-defaults` | Print the program argument list and exit. | | `--no-defaults` | Don't read default options from any option file. | | `--defaults-file=#` | Only read default options from the given file #. | | `--defaults-extra-file=#` | Read this file after the global files are read. | | `--defaults-group-suffix=#` | In addition to the default option groups, also read option groups with this suffix. | #### Option Groups `mysqld_safe` reads options from the following [option groups](../configuring-mariadb-with-option-files/index#option-groups) from [option files](../configuring-mariadb-with-option-files/index): | Group | Description | | --- | --- | | `[mysqld_multi]` | Options read by `mysqld_multi`, which includes both MariaDB Server and MySQL Server. | `mysqld_multi` also searches [option files](../configuring-mariadb-with-option-files/index) for [option groups](../configuring-mariadb-with-option-files/index#option-groups) with names like `[mysqldN]`, where `N` can be any positive integer. This number is referred to in the following discussion as the option group number, or `GNR`: | Group | Description | | --- | --- | | `[mysqldN]` | Options read by a `mysqld` instance managed by `mysqld_multi`, which includes both MariaDB Server and MySQL Server. The `N` refers to the instance's `GNR`. | `GNR` values distinguish option groups from one another and are used as arguments to `mysqld_multi` to specify which servers you want to start, stop, or obtain a status report for. The `GNR` value should be the number at the end of the option group name in the option file. For example, the `GNR` for an option group named `[mysqld17]` is `17`. Options listed in these option groups are the same that you would use in the regular server option groups used for configuring `mysqld`. However, when using multiple servers, it is necessary that each one use its own value for options such as the Unix socket file and TCP/IP port number. The `[mysqld_multi]` option group can be used for options that are needed for `mysqld_multi` itself. `[mysqldN]` option groups can be used for options passed to specific `mysqld` instances. The regular server [option groups](../configuring-mariadb-with-option-files/index#option-groups) can also be used for common options that are read by all instances: | Group | Description | | --- | --- | | `[mysqld]` | Options read by `mysqld`, which includes both MariaDB Server and MySQL Server. | | `[server]` | Options read by MariaDB Server. | | `[mysqld-X.Y]` | Options read by a specific version of `mysqld`, which includes both MariaDB Server and MySQL Server. For example, `[mysqld-5.5]`. | | `[mariadb]` | Options read by MariaDB Server. | | `[mariadb-X.Y]` | Options read by a specific version of MariaDB Server. | | `[client-server]` | Options read by all MariaDB [client programs](../clients-utilities/index) and the MariaDB Server. This is useful for options like socket and port, which is common between the server and the clients. | | `[galera]` | Options read by a galera-capable MariaDB Server. Available on systems compiled with Galera support. | For an example of how you might set up an option file, use this command: ``` mysqld_multi --example ``` ### Authentication and Privileges Make sure that the MariaDB account used for stopping the `mysqld` processes (with the `[mysqladmin](../mysqladmin/index)` utility) has the same user name and password for each server. Also, make sure that the account has the `SHUTDOWN` privilege. If the servers that you want to manage have different user names or passwords for the administrative accounts, you might want to create an account on each server that has the same user name and password. For example, you might set up a common `multi_admin` account by executing the following commands for each server: ``` shell> mysql -u root -S /tmp/mysql.sock -p Enter password: mysql> GRANT SHUTDOWN ON *.* -> TO ´multi_admin´@´localhost´ IDENTIFIED BY ´multipass´; ``` Change the connection parameters appropriately when connecting to each one. Note that the host name part of the account name must allow you to connect as `multi_admin` from the host where you want to run `mysqld_multi`. User Account ------------ Make sure that the data directory for each server is fully accessible to the Unix account that the specific `mysqld` process is started as. If you run the `mysqld_multi` script as the Unix `root` account, and if you want the `mysqld` process to be started with another Unix account, then you can use use the `--user` option with `mysqld`. If you specify the `--user` option in an option file, and if you did not run the `mysqld_multi` script as the Unix `root` account, then it will just log a warning and the `mysqld` processes are started under the original Unix account. Do not run the `mysqld` process as the Unix `root` account, unless you know what you are doing. Example ------- The following example shows how you might set up an option file for use with mysqld\_multi. The order in which the mysqld programs are started or stopped depends on the order in which they appear in the option file. Group numbers need not form an unbroken sequence. The first and fifth [mysqldN] groups were intentionally omitted from the example to illustrate that you can have “gaps” in the option file. This gives you more flexibility. ``` # This file should probably be in your home dir (~/.my.cnf) # or /etc/my.cnf # Version 2.1 by Jani Tolonen [mysqld_multi] mysqld = /usr/local/bin/mysqld_safe mysqladmin = /usr/local/bin/mysqladmin user = multi_admin password = multipass [mysqld2] socket = /tmp/mysql.sock2 port = 3307 pid-file = /usr/local/mysql/var2/hostname.pid2 datadir = /usr/local/mysql/var2 language = /usr/local/share/mysql/english user = john [mysqld3] socket = /tmp/mysql.sock3 port = 3308 pid-file = /usr/local/mysql/var3/hostname.pid3 datadir = /usr/local/mysql/var3 language = /usr/local/share/mysql/swedish user = monty [mysqld4] socket = /tmp/mysql.sock4 port = 3309 pid-file = /usr/local/mysql/var4/hostname.pid4 datadir = /usr/local/mysql/var4 language = /usr/local/share/mysql/estonia user = tonu [mysqld6] socket = /tmp/mysql.sock6 port = 3311 pid-file = /usr/local/mysql/var6/hostname.pid6 datadir = /usr/local/mysql/var6 language = /usr/local/share/mysql/japanese user = jani ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb EXCEPT EXCEPT ====== **MariaDB starting with [10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/)**EXCEPT was introduced in [MariaDB 10.3.0](https://mariadb.com/kb/en/mariadb-1030-release-notes/). The result of `EXCEPT` is all records of the left `SELECT` result set except records which are in right `SELECT` result set, i.e. it is subtraction of two result sets. From [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/), `MINUS` is a synonym. Syntax ====== ``` SELECT ... (INTERSECT [ALL | DISTINCT] | EXCEPT [ALL | DISTINCT] | UNION [ALL | DISTINCT]) SELECT ... [(INTERSECT [ALL | DISTINCT] | EXCEPT [ALL | DISTINCT] | UNION [ALL | DISTINCT]) SELECT ...] [ORDER BY [column [, column ...]]] [LIMIT {[offset,] row_count | row_count OFFSET offset}] ``` Please note: * Brackets for explicit operation precedence are not supported; use a subquery in the `FROM` clause as a workaround). Description ----------- MariaDB has supported `EXCEPT` and [INTERSECT](../intersect/index) in addition to [UNION](../union/index) since [MariaDB 10.3](../what-is-mariadb-103/index). All behavior for naming columns, `ORDER BY` and `LIMIT` is the same as for [`UNION`](../union/index). `EXCEPT` implicitly supposes a `DISTINCT` operation. The result of `EXCEPT` is all records of the left `SELECT` result except records which are in right `SELECT` result set, i.e. it is subtraction of two result sets. `EXCEPT` and `UNION` have the same operation precedence and `INTERSECT` has a higher precedence, unless [running in Oracle mode](../sql_modeoracle/index), in which case all three have the same precedence. **MariaDB starting with [10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/)**### Parentheses From [MariaDB 10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/), parentheses can be used to specify precedence. Before this, a syntax error would be returned. **MariaDB starting with [10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/)**### ALL/DISTINCT `EXCEPT ALL` and `EXCEPT DISTINCT` were introduced in [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/). The `ALL` operator leaves duplicates intact, while the `DISTINCT` operator removes duplicates. `DISTINCT` is the default behavior if neither operator is supplied, and the only behavior prior to [MariaDB 10.5](../what-is-mariadb-105/index). Examples -------- Show customers which are not employees: ``` (SELECT e_name AS name, email FROM customers) EXCEPT (SELECT c_name AS name, email FROM employees); ``` Difference between [UNION](../union/index), EXCEPT and [INTERSECT](../intersect/index). `INTERSECT ALL` and `EXCEPT ALL` are available from [MariaDB 10.5.0](https://mariadb.com/kb/en/mariadb-1050-release-notes/). ``` CREATE TABLE seqs (i INT); INSERT INTO seqs VALUES (1),(2),(2),(3),(3),(4),(5),(6); SELECT i FROM seqs WHERE i <= 3 UNION SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | | 3 | | 4 | | 5 | | 6 | +------+ SELECT i FROM seqs WHERE i <= 3 UNION ALL SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | | 2 | | 3 | | 3 | | 3 | | 3 | | 4 | | 5 | | 6 | +------+ SELECT i FROM seqs WHERE i <= 3 EXCEPT SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | +------+ SELECT i FROM seqs WHERE i <= 3 EXCEPT ALL SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 1 | | 2 | | 2 | +------+ SELECT i FROM seqs WHERE i <= 3 INTERSECT SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 3 | +------+ SELECT i FROM seqs WHERE i <= 3 INTERSECT ALL SELECT i FROM seqs WHERE i>=3; +------+ | i | +------+ | 3 | | 3 | +------+ ``` Parentheses for specifying precedence, from [MariaDB 10.4.0](https://mariadb.com/kb/en/mariadb-1040-release-notes/) ``` CREATE OR REPLACE TABLE t1 (a INT); CREATE OR REPLACE TABLE t2 (b INT); CREATE OR REPLACE TABLE t3 (c INT); INSERT INTO t1 VALUES (1),(2),(3),(4); INSERT INTO t2 VALUES (5),(6); INSERT INTO t3 VALUES (1),(6); ((SELECT a FROM t1) UNION (SELECT b FROM t2)) EXCEPT (SELECT c FROM t3); +------+ | a | +------+ | 2 | | 3 | | 4 | | 5 | +------+ (SELECT a FROM t1) UNION ((SELECT b FROM t2) EXCEPT (SELECT c FROM t3)); +------+ | a | +------+ | 1 | | 2 | | 3 | | 4 | | 5 | +------+ ``` See Also -------- * [UNION](../union/index) * [INTERSECT](../intersect/index) * [Get Set for Set Theory: UNION, INTERSECT and EXCEPT in SQL](https://www.youtube.com/watch?v=UNi-fVSpRm0) (video tutorial) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Recommended Settings for Benchmarks Recommended Settings for Benchmarks =================================== Running benchmarks requires a lot of different settings. In this article we collect our best known settings and recommendations. Hardware and BIOS Settings -------------------------- We have had good experiences with Intel's hyperthreading on newer Xeon CPUs. Please turn on hyperthreading in your BIOS. NUMA ---- The NUMA architecture attaches resources (most important: memory) to individual NUMA nodes (typically: NUMA node = cpu socket). This results in a performance penalty when a cpu core from one NUMA node accesses memory from another NUMA node. The NUMA topology can be checked with the *numactl* command: ``` ~ $numactl --hardware available: 2 nodes (0-1) node 0 cpus: 0 1 2 3 4 5 12 13 14 15 16 17 node 0 size: 12278 MB node 0 free: 11624 MB node 1 cpus: 6 7 8 9 10 11 18 19 20 21 22 23 node 1 size: 12288 MB node 1 free: 11778 MB node distances: node 0 1 0: 10 21 1: 21 10 ``` The Linux kernel uses ACPI tables from BIOS to detect if the hardware is NUMA. On NUMA hardware extra optimizations kick in: * if a task has been scheduled on a certain NUMA node, the scheduler tries to put it on the same node again in the future * if a task running on a certain NUMA node allocates memory, the kernel tries hard to map physical memory from the same NUMA node This results in all kinds of weird behavior when you run one big process (mysqld) that consumes most of the memory. In such cases it is recommended to either turn off NUMA (BIOS or kernel command line) or prefix such problem processes with *numactl --interleave all*. You can enable this by running [mysqld\_safe](../mysqld_safe/index) with the `--numa-interleave` option. [More details can be found here](http://blog.jcole.us/2010/09/28/mysql-swap-insanity-and-the-numa-architecture/). Linux Kernel Settings --------------------- See [configuring Linux for MariaDB](../configuring-linux-for-mariadb/index). InnoDB Settings --------------- [innodb\_buffer\_pool\_size](../server-system-variables/index#innodb_buffer_pool_size) to about 80% of RAM or leaving <5G RAM free (on large RAM systems). Less if lots of connections are used. [innodb\_log\_file\_size](../server-system-variables/index#innodb_log_file_size) to be larger than the amount of writes in the test run or sufficient to cover several minutes of the test run at least. MyISAM Settings --------------- General Settings ---------------- [threads\_cache\_size](../server-system-variables/index#threads_cache_size) should be the same as [max\_connections](../server-system-variables/index#max_connections) (unless using thread pools). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Relational Databases: Views Relational Databases: Views =========================== Views are virtual tables. They are only a structure, and contain no data. Their purpose is to allow a user to see a subset of the actual data. A view can consist of a subset of one table. For example, the *student view*, below, is a subset of the *student table*. | Student View | | --- | | First name | | Surname | | Grade | | Student Table | | --- | | Student\_id | | First name | | Surname | | Grade | | Address | | Telephone | This view could be used to allow other students to see their fellow student's marks but not allow them access to personal information. Alternatively, a view could be a combination of a number of tables, such as the view below: | Student View | | --- | | First name | | Surname | | Grade | | Student Table | | --- | | Student\_id | | First name | | Surname | | Address | | Telephone | | Course Table | | --- | | Course\_id | | Course description | | Grade Table | | --- | | Student\_id | | Course\_id | | Grade | Views are also useful for security. In larger organizations, where many developers may be working on a project, views allow developers to access only the data they need. What they don't need, even if it is in the same table, is hidden from them, safe from being seen or manipulated. It also allows queries to be simplified for developers. For example, without the view, a developer would have to retrieve the fields in the view with the following sort of query ``` SELECT first_name, surname, course_description, grade FROM student, grade, course WHERE grade.student_id = student.student_id AND grade.course_id = course.course_id ``` With the view, a developer could do the same with the following: ``` SELECT first_name, surname, course_description, grade FROM student_grade_view ``` Much simpler for a junior developer who hasn't yet learned to do joins, and it's just less hassle for a senior developer too! For more use cases, see the [Views Tutorial](../views-tutorial/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.general_log Table mysql.general\_log Table ======================== The `mysql.general_log` table stores the contents of the [General Query Log](../general-query-log/index) if general logging is active and the output is being written to table (see [Writing logs into tables](../writing-logs-into-tables/index)). It contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | `event_time` | `timestamp(6)` | NO | | `CURRENT_TIMESTAMP(6)` | Time the query was executed. | | `user_host` | `mediumtext` | NO | | `NULL` | User and host combination. | | `thread_id` | `int(11)` | NO | | `NULL` | Thread id. | | `server_id` | `int(10) unsigned` | NO | | `NULL` | Server id. | | `command_type` | `varchar(64)` | NO | | `NULL` | Type of command. | | `argument` | `mediumtext` | NO | | `NULL` | Full query. | Example ------- ``` SELECT * FROM mysql.general_log\G *************************** 1. row *************************** event_time: 2014-11-11 08:40:04.117177 user_host: root[root] @ localhost [] thread_id: 74 server_id: 1 command_type: Query argument: SELECT * FROM test.s *************************** 2. row *************************** event_time: 2014-11-11 08:40:10.501131 user_host: root[root] @ localhost [] thread_id: 74 server_id: 1 command_type: Query argument: SELECT * FROM mysql.general_log ... ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb TO_CHAR TO\_CHAR ======== **MariaDB starting with [10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/)**The TO\_CHAR function was introduced in [MariaDB 10.6.1](https://mariadb.com/kb/en/mariadb-1061-release-notes/) to enhance Oracle compatibility. Syntax ------ ``` TO_CHAR(expr[, fmt]) ``` Description ----------- The `TO_CHAR` function converts an *expr* of type [date](../date/index), [datetime](../datetime/index), [time](../time/index) or [timestamp](../timestamp/index) to a string. The optional *fmt* argument supports YYYY/YYY/YY/RRRR/RR/MM/MON/MONTH/MI/DD/DY/HH/HH12/HH24/SS and special characters. The default value is "YYYY-MM-DD HH24:MI:SS". In Oracle, TO\_CHAR can also be used to convert numbers to strings, but this is not supported in MariaDB and will give an error. Examples -------- ``` SELECT TO_CHAR('1980-01-11 04:50:39', 'YYYY-MM-DD'); +----------------------------------------------+ | TO_CHAR('1980-01-11 04:50:39', 'YYYY-MM-DD') | +----------------------------------------------+ | 1980-01-11 | +----------------------------------------------+ SELECT TO_CHAR('1980-01-11 04:50:39', 'HH24-MI-SS'); +----------------------------------------------+ | TO_CHAR('1980-01-11 04:50:39', 'HH24-MI-SS') | +----------------------------------------------+ | 04-50-39 | +----------------------------------------------+ SELECT TO_CHAR('00-01-01 00:00:00', 'YY-MM-DD HH24:MI:SS'); +-----------------------------------------------------+ | TO_CHAR('00-01-01 00:00:00', 'YY-MM-DD HH24:MI:SS') | +-----------------------------------------------------+ | 00-01-01 00:00:00 | +-----------------------------------------------------+ SELECT TO_CHAR('99-12-31 23:59:59', 'YY-MM-DD HH24:MI:SS'); +-----------------------------------------------------+ | TO_CHAR('99-12-31 23:59:59', 'YY-MM-DD HH24:MI:SS') | +-----------------------------------------------------+ | 99-12-31 23:59:59 | +-----------------------------------------------------+ SELECT TO_CHAR('9999-12-31 23:59:59', 'YY-MM-DD HH24:MI:SS'); +-------------------------------------------------------+ | TO_CHAR('9999-12-31 23:59:59', 'YY-MM-DD HH24:MI:SS') | +-------------------------------------------------------+ | 99-12-31 23:59:59 | +-------------------------------------------------------+ SELECT TO_CHAR('21-01-03 08:30:00', 'Y-MONTH-DY HH:MI:SS'); +-----------------------------------------------------+ | TO_CHAR('21-01-03 08:30:00', 'Y-MONTH-DY HH:MI:SS') | +-----------------------------------------------------+ | 1-January -Sun 08:30:00 | +-----------------------------------------------------+ ``` See Also -------- * [SQL\_MODE=ORACLE](../sql_modeoracle/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Roles Overview Roles Overview ============== Description ----------- A role bundles a number of privileges together. It assists larger organizations where, typically, a number of users would have the same privileges, and, previously, the only way to change the privileges for a group of users was by changing each user's privileges individually. Alternatively, multiple external users could have been assigned the same user, and there would have been no way to see which actual user was responsible for which action. With roles, managing this is easy. For example, there could be a number of users assigned to a journalist role, with identical privileges. Changing the privileges for all the journalists is a matter of simply changing the role's privileges, while the individual user is still linked with any changes that take place. Roles are created with the [CREATE ROLE](../create-role/index) statement, and dropped with the [DROP ROLE](../drop-role/index) statement. Roles are then assigned to a user with an extension to the [GRANT](../grant/index#roles) statement, while privileges are assigned to a role in the regular way with [GRANT](../grant/index). Similarly, the [REVOKE](../revoke/index) statement can be used to both revoke a role from a user, or revoke a privilege from a role. Once a user has connected, he can obtain all privileges associated with a role by **setting** a role with the [SET ROLE](../set-role/index) statement. The [CURRENT\_ROLE](../current_role/index) function returns the currently set role for the session, if any. Only roles granted directly to a user can be set, roles granted to other roles cannot. Instead the privileges granted to a role, which is, in turn, granted to another role (grantee), will be immediately available to any user who sets this second grantee role. The [SET DEFAULT ROLE](../set-default-role/index) statement allows one to set a default role for a user. A default role is automatically enabled when a user connects (an implicit SET ROLE statement is executed immediately after a connection is established). Roles were implemented as a GSoC 2013 project by Vicentiu Ciorbaru. System Tables ------------- Information about roles and who they've been granted to can be found in the [Information Schema APPLICABLE\_ROLES table](../information-schema-applicable_roles-table/index) as well as the [mysql.ROLES\_MAPPING table](../mysqlroles_mapping-table/index). The [Information Schema ENABLED\_ROLES table](../information-schema-enabled_roles-table/index) shows the enabled roles for the current session. Examples -------- Creating a role and granting a privilege: ``` CREATE ROLE journalist; GRANT SHOW DATABASES ON *.* TO journalist; GRANT journalist to hulda; ``` Note, that hulda has no `SHOW DATABASES` privilege, even though she was granted the journalist role. She needs to **set** the role first: ``` SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | +--------------------+ SELECT CURRENT_ROLE; +--------------+ | CURRENT_ROLE | +--------------+ | NULL | +--------------+ SET ROLE journalist; SELECT CURRENT_ROLE; +--------------+ | CURRENT_ROLE | +--------------+ | journalist | +--------------+ SHOW DATABASES; +--------------------+ | Database | +--------------------+ | ... | | information_schema | | mysql | | performance_schema | | test | | ... | +--------------------+ SET ROLE NONE; ``` Roles can be granted to roles: ``` CREATE ROLE writer; GRANT SELECT ON data.* TO writer; GRANT writer TO journalist; ``` But one does not need to set a role granted to a role. For example, hulda will automatically get all writer privileges when she sets the journalist role: ``` SELECT CURRENT_ROLE; +--------------+ | CURRENT_ROLE | +--------------+ | NULL | +--------------+ SHOW TABLES FROM data; Empty set (0.01 sec) SET ROLE journalist; SELECT CURRENT_ROLE; +--------------+ | CURRENT_ROLE | +--------------+ | journalist | +--------------+ SHOW TABLES FROM data; +------------------------------+ | Tables_in_data | +------------------------------+ | set1 | | ... | +------------------------------+ ``` Roles and Views (and Stored Routines) ------------------------------------- When a user sets a role, he, in a sense, has two identities with two associated sets of privileges. But a view (or a stored routine) can have only one definer. So, when a view (or a stored routine) is created with the `SQL SECURITY DEFINER`, one can specify whether the definer should be `CURRENT_USER` (and the view will have none of the privileges of the user's role) or `CURRENT_ROLE` (in this case, the view will use role's privileges, but none of the user's privileges). As a result, sometimes one can create a view that is impossible to use. ``` CREATE ROLE r1; GRANT ALL ON db1.* TO r1; GRANT r1 TO foo@localhost; GRANT ALL ON db.* TO foo@localhost; SELECT CURRENT_USER +---------------+ | current_user | +---------------+ | foo@localhost | +---------------+ SET ROLE r1; CREATE TABLE db1.t1 (i int); CREATE VIEW db.v1 AS SELECT * FROM db1.t1; SHOW CREATE VIEW db.v1; +------+------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+ | View | Create View | character_set_client | collation_connection | +------+------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+ | v1 | CREATE ALGORITHM=UNDEFINED DEFINER=`foo`@`localhost` SQL SECURITY DEFINER VIEW `db`.`v1` AS SELECT `db1`.`t1`.`i` AS `i` from `db1`.`t1` | utf8 | utf8_general_ci | +------+------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+ CREATE DEFINER=CURRENT_ROLE VIEW db.v2 AS SELECT * FROM db1.t1; SHOW CREATE VIEW db.b2; +------+-----------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+ | View | Create View | character_set_client | collation_connection | +------+-----------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+ | v2 | CREATE ALGORITHM=UNDEFINED DEFINER=`r1` SQL SECURITY DEFINER VIEW `db`.`v2` AS select `db1`.`t1`.`a` AS `a` from `db1`.`t1` | utf8 | utf8_general_ci | +------+-----------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+ ``` Other Resources --------------- * [Roles Review](http://ocelot.ca/blog/blog/2014/01/12/roles-review/) by Peter Gulutzan Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb DBT3 Automation Scripts DBT3 Automation Scripts ======================= DBT-3 (OSDL Database Test 3) is a workload tool for the Linux kernel that OSDL (Open Source Development Labs, inc) developed based on TPC-H which is provided by the Transaction Performance Processing Council (TPC). DBT-3, like TPC-H, simulates an actual decision-making support system and models complex business analysis applications that perform data processing jobs for making better business decisions. By running the workload that DBT-3 simulates, it is possible to verify and measure the performances of the Linux kernel in an actual decision-making support system. DBT-3 uses the "scale factor (SF)" as a stress indicator of the system. By varying the SF, it becomes possible to make the size of a database the SF times its size. The tests performed by DBT-3 comprise the three tests listed below. DBT-3 obtains the execution times of these three tests as well as the system status information and database statistics information. 1. **Load test** * Enters the data to be used for the Power and Throughput tests into the database. Makes a bulk insert of the huge CSV data corresponding to the scale factor into the database. 2. **Power test** * Performs 22 complex queries. 3. **Throughput test** * Performs the same 22 queries as in the Power test simultaneously in more than one process. For the purpose of this task, only the Power test is performed over preliminary prepared database with various Scale factors. The time for each query execution will be measured and stored into a database. Later the results of one whole test with all 22 queries will be rendered into a histogram graphics comparing it to different configurations. Benchmark environment preparation --------------------------------- ### sudo rights The user that will run the benchmark must have sudo rights on the machine. For clearing the system caches between query runs, the automation script uses the following command: ``` sudo /sbin/sysctl vm.drop_caches=3 ``` This command must be run with superuser rights. Even if a user supplies a password to sudo, this password expires after some timeout. In order for this command to be run without requiring password, the following line should be added to the sudoers file (edit it with the `"sudo visudo"` command): ``` 'your_username' ALL=NOPASSWD:/sbin/sysctl ``` ...where `'your_username'` is the user that will run the benchmark. ### Required software The automated DBT3 benchmark requires the following software: * **[Perl](http://www.perl.org/)** + **Project home:** <http://www.perl.org/> * **[mariadb-tools](https://launchpad.net/mariadb-tools)** + **Project home:** <https://launchpad.net/mariadb-tools> + The project folder is called "`dbt3_benchmark`" and is under `mariadb-tools`. * **[dbt3-1.9](http://sourceforge.net/projects/osdldbt/files/dbt3/)** + **Download location:** <http://sourceforge.net/projects/osdldbt/files/dbt3/> * **[Gnuplot 4.4](http://www.gnuplot.info/)** — graphics output program. + **Project home:** <http://www.gnuplot.info/> * **[Config::Auto](http://search.cpan.org/~simon/Config-Auto-0.03/Auto.pm)** — a Perl module that reads configuration files. To install it use the following command: ``` sudo cpan Config::Auto ``` * **[DBD::mysql](http://search.cpan.org/~capttofu/DBD-mysql-4.020/lib/DBD/mysql.pm)** — a Perl module to connect to MariaDB/MySQL and PostgreSQL. To install it use the following command: ``` sudo cpan DBD::mysql ``` **NOTE:** You may receive an error saying that CPAN could not find `mysql_config`. In this case you have to install the mysql client development library. In OpenSuse the command is: ``` sudo zypper install libmysqlclient-devel ``` Alternatively this module can be installed manually by following these steps: 1. Download DBD-mysql-4.020.tar.gz from <http://search.cpan.org/~capttofu/DBD-mysql-4.020/lib/DBD/mysql.pm> and unpack it 2. Run the perl script PerlMake.pl under the unzipped dir: ``` perl Makefile.PL --mysql_config=/path/to/some/mysql_binary_distribution/bin/mysql_config ``` 3. Run `make` to compile `DBD::mysql`: ``` make ``` 4. Add the necessary paths in order to run `DBD::mysql`: ``` export PERL5LIB="/path/to/unzipped_DBD_mysql/DBD-mysql-4.020/lib" export LD_LIBRARY_PATH="/path/to/unzipped_DBD_mysql/DBD-mysql-4.020/blib/arch/auto/DBD/mysql/:/path/to/some/mysql_binary_distribution/lib/" ``` ### Tested DBMS * **[MySQL 5.5.x](http://dev.mysql.com/downloads/mysql/#downloads)** + **Download location:** <http://dev.mysql.com/downloads/mysql/#downloads> → Generally Available (GA) Releases → Linux - Generic 2.6 (x86, 64-bit), Compressed TAR Archive - downloads mysql-5.5.x-linux2.6-x86\_64.tar.gz - gzipped tar file for Linux x86 * **[MySQL 5.6.x](http://dev.mysql.com/downloads/mysql/#downloads)** + **Download location:** <http://dev.mysql.com/downloads/mysql/#downloads> → Development Releases → Linux - Generic 2.6 (x86, 64-bit), Compressed TAR Archive - downloads mysql-5.6.x-m5-linux2.6-x86\_64.tar.gz - gzipped tar file for Linux x86 * **[MariaDB 5.3.x](https://launchpad.net/maria/5.3)** + **Download location:** <https://launchpad.net/maria/5.3> , downloaded with Bazaar: ``` bzr branch lp:maria/5.3 ``` * **[MariaDB 5.5.x](https://launchpad.net/maria/5.3)** + **Download location:** <https://launchpad.net/maria/5.5> , downloaded with Bazaar: ``` bzr branch lp:maria/5.5 ``` * **[PostgreSQL](http://www.postgresql.org/ftp/source/v9.1rc1/)** + **Download location:** <http://www.postgresql.org/ftp/source/v9.1rc1/> **NOTE:** The DBT3 benchmark requires a lot of disk space (for example MySQL 5.5.x + MyISAM database with scale factor 30 takes about 50 GB). Also some queries require the utilization of temp tables under the directory set by the `--tmpdir` startup parameter passed to `mysqld`. In the prepared configuration files the temp directory is pointed to the `mysql` system directory of the binary distribution, but one should reassure that there is enough free space available for the temp directory. Installation instructions ------------------------- **NOTE:** The directory where all the files will be downloaded or installed will be referred as `$PROJECT_HOME`. This could be for example `~/benchmark/dbt3`. ### Download **[mariadb-tools](https://launchpad.net/mariadb-tools)** 1. Go to your project folder ``` cd $PROJECT_HOME ``` 2. Get the latest branch from LaunchPad with Bazaar: ``` bzr branch lp:mariadb-tools ``` Now the project for the dbt3 benchmark test will be in the following dir: ``` $PROJECT_HOME/mariadb-tools/dbt3_benchmark/ ``` The project `dbt3_benchmark` has the following directories and files: * **config** — a folder where the configuration files for MariaDB, MySQL and PostgreSQL are stored. They are divided into subfolders named '`sXX`', where `XX` is the scale factor. * **dbt3\_mysql** — a folder with all the necessary files for preparing DBT3 databases and queries for the tests with MySQL and MariaDB * **tests** — a folder where the different test configurations are stored. It contains the following directories: + **db\_conf** — here are stored the database configuration files + **queries\_conf** — here are stored the different queries configuration files + **results\_db\_conf** — here is stored the configuration of the results database + **test\_conf** — here are the test configurations + **launcher.pl** — a perl script that automates the test. Details about calling and functionality of this file are listed later on this page. ### Prepare benchmark workload and queries For the purpose of the benchmark from [DBT3-1.9](http://sourceforge.net/projects/osdldbt/files/dbt3/) we will only need **DBGEN** and **QGEN**. DBGEN is a tool that generates a workload for the test and QGEN is a tool that generates the queries used for the test. 1. Go to <http://sourceforge.net/projects/osdldbt/files/dbt3/> 2. Download the archive for DBT3 1.9 into your project folder $PROJECT\_HOME 3. Unzip the archive into your project folder ``` cd $PROJECT_HOME tar -zxf dbt3-1.9.tar.gz ``` 4. Copy the file tpcd.h into the dbt3 folder. This step includes the necessary labels for MySQL/MariaDB when building queries. ``` cp $PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/tpcd.h $PROJECT_HOME/dbt3-1.9/src/dbgen/ ``` 5. Copy the file Makefile under `$PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/` into the dbt3 folder * **NOTE:** This step is executed only if you want to overwrite the default behavior of PostgreSQL settings. After copying this Makefile and building the project, QGEN will be set to generate queries for MariaDB/MySQL. If you skip this step, QGEN will generate queries for PostgreSQL by default. ``` cp $PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/Makefile $PROJECT_HOME/dbt3-1.9/src/dbgen/ ``` 6. Go to $PROJECT\_HOME/dbt3-1.9/src/dbgen and build the project ``` cd $PROJECT_HOME/dbt3-1.9/src/dbgen make ``` 7. Set the variable DSS\_QUERY to the folder with template queries for MariaDB/MySQL or for PostgreSQL 1. If you want to build the queries that fit MariaDB/MySQL dialect execute the following command: ``` export DSS_QUERY=$PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/mysql_queries/ ``` 2. If you want to use the default PostgreSQL templates, execute the following command: ``` export DSS_QUERY=$PROJECT_HOME/dbt3-1.9/queries/pgsql/ ``` 8. Create a directory to store the generated queries in ``` mkdir $PROJECT_HOME/gen_query ``` 9. Generate the queries **NOTE:** The examples use scale factor 30. If you want different scale, change the value of `-s` parameter * ``` cd $PROJECT_HOME/dbt3-1.9/src/dbgen ./qgen -s 30 1 > $PROJECT_HOME/gen_query/s30-m/1.sql ./qgen -s 30 2 > $PROJECT_HOME/gen_query/s30-m/2.sql ./qgen -s 30 3 > $PROJECT_HOME/gen_query/s30-m/3.sql ./qgen -s 30 4 > $PROJECT_HOME/gen_query/s30-m/4.sql ./qgen -s 30 5 > $PROJECT_HOME/gen_query/s30-m/5.sql ./qgen -s 30 6 > $PROJECT_HOME/gen_query/s30-m/6.sql ./qgen -s 30 7 > $PROJECT_HOME/gen_query/s30-m/7.sql ./qgen -s 30 8 > $PROJECT_HOME/gen_query/s30-m/8.sql ./qgen -s 30 9 > $PROJECT_HOME/gen_query/s30-m/9.sql ./qgen -s 30 10 > $PROJECT_HOME/gen_query/s30-m/10.sql ./qgen -s 30 11 > $PROJECT_HOME/gen_query/s30-m/11.sql ./qgen -s 30 12 > $PROJECT_HOME/gen_query/s30-m/12.sql ./qgen -s 30 13 > $PROJECT_HOME/gen_query/s30-m/13.sql ./qgen -s 30 14 > $PROJECT_HOME/gen_query/s30-m/14.sql ./qgen -s 30 15 > $PROJECT_HOME/gen_query/s30-m/15.sql ./qgen -s 30 16 > $PROJECT_HOME/gen_query/s30-m/16.sql ./qgen -s 30 17 > $PROJECT_HOME/gen_query/s30-m/17.sql ./qgen -s 30 18 > $PROJECT_HOME/gen_query/s30-m/18.sql ./qgen -s 30 19 > $PROJECT_HOME/gen_query/s30-m/19.sql ./qgen -s 30 20 > $PROJECT_HOME/gen_query/s30-m/20.sql ./qgen -s 30 21 > $PROJECT_HOME/gen_query/s30-m/21.sql ./qgen -s 30 22 > $PROJECT_HOME/gen_query/s30-m/22.sql ``` 10. Generate the explain queries ``` ./qgen -s 30 -x 1 > $PROJECT_HOME/gen_query/s30-m/1_explain.sql ./qgen -s 30 -x 2 > $PROJECT_HOME/gen_query/s30-m/2_explain.sql ./qgen -s 30 -x 3 > $PROJECT_HOME/gen_query/s30-m/3_explain.sql ./qgen -s 30 -x 4 > $PROJECT_HOME/gen_query/s30-m/4_explain.sql ./qgen -s 30 -x 5 > $PROJECT_HOME/gen_query/s30-m/5_explain.sql ./qgen -s 30 -x 6 > $PROJECT_HOME/gen_query/s30-m/6_explain.sql ./qgen -s 30 -x 7 > $PROJECT_HOME/gen_query/s30-m/7_explain.sql ./qgen -s 30 -x 8 > $PROJECT_HOME/gen_query/s30-m/8_explain.sql ./qgen -s 30 -x 9 > $PROJECT_HOME/gen_query/s30-m/9_explain.sql ./qgen -s 30 -x 10 > $PROJECT_HOME/gen_query/s30-m/10_explain.sql ./qgen -s 30 -x 11 > $PROJECT_HOME/gen_query/s30-m/11_explain.sql ./qgen -s 30 -x 12 > $PROJECT_HOME/gen_query/s30-m/12_explain.sql ./qgen -s 30 -x 13 > $PROJECT_HOME/gen_query/s30-m/13_explain.sql ./qgen -s 30 -x 14 > $PROJECT_HOME/gen_query/s30-m/14_explain.sql ./qgen -s 30 -x 15 > $PROJECT_HOME/gen_query/s30-m/15_explain.sql ./qgen -s 30 -x 16 > $PROJECT_HOME/gen_query/s30-m/16_explain.sql ./qgen -s 30 -x 17 > $PROJECT_HOME/gen_query/s30-m/17_explain.sql ./qgen -s 30 -x 18 > $PROJECT_HOME/gen_query/s30-m/18_explain.sql ./qgen -s 30 -x 19 > $PROJECT_HOME/gen_query/s30-m/19_explain.sql ./qgen -s 30 -x 20 > $PROJECT_HOME/gen_query/s30-m/20_explain.sql ./qgen -s 30 -x 21 > $PROJECT_HOME/gen_query/s30-m/21_explain.sql ./qgen -s 30 -x 22 > $PROJECT_HOME/gen_query/s30-m/22_explain.sql ``` Now the generated queries for MariaDB/MySQL test are ready and are stored into the folder `$PROJECT_HOME/gen_query/s30-m/` (-m is for MariaDB/MySQL). Additional reorganization of directories is up to the user. 11. Create a directory for the generated workload ``` mkdir $PROJECT_HOME/gen_data/s30 ``` 12. Set the variable DSS\_PATH to the folder with the generated table data. The generated workload for the test will be generated there. ``` export DSS_PATH=$PROJECT_HOME/gen_data/s30/ ``` 13. Generate the table data * **NOTE:** The example uses scale factor = `30`. If you want to change it, you should change the parameter `-s`. ``` ./dbgen -vfF -s 30 ``` * Now the generated data load is stored into the folder set in `$DSS_PATH = $PROJECT_HOME/gen_data/` For the purpose of this benchmark these steps have been performed for scale factor 30 and are stored on facebook-maria1 in the following locations: * `/benchmark/dbt3/gen_data/s30` — the data load for scale factor 30 * `/benchmark/dbt3/gen_query/s30-m` — generated queries for MariaDB/MySQL with scale factor 30 * `/benchmark/dbt3/gen_query/s30-p` — generated queries for PostgreSQL with scale factor 30 See [DBT3 example preparation time](../dbt3-example-preparation-time/index) to see how long it would take you to prepare the databases for the test. ### Download **[MySQL 5.5.x](http://dev.mysql.com/downloads/mysql/#downloads)** 1. Download the tar.gz file into your project folder `$PROJECT_HOME/bin/` for example 2. Unzip the archive with the following command: ``` gunzip < mysql-5.5.x-linux2.6-x86_64.tar.gz |tar xf - ``` Now the server could be started with the following command: ``` $PROJECT_HOME/bin/mysql-5.5.x-linux2.6-x86_64/bin/mysqld_safe --datadir=some/data/dir & ``` ### Download **[MySQL 5.6.x](http://dev.mysql.com/downloads/mysql/#downloads)** 1. Download the tar.gz file into your project folder `$PROJECT_HOME/bin/` for example 2. Unzip the archive with the following command: ``` gunzip < mysql-5.6.x-m5-linux2.6-x86_64.tar.gz |tar xf - ``` Now the server could be started with the following command: ``` $PROJECT_HOME/bin/mysql-5.6.x-m5-linux2.6-x86_64/bin/mysqld_safe --datadir=some/data/dir & ``` ### Download and build [MariaDB 5.3](../what-is-mariadb-53/index).x / [MariaDB 5.5](../what-is-mariadb-55/index).x **NOTE:** These steps are the same for [MariaDB 5.5](../what-is-mariadb-55/index).x with properly replaced version numbers 1. Download with Bazaar the [mariadb 5.3](../what-is-mariadb-53/index) project ``` bzr branch lp:maria/5.3 mv 5.3/ mariadb-5.3 ``` 2. Build MariaDB ``` cd mariadb-5.3/ ./BUILD/compile-amd64-max ``` 3. Build a binary distribution tar.gz file ``` ./scripts/make_binary_distribution ``` 4. Move the generated tar.gz file and unzip it to $PROJECT\_HOME/bin from where it will be used by the automation script ``` mv mariadb-5.3.x-beta-linux-x86_64.tar.gz $PROJECT_HOME/bin/ cd $PROJECT_HOME/bin/ tar -xf mariadb-5.3.x-beta-linux-x86_64.tar.gz ``` Now the server could be started with the following command: ``` $PROJECT_HOME/bin/mariadb-5.3.x-beta-linux-x86_64/bin/mysqld_safe --datadir=some/data/dir & ``` ### Prepare the databases for the benchmark **NOTE:** These instructions are the same for MariaDB, MySQL 5.5.x and MySQL 5.6.x with changing only the database home folders, noted here as $DB\_HOME (for example for MySQL 5.5.x $DB\_HOME is `$PROJECT_HOME/bin/mysql-5.5.x-linux2.6-x86_64`). Also you can prepare InnoDB storage engine test databases. Instructions for preparing PostgreSQL could be found in the section for downloading, building and preparing PostgreSQL later on this page. 1. Open the file `$PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/make-dbt3-db_innodb.sql` and edit the values for the call of the sql commands that look like this one: ``` LOAD DATA INFILE '/some/path/to/gen_data/nation.tbl' into table nation fields terminated by '|'; ``` * They all look the same but operate with different tables. * Replace "/some/path/to/gen\_data/" with the proper directory where the generated data load is stored. At the end the same command could look like this: ``` LOAD DATA INFILE '~/benchmark/dbt3/gen_data/s30/nation.tbl' into table nation fields terminated by '|'; ``` 2. Create an empty MySQL database into a folder that will be used for the benchmark ``` cd $DB_HOME ./scripts/mysql_install_db --defaults-file=$PROJECT_HOME/mariadb-tools/dbt3_benchmark/config/s30/load_mysql_myisam_my.cnf --basedir=$DB_HOME --datadir=$PROJECT_HOME/db_data/myisam-s30/ ``` * **NOTE:** For InnoDB change the defaults-file to `load_mysql_innodb_my.cnf`. 3. Start the mysqld process`./bin/mysqld_safe --defaults-file=$PROJECT_HOME/mariadb-tools/dbt3_benchmark/config/s30/load_mysql_myisam_my.cnf --tmpdir=$PROJECT_HOME/temp/ --socket=$PROJECT_HOME/temp/mysql.sock --datadir=$PROJECT_HOME/db_data/myisam-s30/ &` * **NOTE:** For InnoDB change the defaults-file to `load_mysql_innodb_my.cnf`. Also make sure that you have enough space in the directory set by the parameter `--tmpdir`, since loading the database could take a lot of temporary space. 4. Load the data into the database by executing the file `make-dbt3-db_pre_create_PK.sql` (for InnoDB) or `make-dbt3-db_post_create_PK.sql` (for MyISAM)`./bin/mysql -u root -S $PROJECT_HOME/temp/mysql.sock < $PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/make-dbt3-db_post_create_PK.sql` * **NOTE:** For faster creation, it is recommended to use `make-dbt3-db_pre_create_PK.sql` for loading InnoDB and `make-dbt3-db_post_create_PK.sql` for loading MyISAM databases. 5. Shutdown the database server: ``` ./bin/mysqladmin --user=root --socket=$PROJECT_HOME/temp/mysql.sock shutdown 0 ``` Now you have a database loaded with scale 30. Its datadir is `$PROJECT_HOME/db_data/myisam-s30/` The same steps can be reproduced for different scale factors and for different storage engines. ### Download, build and prepare **[PostgreSQL](http://www.postgresql.org/ftp/source/v9.1rc1/)** 1. Go to <http://www.postgresql.org/ftp/source/v9.1rc1/> 2. Download the file under the link postgresql-9.1rc1.tar.gz 3. Unzip the archive to your project folder ``` gunzip < postgresql-9.1rc1.tar.gz |tar xf - ``` 4. Execute the following commnads into the shell to install PostgreSQL: ``` mkdir $PROJECT_HOME/PostgreSQL_bin cd $PROJECT_HOME/postgresql-9.1rc1 ./configure --prefix=$PROJECT_HOME/bin/PostgreSQL_bin make make install ``` * **NOTE:** Configure script may not find the following libraries: readline and zlib. In that case you can run configure without these libraries by adding the following parameters to the command line: `--without-readline --without-zlib` 5. Prepare the database to test with: ``` mkdir $PROJECT_HOME/db_data/postgre_s30 cd $PROJECT_HOME/bin/PostgreSQL_bin ./bin/initdb -D $PROJECT_HOME/db_data/postgre_s30 ``` 6. Start the server: ``` ./bin/postgres -D $PROJECT_HOME/db_data/postgre_s30 -p 54322 & ``` 7. Load the dataload into the DB ``` ./bin/createdb -O {YOUR_USERNAME} dbt3 -p 54322 ./bin/psql -p 54322 -d dbt3 -f $PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/make-dbt3-db_pg.sql ``` * **NOTE:** Here under `{YOUR_USERNAME}` you should put the database owner. 8. Stop the server: ``` ./bin/pg_ctl -D $PROJECT_HOME/db_data/postgre_s30/ -p 54322 stop ``` The steps for preparing the workload for the benchmark on facebook-maria1 are already made for MariaDB, MySQL and PostgreSQL. Here are the directories for the different DBMS, storage engines and scale factors that are prepared on facebook-maria1: * `~/benchmark/dbt3/db_data/myisam_s30` — datadir for MariaDB/MySQL + MyISAM with scale factor 30 * `~/benchmark/dbt3/db_data/innodb_mariadb_s30` — datadir for MariaDB + InnoDB with scale factor 30 (TODO) * `~/benchmark/dbt3/db_data/innodb_mysql_s30` — datadir for MySQL + InnoDB with scale factor 30 (TODO) * `~/benchmark/dbt3/db_data/postgre_s30` — datadir for PostgreSQL with scale factor 30 (TODO) ### Prepare the results database The results of the benchmark will be stored in a separate database that will be run by [MariaDB 5.3](../what-is-mariadb-53/index).x. **NOTE:** The results database will be a subject to change in future versions of the DBT3 benchmarking project. The database is created by the file `$PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/make-results-db.sql`. In that file you can find details about every table and column in the database. To prepare the database for work follow these steps: 1. Go to [MariaDB 5.3](../what-is-mariadb-53/index).x installation directory ``` cd $PROJECT_HOME/bin/mariadb-5.3.x-beta-linux-x86_64 ``` 2. Install the system database tables into the datadir for the results (for example `$PROJECT_HOME/db_data/dbt3_results_db`) ``` ./scripts/mysql_install_db --datadir=$PROJECT_HOME/db_data/dbt3_results_db ``` 3. Start mysqld for results db ``` ./bin/mysqld_safe --defaults-file=$PROJECT_HOME/mariadb-tools/dbt3_benchmark/config/results_mariadb_my.cnf --port=12340 --socket=$PROJECT_HOME/temp/mysql_results.sock --datadir=$PROJECT_HOME/db_data/dbt3_results_db/ & ``` 4. Install the database ``` ./bin/mysql -u root -P 12340 -S $PROJECT_HOME/temp/mysql_results.sock < $PROJECT_HOME/mariadb-tools/dbt3_benchmark/dbt3_mysql/make-results-db.sql ``` 5. Shutdown the results db server: ``` ./bin/mysqladmin --user=root --port=12340 --socket=$PROJECT_HOME/temp/mysql_results.sock shutdown 0 ``` Automation script ----------------- ### Configuring and running a benchmark In order to run a benchmark, one should have: * 5 configuration files: 1. **DBMS** server configuration (see <#dbms-server-configuration>) 2. **Test** configuration (see <#test-configuration>) 3. **Queries** configuration (see <#queries-configuration>) 4. **Results database** configuration (see <#results-database-configuration>) 5. **Top-level** configuration file that combines all of the above (see <#top-level-configuration>) * an **automation script `launcher.pl`** that could be found under `mariadb-tools/dbt3_benchmark/` * **startup parameters** that should be passed to the automation script (see <#script-startup-parameters>). Details about each of these is given in the following sections. Each benchmark is configured by a set of configuration files. One can find example (default) configuration files under the directory 'mariadb-tools/dbt3\_benchmark/tests'. Each configuration file has an 'ini' configuration syntax and is parsed by the perl automation script with the CPAN module [Config::Auto](http://search.cpan.org/~simon/Config-Auto-0.03/Auto.pm) #### Configuration keywords Every configuration file could contain keywords that will be replaced by the script with particular values. They are used for convenience when you want to make your configuration files more common to the environment that you have prepared for the benchmark. These keywords are: * `$PROJECT_HOME` — used as the directory where the project '`mariadb-tools`' is located or as a base path for the whole project (e.g. "`DBMS_HOME = $PROJECT_HOME/bin/mariadb-5.3.x-beta-linux-x86_64`"). It is replaced by the value set with the startup parameter **'project-home**' passed to **launcher.pl**, * `$DATADIR_HOME` — used as the directory where the datadir folders are located for the benchmark (e.g. "`$DATADIR_HOME/myisam-s30`"). It is replaced by the value set with the startup parameter **'datadir-home'** passed to **launcher.pl**. * `$QUERIES_HOME` — used as the directory where the queries are located (e.g. "`$QUERIES_HOME/s30-m`" — queries for MariaDB/MySQL for scale factor 30). It is replaced by the value set with the startup parameter **'queries-home'** passed to **launcher.pl**. * `$SCALE_FACTOR` — the scale factor that will be used. It is usually a part of the name of the datadir directory (e.g. "`$DATADIR_HOME/myisam-s$SCALE_FACTOR`"), the queries directory (e.g. "`$QUERIES_HOME/s$SCALE_FACTOR-m`") or the database configuration directory (e.g. `$PROJECT_HOME/mariadb-tools/dbt3_benchmark/config/s$SCALE_FACTOR`). It is replaced by the value set with the startup parameter **'scale-factor'** passed to **launcher.pl**. Note that if any of the configuration files contains such keyword, the corresponding startup parameter passed to **launcher.pl** will become required. #### Top-level configuration A top-level configuration file provides paths to the **Test, DBMS, Queries** and **Results database** configurations files There are default configuration files in the directory `mariadb-tools/dbt3_benchmark/tests/` and contain the following settings: | Parameter | Description | | --- | --- | | `RESULTS_DB_CONFIG` | The configuration file for results DB settings | | `TEST_CONFIG` | The configuration file for the test settings | | `QUERIES_CONFIG` | The configuration file for the queries settings | | `DB_CONFIG` | The configuration file for the DBMS server settigns | This file has the following format: ``` [common] RESULTS_DB_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/results_db_conf/results_db.conf TEST_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/test_conf/test_myisam.conf [mariadb_5_3] QUERIES_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/queries_conf/queries.conf DB_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/db_conf/db_mariadb_5_3_myisam.conf [mysql_5_5] QUERIES_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/queries_conf/queries_mysql.conf DB_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/db_conf/db_mysql_5_5_myisam.conf ... ``` **NOTE:** The settings `RESULTS_DB_CONFIG` and `TEST_CONFIG` should be set under the `[common]` section. They are common for the whole test (although some settings from `TEST_CONFIG` could be overridden in the `QUERIES_CONFIG` file). All settings that combine `QUERIES_CONFIG` and `DB_CONFIG` should be in a separate section (e.g. `[mariadb_5_3]`). A test configuration is passed as an input parameter to the automation script with the parameter `--test=/path/to/some_test_configuration.conf` (see <#script-startup-parameters>) #### DBMS server configuration These configuration files contain settings that describe the benchmarked DBMS. They are usually contained into the folder `mariadb-tools/dbt3_benchmark/tests/db_conf`. Here is the list of parameters that could be set into this configuration file: | Parameter | Description | | --- | --- | | `DBMS_HOME` | Where the instalation folder of MariaDB / MySQL / PostgreSQL is located.**NOTE:** The automation script uses "`./bin/mysqld_safe`" to start the `mysqld` process. So the versions of MariaDB and MySQL should be a "binary distribution" ones. | | `DBMS_USER` | The database user that will be used. | | `CONFIG_FILE` | The config file that mysqld or postgres will use when starting | | `SOCKET` | The socket that will be used to start the server | | `PORT` | The port that the server will be started on | | `HOST` | The host where the server is located | | `DATADIR` | Where the datadir for mysqld or postgres is located | | `TMPDIR` | Where the temp tables will be created while sorting and grouping. | | `DBNAME` | The database (schema) name where the benchmark tables are located. | | `KEYWORD` | This text will be stored into the results database as a keyword. Also will be used as a name for a subfolder with results and statistics. | | `DBMS` | Database Management System that will be used. Possible values: "MySQL", "MariaDB" and "PostgreSQL" | | `STORAGE_ENGINE` | The storage engine that was used (MyISAM, InnoDB, etc.) | | `STARTUP_PARAMS` | Any startup parameters that will be used while starting the mysqld process or postgres process. Same format as given on the command line. | | `GRAPH_HEADING` | The heading of the graphic for that particular test. | | `MYSQL_SYSTEM_DIR` | See *"`MYSQL_SYSTEM_DIR` note"*, below. | | `READ_ONLY` | If set to 1, mysqld process will be started with '`--read-only`' startup parameter | | `PRE_RUN_SQL` | SQL commands that are run prior each query run | | `POST_RUN_SQL` | SQL commands that are run after each query run | | `PRE_TEST_SQL` | SQL commands that are run prior the whole test with that database settings | | `POST_TEST_SQL` | SQL commands that are run after the whole test with that database settings | **`MYSQL_SYSTEM_DIR` note:** This option is added for convenience when you want to save time and disk space for generating databases for different DBMS (and different versions) and use a single data directory for all of them. When running different versions of MariaDB/MySQL over a single datadir, one should run [mysql-upgrade](http://dev.mysql.com/doc/refman/5.5/en/mysql-upgrade.html) in order to fix the system tables. So in one data directory, you could prepare the following directories for different MariaDB/MySQL system directories: * `mysql_mysql_5_5` — a copy of the system directory '`mysql`' upgraded by MySQL 5.5.x * `mysql_mariadb_5_3` — a copy of the system directory '`mysql`' upgraded by [MariaDB 5.3](../what-is-mariadb-53/index).x * `mysql_mariadb_5_5` — a copy of the system directory '`mysql`' upgraded by [MariaDB 5.5](../what-is-mariadb-55/index).x If `MYSQL_SYSTEM_DIR` is set to one of these directories, the automation script will unlink the current system directory 'mysql' and make a new symbolic link with that name to the one in the setting. Here is an example command that will be executed: ``` unlink /path/to/datadir/mysql ln -s /path/to/value/in/MYSQL_SYSTEM_DIR/mysql_mariadb_5_3 /path/to/datadir/mysql ``` **NOTE:** This approach is suitable for MyISAM tests. The configuration file looks like this: ``` [db_settings] DBMS_HOME = $PROJECT_HOME/bin/mariadb-5.3.2-beta-linux-x86_64 DBMS_USER = root ... ``` Note that the section `[db_settings]` is required for the file to be properly parsed by the automation script. #### Test configuration These configuration files contain settings describing the test. They are usually contained into the folder **mariadb-tools/dbt3\_benchmark/tests/test\_conf**. Here is the list of parameters that could be set into this configuration file: | Parameter | Description | | --- | --- | | `QUERIES_AT_ONCE` | If set to `1`, then all the queries are executed sequentially without restarting the server or clearing the caches between queries. | | `CLEAR_CACHES` | If set to `1`, the disk caches will be cleared before each query test. | | `WARMUP` | Perform a warm-up runs before running the query. | | `EXPLAIN` | Run an Explain command prior the run of the query. The explain results will be stored in a file under the results output directory. | | `RUN` | Perform the actual test | | `ANALYZE_EXPLAIN` | A result extraction mechanism where only the best execution plan (results from `EXPLAIN` select) will be measured. It is designed to be used when benchmarking InnoDB storage engine where execution plan is changing between server restarts (see <#results-extraction-mechanisms>). | | `MIN_MAX_OUT_OF_N` | A result extraction mechanism where the minimal and maximal values out of `N` (set by the parameter `NUM_TESTS`) tests are taken as a result. This could be used when InnoDB storage engine is tested (see <#results-extraction-mechanisms>). | | `SIMPLE_AVERAGE` | A result extraction mechanism where the final result is the average time taken for the tests. The number of tests is per query is set by the NUM\_TESTS parameter. Note that if even one test has timed out, the result is 'time-out'. This is used when testing MyISAM storage engine since there the execution plan is constant (see <#results-extraction-mechanisms>). | | `NUM_TESTS` | How many tests should be performed for each query. When ANALYZE\_EXPLAIN is set, this value could be set to 0, meaning that the tests will continue until enough results are extracted (see setting `CLUSTER_SIZE`). This parameter is very important when `MIN_MAX_OUT_OF_N` or `SIMPLE_AVERAGE` is selected. | | `MAX_SKIPPED_TESTS` | When ANALYZE\_EXPLAIN is set and an execution plan that is slower is selected, the execution of the query is skipped and the server is restarted in order to change the execution plan. If the server is restarted more than `MAX_SKIPPED_TESTS`, there are obviously no more different execution plans and the script continues to the next query benchmark. | | `WARMUPS_COUNT` | How many warmup runs will be performed prior the actual benchmark run. | | `CLUSTER_SIZE` | How big a cluster with results for a query should be in order to extract the final result. It is used when `ANALYZE_EXPLAIN` is selected as a result extraction method. | | `MAX_QUERY_TIME` | The maximum time that one query will be tested. Currently it is applicable only when `ANALYZE_EXPLAIN` is selected. | | `TIMEOUT` | The maximum time that one query could run. Currently timeout is applicable only for MySQL and MariaDB. | | `OS_STATS_INTERVAL` | What is the time interval between extraction of OS statistics for CPU, memory, etc. | | `PRE_RUN_OS` | OS commands that should be executed prior each query run | | `POST_RUN_OS` | OS commands that should be executed after each query run | | `PRE_TEST_OS` | OS commands that should be executed prior the whole test | | `POST_TEST_OS` | OS commands that should be executed after the whole test is complete | The configuration file looks like this: ``` QUERIES_AT_ONCE = 0 CLEAR_CACHES = 1 WARMUP = 0 ... ``` #### Queries configuration These configuration files contain the list of all the queries that will be benchmarked against each database. Some settings from `DBMS server configuration` and `Test configuration` could be overridden into the `Queries configuration` files. The folder that contains such configurations is `mariadb-tools/dbt3_benchmark/tests/queries_conf`. Here is the list of parameters that could be set into this configuration file: | Parameter | Description | | --- | --- | | `QUERIES_HOME` | Where the queries are located on disk. This value is concatenated to the `QUERY` setting and this makes the path to the particular query. **NOTE:** This setting should be set under the section `[queries_settings]`. | | `CONFIG_FILE` | This overrides the startup setting `CONFIG_FILE` from **DMBS server** configuration file and sets the database configuration file that is used. It could be used if some configuration file without any optimizations should be set for this particular queries configuration file.**NOTE:** This setting should be set under the section `[queries_settings]`. | | `QUERY` | The name of the query located into `QUERIES_HOME` folder. E.g. "1.sql" | | `EXPLAIN_QUERY` | The name of the explain query into `QUERIES_HOME` folder. E.g. "1\_explain.sql" | | `TMPDIR` | This overrides the setting TMPDIR from the `DMBS server` configuration. | | `STARTUP_PARAMS` | This overrides the setting `STARTUP_PARAMS` from the `DMBS server` configuration. Using this setting one could change the particular startup parameters (like optimizations and buffers) for the DB server. | | `PRE_RUN_SQL` | This overrides the setting `PRE_RUN_SQL` from the **DMBS server** configuration. | | `POST_RUN_SQL` | This overrides the setting `POST_RUN_SQL` from the **DMBS server** configuration. | | `RUN` | This overrides the setting `RUN` from the **test** configuration. | | `EXPLAIN` | This overrides the setting `EXPLAIN` from the **test** configuration. | | `TIMEOUT` | This overrides the setting `TIMEOUT` from the **test** configuration. | | `NUM_TESTS` | This overrides the setting `NUM_TESTS` from the **test** configuration. | | `MAX_SKIPPED_TESTS` | This overrides the setting `MAX_SKIPPED_TESTS` from the **test** configuration. | | `WARMUP` | This overrides the setting `WARMUP` from the **test** configuration. | | `WARMUPS_COUNT` | This overrides the setting `WARMUPS_COUNT` from the **test** configuration. | | `MAX_QUERY_TIME` | This overrides the setting `MAX_QUERY_TIME` from the **test** configuration. | | `CLUSTER_SIZE` | This overrides the setting `CLUSTER_SIZE` from the **test** configuration. | | `PRE_RUN_OS` | This overrides the setting `PRE_RUN_OS` from the **test** configuration. | | `POST_RUN_OS` | This overrides the setting `POST_RUN_OS` from the **test** configuration. | | `OS_STATS_INTERVAL` | This overrides the setting `OS_STATS_INTERVAL` from the **test** configuration. | The queries configuration file could look like this: ``` [queries_settings] QUERIES_HOME = /path/to/queries [query1] QUERY=1.sql EXPLAIN_QUERY=1_explain.sql STARTUP_PARAMS= [query2] QUERY=2.sql EXPLAIN_QUERY=2_explain.sql STARTUP_PARAMS=--optimizer_switch='mrr=on' --mrr_buffer_size=8M --some_startup_parmas ... ``` ...where "`QUERIES_HOME = /path/to/queries`" could be replaced with "`QUERIES_HOME = $QUERIES_HOME/s$SCALE_FACTOR-m`" for example and thus `$QUERIES_HOME` and $SCALE\_FACTOR will be replaced by the script startup parameters passed to `launcher.pl` (see <#script-startup-parameters>) **NOTE:** The section `[queries_settings]` is required for the configuration file to be parsed correctly. Also each query settings should be set under an uniquely named configuration section (e.g. `[query1]` or `[1.sql]`) #### Results database configuration These configuration files contain settings about the database where the results will be stored. They are usually contained into the folder `mariadb-tools/dbt3_benchmark/tests/results_db_conf`. Here is the list of parameters that could be set into this configuration file: | Parameter | Description | | --- | --- | | `DBMS_HOME` | Where the database directory is located. E.g. "`$PROJECT_HOME/mariadb-5.3.x-beta-linux-x86_64`". This should be a binary distribution of MariaDB or MySQL. | | `DBMS_USER` | The user that will be used by the DBMS | | `DATADIR` | Where the data directory is located for the results database | | `CONFIG_FILE` | What the configuration file used by the database is. | | `SOCKET` | The socket that will be used by the results database. This should be different socket than the one provided for the testing databases. | | `PORT` | The port that the results database will use. This should be different port than the one provided for the testing databases. | | `STARTUP_PARAMS` | Any startup parameters that should be set to start the server. | | `DBNAME` | The database name to use. | | `HOST` | The host where the results database is. | The results database configuration could look like this: ``` DBMS_HOME = $PROJECT_HOME/mariadb-5.3.x-beta-linux-x86_64 DBMS_USER = root ... ``` #### Script startup parameters `launcher.pl` could accept startup parameters called in the manner "`--some-param`". Note that these startup parameters are case-sensitive. The ones that are with upper-case are used when overriding a setting in some of the configuration files. Here is a list of the startup parameters: | Parameter | Description | | --- | --- | | `test` | The top-level benchmark configuration file that will be run. This is a **required** startup parameter. | | `results-output-dir` | Where the results of the benchmark will be stored. A timestamp is automatically attached to the directory name so that it keeps track of time and date of the benchmark. This is a **required** parameter. | | `dry-run` | If set, no benchmark will be performed. Instead only messages will be displayed for the actions that were intended to be done. | | `project-home` | Required if any configuration file uses the variable '`$PROJECT_HOME`'. If all configuration files use absolute paths, not used. | | `datadir-home` | The value in this parameter will replace any occurrences of the string '`$DATADIR_HOME`' into the configuration files. If there are no such occurances, it is not a required parameter. | | `queries-home` | The value in this parameter will replace any occurrences of the string '`$QUERIES_HOME`' into the configuration files. If there are no such occurances, it is not a required parameter. | | `scale-factor` | The value in this parameter will replace any occurrences of the string '`$SCALE_FACTOR`' into the configuration files. If there are no such occurances, it is not a required parameter. | | `CLEAR_CACHES` | If set. this overrides the default setting set into the **test** configuration file. | | `QUERIES_AT_ONCE` | If set. this overrides the default setting set into the **test** configuration file. | | `RUN` | If set. this overrides the default setting set into the **test** configuration file. | | `EXPLAIN` | If set. this overrides the default setting set into the **test** configuration file. | | `TIMEOUT` | If set. this overrides the default setting set into the **test** configuration file. | | `NUM_TESTS` | If set. this overrides the default setting set into the **test** configuration file. | | `MAX_SKIPPED_TESTS` | If set. this overrides the default setting set into the **test** configuration file. | | `WARMUP` | If set. this overrides the default setting set into the **test** configuration file. | | `WARMUPS_COUNT` | If set. this overrides the default setting set into the **test** configuration file. | | `MAX_QUERY_TIME` | If set. this overrides the default setting set into the **test** configuration file. | | `CLUSTER_SIZE` | If set. this overrides the default setting set into the **test** configuration file. | | `PRE_RUN_OS` | If set. this overrides the default setting set into the **test** configuration file. | | `POST_RUN_OS` | If set. this overrides the default setting set into the **test** configuration file. | | `OS_STATS_INTERVAL` | If set. this overrides the default setting set into the **test** configuration file. | ### Results extraction mechanisms There are three possible result extraction mechanisms. They are set by the parameters set into the test configuration file: * `ANALYZE_EXPLAIN` * `MIN_MAX_OUT_OF_N` * `SIMPLE_AVERAGE` Only one of these should be set to true (1). **`ANALYZE_EXPLAIN`** is used for benchmarking InnoDB storage engine where the execution plan could change for the same query when the server is restarted. It is designed to run the query only with the fastest execution plan. This means that the server is restarted if the current execution plan is proven slower than the other. As a final result is taken the result for the query plan that turns out to be fastest and there are at least `CLUSTER_SIZE` tests with it for that query. By setting the configuration parameter `NUM_TESTS` you can set a maximum test runs that when reached will get the best cluster's average time (even if it is less than `CLUSTER_SIZE`). Also when a timeout for that query (`MAX_QUERY_TIME`) is reached, the scoring mechanism will return the best available cluster result. **`MIN_MAX_OUT_OF_N`** is also used for benchmarking InnoDB storage engine. As a result are stored the values for the fastest and the slowest run. It is assumed that when the execution plan has changed it has different execution plan and we are interested only in the min and max time. **`SIMPLE_AVERAGE`** is used for benchmarking storage engines that do not change the execution plan between restarts like MyISAM. The final result is the average execution time from all the test runs for the query. ### Results graphics After each query test run, the result is stored into a file named **results.dat** located into `{RESULTS_OUTPUT_DIR}`. This file is designed to be easy to be read by the plotting program Gnuplot 4.4. It is divided into blocks, separated by several new lines. Each block starts with a comment line containing details for the current block of results. Queries that have timed out have a value of `100000` so that they run out of the graphics and are cut off. Other queries have their real times (in seconds) starting from `0`. The graphics is cut off on the y-axis on the longest time for `completed test + 20%`. For example if the longest time is `100` seconds, the graphics is cut-off to `120` seconds. Thus the timed out queries will be truncated by this limitation and will seem as really timed out. During the test run, a gnuplot script file is generated with the necessary parameters for the graphics to be generated automatically. After each query test run is complete, the graphic is regenerated, so that the user can see the current results before the whole benchmark is complete. This file is called `gnuplot_script.txt` and is located into `{RESULTS_OUTPUT_DIR}`. The user can edit it to fine-tune the parameters or headings after the test is complete so that one could get the look and feel he/she wants for the final result. ### Script output #### Benchmark output In the directory set by the parameter {RESULTS\_OUTPUT\_DIR} (example: `/benchmark/dbt3/results/myisam_test_2011-12-08_191427/`) there are the following files/directories: * A directory for each test, named as the parameter {KEYWORD} from the test configuration (example: `mariadb-5-3-2`) * **cpu\_info.txt** — the output of "`/bin/cat /proc/cpuinfo`" OS command * **uname.txt** — the output of "`uname -a`" OS command * **results.dat** — the results of each query execution in one file. This file will be used as a datafile for the gnuplot script. It also contains the ratio between the current test and the first one. * **gnuplot\_script.txt** — the Gnuplot script that renders the graphics. * **graphics.jpeg** — the output graphics * A **benchmark** configuration file (example: `myisam_test_mariadb_5_3_mysql_5_5_mysql_5_6.conf`) copied from `mariadb-tools/dbt3_benchmark/tests/` * A **results database** configuration file (example: `results_db.conf`) copied from `mariadb-tools/dbt3_benchmark/tests/results_db_conf/` * A **test** configuration file (example: `test_myisam.conf`) copied from `mariadb-tools/dbt3_benchmark/tests/test_conf/` #### Test output In the subdirectory for the particular test, set by the parameter {KEYWORD} (example: `/benchmark/dbt3/results/myisam_test_2011-12-08_191427/mariadb-5-3-2/`), there are the following files: * **pre\_test\_os\_resutls.txt** - the output of the OS commands (if any) executed before the first query run for that test * **pre\_test\_sql\_resutls.txt** - the output of the SQL commands (if any) executed before the first query run for that test * **post\_test\_os\_resutls.txt** - the output of the OS commands (if any) executed after the last query run for that test * **post\_test\_sql\_resutls.txt** - the output of the SQL commands (if any) executed after the last query run for that test * **all\_explains.txt** - a file containing all the explain queries, their startup parameters for the benchmark and the explain result * The **config file** (my.cnf) that was passed to mysqld or postgres (example: `mariadb_myisam_my.cnf`) copied from `mariadb-tools/dbt3_benchmark/config/s$SCALE_FACTOR/` * The **queries** configuration file (example: ''queries-mariadb.conf'') copied from `mariadb-tools/dbt3_benchmark/tests/queries_conf/` * The **database** configuration file (example: ''db\_mariadb\_5\_3\_myisam.conf'') copied from `mariadb-tools/dbt3_benchmark/tests/db_conf/` #### Query output For each query execution there are several files that are outputted by the automation script. They are all saved under the subdirectory set by the parameters `{KEYWORD}`: * Explain result - a file named '**{query\_name}\_{number\_of\_query\_run}\_results.txt**' (example: '**1\_explain.sql\_1\_results.txt**' — first test for 1\_explain.sql) * Pre-run OS commands - OS commands, executed before the actual query run. Output is a file named '**pre\_run\_os\_q\_{query\_name}\_no\_{number\_of\_query\_run}\_results.txt**' (example: '**pre\_run\_os\_q\_1.sql\_no\_2\_results.txt**' — second test for query 1.sql) * Pre-run SQL commands - SQL commands executed before the actual query run. Output is a file named '**pre\_run\_sql\_q\_{query\_name}\_no\_{number\_of\_query\_run}\_results.txt**'. * Post-run OS commands - OS commands, executed after the actual query run. Output is a file named '**post\_run\_os\_q\_{query\_name}\_no\_{number\_of\_query\_run}\_results.txt**'. * Post-run SQL commands - SQL commands executed after the actual query run. Output is a file named '**post\_run\_sql\_q\_{query\_name}\_no\_{number\_of\_query\_run}\_results.txt**'. * CPU utilization statistics: '**{query\_name}\_no\_{number\_of\_query\_run}\_sar\_u.txt**' * I/O and transfer rate statistics: '**{query\_name}\_no\_{number\_of\_query\_run}\_sar\_b.txt**' * Memory utilization statistics: '**{query\_name}\_no\_{number\_of\_query\_run}\_sar\_r.txt**' ### Hooks The automation script provides hooks that allow the user to add both SQL and OS commands prior and after each test. Here is a list of all possible hooks: * Pre-test SQL hook: it is set with the parameter `PRE_TEST_SQL`. Contains SQL commands that are run once for the whole test configuration before the first run. (Example: "`use dbt3; select version(); show variables; show engines; show table status;`") * Post-test SQL hook: it is set with the parameter `POST_TEST_SQL`. Contains SQL commands that are run once for the whole test configuration after the last run. * Pre-test OS hook: it is set with the parameter `PRE_TEST_OS`. Contains OS commands that are run once for the whole test configuration before the first run. * Post-test OS hook: it is set with the parameter `POST_TEST_OS`. Contains OS commands that are run once for the whole test configuration after the last run. * Pre-run SQL hook: it is set with the parameter `PRE_RUN_SQL`. Contains SQL commands that are run prior each query run. (Example: "`flush status; set global userstat=on;`") * Post-run SQL hook: it is set with the parameter `POST_RUN_SQL`. Contains SQL commands that are run after each query run. (Example: "`show status; select \* from information\_schema.TABLE\_STATISTICS;`") * Pre-run OS hook: it is set with the parameter `PRE_RUN_OS`. Contains OS commands that are run once prior each query run. * Post-run OS hook: it is set with the parameter `POST_RUN_OS`. Contains OS commands that are run once after each query run. The results of these commands is stored into the `{RESULTS_OUTPUT_DIR}/{KEYWORD}` folder (see <#script-output>) ### Activities Here are the main activities that this script does: 1. Parse the configuration files and check the input parameters - if any of the required parameters is missing, the script will stop resulting an error. 2. Collect hardware information - collecting information about the hardware of the machine that the benchmark is run. Currently it collects `cpuinfo` and `uname`. Results of these commands are stored into the results output directory set as an input parameter 3. Loop through the passed test configurations For each passed in test configuration the script does the following: 1. Start the results database server. The results of the test are stored into that database. 2. Clears the caches on the server Clearing the caches is done with the following command: ``` sudo /sbin/sysctl vm.drop_caches=3 ``` * **NOTE:** In order to clear the caches, the user is required to have sudo rights and the following line should be added to the `sudoers` file (edit it with "`sudo vusudo`" command): ``` {your_username} ALL=NOPASSWD:/sbin/sysctl ``` 3. Start the database server 4. Perform pre-test SQL commands. The results are stored under `results_output_dir/{KEYWORD}` folder and are called `pre_test_sql_results.txt`. `{KEYWORD}` is a unique keyword for the current database configuration. 5. Perform pre-test OS commands. The results are stored under `results_output_dir/{KEYWORD}` folder and are called `pre_test_os_results.txt`. * **NOTE:** If in the test configuration the setting QUERIES\_AT\_ONCE is set to 0, then the server is restarted between each query run. Thus the steps 3.2, 3.3, 3.4 and 3.5 are executed only once right before step 3.6.2. 6. Read all query configurations and execute the following for each of them: 1. Check the test configuration parameters. If something is wrong with some required parameter, the program will exit resulting an error. 2. Get the server version if that's the first run of the query 3. Perform pre-run OS commands in shell. The results of these queries are stored into a file named `pre_run_os_q_{QUERY}_no_{RUN_NO}_results.txt` under `results_output_dir/{KEYWORD}` where `{QUERY}` is the query name (ex: `1.sql`), `{RUN_NO}` is the sequential run number and `{KEYWORD}` is a unique keyword for the particular test configuration. 4. Perform pre-run SQL queries. The results of these queries are stored into a file named `pre_run_sql_q_{QUERY}_no_{RUN_NO}_results.txt` under `results_output_dir/{KEYWORD}` where `{QUERY}` is the query name (ex: `1.sql`), `{RUN_NO}` is the sequential run number and `{KEYWORD}` is a unique keyword for the particular test configuration. 5. Perform warm-up runs if set into the test configuration file 6. Perform actual test run and measure time. * During this step, a new child process is created in order to measure the statistics of the OS. Currently the statistics being collected are: + CPU utilization statistics. The command for this is: ``` sar -u 0 2>null ``` + I/O and transfer rate statistics. The command for this is: ``` sar -b 0 2>null ``` + Memory utilization statistics. The command for this is: ``` sar -r 0 2>null ``` * These statistics are measured every N seconds, where `N` is set with the `OS_STATS_INTERVAL` test configuration parameter. * The test run for MariaDB and MySQL has an implemented mechanism for cut-off when timeout exceeds. It is controlled with the `TIMEOUT` test parameter. Currently for PostgreSQL there is no such functionality and should be implemented in future versions. 7. Execute the "explain" statement for that query. * **NOTE:** Running `EXPLAIN` queries with MySQL prior version 5.6.3 could result in long running queries since MySQL has to execute the whole query when there are nested selects in it. For MariaDB and PostgreSQL there is no such problem. The long-running explain queries are for queries #7, 8, 9, 13 and 15. For that reason in MySQL prior version 5.6.3 for these queries no `EXPLAIN` selects should be executed. 8. Perform post-run SQL queries 9. Perform post-run OS commands in shell 10. Log the results into the results database 11. A graphics with the current results is generated using Gnuplot 7. Shutdown the database server. 8. Perform post-test SQL commands. The results are stored under `results_output_dir/{KEYWORD}` folder and are called `post_test_sql_results.txt`. 9. Perform post-test OS commands. The results are stored under `results_output_dir/{KEYWORD}` folder and are called `post_test_os_results.txt`. 10. Stop the results database server ### Script calling examples * Example call for MyISAM test for scale factor 30 and timeout 10 minutes: ``` perl launcher.pl \ --project-home=/path/to/project/home/ \ --results-output-dir=/path/to/project/home/results/myisam_test \ --datadir=/path/to/project/home/db_data/ \ --test=/path/to/project/home/mariadb-tools/dbt3_benchmark/tests/myisam_test_mariadb_5_3_mysql_5_5_mysql_5_6.conf \ --queries-home=/path/to/project/home/gen_query/ \ --scale-factor=30 \ --TIMEOUT=600 ``` ...where `/path/to/project/home` is where the `mariadb-tools` project is located. This will replace all occurrences of the string "$PROJECT\_HOME" in the configuration files (example: "`TMPDIR = $PROJECT_HOME/temp/`" will become "`TMPDIR = /path/to/project/home/temp/`"). `--TIMEOUT` overrides the timeout setting into the test configuration file to 10 minutes. * Example for InnoDB test for scale factor 30 with 2 hours timeout per query and 3 runs for each query: ``` perl launcher.pl \ --project-home=/path/to/project/home/ \ --results-output-dir=/path/to/project/home/results/innodb_test \ --datadir=/path/to/project/home/db_data/ \ --test=/path/to/project/home/mariadb-tools/dbt3_benchmark/tests/innodb_test_mariadb_5_3_mysql_5_5_mysql_5_6.conf \ --queries-home=/path/to/project/home/gen_query/ \ --scale-factor=30 \ --TIMEOUT=7200 \ --NUM_TESTS=3 ``` * If a newer version of [MariaDB 5.5](../what-is-mariadb-55/index) is available: + copy or edit the **DMBS server** configuration file `mariadb-tools/dbt3_benchmark/tests/db_conf/db_mariadb_5_5_myisam.conf` and change the parameter `DBMS_HOME` to the new binary distribution. You can also edit `KEYWORD` and `GRAPH_HEADING` * If you want to add additional test in the MyISAM benchmark for [MariaDB 5.3](../what-is-mariadb-53/index), but with another defaults-file (my.cnf): + copy or edit the **DMBS server** configuration file `mariadb-tools/dbt3_benchmark/tests/db_conf/db_mariadb_5_3_myisam.conf` and change the parameter CONFIG\_FILE to the new my.cnf + copy or edit the **test** configuration file `mariadb-tools/dbt3_benchmark/tests/myisam_test_mariadb_5_3_mysql_5_5_mysql_5_6.conf` and add the new configuration settings: ``` [mariadb_5_3_new_configuration] QUERIES_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/queries_conf/queries-mariadb.conf DB_CONFIG = $PROJECT_HOME/mariadb-tools/dbt3_benchmark/tests/db_conf/db_mariadb_5_3_myisam_new_configuration.conf ``` * If you want to add additional startup parameters for query 6 for MariaDB for example: + copy or edit the file `mariadb-tools/dbt3_benchmark/tests/queries_conf/queries-mariadb.conf` and add a parameter "`STARTUP_PARAMS=--optimizer_switch='mrr=on' --mrr_buffer_size=96M`" for example for the section for query 6. + copy or edit the **test** configuration file `mariadb-tools/dbt3_benchmark/tests/myisam_test_mariadb_5_3_mysql_5_5_mysql_5_6.conf` to include the new **queries** configuration file Results ------- ### MyISAM test DBT3 benchmark for the following configuration: * [MariaDB 5.3.2](https://mariadb.com/kb/en/mariadb-532-release-notes/) Beta + MyISAM * [MariaDB 5.5.18](https://mariadb.com/kb/en/mariadb-5518-release-notes/) + MyISAM * MySQL 5.5.19 + MyISAM * MySQL 5.6.4 + MyISAM Results page: [DBT3 benchmark results MyISAM](../dbt3-benchmark-results-myisam/index) ### InnoDB test DBT3 benchmark for the following configuration: * [MariaDB 5.3.2](https://mariadb.com/kb/en/mariadb-532-release-notes/) Beta + XtraDB * [MariaDB 5.5.18](https://mariadb.com/kb/en/mariadb-5518-release-notes/) + XtraDB * MySQL 5.5.19 + InnoDB * MySQL 5.6.4 + InnoDB Results page: [DBT3 benchmark results InnoDB](../dbt3-benchmark-results-innodb/index) ### PostgreSQL test DBT3 benchmark for the following configuration: * [MariaDB 5.3.2](https://mariadb.com/kb/en/mariadb-532-release-notes/) Beta + XtraDB * MySQL 5.6.4 + InnoDB * PostgreSQL Results page: (TODO) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb JSON_ARRAY JSON\_ARRAY =========== **MariaDB starting with [10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/)**JSON functions were added in [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/). Syntax ------ ``` JSON_ARRAY([value[, value2] ...]) ``` Description ----------- Returns a JSON array containing the listed values. The list can be empty. Example ------- ``` SELECT Json_Array(56, 3.1416, 'My name is "Foo"', NULL); +--------------------------------------------------+ | Json_Array(56, 3.1416, 'My name is "Foo"', NULL) | +--------------------------------------------------+ | [56, 3.1416, "My name is \"Foo\"", null] | +--------------------------------------------------+ ``` See also -------- * [JSON\_MAKE\_ARRAY](../connect-json-table-type/index#json_make_array), the CONNECT storage engine function Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Buildbot Setup for Virtual Machines - Debian 4 amd64 Buildbot Setup for Virtual Machines - Debian 4 amd64 ==================================================== ``` cd /kvm/vms qemu-img create -f qcow2 vm-debian4-amd64-serial.qcow2 8G kvm -m 2047 -hda /kvm/vms/vm-debian4-amd64-serial.qcow2 -cdrom /kvm/debian-40r8-amd64-netinst.iso -redir 'tcp:2240::22' -boot d -smp 2 -cpu qemu64 -net nic,model=e1000 -net user ``` Serial console and account setup -------------------------------- From base install, setup for serial port, and setup accounts for passwordless ssh login and sudo: ``` kvm -m 2047 -hda /kvm/vms/vm-debian4-amd64-serial.qcow2 -cdrom /kvm/debian-40r8-amd64-netinst.iso -redir 'tcp:2240::22' -boot c -smp 2 -cpu qemu64 -net nic,model=e1000 -net user su apt-get install sudo openssh-server VISUAL=vi visudo # Add at the end:t %sudo ALL=NOPASSWD: ALL # Add account <USER> to group sudo # Copy in public ssh key. # Add in /etc/inittab: S0:2345:respawn:/sbin/getty -L ttyS0 19200 vt100 ``` Add to /boot/grub/menu.lst: ``` serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1 terminal --timeout=3 serial console ``` also add in menu.lst to kernel line: ``` console=tty0 console=ttyS0,115200n8 # Add user buildbot, with disabled password. Add as sudo, and add ssh key. sudo /usr/sbin/adduser --disabled-password buildbot sudo /usr/sbin/adduser buildbot sudo sudo su - buildbot mkdir .ssh # Add all necessary keys. cat >.ssh/authorized_keys chmod -R go-rwx .ssh ``` VM for build ------------ ``` qemu-img create -b vm-debian4-amd64-serial.qcow2 -f qcow2 vm-debian4-amd64-build.qcow2 kvm -m 2047 -hda /kvm/vms/vm-debian4-amd64-build.qcow2 -cdrom /kvm/debian-40r8-amd64-netinst.iso -redir 'tcp:2240::22' -boot c -smp 2 -cpu qemu64 -net nic,model=e1000 -net user -nographic sudo apt-get build-dep mysql-server-5.0 # Some latex packages fail to install because they complain that the # source is more than 5 years old! I solved by setting back the clock a # couple of years temporarily ... sudo apt-get install devscripts doxygen texlive-latex-base gs lsb-release fakeroot libevent-dev libssl-dev zlib1g-dev libreadline5-dev ``` VM for install testing ---------------------- ``` qemu-img create -b vm-debian4-amd64-serial.qcow2 -f qcow2 vm-debian4-amd64-install.qcow2 kvm -m 2047 -hda /kvm/vms/vm-debian4-amd64-install.qcow2 -cdrom /kvm/debian-40r8-amd64-netinst.iso -redir 'tcp:2240::22' -boot c -smp 2 -cpu qemu64 -net nic,model=e1000 -net user -nographic ``` See the [General Principles](../buildbot-setup-for-virtual-machines-general-principles/index) article for how to make the '`my.seed`' file. ``` # No packages mostly! sudo apt-get install debconf-utils cat >>/etc/apt/sources.list <<END deb file:///home/buildbot/buildbot/debs binary/ deb-src file:///home/buildbot/buildbot/debs source/ END sudo debconf-set-selections /tmp/my.seed ``` VM for upgrade testing ---------------------- ``` qemu-img create -b vm-debian4-amd64-install.qcow2 -f qcow2 vm-debian4-amd64-upgrade.qcow2 kvm -m 2047 -hda /kvm/vms/vm-debian4-amd64-upgrade.qcow2 -cdrom /kvm/debian-40r8-amd64-netinst.iso -redir 'tcp:2240::22' -boot c -smp 2 -cpu qemu64 -net nic,model=e1000 -net user -nographic sudo apt-get install mysql-server-5.0 mysql -uroot -prootpass -e "create database mytest; use mytest; create table t(a int primary key); insert into t values (1); select * from t" ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Running MariaDB from the Build Directory Running MariaDB from the Build Directory ======================================== You can run mysqld directly from the build directory (without doing `make install`). Starting mariadbd After Build on Windows ---------------------------------------- On Windows, the data directory is produced during the build. The simplest way to start database from the command line is: 1. Go to the directory where mariadbd.exe is located (subdirectory sql\Debug or sql\Relwithdebinfo of the build directory) 2. From here, execute, if you are using [MariaDB 10.5](../what-is-mariadb-105/index) or newer, ``` mariadbd.exe --console ``` else ``` mysqld.exe --console ``` As usual, you can pass other server parameters on the command line, or store them in a my.ini configuraton file and pass `--defaults-file=path\to\my.ini` The default search path on Windows for the my.ini file is: * GetSystemWindowsDirectory() * GetWindowsDirectory() * C:\ * Directory where the executable is located Starting mysqld After Build on Unix ----------------------------------- Copy the following to your '`~/.my.cnf`' file. There are two lines you have to edit: '`datadir=`' and '`language=`'. Be sure to change them to match your environment. ``` # Example MariadB config file. # You can copy this to one of: # /etc/my.cnf to set global options, # /mysql-data-dir/my.cnf to get server specific options or # ~/my.cnf for user specific options. # # One can use all long options that the program supports. # Run the program with --help to get a list of available options # This will be passed to all MariaDB clients [client] #password=my_password #port=3306 #socket=/tmp/mysql.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # The mariadb server (both [mysqld] and [mariadb] works here) [mariadb] #port=3306 #socket=/tmp/mysql.sock # The following three entries caused mysqld 10.0.1-MariaDB (and possibly other versions) to abort... # skip-locking # set-variable = key_buffer=16M loose-innodb_data_file_path = ibdata1:1000M loose-mutex-deadlock-detector gdb ######### Fix the two following paths # Where you want to have your database datadir=/path/to/data/dir # Where you have your mysql/MariaDB source + sql/share/english language=/path/to/src/dir/sql/share/english ########## One can also have a different path for different versions, to simplify development. [mariadb-10.1] lc-messages-dir=/my/maria-10.1/sql/share [mariadb-10.2] lc-messages-dir=/my/maria-10.2/sql/share [mysqldump] quick set-variable = max_allowed_packet=16M [mysql] no-auto-rehash [myisamchk] set-variable= key_buffer=128M ``` With the above file in place, go to your MariaDB source directory and execute: ``` ./scripts/mysql_install_db --srcdir=$PWD --datadir=/path/to/data/dir --user=$LOGNAME ``` Above '$PWD' is the environment variable that points to your current directory. If you added `datadir` to your `my.cnf`, you don't have to give this option above. Also above, --user=$LOGNAME is necessary when using msqyld 10.0.1-MariaDB (and possibly other versions) Now you can start `mariadbd` (or `mysqld` if you are using a version older than [MariaDB 10.5](../what-is-mariadb-105/index)) in the debugger: ``` cd sql ddd ./mariadbd & ``` Or start mysqld on its own: ``` cd sql ./mariadbd & ``` After starting up `mariadbd` using one of the above methods (with the debugger or without), launch the client (as root if you don't have any users setup yet). ``` ../client/mysql ``` Using a Storage Engine Plugin ----------------------------- The simplest case is to compile the storage engine into MariaDB: ``` cmake -DWITH_PLUGIN_<plugin_name>=1` . ``` Another option is to point `mariadbd` to the storage engine directory: ``` ./mariadbd --plugin-dir={build-dir-path}/storage/connect/.libs ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Stored Routine Limitations Stored Routine Limitations ========================== The following SQL statements are not permitted inside any [stored routines](../stored-programs-and-views/index) ([stored functions](../stored-functions/index), [stored procedures](../stored-procedures/index), [events](../events/index) or [triggers](../triggers/index)). * [ALTER VIEW](../alter-view/index); you can use [CREATE OR REPLACE VIEW](../create-view/index) instead. * [LOAD DATA](../load-data/index) and [LOAD TABLE](../load-table-from-master/index). * [CHANGE MASTER TO](../change-master-to/index) * [INSERT DELAYED](../insert-delayed/index) is permitted, but the statement is handled as a regular [INSERT](../insert/index). * [LOCK TABLES](../lock-tables/index) and [UNLOCK TABLES](../unlock-tables/index). * References to [local variables](../declare-variable/index) within prepared statements inside a stored routine (use [user-defined variables](../user-defined-variables/index) instead). * [BEGIN (WORK)](../start-transaction/index) is treated as the beginning of a [BEGIN END](../begin-end/index) block, not a transaction, so [START TRANSACTION](../start-transaction/index) needs to be used instead. * The number of permitted recursive calls is limited to [max\_sp\_recursion\_depth](../server-system-variables/index#max_sp_recursion_depth). If this variable is 0 (default), recursivity is disabled. The limit does not apply to stored functions. * Most statements that are not permitted in prepared statements are not permitted in stored programs. See [Prepare Statement:Permitted statements](../prepare-statement/index#permitted-statements) for a list of statements that can be used. [SIGNAL](../signal/index), [RESIGNAL](../resignal/index) and [GET DIAGNOSTICS](../get-diagnostics/index) are exceptions, and may be used in stored routines. There are also further limitations specific to the kind of stored routine. Note that, if a stored program calls another stored program, the latter will inherit the caller's limitations. So, for example, if a stored procedure is called by a stored function, that stored procedure will not be able to produce a result set, because stored functions can't do this. See Also -------- * [Stored Function Limitations](../stored-function-limitations/index) * [Trigger Limitations](../trigger-limitations/index) * [Event Limitations](../event-limitations/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_transactions_summary_by_thread_by_event_name Table Performance Schema events\_transactions\_summary\_by\_thread\_by\_event\_name Table =================================================================================== **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**The events\_transactions\_summary\_by\_thread\_by\_event\_name table was introduced in [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/). The `events_transactions_summary_by_thread_by_event_name` table contains information on transaction events aggregated by thread and event name. The table contains the following columns: ``` +----------------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------------------+---------------------+------+-----+---------+-------+ | THREAD_ID | bigint(20) unsigned | NO | | NULL | | | EVENT_NAME | varchar(128) | NO | | NULL | | | COUNT_STAR | bigint(20) unsigned | NO | | NULL | | | SUM_TIMER_WAIT | bigint(20) unsigned | NO | | NULL | | | MIN_TIMER_WAIT | bigint(20) unsigned | NO | | NULL | | | AVG_TIMER_WAIT | bigint(20) unsigned | NO | | NULL | | | MAX_TIMER_WAIT | bigint(20) unsigned | NO | | NULL | | | COUNT_READ_WRITE | bigint(20) unsigned | NO | | NULL | | | SUM_TIMER_READ_WRITE | bigint(20) unsigned | NO | | NULL | | | MIN_TIMER_READ_WRITE | bigint(20) unsigned | NO | | NULL | | | AVG_TIMER_READ_WRITE | bigint(20) unsigned | NO | | NULL | | | MAX_TIMER_READ_WRITE | bigint(20) unsigned | NO | | NULL | | | COUNT_READ_ONLY | bigint(20) unsigned | NO | | NULL | | | SUM_TIMER_READ_ONLY | bigint(20) unsigned | NO | | NULL | | | MIN_TIMER_READ_ONLY | bigint(20) unsigned | NO | | NULL | | | AVG_TIMER_READ_ONLY | bigint(20) unsigned | NO | | NULL | | | MAX_TIMER_READ_ONLY | bigint(20) unsigned | NO | | NULL | | +----------------------+---------------------+------+-----+---------+-------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb LOAD Data into Tables or Index LOAD Data into Tables or Index =============================== Loading data quickly into MariaDB | Title | Description | | --- | --- | | [LOAD DATA INFILE](../load-data-infile/index) | Read rows from a text file into a table. | | [LOAD INDEX](../load-index/index) | Loads one or more indexes from one or more MyISAM/Aria tables into a key buffer. | | [LOAD XML](../load-xml/index) | Load XML data into a table | | [LOAD\_FILE](../load_file/index) | Returns file contents as a string. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Kubernetes and MariaDB Kubernetes and MariaDB ======================= General information and hints on how to deploy MariaDB Kubernetes containers. Kubernetes is an open source containers orchestration system. It automates deployments, horizontal scaling, configuration and operations. It is often referred to as K8s. | Title | Description | | --- | --- | | [Kubernetes Overview for MariaDB Users](../kubernetes-overview-for-mariadb-users/index) | An overview of Kubernetes and how it works with MariaDB. | | [Kubernetes Operators for MariaDB](../kubernetes-operators-for-mariadb/index) | An overview of Kubernetes operators that can be used with MariaDB | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ps_is_consumer_enabled ps\_is\_consumer\_enabled ========================= Syntax ------ ``` sys.ps_is_consumer_enabled(consumer) ``` Description ----------- `ps_is_consumer_enabled` is a [stored function](../stored-functions/index) available with the [Sys Schema](../sys-schema/index). It returns an ENUM('YES','NO') depending on whether Performance Schema instrumentation for the given consumer is enabled, and NULL if not given a valid consumer name. Examples -------- ``` SELECT sys.ps_is_consumer_enabled('global_instrumentation'); +------------------------------------------------------+ | sys.ps_is_consumer_enabled('global_instrumentation') | +------------------------------------------------------+ | YES | +------------------------------------------------------+ SELECT sys.ps_is_consumer_enabled('events_stages_current'); +-----------------------------------------------------+ | sys.ps_is_consumer_enabled('events_stages_current') | +-----------------------------------------------------+ | NO | +-----------------------------------------------------+ SELECT sys.ps_is_consumer_enabled('nonexistent_consumer'); +----------------------------------------------------+ | sys.ps_is_consumer_enabled('nonexistent_consumer') | +----------------------------------------------------+ | NULL | +----------------------------------------------------+ ``` See Also -------- * [Performance Schema setup\_consumers Table](../performance-schema-setup_consumers-table/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Compiling MariaDB with Extra Modules/Options Compiling MariaDB with Extra Modules/Options ============================================= | Title | Description | | --- | --- | | [Compiling MariaDB with TCMalloc](../compiling-mariadb-with-tcmalloc/index) | TCMalloc is a malloc replacement library optimized for multi-threaded usage. | | [Compiling MariaDB with Vanilla XtraDB](../compiling-mariadb-with-vanilla-xtradb/index) | Sometimes, one needs to have MariaDB compiled with Vanilla XtraDB. This pag... | | [Specifying Which Plugins to Build](../specifying-which-plugins-to-build/index) | Specifying which plugins to build. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb IFNULL IFNULL ====== Syntax ------ ``` IFNULL(expr1,expr2) NVL(expr1,expr2) ``` Description ----------- If *`expr1`* is not NULL, IFNULL() returns *`expr1`*; otherwise it returns *`expr2`*. IFNULL() returns a numeric or string value, depending on the context in which it is used. From [MariaDB 10.3](../what-is-mariadb-103/index), NVL() is an alias for IFNULL(). Examples -------- ``` SELECT IFNULL(1,0); +-------------+ | IFNULL(1,0) | +-------------+ | 1 | +-------------+ SELECT IFNULL(NULL,10); +-----------------+ | IFNULL(NULL,10) | +-----------------+ | 10 | +-----------------+ SELECT IFNULL(1/0,10); +----------------+ | IFNULL(1/0,10) | +----------------+ | 10.0000 | +----------------+ SELECT IFNULL(1/0,'yes'); +-------------------+ | IFNULL(1/0,'yes') | +-------------------+ | yes | +-------------------+ ``` See Also -------- * [NULL values](../null-values/index) * [IS NULL operator](../is-null/index) * [IS NOT NULL operator](../is-not-null/index) * [COALESCE function](../coalesce/index) * [NULLIF function](../nullif/index) * [CONNECT data types](../connect-data-types/index#null-handling) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Galera Cluster Address Galera Cluster Address ====================== URL's in [Galera](../galera/index) take a particular format: ``` <schema>://<cluster_address>[?option1=value1[&option2=value2]] ``` Schema ------ * `gcomm` - This is the option to use for a working implementation. * `dummy` - Used for running tests and profiling, does not do any actual replication, and all following parameters are ignored. Cluster address --------------- * The cluster address shouldn't be empty like `gcomm://`. This should never be hardcoded into any configuration files. * To connect the node to an existing cluster, the cluster address should contain the address of any member of the cluster you want to join. * The cluster address can also contain a comma-separated list of multiple members of the cluster. It is good practice to list all possible members of the cluster, for example `gcomm:*<node1 name or ip>,<node2 name or ip2>,<node3 name or ip>*`. Alternately if multicast is use put the multicast address instead of the list of nodes. Each member address or multicast address can specify `<node name or ip>:<port>` if a non-default port is used. Option list ----------- * The [wsrep\_provider\_options](../galera-cluster-system-variables/index#wsrep_provider_options) variable is used to set a [list of options](../wsrep_provider_options/index). These parameters can also be provided (and overridden) as part of the URL. Unlike options provided in a configuration file, they will not endure, and need to be resubmitted with each connection. A useful option to set is `pc.wait_prim=no` to ensure the server will start running even if it can't determine a primary node. This is useful if all members go down at the same time. Port ---- By default, gcomm listens on all interfaces. The port is either provided in the cluster address, or will default to 4567 if not set. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema QUERY_CACHE_INFO Table Information Schema QUERY\_CACHE\_INFO Table =========================================== Description ----------- The table is not a standard Information Schema table, and is a MariaDB extension. The `QUERY_CACHE_INFO` table is created by the [QUERY\_CACHE\_INFO](../query_cache_info-plugin/index) plugin, and allows you to see the contents of the [query cache](../query-cache/index). It creates a table in the [information\_schema](../information_schema/index) database that shows all queries that are in the cache. You must have the `PROCESS` privilege (see [GRANT](../grant/index)) to use this table. It contains the following columns: | Column | Description | | --- | --- | | `STATEMENT_SCHEMA` | Database used when query was included | | `STATEMENT_TEXT` | Query text | | `RESULT_BLOCKS_COUNT` | Number of result blocks | | `RESULT_BLOCKS_SIZE` | Size in bytes of result blocks | | `RESULT_BLOCKS_SIZE_USED` | Size in bytes of used blocks | | `LIMIT` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `MAX_SORT_LENGTH` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `GROUP_CONCAT_MAX_LENGTH` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `CHARACTER_SET_CLIENT` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `CHARACTER_SET_RESULT` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `COLLATION` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `TIMEZONE` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `DEFAULT_WEEK_FORMAT` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `DIV_PRECISION_INCREMENT` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `SQL_MODE` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `LC_TIME_NAMES` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `CLIENT_LONG_FLAG` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `CLIENT_PROTOCOL_41` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `PROTOCOL_TYPE` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `MORE_RESULTS_EXISTS` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `IN_TRANS` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `AUTOCOMMIT` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `PACKET_NUMBER` | Added [MariaDB 10.1.8](https://mariadb.com/kb/en/mariadb-1018-release-notes/). | | `HITS` | Incremented each time the query cache is hit. Added [MariaDB 10.3.2](https://mariadb.com/kb/en/mariadb-1032-release-notes/). | For example: ``` SELECT * FROM information_schema.QUERY_CACHE_INFO; +------------------+-----------------+---------------------+--------------------+-------------------------+ | STATEMENT_SCHEMA | STATEMENT_TEXT | RESULT_BLOCKS_COUNT | RESULT_BLOCKS_SIZE | RESULT_BLOCKS_SIZE_USED | +------------------+-----------------+---------------------+--------------------+-------------------------+ ... | test | SELECT * FROM a | 1 | 512 | 143 | | test | select * FROM a | 1 | 512 | 143 | ... +------------------+-----------------+---------------------+--------------------+------------------------- ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CUME_DIST CUME\_DIST ========== **MariaDB starting with [10.2](../what-is-mariadb-102/index)**The CUME\_DIST() function was first introduced with [window functions](../window-functions/index) in [MariaDB 10.2.0](https://mariadb.com/kb/en/mariadb-1020-release-notes/). Syntax ------ ``` CUME_DIST() OVER ( [ PARTITION BY partition_expression ] [ ORDER BY order_list ] ) ``` Description ----------- CUME\_DIST() is a [window function](../window-functions/index) that returns the cumulative distribution of a given row. The following formula is used to calculate the value: ``` (number of rows <= current row) / (total rows) ``` Examples -------- ``` create table t1 ( pk int primary key, a int, b int ); insert into t1 values ( 1 , 0, 10), ( 2 , 0, 10), ( 3 , 1, 10), ( 4 , 1, 10), ( 8 , 2, 10), ( 5 , 2, 20), ( 6 , 2, 20), ( 7 , 2, 20), ( 9 , 4, 20), (10 , 4, 20); select pk, a, b, rank() over (order by a) as rank, percent_rank() over (order by a) as pct_rank, cume_dist() over (order by a) as cume_dist from t1; +----+------+------+------+--------------+--------------+ | pk | a | b | rank | pct_rank | cume_dist | +----+------+------+------+--------------+--------------+ | 1 | 0 | 10 | 1 | 0.0000000000 | 0.2000000000 | | 2 | 0 | 10 | 1 | 0.0000000000 | 0.2000000000 | | 3 | 1 | 10 | 3 | 0.2222222222 | 0.4000000000 | | 4 | 1 | 10 | 3 | 0.2222222222 | 0.4000000000 | | 5 | 2 | 20 | 5 | 0.4444444444 | 0.8000000000 | | 6 | 2 | 20 | 5 | 0.4444444444 | 0.8000000000 | | 7 | 2 | 20 | 5 | 0.4444444444 | 0.8000000000 | | 8 | 2 | 10 | 5 | 0.4444444444 | 0.8000000000 | | 9 | 4 | 20 | 9 | 0.8888888889 | 1.0000000000 | | 10 | 4 | 20 | 9 | 0.8888888889 | 1.0000000000 | +----+------+------+------+--------------+--------------+ select pk, a, b, percent_rank() over (order by pk) as pct_rank, cume_dist() over (order by pk) as cume_dist from t1 order by pk; +----+------+------+--------------+--------------+ | pk | a | b | pct_rank | cume_dist | +----+------+------+--------------+--------------+ | 1 | 0 | 10 | 0.0000000000 | 0.1000000000 | | 2 | 0 | 10 | 0.1111111111 | 0.2000000000 | | 3 | 1 | 10 | 0.2222222222 | 0.3000000000 | | 4 | 1 | 10 | 0.3333333333 | 0.4000000000 | | 5 | 2 | 20 | 0.4444444444 | 0.5000000000 | | 6 | 2 | 20 | 0.5555555556 | 0.6000000000 | | 7 | 2 | 20 | 0.6666666667 | 0.7000000000 | | 8 | 2 | 10 | 0.7777777778 | 0.8000000000 | | 9 | 4 | 20 | 0.8888888889 | 0.9000000000 | | 10 | 4 | 20 | 1.0000000000 | 1.0000000000 | +----+------+------+--------------+--------------+ select pk, a, b, percent_rank() over (partition by a order by a) as pct_rank, cume_dist() over (partition by a order by a) as cume_dist from t1; +----+------+------+--------------+--------------+ | pk | a | b | pct_rank | cume_dist | +----+------+------+--------------+--------------+ | 1 | 0 | 10 | 0.0000000000 | 1.0000000000 | | 2 | 0 | 10 | 0.0000000000 | 1.0000000000 | | 3 | 1 | 10 | 0.0000000000 | 1.0000000000 | | 4 | 1 | 10 | 0.0000000000 | 1.0000000000 | | 5 | 2 | 20 | 0.0000000000 | 1.0000000000 | | 6 | 2 | 20 | 0.0000000000 | 1.0000000000 | | 7 | 2 | 20 | 0.0000000000 | 1.0000000000 | | 8 | 2 | 10 | 0.0000000000 | 1.0000000000 | | 9 | 4 | 20 | 0.0000000000 | 1.0000000000 | | 10 | 4 | 20 | 0.0000000000 | 1.0000000000 | +----+------+------+--------------+--------------+ ``` See Also -------- * [PERCENT\_RANK()](../percent_rank/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Relational Databases: Table Keys Relational Databases: Table Keys ================================ A *key*, or *index*, as the term itself indicates, unlocks access to the tables. If you know the key, you know how to identify specific records and the relationships between the tables. Each key consists of one or more fields, or field prefix. The order of columns in an index is significant. Each key has a name. A *candidate key* is a field, or combination of fields, that uniquely identifies a record. It cannot contain a null value, and its value must be unique. (With duplicates, you would no longer be identifying a unique record). A *primary key* (PK) is a candidate key that has been designated to identify unique records in the table throughout the database structure. A *surrogate key* is a primary key that contains unique values automatically generated by the database system - usually, integer numbers. A surrogate key has no meaning, except uniquely identifying a record. This is the most common type of primary key. For example, see the following table: | Customer\_code | First\_name | Surname | Telephone\_number | | --- | --- | --- | --- | | 1 | Ariane | Edison | 448-2143 | | 2 | Georgei | Edison | 448-2142 | | 3 | Abbas | Edison | 9231-5312 | At first glance, there are two possible candidate keys for this table. Either *customer\_code* or a combination of *first\_name*, *surname* and *telephone\_number* would suffice. It is always better to choose the candidate key with the least number of fields for the primary key, so you would choose *customer\_code* in this example (note that it is a surrogate key). Upon reflection, there is also the possibility of the second combination not being unique. The combination of *first\_name*, *surname* and *telephone\_number* could in theory be duplicated, such as where a father has a son of the same name who is contactable at the same telephone number. This system would have to expressly exclude this possibility for these three fields to be considered for the status of primary key. There may be many Ariane Edisons, but you avoid confusion by assigning each a unique number. Once a primary key has been created, the remaining candidates are labeled as *alternate keys*. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Kubernetes Operators for MariaDB Kubernetes Operators for MariaDB ================================ Operators basically instruct Kubernetes about how to manage a certain technology. Kubernetes comes with some default operators, but it is possible to create custom operators. Operators created by the community can be found on [OperatorHub.io](https://operatorhub.io/). Custom Operators ---------------- Kubernetes provides a declarative API. To support a specific (i.e. MariaDB) technology or implement a desired behavior (i.e. provisioning a [replica](../standard-replication/index)), we extend Kubernetes API. This involves creating two main components: * A custom resource. * A custom controller. A custom resource adds an API endpoint, so the resource can be managed via the API server. It includes functionality to get information about the resource, like a list of the existing servers. A custom controller implements the checks that must be performed against the resource to check if its state should be corrected using the API. In the case of MariaDB, some reasonable checks would be verifying that it accepts connections, replication is running, and a server is (or is not) read only. MariaDB Operator ---------------- [OperatorHub.io](https://operatorhub.io/) has a [MariaDB operator](https://operatorhub.io/operator/mariadb-operator-app). At the time of this writing it is in alpha stage, so please check its maturity before using it. MariaDB operator is open source and is released under the terms of the MIT license. The source code is [available on GitHub](https://github.com/abalki001/mariadb-operator). The `README.md` file shows usage examples. It defines the following custom resources: * MariaDB server. * MariaDB Backup. [mariabackup](../mariabackup/index) is used. * MariaDB Monitor. Prometheus metrics are exposed on port 9090. Other Operators --------------- If you know about other MariaDB operators, feel free to add them to this page (see [Writing and Editing Knowledge Base Articles](../writing-and-editing-knowledge-base-articles/index)). MySQL and Percona Server operators should work as well, though some changes may be necessary to fix [incompatibilities](../mariadb-vs-mysql-compatibility/index) or take advantage of certain [MariaDB features](../mariadb-vs-mysql-features/index). --- Content initially contributed by [Vettabase Ltd](https://vettabase.com/). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Getting, Installing, and Upgrading MariaDB Getting, Installing, and Upgrading MariaDB =========================================== | Title | Description | | --- | --- | | [Where to Download MariaDB](../where-to-download-mariadb/index) | Downloading tarballs, binaries, packages, and the source code for MariaDB. | | [MariaDB Binary Packages](../binary-packages/index) | Instructions on installing MariaDB binaries and packages. | | [Upgrading MariaDB](../upgrading/index) | Upgrading from an earlier version, or from MySQL | | [Downgrading between Major Versions of MariaDB](../downgrading-between-major-versions-of-mariadb/index) | Downgrading MariaDB is not supported. | | [Compiling MariaDB From Source](../compiling-mariadb-from-source/index) | Articles on compiling MariaDB from source | | [Starting and Stopping MariaDB](../starting-and-stopping-mariadb/index) | Articles related to starting and stopping MariaDB Server. | | [MariaDB Performance & Advanced Configurations](../mariadb-performance-advanced-configurations/index) | Articles of how to setup your MariaDB optimally on different systems | | [Troubleshooting Installation Issues](../troubleshooting-installation-issues/index) | Articles relating to installation issues users might run into | | [Installing System Tables (mysql\_install\_db)](../installing-system-tables-mysql_install_db/index) | Using mysql\_install\_db to create the system tables in the 'mysql' database directory. | | [mysql\_install\_db.exe](../mysql_install_dbexe/index) | Windows equivalent of mysql\_install\_db for creating the system tables etc. | | [Configuring MariaDB with Option Files](../configuring-mariadb-with-option-files/index) | Configuring MariaDB with my.cnf and other option files. | | [MariaDB Environment Variables](../mariadb-environment-variables/index) | List of environment variables used by MariaDB. | | [Puppet and MariaDB](../puppet-and-mariadb/index) | Puppet modules that allow you to use MariaDB. | | [MariaDB on Amazon RDS](../mariadb-on-amazon-rds/index) | Getting started with MariaDB on Amazon RDS | | [Obsolete Installation Information](../obsolete-installation-information/index) | Installation-related items that are obsolete | | [Migrating to MariaDB](../migrating-to-mariadb/index) | Migrating to MariaDB from another DBMS. | | [Installing MariaDB on IBM Cloud](../installing-mariadb-on-ibm-cloud/index) | Get MariaDB on IBM Cloud You should have an IBM Cloud account, otherwise ... | | [mysqld Configuration Files and Groups](../mysqld-configuration-files-and-groups/index) | Which configuration files and groups mysqld reads. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb NDB in MariaDB NDB in MariaDB ============== NDB (MySQL Cluster) has been removed completely from [MariaDB 10.1](../what-is-mariadb-101/index). From [MariaDB 10.0](../what-is-mariadb-100/index) and below, it was disabled due to it not being in the main upstream MySQL releases. Upstream has NDB available as a separate download, because Cluster is updated more frequently compared to baseline MySQL. For an actively developed alternative, see [Galera Cluster](../galera/index). One of the prerequisites to having NDB working in MariaDB is for us to get an active maintainer of the NDB code. The [MariaDB community](../community/index) has not had much interest in this feature. If there is interest in this feature, please send email to the [maria-discuss](http://launchpad.net/~maria-discuss) mailing list, or file a request in [Jira](http://jira.mariadb.org). In 'theory' it should be easy for anyone to get ndb in MariaDB to work as well as in MySQL as all the ndb code is still in the tree. If you are interested in (and capable of) doing this, please join the MariaDB project! Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb index_merge sort_intersection index\_merge sort\_intersection =============================== Prior to [MariaDB 5.3](../what-is-mariadb-53/index), the `index_merge` access method supported `union`, `sort-union`, and `intersection` operations. Starting from [MariaDB 5.3](../what-is-mariadb-53/index), the `sort-intersection` operation is also supported. This allows the use of `index_merge` in a broader number of cases. This feature is disabled by default. To enable it, turn on the optimizer switch `index_merge_sort_intersection` like so: ``` SET optimizer_switch='index_merge_sort_intersection=on' ``` Limitations of index\_merge/intersection ---------------------------------------- Prior to [MariaDB 5.3](../what-is-mariadb-53/index), the `index_merge` access method had one intersection strategy called `intersection`. That strategy can only be used when merged index scans produced rowid-ordered streams. In practice this means that an `intersection` could only be constructed from equality (=) conditions. For example, the following query will use `intersection`: ``` MySQL [ontime]> EXPLAIN SELECT AVG(arrdelay) FROM ontime WHERE depdel15=1 AND OriginState ='CA'; +--+-----------+------+-----------+--------------------+--------------------+-------+----+-----+-------------------------------------------------+ |id|select_type|table |type |possible_keys |key |key_len|ref |rows |Extra | +--+-----------+------+-----------+--------------------+--------------------+-------+----+-----+-------------------------------------------------+ | 1|SIMPLE |ontime|index_merge|OriginState,DepDel15|OriginState,DepDel15|3,5 |NULL|76952|Using intersect(OriginState,DepDel15);Using where| +--+-----------+------+-----------+--------------------+--------------------+-------+----+-----+-------------------------------------------------+ ``` but if you replace `OriginState ='CA'` with `OriginState IN ('CA', 'GB')` (which matches the same number of records), then `intersection` is not usable anymore: ``` MySQL [ontime]> explain select avg(arrdelay) from ontime where depdel15=1 and OriginState IN ('CA', 'GB'); +--+-----------+------+----+--------------------+--------+-------+-----+-----+-----------+ |id|select_type|table |type|possible_keys |key |key_len|ref |rows |Extra | +--+-----------+------+----+--------------------+--------+-------+-----+-----+-----------+ | 1|SIMPLE |ontime|ref |OriginState,DepDel15|DepDel15|5 |const|36926|Using where| +--+-----------+------+----+--------------------+--------+-------+-----+-----+-----------+ ``` The latter query would also run 5.x times slower (from 2.2 to 10.8 seconds) in our experiments. How index\_merge/sort\_intersection improves the situation ---------------------------------------------------------- In [MariaDB 5.3](../what-is-mariadb-53/index), when `index_merge_sort_intersection` is enabled, `index_merge` intersection plans can be constructed from non-equality conditions: ``` MySQL [ontime]> explain select avg(arrdelay) from ontime where depdel15=1 and OriginState IN ('CA', 'GB'); +--+-----------+------+-----------+--------------------+--------------------+-------+----+-----+--------------------------------------------------------+ |id|select_type|table |type |possible_keys |key |key_len|ref |rows |Extra | +--+-----------+------+-----------+--------------------+--------------------+-------+----+-----+--------------------------------------------------------+ | 1|SIMPLE |ontime|index_merge|OriginState,DepDel15|DepDel15,OriginState|5,3 |NULL|60754|Using sort_intersect(DepDel15,OriginState); Using where | +--+-----------+------+-----------+--------------------+--------------------+-------+----+-----+--------------------------------------------------------+ ``` In our tests, this query ran in 3.2 seconds, which is not as good as the case with two equalities, but still much better than 10.8 seconds we were getting without `sort_intersect`. The `sort_intersect` strategy has higher overhead than `intersect` but is able to handle a broader set of `WHERE` conditions. When to Use ----------- `index_merge/sort_intersection` works best on tables with lots of records and where intersections are sufficiently large (but still small enough to make a full table scan overkill). The benefit is expected to be bigger for io-bound loads. See Also -------- * [What is MariaDB 5.3](../what-is-mariadb-53/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Performance Schema Overview Performance Schema Overview =========================== The Performance Schema is a feature for monitoring server performance. Introduction ------------ It is implemented as a storage engine, and so will appear in the list of storage engines available. ``` SHOW ENGINES; +--------------------+---------+----------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +--------------------+---------+----------------------------------+--------------+------+------------+ | ... | | | | | | | PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO | | ... | | | | | | +--------------------+---------+----------------------------------+--------------+------+------------+ ``` However, `performance_schema` is not a regular storage engine for storing data, it's a mechanism for implementing the Performance Schema feature. The storage engine contains a database called `performance_schema`, which in turn consists of a number of tables that can be queried with regular SQL statements, returning specific performance information. ``` USE performance_schema ``` ``` SHOW TABLES; +----------------------------------------------------+ | Tables_in_performance_schema | +----------------------------------------------------+ | accounts | ... | users | +----------------------------------------------------+ 80 rows in set (0.00 sec) ``` See [List of Performance Schema Tables](../list-of-performance-schema-tables/index) for a full list and links to detailed descriptions of each table. From [MariaDB 10.5](../what-is-mariadb-105/index), there are 80 Performance Schema tables, while until [MariaDB 10.4](../what-is-mariadb-104/index), there are 52. Activating the Performance Schema --------------------------------- The performance schema is disabled by default for performance reasons. You can check its current status by looking at the value of the [performance\_schema](../performance-schema-system-variables/index#performance_schema) system variable. ``` SHOW VARIABLES LIKE 'performance_schema'; +--------------------+-------+ | Variable_name | Value | +--------------------+-------+ | performance_schema | ON | +--------------------+-------+ ``` The performance schema cannot be activated at runtime - it must be set when the server starts by adding the following line in your `my.cnf` configuration file. ``` performance_schema=ON ``` Until [MariaDB 10.4](../what-is-mariadb-104/index), all memory used by the Performance Schema is allocated at startup. From [MariaDB 10.5](../what-is-mariadb-105/index), some memory is allocated dynamically, depending on load, number of connections, number of tables open etc. Enabling the Performance Schema ------------------------------- You need to set up all consumers (starting collection of data) and instrumentations (what to collect): ``` UPDATE performance_schema.setup_consumers SET ENABLED = 'YES'; UPDATE performance_schema.setup_instruments SET ENABLED = 'YES', TIMED = 'YES'; ``` You can decide what to enable/disable with `WHERE NAME like "%what_to_enable"`; You can disable instrumentations by setting `ENABLED` to `"NO"`. You can also do this in your my.cnf file. The following enables all instrumentation of all stages (computation units) in MariaDB: ``` [mysqld] performance_schema=ON performance-schema-instrument='stage/%=ON' performance-schema-consumer-events-stages-current=ON performance-schema-consumer-events-stages-history=ON performance-schema-consumer-events-stages-history-long=ON ``` Listing Performance Schema Variables ------------------------------------ ``` SHOW VARIABLES LIKE "perf%"; +--------------------------------------------------------+-------+ | Variable_name | Value | +--------------------------------------------------------+-------+ | performance_schema | ON | ... | performance_schema_users_size | 100 | +--------------------------------------------------------+-------+ ``` See [Performance Schema System Variables](../performance-schema-system-variables/index) for a full list of available system variables. Note that the "consumer" events are not shown on this list, as they are only available as options, not as system variables, and they can only be enabled at [startup](../mysqld-options/index#performance-schema-options). Column Comments --------------- **MariaDB starting with [10.7.1](https://mariadb.com/kb/en/mariadb-1071-release-notes/)**From [MariaDB 10.7.1](https://mariadb.com/kb/en/mariadb-1071-release-notes/), comments have been added to table columns in the Performance Schema. These can be viewed with, for example: ``` SELECT column_name, column_comment FROM information_schema.columns WHERE table_schema='performance_schema' AND table_name='file_instances'; ... *************************** 2. row *************************** column_name: EVENT_NAME column_comment: Instrument name associated with the file. *************************** 3. row *************************** column_name: OPEN_COUNT column_comment: Open handles on the file. A value of greater than zero means that the file is currently open. ... ``` See Also -------- * [Performance schema options](../mysqld-options/index#performance-schema-options) * [SHOW ENGINE STATUS](../show-engine/index) * [SHOW PROFILE](../show-profile/index) * [ANALYZE STATEMENT](https://mariadb.com/analyze-statement) * [Performance schema in MySQL 5.6](https://dev.mysql.com/doc/refman/5.6/en/performance-schema.html). All things here should also work for MariaDB. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Percona XtraBackup Build Instructions Percona XtraBackup Build Instructions ===================================== In [MariaDB 10.1](../what-is-mariadb-101/index) and later, [Mariabackup](../mariabackup/index) is the recommended backup method to use instead of Percona XtraBackup. In [MariaDB 10.3](../what-is-mariadb-103/index), Percona XtraBackup is **not supported**. See [Percona XtraBackup Overview: Compatibility with MariaDB](../percona-xtrabackup-overview/index#compatibility-with-mariadb) for more information. In [MariaDB 10.2](../what-is-mariadb-102/index) and [MariaDB 10.1](../what-is-mariadb-101/index), Percona XtraBackup is only **partially supported**. See [Percona XtraBackup Overview: Compatibility with MariaDB](../percona-xtrabackup-overview/index#compatibility-with-mariadb) for more information. Build instructions for [Percona XtraBackup](../percona-xtrabackup/index). Solaris 10 (SunOS 5.10) notes: Edit utils/build.sh and add -lrt -m64 to CFLAGS and CXXFLAGS. Make sure that you're using GNU utils for building, including make, cmake, gcc, gawk, getopt, autotools, libtool, automake, autoconf and bazaar. If you want to change MySQL version which to build against with edit one of the following lines: MYSQL\_51\_VERSION=... MYSQL\_55\_VERSION=... PS\_51\_VERSION=... PS\_55\_VERSION=.. When ready run one of the following depending on the MySQL version which you want to build with: AUTO\_DOWNLOAD="yes" ./utils/build.sh xtradb (build against XtraDB 5.1) AUTO\_DOWNLOAD="yes" ./utils/build.sh innodb51\_builtin (build against built-in InnoDB in MySQL 5.1) AUTO\_DOWNLOAD="yes" ./utils/build.sh xtradb55 (build against XtraDB 5.5) AUTO\_DOWNLOAD="yes" ./utils/build.sh innodb55 (build against InnoDB in MySQL 5.5) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb USE INDEX USE INDEX ========= You can limit which indexes are considered with the `USE INDEX` option. Syntax ------ ``` USE INDEX [{FOR {JOIN|ORDER BY|GROUP BY}] ([index_list]) ``` Description ----------- The default is 'FOR JOIN', which means that the hint only affects how the WHERE clause is optimized. USE INDEX is used after the table name in the FROM clause. USE INDEX cannot use an [ignored index](../ignored-indexes/index) - it will be treated as if it doesn't exist. ### Index Prefixes When using index hints (USE, FORCE or IGNORE INDEX), the index name value can also be an unambiguous prefix of an index name. Example ------- ``` CREATE INDEX Name ON City (Name); CREATE INDEX CountryCode ON City (Countrycode); EXPLAIN SELECT Name FROM City USE INDEX (CountryCode) WHERE name="Helsingborg" AND countrycode="SWE"; ``` This produces: ``` id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE City ref CountryCode CountryCode 3 const 14 Using where ``` If we had not used USE INDEX, the Name index would have been in possible keys. See Also -------- * [Index Hints: How to Force Query Plans](../index-hints-how-to-force-query-plans/index) for more details * [IGNORE INDEX](../ignore-index/index) * [FORCE INDEX](../force-index/index) * [Ignored Indexes](../ignored-indexes/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema setup_instruments Table Performance Schema setup\_instruments Table =========================================== The `setup_instruments` table contains a list of instrumented object classes for which it is possible to collect events. There is one row for each instrument in the source code. When an instrument is enabled and executed, instances are created which are then stored in the [cond\_instances](../performance-schema-cond_instances-table/index), [file\_instances](../performance-schema-file_instances-table/index), [mutex\_instances](../performance-schema-mutex_instances-table/index), [rwlock\_instances](../performance-schema-rwlock_instances-table/index) or [socket\_instance](../performance-schema-socket_instances-table/index) tables. It contains the following columns: | Column | Description | | --- | --- | | `NAME` | Instrument name | | `ENABLED` | Whether or not the instrument is enabled. It can be disabled, and the instrument will produce no events. | | `TIMED` | Whether or not the instrument is timed. It can be set, but if disabled, events produced by the instrument will have `NULL` values for the corresponding `TIMER_START`, `TIMER_END`, and `TIMER_WAIT` values. | Example ------- From [MariaDB 10.5.7](https://mariadb.com/kb/en/mariadb-1057-release-notes/), default settings with the Performance Schema enabled: ``` SELECT * FROM setup_instruments ORDER BY name; +--------------------------------------------------------------------------------+---------+-------+ | NAME | ENABLED | TIMED | +--------------------------------------------------------------------------------+---------+-------+ | idle | YES | YES | | memory/csv/blobroot | NO | NO | | memory/csv/row | NO | NO | | memory/csv/tina_set | NO | NO | | memory/csv/TINA_SHARE | NO | NO | | memory/csv/Transparent_file | NO | NO | | memory/innodb/adaptive hash index | NO | NO | | memory/innodb/btr0btr | NO | NO | | memory/innodb/btr0buf | NO | NO | | memory/innodb/btr0bulk | NO | NO | | memory/innodb/btr0cur | NO | NO | | memory/innodb/btr0pcur | NO | NO | | memory/innodb/btr0sea | NO | NO | | memory/innodb/buf0buf | NO | NO | | memory/innodb/buf0dblwr | NO | NO | | memory/innodb/buf0dump | NO | NO | | memory/innodb/buf_buf_pool | NO | NO | | memory/innodb/dict0dict | NO | NO | | memory/innodb/dict0mem | NO | NO | | memory/innodb/dict0stats | NO | NO | | memory/innodb/dict_stats_bg_recalc_pool_t | NO | NO | | memory/innodb/dict_stats_index_map_t | NO | NO | | memory/innodb/dict_stats_n_diff_on_level | NO | NO | | memory/innodb/eval0eval | NO | NO | | memory/innodb/fil0crypt | NO | NO | | memory/innodb/fil0fil | NO | NO | | memory/innodb/fsp0file | NO | NO | | memory/innodb/fts0ast | NO | NO | | memory/innodb/fts0blex | NO | NO | | memory/innodb/fts0config | NO | NO | | memory/innodb/fts0file | NO | NO | | memory/innodb/fts0fts | NO | NO | | memory/innodb/fts0opt | NO | NO | | memory/innodb/fts0pars | NO | NO | | memory/innodb/fts0que | NO | NO | | memory/innodb/fts0sql | NO | NO | | memory/innodb/fts0tlex | NO | NO | | memory/innodb/gis0sea | NO | NO | | memory/innodb/handler0alter | NO | NO | | memory/innodb/hash0hash | NO | NO | | memory/innodb/ha_innodb | NO | NO | | memory/innodb/i_s | NO | NO | | memory/innodb/lexyy | NO | NO | | memory/innodb/lock0lock | NO | NO | | memory/innodb/mem0mem | NO | NO | | memory/innodb/os0event | NO | NO | | memory/innodb/os0file | NO | NO | | memory/innodb/other | NO | NO | | memory/innodb/pars0lex | NO | NO | | memory/innodb/rem0rec | NO | NO | | memory/innodb/row0ftsort | NO | NO | | memory/innodb/row0import | NO | NO | | memory/innodb/row0log | NO | NO | | memory/innodb/row0merge | NO | NO | | memory/innodb/row0mysql | NO | NO | | memory/innodb/row0sel | NO | NO | | memory/innodb/row_log_buf | NO | NO | | memory/innodb/row_merge_sort | NO | NO | | memory/innodb/srv0start | NO | NO | | memory/innodb/std | NO | NO | | memory/innodb/sync0arr | NO | NO | | memory/innodb/sync0debug | NO | NO | | memory/innodb/sync0rw | NO | NO | | memory/innodb/sync0start | NO | NO | | memory/innodb/sync0types | NO | NO | | memory/innodb/trx0i_s | NO | NO | | memory/innodb/trx0roll | NO | NO | | memory/innodb/trx0rseg | NO | NO | | memory/innodb/trx0seg | NO | NO | | memory/innodb/trx0trx | NO | NO | | memory/innodb/trx0undo | NO | NO | | memory/innodb/ut0list | NO | NO | | memory/innodb/ut0mem | NO | NO | | memory/innodb/ut0new | NO | NO | | memory/innodb/ut0pool | NO | NO | | memory/innodb/ut0rbt | NO | NO | | memory/innodb/ut0wqueue | NO | NO | | memory/innodb/xtrabackup | NO | NO | | memory/memory/HP_INFO | NO | NO | | memory/memory/HP_KEYDEF | NO | NO | | memory/memory/HP_PTRS | NO | NO | | memory/memory/HP_SHARE | NO | NO | | memory/myisam/filecopy | NO | NO | | memory/myisam/FTB | NO | NO | | memory/myisam/FTPARSER_PARAM | NO | NO | | memory/myisam/FT_INFO | NO | NO | | memory/myisam/ft_memroot | NO | NO | | memory/myisam/ft_stopwords | NO | NO | | memory/myisam/keycache_thread_var | NO | NO | | memory/myisam/MI_DECODE_TREE | NO | NO | | memory/myisam/MI_INFO | NO | NO | | memory/myisam/MI_INFO::bulk_insert | NO | NO | | memory/myisam/MI_INFO::ft1_to_ft2 | NO | NO | | memory/myisam/MI_SORT_PARAM | NO | NO | | memory/myisam/MI_SORT_PARAM::wordroot | NO | NO | | memory/myisam/MYISAM_SHARE | NO | NO | | memory/myisam/MYISAM_SHARE::decode_tables | NO | NO | | memory/myisam/preload_buffer | NO | NO | | memory/myisam/record_buffer | NO | NO | | memory/myisam/SORT_FT_BUF | NO | NO | | memory/myisam/SORT_INFO::buffer | NO | NO | | memory/myisam/SORT_KEY_BLOCKS | NO | NO | | memory/myisam/stPageList::pages | NO | NO | | memory/myisammrg/children | NO | NO | | memory/myisammrg/MYRG_INFO | NO | NO | | memory/partition/ha_partition::file | NO | NO | | memory/partition/ha_partition::part_ids | NO | NO | | memory/partition/Partition_admin | NO | NO | | memory/partition/Partition_share | NO | NO | | memory/partition/partition_sort_buffer | NO | NO | | memory/performance_schema/accounts | YES | NO | | memory/performance_schema/cond_class | YES | NO | | memory/performance_schema/cond_instances | YES | NO | | memory/performance_schema/events_stages_history | YES | NO | | memory/performance_schema/events_stages_history_long | YES | NO | | memory/performance_schema/events_stages_summary_by_account_by_event_name | YES | NO | | memory/performance_schema/events_stages_summary_by_host_by_event_name | YES | NO | | memory/performance_schema/events_stages_summary_by_thread_by_event_name | YES | NO | | memory/performance_schema/events_stages_summary_by_user_by_event_name | YES | NO | | memory/performance_schema/events_stages_summary_global_by_event_name | YES | NO | | memory/performance_schema/events_statements_current | YES | NO | | memory/performance_schema/events_statements_current.sqltext | YES | NO | | memory/performance_schema/events_statements_current.tokens | YES | NO | | memory/performance_schema/events_statements_history | YES | NO | | memory/performance_schema/events_statements_history.sqltext | YES | NO | | memory/performance_schema/events_statements_history.tokens | YES | NO | | memory/performance_schema/events_statements_history_long | YES | NO | | memory/performance_schema/events_statements_history_long.sqltext | YES | NO | | memory/performance_schema/events_statements_history_long.tokens | YES | NO | | memory/performance_schema/events_statements_summary_by_account_by_event_name | YES | NO | | memory/performance_schema/events_statements_summary_by_digest | YES | NO | | memory/performance_schema/events_statements_summary_by_digest.tokens | YES | NO | | memory/performance_schema/events_statements_summary_by_host_by_event_name | YES | NO | | memory/performance_schema/events_statements_summary_by_program | YES | NO | | memory/performance_schema/events_statements_summary_by_thread_by_event_name | YES | NO | | memory/performance_schema/events_statements_summary_by_user_by_event_name | YES | NO | | memory/performance_schema/events_statements_summary_global_by_event_name | YES | NO | | memory/performance_schema/events_transactions_history | YES | NO | | memory/performance_schema/events_transactions_history_long | YES | NO | | memory/performance_schema/events_transactions_summary_by_account_by_event_name | YES | NO | | memory/performance_schema/events_transactions_summary_by_host_by_event_name | YES | NO | | memory/performance_schema/events_transactions_summary_by_thread_by_event_name | YES | NO | | memory/performance_schema/events_transactions_summary_by_user_by_event_name | YES | NO | | memory/performance_schema/events_waits_history | YES | NO | | memory/performance_schema/events_waits_history_long | YES | NO | | memory/performance_schema/events_waits_summary_by_account_by_event_name | YES | NO | | memory/performance_schema/events_waits_summary_by_host_by_event_name | YES | NO | | memory/performance_schema/events_waits_summary_by_thread_by_event_name | YES | NO | | memory/performance_schema/events_waits_summary_by_user_by_event_name | YES | NO | | memory/performance_schema/file_class | YES | NO | | memory/performance_schema/file_handle | YES | NO | | memory/performance_schema/file_instances | YES | NO | | memory/performance_schema/hosts | YES | NO | | memory/performance_schema/memory_class | YES | NO | | memory/performance_schema/memory_summary_by_account_by_event_name | YES | NO | | memory/performance_schema/memory_summary_by_host_by_event_name | YES | NO | | memory/performance_schema/memory_summary_by_thread_by_event_name | YES | NO | | memory/performance_schema/memory_summary_by_user_by_event_name | YES | NO | | memory/performance_schema/memory_summary_global_by_event_name | YES | NO | | memory/performance_schema/metadata_locks | YES | NO | | memory/performance_schema/mutex_class | YES | NO | | memory/performance_schema/mutex_instances | YES | NO | | memory/performance_schema/prepared_statements_instances | YES | NO | | memory/performance_schema/rwlock_class | YES | NO | | memory/performance_schema/rwlock_instances | YES | NO | | memory/performance_schema/scalable_buffer | YES | NO | | memory/performance_schema/session_connect_attrs | YES | NO | | memory/performance_schema/setup_actors | YES | NO | | memory/performance_schema/setup_objects | YES | NO | | memory/performance_schema/socket_class | YES | NO | | memory/performance_schema/socket_instances | YES | NO | | memory/performance_schema/stage_class | YES | NO | | memory/performance_schema/statement_class | YES | NO | | memory/performance_schema/table_handles | YES | NO | | memory/performance_schema/table_io_waits_summary_by_index_usage | YES | NO | | memory/performance_schema/table_lock_waits_summary_by_table | YES | NO | | memory/performance_schema/table_shares | YES | NO | | memory/performance_schema/threads | YES | NO | | memory/performance_schema/thread_class | YES | NO | | memory/performance_schema/users | YES | NO | | memory/sql/acl_cache | NO | NO | | memory/sql/binlog_cache_mngr | NO | NO | | memory/sql/binlog_pos | NO | NO | | memory/sql/binlog_statement_buffer | NO | NO | | memory/sql/binlog_ver_1_event | NO | NO | | memory/sql/bison_stack | NO | NO | | memory/sql/Blob_mem_storage::storage | NO | NO | | memory/sql/DATE_TIME_FORMAT | NO | NO | | memory/sql/dboptions_hash | NO | NO | | memory/sql/DDL_LOG_MEMORY_ENTRY | NO | NO | | memory/sql/display_table_locks | NO | NO | | memory/sql/errmsgs | NO | NO | | memory/sql/Event_basic::mem_root | NO | NO | | memory/sql/Event_queue_element_for_exec::names | NO | NO | | memory/sql/Event_scheduler::scheduler_param | NO | NO | | memory/sql/Filesort_info::merge | NO | NO | | memory/sql/Filesort_info::record_pointers | NO | NO | | memory/sql/frm::string | NO | NO | | memory/sql/gdl | NO | NO | | memory/sql/Gis_read_stream::err_msg | NO | NO | | memory/sql/global_system_variables | NO | NO | | memory/sql/handler::errmsgs | NO | NO | | memory/sql/handlerton | NO | NO | | memory/sql/hash_index_key_buffer | NO | NO | | memory/sql/host_cache::hostname | NO | NO | | memory/sql/ignored_db | NO | NO | | memory/sql/JOIN_CACHE | NO | NO | | memory/sql/load_env_plugins | NO | NO | | memory/sql/Locked_tables_list::m_locked_tables_root | NO | NO | | memory/sql/MDL_context::acquire_locks | NO | NO | | memory/sql/MPVIO_EXT::auth_info | NO | NO | | memory/sql/MYSQL_BIN_LOG::basename | NO | NO | | memory/sql/MYSQL_BIN_LOG::index | NO | NO | | memory/sql/MYSQL_BIN_LOG::recover | NO | NO | | memory/sql/MYSQL_LOCK | NO | NO | | memory/sql/MYSQL_LOG::name | NO | NO | | memory/sql/mysql_plugin | NO | NO | | memory/sql/mysql_plugin_dl | NO | NO | | memory/sql/MYSQL_RELAY_LOG::basename | NO | NO | | memory/sql/MYSQL_RELAY_LOG::index | NO | NO | | memory/sql/my_str_malloc | NO | NO | | memory/sql/NAMED_ILINK::name | NO | NO | | memory/sql/native_functions | NO | NO | | memory/sql/plugin_bookmark | NO | NO | | memory/sql/plugin_int_mem_root | NO | NO | | memory/sql/plugin_mem_root | NO | NO | | memory/sql/Prepared_statement::main_mem_root | NO | NO | | memory/sql/Prepared_statement_map | NO | NO | | memory/sql/PROFILE | NO | NO | | memory/sql/Query_cache | NO | NO | | memory/sql/Queue::queue_item | NO | NO | | memory/sql/QUICK_RANGE_SELECT::alloc | NO | NO | | memory/sql/QUICK_RANGE_SELECT::mrr_buf_desc | NO | NO | | memory/sql/Relay_log_info::group_relay_log_name | NO | NO | | memory/sql/root | NO | NO | | memory/sql/Row_data_memory::memory | NO | NO | | memory/sql/rpl_filter memory | NO | NO | | memory/sql/Rpl_info_file::buffer | NO | NO | | memory/sql/servers_cache | NO | NO | | memory/sql/SLAVE_INFO | NO | NO | | memory/sql/Sort_param::tmp_buffer | NO | NO | | memory/sql/sp_head::call_mem_root | NO | NO | | memory/sql/sp_head::execute_mem_root | NO | NO | | memory/sql/sp_head::main_mem_root | NO | NO | | memory/sql/sql_acl_mem | NO | NO | | memory/sql/sql_acl_memex | NO | NO | | memory/sql/String::value | NO | NO | | memory/sql/ST_SCHEMA_TABLE | NO | NO | | memory/sql/Sys_var_charptr::value | NO | NO | | memory/sql/TABLE | NO | NO | | memory/sql/table_mapping::m_mem_root | NO | NO | | memory/sql/TABLE_RULE_ENT | NO | NO | | memory/sql/TABLE_SHARE::mem_root | NO | NO | | memory/sql/Table_triggers_list | NO | NO | | memory/sql/Table_trigger_dispatcher::m_mem_root | NO | NO | | memory/sql/TC_LOG_MMAP::pages | NO | NO | | memory/sql/THD::db | NO | NO | | memory/sql/THD::handler_tables_hash | NO | NO | | memory/sql/thd::main_mem_root | NO | NO | | memory/sql/THD::sp_cache | NO | NO | | memory/sql/THD::transactions::mem_root | NO | NO | | memory/sql/THD::variables | NO | NO | | memory/sql/tz_storage | NO | NO | | memory/sql/udf_mem | NO | NO | | memory/sql/Unique::merge_buffer | NO | NO | | memory/sql/Unique::sort_buffer | NO | NO | | memory/sql/user_conn | NO | NO | | memory/sql/User_level_lock | NO | NO | | memory/sql/user_var_entry | NO | NO | | memory/sql/user_var_entry::value | NO | NO | | memory/sql/XID | NO | NO | | stage/aria/Waiting for a resource | NO | NO | | stage/innodb/alter table (end) | YES | YES | | stage/innodb/alter table (insert) | YES | YES | | stage/innodb/alter table (log apply index) | YES | YES | | stage/innodb/alter table (log apply table) | YES | YES | | stage/innodb/alter table (merge sort) | YES | YES | | stage/innodb/alter table (read PK and internal sort) | YES | YES | | stage/innodb/buffer pool load | YES | YES | | stage/mysys/Waiting for table level lock | NO | NO | | stage/sql/After apply log event | NO | NO | | stage/sql/After create | NO | NO | | stage/sql/After opening tables | NO | NO | | stage/sql/After table lock | NO | NO | | stage/sql/Allocating local table | NO | NO | | stage/sql/altering table | NO | NO | | stage/sql/Apply log event | NO | NO | | stage/sql/Changing master | NO | NO | | stage/sql/Checking master version | NO | NO | | stage/sql/checking permissions | NO | NO | | stage/sql/checking privileges on cached query | NO | NO | | stage/sql/Checking query cache for query | NO | NO | | stage/sql/closing tables | NO | NO | | stage/sql/Commit | NO | NO | | stage/sql/Commit implicit | NO | NO | | stage/sql/Committing alter table to storage engine | NO | NO | | stage/sql/Connecting to master | NO | NO | | stage/sql/Converting HEAP to Aria | NO | NO | | stage/sql/copy to tmp table | YES | YES | | stage/sql/Copying to group table | NO | NO | | stage/sql/Copying to tmp table | NO | NO | | stage/sql/Creating delayed handler | NO | NO | | stage/sql/Creating sort index | NO | NO | | stage/sql/creating table | NO | NO | | stage/sql/Creating tmp table | NO | NO | | stage/sql/Deleting from main table | NO | NO | | stage/sql/Deleting from reference tables | NO | NO | | stage/sql/Discard_or_import_tablespace | NO | NO | | stage/sql/Enabling keys | NO | NO | | stage/sql/End of update loop | NO | NO | | stage/sql/Executing | NO | NO | | stage/sql/Execution of init_command | NO | NO | | stage/sql/Explaining | NO | NO | | stage/sql/Filling schema table | NO | NO | | stage/sql/Finding key cache | NO | NO | | stage/sql/Finished reading one binlog; switching to next binlog | NO | NO | | stage/sql/Flushing relay log and master info repository. | NO | NO | | stage/sql/Flushing relay-log info file. | NO | NO | | stage/sql/Freeing items | NO | NO | | stage/sql/Fulltext initialization | NO | NO | | stage/sql/Got handler lock | NO | NO | | stage/sql/Got old table | NO | NO | | stage/sql/init | NO | NO | | stage/sql/init for update | NO | NO | | stage/sql/Insert | NO | NO | | stage/sql/Invalidating query cache entries (table list) | NO | NO | | stage/sql/Invalidating query cache entries (table) | NO | NO | | stage/sql/Killing slave | NO | NO | | stage/sql/Logging slow query | NO | NO | | stage/sql/Making temporary file (append) before replaying LOAD DATA INFILE | NO | NO | | stage/sql/Making temporary file (create) before replaying LOAD DATA INFILE | NO | NO | | stage/sql/Manage keys | NO | NO | | stage/sql/Master has sent all binlog to slave; waiting for more updates | NO | NO | | stage/sql/Opening tables | NO | NO | | stage/sql/Optimizing | NO | NO | | stage/sql/Preparing | NO | NO | | stage/sql/preparing for alter table | NO | NO | | stage/sql/Processing binlog checkpoint notification | NO | NO | | stage/sql/Processing requests | NO | NO | | stage/sql/Purging old relay logs | NO | NO | | stage/sql/Query end | NO | NO | | stage/sql/Queueing master event to the relay log | NO | NO | | stage/sql/Reading event from the relay log | NO | NO | | stage/sql/Reading semi-sync ACK from slave | NO | NO | | stage/sql/Recreating table | NO | NO | | stage/sql/Registering slave on master | NO | NO | | stage/sql/Removing duplicates | NO | NO | | stage/sql/Removing tmp table | NO | NO | | stage/sql/Rename | NO | NO | | stage/sql/Rename result table | NO | NO | | stage/sql/Requesting binlog dump | NO | NO | | stage/sql/Reschedule | NO | NO | | stage/sql/Reset for next command | NO | NO | | stage/sql/Rollback | NO | NO | | stage/sql/Rollback_implicit | NO | NO | | stage/sql/Searching rows for update | NO | NO | | stage/sql/Sending binlog event to slave | NO | NO | | stage/sql/Sending cached result to client | NO | NO | | stage/sql/Sending data | NO | NO | | stage/sql/setup | NO | NO | | stage/sql/Show explain | NO | NO | | stage/sql/Slave has read all relay log; waiting for more updates | NO | NO | | stage/sql/Sorting | NO | NO | | stage/sql/Sorting for group | NO | NO | | stage/sql/Sorting for order | NO | NO | | stage/sql/Sorting result | NO | NO | | stage/sql/starting | NO | NO | | stage/sql/Starting cleanup | NO | NO | | stage/sql/Statistics | NO | NO | | stage/sql/Stopping binlog background thread | NO | NO | | stage/sql/Storing result in query cache | NO | NO | | stage/sql/Storing row into queue | NO | NO | | stage/sql/System lock | NO | NO | | stage/sql/table lock | NO | NO | | stage/sql/Unlocking tables | NO | NO | | stage/sql/Update | NO | NO | | stage/sql/Updating | NO | NO | | stage/sql/Updating main table | NO | NO | | stage/sql/Updating reference tables | NO | NO | | stage/sql/Upgrading lock | NO | NO | | stage/sql/User lock | NO | NO | | stage/sql/User sleep | NO | NO | | stage/sql/Verifying table | NO | NO | | stage/sql/Waiting for background binlog tasks | NO | NO | | stage/sql/Waiting for backup lock | NO | NO | | stage/sql/Waiting for delay_list | NO | NO | | stage/sql/Waiting for event metadata lock | NO | NO | | stage/sql/Waiting for GTID to be written to binary log | NO | NO | | stage/sql/Waiting for handler insert | NO | NO | | stage/sql/Waiting for handler lock | NO | NO | | stage/sql/Waiting for handler open | NO | NO | | stage/sql/Waiting for INSERT | NO | NO | | stage/sql/Waiting for master to send event | NO | NO | | stage/sql/Waiting for master update | NO | NO | | stage/sql/Waiting for next activation | NO | NO | | stage/sql/Waiting for other master connection to process the same GTID | NO | NO | | stage/sql/Waiting for parallel replication deadlock handling to complete | NO | NO | | stage/sql/Waiting for prior transaction to commit | NO | NO | | stage/sql/Waiting for prior transaction to start commit | NO | NO | | stage/sql/Waiting for query cache lock | NO | NO | | stage/sql/Waiting for requests | NO | NO | | stage/sql/Waiting for room in worker thread event queue | NO | NO | | stage/sql/Waiting for schema metadata lock | NO | NO | | stage/sql/Waiting for semi-sync ACK from slave | NO | NO | | stage/sql/Waiting for semi-sync slave connection | NO | NO | | stage/sql/Waiting for slave mutex on exit | NO | NO | | stage/sql/Waiting for slave thread to start | NO | NO | | stage/sql/Waiting for stored function metadata lock | NO | NO | | stage/sql/Waiting for stored package body metadata lock | NO | NO | | stage/sql/Waiting for stored procedure metadata lock | NO | NO | | stage/sql/Waiting for table flush | NO | NO | | stage/sql/Waiting for table metadata lock | NO | NO | | stage/sql/Waiting for the next event in relay log | NO | NO | | stage/sql/Waiting for the scheduler to stop | NO | NO | | stage/sql/Waiting for the slave SQL thread to advance position | NO | NO | | stage/sql/Waiting for the slave SQL thread to free enough relay log space | NO | NO | | stage/sql/Waiting for trigger metadata lock | NO | NO | | stage/sql/Waiting for work from SQL thread | NO | NO | | stage/sql/Waiting in MASTER_GTID_WAIT() | NO | NO | | stage/sql/Waiting in MASTER_GTID_WAIT() (primary waiter) | NO | NO | | stage/sql/Waiting on empty queue | NO | NO | | stage/sql/Waiting to finalize termination | NO | NO | | stage/sql/Waiting until MASTER_DELAY seconds after master executed event | NO | NO | | stage/sql/Writing to binlog | NO | NO | | statement/abstract/new_packet | YES | YES | | statement/abstract/Query | YES | YES | | statement/abstract/relay_log | YES | YES | | statement/com/Binlog Dump | YES | YES | | statement/com/Bulk_execute | YES | YES | | statement/com/Change user | YES | YES | | statement/com/Close stmt | YES | YES | | statement/com/Com_multi | YES | YES | | statement/com/Connect | YES | YES | | statement/com/Connect Out | YES | YES | | statement/com/Create DB | YES | YES | | statement/com/Daemon | YES | YES | | statement/com/Debug | YES | YES | | statement/com/Delayed insert | YES | YES | | statement/com/Drop DB | YES | YES | | statement/com/Error | YES | YES | | statement/com/Execute | YES | YES | | statement/com/Fetch | YES | YES | | statement/com/Field List | YES | YES | | statement/com/Init DB | YES | YES | | statement/com/Kill | YES | YES | | statement/com/Long Data | YES | YES | | statement/com/Ping | YES | YES | | statement/com/Prepare | YES | YES | | statement/com/Processlist | YES | YES | | statement/com/Quit | YES | YES | | statement/com/Refresh | YES | YES | | statement/com/Register Slave | YES | YES | | statement/com/Reset connection | YES | YES | | statement/com/Reset stmt | YES | YES | | statement/com/Set option | YES | YES | | statement/com/Shutdown | YES | YES | | statement/com/Slave_IO | YES | YES | | statement/com/Slave_SQL | YES | YES | | statement/com/Slave_worker | YES | YES | | statement/com/Sleep | YES | YES | | statement/com/Statistics | YES | YES | | statement/com/Table Dump | YES | YES | | statement/com/Time | YES | YES | | statement/com/Unimpl get tid | YES | YES | | statement/scheduler/event | YES | YES | | statement/sp/agg_cfetch | YES | YES | | statement/sp/cclose | YES | YES | | statement/sp/cfetch | YES | YES | | statement/sp/copen | YES | YES | | statement/sp/cpop | YES | YES | | statement/sp/cpush | YES | YES | | statement/sp/cursor_copy_struct | YES | YES | | statement/sp/error | YES | YES | | statement/sp/freturn | YES | YES | | statement/sp/hpop | YES | YES | | statement/sp/hpush_jump | YES | YES | | statement/sp/hreturn | YES | YES | | statement/sp/jump | YES | YES | | statement/sp/jump_if_not | YES | YES | | statement/sp/preturn | YES | YES | | statement/sp/set | YES | YES | | statement/sp/set_case_expr | YES | YES | | statement/sp/set_trigger_field | YES | YES | | statement/sp/stmt | YES | YES | | statement/sql/ | YES | YES | | statement/sql/alter_db | YES | YES | | statement/sql/alter_db_upgrade | YES | YES | | statement/sql/alter_event | YES | YES | | statement/sql/alter_function | YES | YES | | statement/sql/alter_procedure | YES | YES | | statement/sql/alter_sequence | YES | YES | | statement/sql/alter_server | YES | YES | | statement/sql/alter_table | YES | YES | | statement/sql/alter_tablespace | YES | YES | | statement/sql/alter_user | YES | YES | | statement/sql/analyze | YES | YES | | statement/sql/assign_to_keycache | YES | YES | | statement/sql/backup | YES | YES | | statement/sql/backup_lock | YES | YES | | statement/sql/begin | YES | YES | | statement/sql/binlog | YES | YES | | statement/sql/call_procedure | YES | YES | | statement/sql/change_db | YES | YES | | statement/sql/change_master | YES | YES | | statement/sql/check | YES | YES | | statement/sql/checksum | YES | YES | | statement/sql/commit | YES | YES | | statement/sql/compound_sql | YES | YES | | statement/sql/create_db | YES | YES | | statement/sql/create_event | YES | YES | | statement/sql/create_function | YES | YES | | statement/sql/create_index | YES | YES | | statement/sql/create_package | YES | YES | | statement/sql/create_package_body | YES | YES | | statement/sql/create_procedure | YES | YES | | statement/sql/create_role | YES | YES | | statement/sql/create_sequence | YES | YES | | statement/sql/create_server | YES | YES | | statement/sql/create_table | YES | YES | | statement/sql/create_trigger | YES | YES | | statement/sql/create_udf | YES | YES | | statement/sql/create_user | YES | YES | | statement/sql/create_view | YES | YES | | statement/sql/dealloc_sql | YES | YES | | statement/sql/delete | YES | YES | | statement/sql/delete_multi | YES | YES | | statement/sql/do | YES | YES | | statement/sql/drop_db | YES | YES | | statement/sql/drop_event | YES | YES | | statement/sql/drop_function | YES | YES | | statement/sql/drop_index | YES | YES | | statement/sql/drop_package | YES | YES | | statement/sql/drop_package_body | YES | YES | | statement/sql/drop_procedure | YES | YES | | statement/sql/drop_role | YES | YES | | statement/sql/drop_sequence | YES | YES | | statement/sql/drop_server | YES | YES | | statement/sql/drop_table | YES | YES | | statement/sql/drop_trigger | YES | YES | | statement/sql/drop_user | YES | YES | | statement/sql/drop_view | YES | YES | | statement/sql/empty_query | YES | YES | | statement/sql/error | YES | YES | | statement/sql/execute_immediate | YES | YES | | statement/sql/execute_sql | YES | YES | | statement/sql/flush | YES | YES | | statement/sql/get_diagnostics | YES | YES | | statement/sql/grant | YES | YES | | statement/sql/grant_role | YES | YES | | statement/sql/ha_close | YES | YES | | statement/sql/ha_open | YES | YES | | statement/sql/ha_read | YES | YES | | statement/sql/help | YES | YES | | statement/sql/insert | YES | YES | | statement/sql/insert_select | YES | YES | | statement/sql/install_plugin | YES | YES | | statement/sql/kill | YES | YES | | statement/sql/load | YES | YES | | statement/sql/lock_tables | YES | YES | | statement/sql/optimize | YES | YES | | statement/sql/preload_keys | YES | YES | | statement/sql/prepare_sql | YES | YES | | statement/sql/purge | YES | YES | | statement/sql/purge_before_date | YES | YES | | statement/sql/release_savepoint | YES | YES | | statement/sql/rename_table | YES | YES | | statement/sql/rename_user | YES | YES | | statement/sql/repair | YES | YES | | statement/sql/replace | YES | YES | | statement/sql/replace_select | YES | YES | | statement/sql/reset | YES | YES | | statement/sql/resignal | YES | YES | | statement/sql/revoke | YES | YES | | statement/sql/revoke_all | YES | YES | | statement/sql/revoke_role | YES | YES | | statement/sql/rollback | YES | YES | | statement/sql/rollback_to_savepoint | YES | YES | | statement/sql/savepoint | YES | YES | | statement/sql/select | YES | YES | | statement/sql/set_option | YES | YES | | statement/sql/show_authors | YES | YES | | statement/sql/show_binlogs | YES | YES | | statement/sql/show_binlog_events | YES | YES | | statement/sql/show_binlog_status | YES | YES | | statement/sql/show_charsets | YES | YES | | statement/sql/show_collations | YES | YES | | statement/sql/show_contributors | YES | YES | | statement/sql/show_create_db | YES | YES | | statement/sql/show_create_event | YES | YES | | statement/sql/show_create_func | YES | YES | | statement/sql/show_create_package | YES | YES | | statement/sql/show_create_package_body | YES | YES | | statement/sql/show_create_proc | YES | YES | | statement/sql/show_create_table | YES | YES | | statement/sql/show_create_trigger | YES | YES | | statement/sql/show_create_user | YES | YES | | statement/sql/show_databases | YES | YES | | statement/sql/show_engine_logs | YES | YES | | statement/sql/show_engine_mutex | YES | YES | | statement/sql/show_engine_status | YES | YES | | statement/sql/show_errors | YES | YES | | statement/sql/show_events | YES | YES | | statement/sql/show_explain | YES | YES | | statement/sql/show_fields | YES | YES | | statement/sql/show_function_status | YES | YES | | statement/sql/show_generic | YES | YES | | statement/sql/show_grants | YES | YES | | statement/sql/show_keys | YES | YES | | statement/sql/show_open_tables | YES | YES | | statement/sql/show_package_body_status | YES | YES | | statement/sql/show_package_status | YES | YES | | statement/sql/show_plugins | YES | YES | | statement/sql/show_privileges | YES | YES | | statement/sql/show_procedure_status | YES | YES | | statement/sql/show_processlist | YES | YES | | statement/sql/show_profile | YES | YES | | statement/sql/show_profiles | YES | YES | | statement/sql/show_relaylog_events | YES | YES | | statement/sql/show_slave_hosts | YES | YES | | statement/sql/show_slave_status | YES | YES | | statement/sql/show_status | YES | YES | | statement/sql/show_storage_engines | YES | YES | | statement/sql/show_tables | YES | YES | | statement/sql/show_table_status | YES | YES | | statement/sql/show_triggers | YES | YES | | statement/sql/show_variables | YES | YES | | statement/sql/show_warnings | YES | YES | | statement/sql/shutdown | YES | YES | | statement/sql/signal | YES | YES | | statement/sql/start_all_slaves | YES | YES | | statement/sql/start_slave | YES | YES | | statement/sql/stop_all_slaves | YES | YES | | statement/sql/stop_slave | YES | YES | | statement/sql/truncate | YES | YES | | statement/sql/uninstall_plugin | YES | YES | | statement/sql/unlock_tables | YES | YES | | statement/sql/update | YES | YES | | statement/sql/update_multi | YES | YES | | statement/sql/xa_commit | YES | YES | | statement/sql/xa_end | YES | YES | | statement/sql/xa_prepare | YES | YES | | statement/sql/xa_recover | YES | YES | | statement/sql/xa_rollback | YES | YES | | statement/sql/xa_start | YES | YES | | transaction | NO | NO | | wait/io/file/aria/control | YES | YES | | wait/io/file/aria/MAD | YES | YES | | wait/io/file/aria/MAI | YES | YES | | wait/io/file/aria/translog | YES | YES | | wait/io/file/csv/data | YES | YES | | wait/io/file/csv/metadata | YES | YES | | wait/io/file/csv/update | YES | YES | | wait/io/file/innodb/innodb_data_file | YES | YES | | wait/io/file/innodb/innodb_log_file | YES | YES | | wait/io/file/innodb/innodb_temp_file | YES | YES | | wait/io/file/myisam/data_tmp | YES | YES | | wait/io/file/myisam/dfile | YES | YES | | wait/io/file/myisam/kfile | YES | YES | | wait/io/file/myisam/log | YES | YES | | wait/io/file/myisammrg/MRG | YES | YES | | wait/io/file/mysys/charset | YES | YES | | wait/io/file/mysys/cnf | YES | YES | | wait/io/file/partition/ha_partition::parfile | YES | YES | | wait/io/file/sql/binlog | YES | YES | | wait/io/file/sql/binlog_cache | YES | YES | | wait/io/file/sql/binlog_index | YES | YES | | wait/io/file/sql/binlog_index_cache | YES | YES | | wait/io/file/sql/binlog_state | YES | YES | | wait/io/file/sql/casetest | YES | YES | | wait/io/file/sql/dbopt | YES | YES | | wait/io/file/sql/des_key_file | YES | YES | | wait/io/file/sql/ERRMSG | YES | YES | | wait/io/file/sql/file_parser | YES | YES | | wait/io/file/sql/FRM | YES | YES | | wait/io/file/sql/global_ddl_log | YES | YES | | wait/io/file/sql/init | YES | YES | | wait/io/file/sql/io_cache | YES | YES | | wait/io/file/sql/load | YES | YES | | wait/io/file/sql/LOAD_FILE | YES | YES | | wait/io/file/sql/log_event_data | YES | YES | | wait/io/file/sql/log_event_info | YES | YES | | wait/io/file/sql/map | YES | YES | | wait/io/file/sql/master_info | YES | YES | | wait/io/file/sql/misc | YES | YES | | wait/io/file/sql/partition_ddl_log | YES | YES | | wait/io/file/sql/pid | YES | YES | | wait/io/file/sql/query_log | YES | YES | | wait/io/file/sql/relaylog | YES | YES | | wait/io/file/sql/relaylog_cache | YES | YES | | wait/io/file/sql/relaylog_index | YES | YES | | wait/io/file/sql/relaylog_index_cache | YES | YES | | wait/io/file/sql/relay_log_info | YES | YES | | wait/io/file/sql/select_to_file | YES | YES | | wait/io/file/sql/send_file | YES | YES | | wait/io/file/sql/slow_log | YES | YES | | wait/io/file/sql/tclog | YES | YES | | wait/io/file/sql/trigger | YES | YES | | wait/io/file/sql/trigger_name | YES | YES | | wait/io/file/sql/wsrep_gra_log | YES | YES | | wait/io/socket/sql/client_connection | NO | NO | | wait/io/socket/sql/server_tcpip_socket | NO | NO | | wait/io/socket/sql/server_unix_socket | NO | NO | | wait/io/table/sql/handler | YES | YES | | wait/lock/metadata/sql/mdl | NO | NO | | wait/lock/table/sql/handler | YES | YES | | wait/synch/cond/aria/BITMAP::bitmap_cond | NO | NO | | wait/synch/cond/aria/COND_soft_sync | NO | NO | | wait/synch/cond/aria/SERVICE_THREAD_CONTROL::COND_control | NO | NO | | wait/synch/cond/aria/SHARE::key_del_cond | NO | NO | | wait/synch/cond/aria/SORT_INFO::cond | NO | NO | | wait/synch/cond/aria/TRANSLOG_BUFFER::prev_sent_to_disk_cond | NO | NO | | wait/synch/cond/aria/TRANSLOG_BUFFER::waiting_filling_buffer | NO | NO | | wait/synch/cond/aria/TRANSLOG_DESCRIPTOR::log_flush_cond | NO | NO | | wait/synch/cond/aria/TRANSLOG_DESCRIPTOR::new_goal_cond | NO | NO | | wait/synch/cond/innodb/commit_cond | NO | NO | | wait/synch/cond/myisam/MI_SORT_INFO::cond | NO | NO | | wait/synch/cond/mysys/COND_alarm | NO | NO | | wait/synch/cond/mysys/COND_timer | NO | NO | | wait/synch/cond/mysys/IO_CACHE_SHARE::cond | NO | NO | | wait/synch/cond/mysys/IO_CACHE_SHARE::cond_writer | NO | NO | | wait/synch/cond/mysys/my_thread_var::suspend | NO | NO | | wait/synch/cond/mysys/THR_COND_threads | NO | NO | | wait/synch/cond/mysys/WT_RESOURCE::cond | NO | NO | | wait/synch/cond/sql/Ack_receiver::cond | NO | NO | | wait/synch/cond/sql/COND_binlog_send | NO | NO | | wait/synch/cond/sql/COND_flush_thread_cache | NO | NO | | wait/synch/cond/sql/COND_group_commit_orderer | NO | NO | | wait/synch/cond/sql/COND_gtid_ignore_duplicates | NO | NO | | wait/synch/cond/sql/COND_manager | NO | NO | | wait/synch/cond/sql/COND_parallel_entry | NO | NO | | wait/synch/cond/sql/COND_prepare_ordered | NO | NO | | wait/synch/cond/sql/COND_queue_state | NO | NO | | wait/synch/cond/sql/COND_rpl_thread | NO | NO | | wait/synch/cond/sql/COND_rpl_thread_pool | NO | NO | | wait/synch/cond/sql/COND_rpl_thread_queue | NO | NO | | wait/synch/cond/sql/COND_rpl_thread_stop | NO | NO | | wait/synch/cond/sql/COND_server_started | NO | NO | | wait/synch/cond/sql/COND_slave_background | NO | NO | | wait/synch/cond/sql/COND_start_thread | NO | NO | | wait/synch/cond/sql/COND_thread_cache | NO | NO | | wait/synch/cond/sql/COND_wait_gtid | NO | NO | | wait/synch/cond/sql/COND_wsrep_donor_monitor | NO | NO | | wait/synch/cond/sql/COND_wsrep_gtid_wait_upto | NO | NO | | wait/synch/cond/sql/COND_wsrep_joiner_monitor | NO | NO | | wait/synch/cond/sql/COND_wsrep_ready | NO | NO | | wait/synch/cond/sql/COND_wsrep_replaying | NO | NO | | wait/synch/cond/sql/COND_wsrep_sst | NO | NO | | wait/synch/cond/sql/COND_wsrep_sst_init | NO | NO | | wait/synch/cond/sql/COND_wsrep_wsrep_slave_threads | NO | NO | | wait/synch/cond/sql/Delayed_insert::cond | NO | NO | | wait/synch/cond/sql/Delayed_insert::cond_client | NO | NO | | wait/synch/cond/sql/Event_scheduler::COND_state | NO | NO | | wait/synch/cond/sql/Item_func_sleep::cond | NO | NO | | wait/synch/cond/sql/Master_info::data_cond | NO | NO | | wait/synch/cond/sql/Master_info::sleep_cond | NO | NO | | wait/synch/cond/sql/Master_info::start_cond | NO | NO | | wait/synch/cond/sql/Master_info::stop_cond | NO | NO | | wait/synch/cond/sql/MDL_context::COND_wait_status | NO | NO | | wait/synch/cond/sql/MYSQL_BIN_LOG::COND_binlog_background_thread | NO | NO | | wait/synch/cond/sql/MYSQL_BIN_LOG::COND_binlog_background_thread_end | NO | NO | | wait/synch/cond/sql/MYSQL_BIN_LOG::COND_bin_log_updated | NO | NO | | wait/synch/cond/sql/MYSQL_BIN_LOG::COND_queue_busy | NO | NO | | wait/synch/cond/sql/MYSQL_BIN_LOG::COND_relay_log_updated | NO | NO | | wait/synch/cond/sql/MYSQL_BIN_LOG::COND_xid_list | NO | NO | | wait/synch/cond/sql/MYSQL_RELAY_LOG::COND_bin_log_updated | NO | NO | | wait/synch/cond/sql/MYSQL_RELAY_LOG::COND_queue_busy | NO | NO | | wait/synch/cond/sql/MYSQL_RELAY_LOG::COND_relay_log_updated | NO | NO | | wait/synch/cond/sql/PAGE::cond | NO | NO | | wait/synch/cond/sql/Query_cache::COND_cache_status_changed | NO | NO | | wait/synch/cond/sql/Relay_log_info::data_cond | NO | NO | | wait/synch/cond/sql/Relay_log_info::log_space_cond | NO | NO | | wait/synch/cond/sql/Relay_log_info::start_cond | NO | NO | | wait/synch/cond/sql/Relay_log_info::stop_cond | NO | NO | | wait/synch/cond/sql/Rpl_group_info::sleep_cond | NO | NO | | wait/synch/cond/sql/show_explain | NO | NO | | wait/synch/cond/sql/TABLE_SHARE::cond | NO | NO | | wait/synch/cond/sql/TABLE_SHARE::COND_rotation | NO | NO | | wait/synch/cond/sql/TABLE_SHARE::tdc.COND_release | NO | NO | | wait/synch/cond/sql/TC_LOG_MMAP::COND_active | NO | NO | | wait/synch/cond/sql/TC_LOG_MMAP::COND_pool | NO | NO | | wait/synch/cond/sql/TC_LOG_MMAP::COND_queue_busy | NO | NO | | wait/synch/cond/sql/THD::COND_wakeup_ready | NO | NO | | wait/synch/cond/sql/THD::COND_wsrep_thd | NO | NO | | wait/synch/cond/sql/User_level_lock::cond | NO | NO | | wait/synch/cond/sql/wait_for_commit::COND_wait_commit | NO | NO | | wait/synch/cond/sql/wsrep_sst_thread | NO | NO | | wait/synch/mutex/aria/LOCK_soft_sync | NO | NO | | wait/synch/mutex/aria/LOCK_trn_list | NO | NO | | wait/synch/mutex/aria/PAGECACHE::cache_lock | NO | NO | | wait/synch/mutex/aria/SERVICE_THREAD_CONTROL::LOCK_control | NO | NO | | wait/synch/mutex/aria/SHARE::bitmap::bitmap_lock | NO | NO | | wait/synch/mutex/aria/SHARE::close_lock | NO | NO | | wait/synch/mutex/aria/SHARE::intern_lock | NO | NO | | wait/synch/mutex/aria/SHARE::key_del_lock | NO | NO | | wait/synch/mutex/aria/SORT_INFO::mutex | NO | NO | | wait/synch/mutex/aria/THR_LOCK_maria | NO | NO | | wait/synch/mutex/aria/TRANSLOG_BUFFER::mutex | NO | NO | | wait/synch/mutex/aria/TRANSLOG_DESCRIPTOR::dirty_buffer_mask_lock | NO | NO | | wait/synch/mutex/aria/TRANSLOG_DESCRIPTOR::file_header_lock | NO | NO | | wait/synch/mutex/aria/TRANSLOG_DESCRIPTOR::log_flush_lock | NO | NO | | wait/synch/mutex/aria/TRANSLOG_DESCRIPTOR::purger_lock | NO | NO | | wait/synch/mutex/aria/TRANSLOG_DESCRIPTOR::sent_to_disk_lock | NO | NO | | wait/synch/mutex/aria/TRANSLOG_DESCRIPTOR::unfinished_files_lock | NO | NO | | wait/synch/mutex/aria/TRN::state_lock | NO | NO | | wait/synch/mutex/csv/tina | NO | NO | | wait/synch/mutex/csv/TINA_SHARE::mutex | NO | NO | | wait/synch/mutex/innodb/buf_dblwr_mutex | NO | NO | | wait/synch/mutex/innodb/buf_pool_mutex | NO | NO | | wait/synch/mutex/innodb/commit_cond_mutex | NO | NO | | wait/synch/mutex/innodb/dict_foreign_err_mutex | NO | NO | | wait/synch/mutex/innodb/dict_sys_mutex | NO | NO | | wait/synch/mutex/innodb/fil_system_mutex | NO | NO | | wait/synch/mutex/innodb/flush_list_mutex | NO | NO | | wait/synch/mutex/innodb/fts_delete_mutex | NO | NO | | wait/synch/mutex/innodb/fts_doc_id_mutex | NO | NO | | wait/synch/mutex/innodb/ibuf_bitmap_mutex | NO | NO | | wait/synch/mutex/innodb/ibuf_mutex | NO | NO | | wait/synch/mutex/innodb/ibuf_pessimistic_insert_mutex | NO | NO | | wait/synch/mutex/innodb/lock_mutex | NO | NO | | wait/synch/mutex/innodb/lock_wait_mutex | NO | NO | | wait/synch/mutex/innodb/log_flush_order_mutex | NO | NO | | wait/synch/mutex/innodb/log_sys_mutex | NO | NO | | wait/synch/mutex/innodb/noredo_rseg_mutex | NO | NO | | wait/synch/mutex/innodb/page_zip_stat_per_index_mutex | NO | NO | | wait/synch/mutex/innodb/pending_checkpoint_mutex | NO | NO | | wait/synch/mutex/innodb/purge_sys_pq_mutex | NO | NO | | wait/synch/mutex/innodb/recalc_pool_mutex | NO | NO | | wait/synch/mutex/innodb/recv_sys_mutex | NO | NO | | wait/synch/mutex/innodb/redo_rseg_mutex | NO | NO | | wait/synch/mutex/innodb/rtr_active_mutex | NO | NO | | wait/synch/mutex/innodb/rtr_match_mutex | NO | NO | | wait/synch/mutex/innodb/rtr_path_mutex | NO | NO | | wait/synch/mutex/innodb/rw_lock_list_mutex | NO | NO | | wait/synch/mutex/innodb/srv_innodb_monitor_mutex | NO | NO | | wait/synch/mutex/innodb/srv_misc_tmpfile_mutex | NO | NO | | wait/synch/mutex/innodb/srv_monitor_file_mutex | NO | NO | | wait/synch/mutex/innodb/srv_threads_mutex | NO | NO | | wait/synch/mutex/innodb/trx_mutex | NO | NO | | wait/synch/mutex/innodb/trx_pool_manager_mutex | NO | NO | | wait/synch/mutex/innodb/trx_pool_mutex | NO | NO | | wait/synch/mutex/innodb/trx_sys_mutex | NO | NO | | wait/synch/mutex/myisam/MI_CHECK::print_msg | NO | NO | | wait/synch/mutex/myisam/MI_SORT_INFO::mutex | NO | NO | | wait/synch/mutex/myisam/MYISAM_SHARE::intern_lock | NO | NO | | wait/synch/mutex/myisammrg/MYRG_INFO::mutex | NO | NO | | wait/synch/mutex/mysys/BITMAP::mutex | NO | NO | | wait/synch/mutex/mysys/IO_CACHE::append_buffer_lock | NO | NO | | wait/synch/mutex/mysys/IO_CACHE::SHARE_mutex | NO | NO | | wait/synch/mutex/mysys/KEY_CACHE::cache_lock | NO | NO | | wait/synch/mutex/mysys/LOCK_alarm | NO | NO | | wait/synch/mutex/mysys/LOCK_timer | NO | NO | | wait/synch/mutex/mysys/LOCK_uuid_generator | NO | NO | | wait/synch/mutex/mysys/my_thread_var::mutex | NO | NO | | wait/synch/mutex/mysys/THR_LOCK::mutex | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_charset | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_heap | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_lock | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_malloc | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_myisam | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_myisam_mmap | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_net | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_open | NO | NO | | wait/synch/mutex/mysys/THR_LOCK_threads | NO | NO | | wait/synch/mutex/mysys/TMPDIR_mutex | NO | NO | | wait/synch/mutex/partition/Partition_share::auto_inc_mutex | NO | NO | | wait/synch/mutex/sql/Ack_receiver::mutex | NO | NO | | wait/synch/mutex/sql/Cversion_lock | NO | NO | | wait/synch/mutex/sql/Delayed_insert::mutex | NO | NO | | wait/synch/mutex/sql/Event_scheduler::LOCK_scheduler_state | NO | NO | | wait/synch/mutex/sql/gtid_waiting::LOCK_gtid_waiting | NO | NO | | wait/synch/mutex/sql/hash_filo::lock | NO | NO | | wait/synch/mutex/sql/HA_DATA_PARTITION::LOCK_auto_inc | NO | NO | | wait/synch/mutex/sql/LOCK_active_mi | NO | NO | | wait/synch/mutex/sql/LOCK_after_binlog_sync | NO | NO | | wait/synch/mutex/sql/LOCK_audit_mask | NO | NO | | wait/synch/mutex/sql/LOCK_binlog | NO | NO | | wait/synch/mutex/sql/LOCK_binlog_state | NO | NO | | wait/synch/mutex/sql/LOCK_commit_ordered | NO | NO | | wait/synch/mutex/sql/LOCK_crypt | NO | NO | | wait/synch/mutex/sql/LOCK_delayed_create | NO | NO | | wait/synch/mutex/sql/LOCK_delayed_insert | NO | NO | | wait/synch/mutex/sql/LOCK_delayed_status | NO | NO | | wait/synch/mutex/sql/LOCK_des_key_file | NO | NO | | wait/synch/mutex/sql/LOCK_error_log | NO | NO | | wait/synch/mutex/sql/LOCK_error_messages | NO | NO | | wait/synch/mutex/sql/LOCK_event_queue | NO | NO | | wait/synch/mutex/sql/LOCK_gdl | NO | NO | | wait/synch/mutex/sql/LOCK_global_index_stats | NO | NO | | wait/synch/mutex/sql/LOCK_global_system_variables | NO | NO | | wait/synch/mutex/sql/LOCK_global_table_stats | NO | NO | | wait/synch/mutex/sql/LOCK_global_user_client_stats | NO | NO | | wait/synch/mutex/sql/LOCK_item_func_sleep | NO | NO | | wait/synch/mutex/sql/LOCK_load_client_plugin | NO | NO | | wait/synch/mutex/sql/LOCK_manager | NO | NO | | wait/synch/mutex/sql/LOCK_parallel_entry | NO | NO | | wait/synch/mutex/sql/LOCK_plugin | NO | NO | | wait/synch/mutex/sql/LOCK_prepared_stmt_count | NO | NO | | wait/synch/mutex/sql/LOCK_prepare_ordered | NO | NO | | wait/synch/mutex/sql/LOCK_rpl_semi_sync_master_enabled | NO | NO | | wait/synch/mutex/sql/LOCK_rpl_status | NO | NO | | wait/synch/mutex/sql/LOCK_rpl_thread | NO | NO | | wait/synch/mutex/sql/LOCK_rpl_thread_pool | NO | NO | | wait/synch/mutex/sql/LOCK_server_started | NO | NO | | wait/synch/mutex/sql/LOCK_slave_background | NO | NO | | wait/synch/mutex/sql/LOCK_slave_state | NO | NO | | wait/synch/mutex/sql/LOCK_start_thread | NO | NO | | wait/synch/mutex/sql/LOCK_stats | NO | NO | | wait/synch/mutex/sql/LOCK_status | NO | NO | | wait/synch/mutex/sql/LOCK_system_variables_hash | NO | NO | | wait/synch/mutex/sql/LOCK_table_cache | NO | NO | | wait/synch/mutex/sql/LOCK_thread_cache | NO | NO | | wait/synch/mutex/sql/LOCK_thread_id | NO | NO | | wait/synch/mutex/sql/LOCK_unused_shares | NO | NO | | wait/synch/mutex/sql/LOCK_user_conn | NO | NO | | wait/synch/mutex/sql/LOCK_uuid_short_generator | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_cluster_config | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_config_state | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_desync | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_donor_monitor | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_group_commit | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_gtid_wait_upto | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_joiner_monitor | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_ready | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_replaying | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_slave_threads | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_SR_pool | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_SR_store | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_sst | NO | NO | | wait/synch/mutex/sql/LOCK_wsrep_sst_init | NO | NO | | wait/synch/mutex/sql/LOG::LOCK_log | NO | NO | | wait/synch/mutex/sql/Master_info::data_lock | NO | NO | | wait/synch/mutex/sql/Master_info::run_lock | NO | NO | | wait/synch/mutex/sql/Master_info::sleep_lock | NO | NO | | wait/synch/mutex/sql/Master_info::start_stop_lock | NO | NO | | wait/synch/mutex/sql/MDL_wait::LOCK_wait_status | NO | NO | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_binlog_background_thread | NO | NO | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_binlog_end_pos | NO | NO | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_index | NO | NO | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_xid_list | NO | NO | | wait/synch/mutex/sql/MYSQL_RELAY_LOG::LOCK_binlog_end_pos | NO | NO | | wait/synch/mutex/sql/MYSQL_RELAY_LOG::LOCK_index | NO | NO | | wait/synch/mutex/sql/PAGE::lock | NO | NO | | wait/synch/mutex/sql/Query_cache::structure_guard_mutex | NO | NO | | wait/synch/mutex/sql/Relay_log_info::data_lock | NO | NO | | wait/synch/mutex/sql/Relay_log_info::log_space_lock | NO | NO | | wait/synch/mutex/sql/Relay_log_info::run_lock | NO | NO | | wait/synch/mutex/sql/Rpl_group_info::sleep_lock | NO | NO | | wait/synch/mutex/sql/Slave_reporting_capability::err_lock | NO | NO | | wait/synch/mutex/sql/TABLE_SHARE::LOCK_ha_data | NO | NO | | wait/synch/mutex/sql/TABLE_SHARE::LOCK_rotation | NO | NO | | wait/synch/mutex/sql/TABLE_SHARE::LOCK_share | NO | NO | | wait/synch/mutex/sql/TABLE_SHARE::tdc.LOCK_table_share | NO | NO | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_active | NO | NO | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_pending_checkpoint | NO | NO | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_pool | NO | NO | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_sync | NO | NO | | wait/synch/mutex/sql/THD::LOCK_thd_data | NO | NO | | wait/synch/mutex/sql/THD::LOCK_thd_kill | NO | NO | | wait/synch/mutex/sql/THD::LOCK_wakeup_ready | NO | NO | | wait/synch/mutex/sql/tz_LOCK | NO | NO | | wait/synch/mutex/sql/wait_for_commit::LOCK_wait_commit | NO | NO | | wait/synch/mutex/sql/wsrep_sst_thread | NO | NO | | wait/synch/rwlock/aria/KEYINFO::root_lock | NO | NO | | wait/synch/rwlock/aria/SHARE::mmap_lock | NO | NO | | wait/synch/rwlock/aria/TRANSLOG_DESCRIPTOR::open_files_lock | NO | NO | | wait/synch/rwlock/myisam/MYISAM_SHARE::key_root_lock | NO | NO | | wait/synch/rwlock/myisam/MYISAM_SHARE::mmap_lock | NO | NO | | wait/synch/rwlock/mysys/SAFE_HASH::mutex | NO | NO | | wait/synch/rwlock/proxy_proto/rwlock | NO | NO | | wait/synch/rwlock/sql/CRYPTO_dynlock_value::lock | NO | NO | | wait/synch/rwlock/sql/LOCK_all_status_vars | NO | NO | | wait/synch/rwlock/sql/LOCK_dboptions | NO | NO | | wait/synch/rwlock/sql/LOCK_grant | NO | NO | | wait/synch/rwlock/sql/LOCK_SEQUENCE | NO | NO | | wait/synch/rwlock/sql/LOCK_ssl_refresh | NO | NO | | wait/synch/rwlock/sql/LOCK_system_variables_hash | NO | NO | | wait/synch/rwlock/sql/LOCK_sys_init_connect | NO | NO | | wait/synch/rwlock/sql/LOCK_sys_init_slave | NO | NO | | wait/synch/rwlock/sql/LOGGER::LOCK_logger | NO | NO | | wait/synch/rwlock/sql/MDL_context::LOCK_waiting_for | NO | NO | | wait/synch/rwlock/sql/MDL_lock::rwlock | NO | NO | | wait/synch/rwlock/sql/Query_cache_query::lock | NO | NO | | wait/synch/rwlock/sql/TABLE_SHARE::LOCK_stat_serial | NO | NO | | wait/synch/rwlock/sql/THD_list::lock | NO | NO | | wait/synch/rwlock/sql/THR_LOCK_servers | NO | NO | | wait/synch/rwlock/sql/THR_LOCK_udf | NO | NO | | wait/synch/rwlock/sql/Vers_field_stats::lock | NO | NO | | wait/synch/sxlock/innodb/btr_search_latch | NO | NO | | wait/synch/sxlock/innodb/dict_operation_lock | NO | NO | | wait/synch/sxlock/innodb/fil_space_latch | NO | NO | | wait/synch/sxlock/innodb/fts_cache_init_rw_lock | NO | NO | | wait/synch/sxlock/innodb/fts_cache_rw_lock | NO | NO | | wait/synch/sxlock/innodb/index_online_log | NO | NO | | wait/synch/sxlock/innodb/index_tree_rw_lock | NO | NO | | wait/synch/sxlock/innodb/trx_i_s_cache_lock | NO | NO | | wait/synch/sxlock/innodb/trx_purge_latch | NO | NO | +--------------------------------------------------------------------------------+---------+-------+ 996 rows in set (0.005 sec) ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SMALLINT SMALLINT ======== Syntax ------ ``` SMALLINT[(M)] [SIGNED | UNSIGNED | ZEROFILL] ``` Description ----------- A small [integer](../sql_language-data_types-int/index). The signed range is -32768 to 32767. The unsigned range is 0 to 65535. If a column has been set to ZEROFILL, all values will be prepended by zeros so that the SMALLINT value contains a number of M digits. **Note:** If the ZEROFILL attribute has been specified, the column will automatically become UNSIGNED. `INT2` is a synonym for `SMALLINT`. For more details on the attributes, see [Numeric Data Type Overview](../numeric-data-type-overview/index). Examples -------- ``` CREATE TABLE smallints (a SMALLINT,b SMALLINT UNSIGNED,c SMALLINT ZEROFILL); ``` With [strict\_mode](../sql-mode/index#strict-mode) set, the default from [MariaDB 10.2.4](https://mariadb.com/kb/en/mariadb-1024-release-notes/): ``` INSERT INTO smallints VALUES (-10,-10,-10); ERROR 1264 (22003): Out of range value for column 'b' at row 1 INSERT INTO smallints VALUES (-10,10,-10); ERROR 1264 (22003): Out of range value for column 'c' at row 1 INSERT INTO smallints VALUES (-10,10,10); INSERT INTO smallints VALUES (32768,32768,32768); ERROR 1264 (22003): Out of range value for column 'a' at row 1 INSERT INTO smallints VALUES (32767,32768,32768); SELECT * FROM smallints; +-------+-------+-------+ | a | b | c | +-------+-------+-------+ | -10 | 10 | 00010 | | 32767 | 32768 | 32768 | +-------+-------+-------+ ``` With [strict\_mode](../sql-mode/index#strict-mode) unset, the default until [MariaDB 10.2.3](https://mariadb.com/kb/en/mariadb-1023-release-notes/): ``` INSERT INTO smallints VALUES (-10,-10,-10); Query OK, 1 row affected, 2 warnings (0.09 sec) Warning (Code 1264): Out of range value for column 'b' at row 1 Warning (Code 1264): Out of range value for column 'c' at row 1 INSERT INTO smallints VALUES (-10,10,-10); Query OK, 1 row affected, 1 warning (0.08 sec) Warning (Code 1264): Out of range value for column 'c' at row 1 INSERT INTO smallints VALUES (-10,10,10); INSERT INTO smallints VALUES (32768,32768,32768); Query OK, 1 row affected, 1 warning (0.04 sec) Warning (Code 1264): Out of range value for column 'a' at row 1 INSERT INTO smallints VALUES (32767,32768,32768); SELECT * FROM smallints; +-------+-------+-------+ | a | b | c | +-------+-------+-------+ | -10 | 0 | 00000 | | -10 | 10 | 00000 | | -10 | 10 | 00010 | | 32767 | 32768 | 32768 | | 32767 | 32768 | 32768 | +-------+-------+-------+ ``` See Also -------- * [Numeric Data Type Overview](../numeric-data-type-overview/index) * [TINYINT](../tinyint/index) * [MEDIUMINT](../mediumint/index) * [INTEGER](../int/index) * [BIGINT](../bigint/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Configuring ColumnStore Local PM Query Mode Configuring ColumnStore Local PM Query Mode =========================================== MariaDB ColumnStore has the ability to query data from just a single [PM](../columnstore-performance-module/index) instead of the whole database through the [UM](../columnstore-user-module/index). In order to accomplish this, the infinidb\_local\_query variable in the my.cnf configuration file is used and maybe set as a default at system wide or set at the session level. ### Enable local PM query during installation Local PM query can be enabled system wide during the install process when running the install script postConfigure. Answer 'y' to this prompt during the install process. ``` NOTE: Local Query Feature allows the ability to query data from a single Performance Module. Check MariaDB ColumnStore Admin Guide for additional information. Enable Local Query feature? [y,n] (n) > ``` [https://mariadb.com/kb/en/library/installing-and-configuring-a-multi-server-columnstore-system-11x/](../library/installing-and-configuring-a-multi-server-columnstore-system-11x/index) ### Enable local PM query systemwide To enable the use of the local PM Query at the instance level, specify `infinidb_local_query =1` (enabled) in the my.cnf configuration file at /usr/local/mariadb/columnstore/mysql. The default is 0 (disabled). ### Enable/disable local PM query at the session level To enable/disable the use of the local PM Query at the session level, the following command is used. Once the session has ended, any subsequent session will return to the default for the instance. ``` set infinidb_local_query = n where n is: * 0 (disabled) * 1 (enabled) ``` At the session level, this variable applies only to executing a query on an individual [PM](../columnstore-performance-module/index) and will error if executed on the [UM](../columnstore-user-module/index). The PM must be set up with the local query option during installation. ### Local PM Query Examples #### Example 1 - SELECT from a single table on local PM to import back on local PM: With the infinidb\_local\_query variable set to 1 (default with local PM Query): ``` mcsmysql -e 'select * from source_schema.source_table;' –N | /usr/local/Calpont/bin/cpimport target_schema target_table -s '\t' –n1 ``` #### Example 2 - SELECT involving a join between a fact table on the PM node and dimension table across all the nodes to import back on local PM: With the infinidb\_local\_query variable set to 0 (default with local PM Query): Create a script (i.e., extract\_query\_script.sql in our example) similar to the following: ``` set infinidb_local_query=0; select fact.column1, dim.column2 from fact join dim using (key) where idbPm(fact.key) = idbLocalPm(); ``` The infinidb\_local\_query is set to 0 to allow query across all PMs. The query is structured so that the UM process on the PM node gets the fact table data locally from the PM node (as indicated by the use of the [idbLocalPm()](../mariadb/columnstore-information-functions/index) function), while the dimension table data is extracted from all the PM nodes. Then you can execute the script to pipe it directly into cpimport: ``` mcsmysql source_schema -N < extract_query_script.sql | /usr/local/mariadb/columnstore/bin/cpimport target_schema target_table -s '\t' –n1 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb INTERVAL INTERVAL ======== Syntax ------ ``` INTERVAL(N,N1,N2,N3,...) ``` Description ----------- Returns the index of the last argument that is less than the first argument or is NULL. Returns 0 if N < N1, 1 if N < N2, 2 if N < N3 and so on or -1 if N is NULL. All arguments are treated as integers. It is required that N1 < N2 < N3 < ... < Nn for this function to work correctly. This is because a fast binary search is used. Examples -------- ``` SELECT INTERVAL(23, 1, 15, 17, 30, 44, 200); +--------------------------------------+ | INTERVAL(23, 1, 15, 17, 30, 44, 200) | +--------------------------------------+ | 3 | +--------------------------------------+ SELECT INTERVAL(10, 1, 10, 100, 1000); +--------------------------------+ | INTERVAL(10, 1, 10, 100, 1000) | +--------------------------------+ | 2 | +--------------------------------+ SELECT INTERVAL(22, 23, 30, 44, 200); +-------------------------------+ | INTERVAL(22, 23, 30, 44, 200) | +-------------------------------+ | 0 | +-------------------------------+ SELECT INTERVAL(10, 2, NULL); +-----------------------+ | INTERVAL(10, 2, NULL) | +-----------------------+ | 2 | +-----------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Optimizing key_buffer_size Optimizing key\_buffer\_size ============================ [key\_buffer\_size](../myisam-system-variables/index#key_buffer_size) is a [MyISAM](../myisam/index) variable which determines the size of the index buffers held in memory, which affects the speed of index reads. Note that Aria tables by default make use of an alternative setting, [aria-pagecache-buffer-size](../aria-server-system-variables/index#aria_pagecache_buffer_size). A good rule of thumb for servers consisting particularly of MyISAM tables is for about 25% or more of the available server memory to be dedicated to the key buffer. A good way to determine whether to adjust the value is to compare the [key\_read\_requests](../server-status-variables/index#key_read_requests) value, which is the total value of requests to read an index, and the [key\_reads](../server-status-variables/index#key_reads) values, the total number of requests that had to be read from disk. The ratio of key\_reads to key\_read\_requests should be as low as possible, 1:100 is the highest acceptable, 1:1000 is better, and 1:10 is terrible. The effective maximum size might be lower than what is set, depending on the server's available physical RAM and the per-process limit determined by the operating system. If you don't make use of MyISAM tables at all, you can set this to a very low value, such as 64K. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb InnoDB COMPRESSED Row Format InnoDB COMPRESSED Row Format ============================ In [MariaDB 10.1](../what-is-mariadb-101/index) and later, an alternative (and usually superior) way to compress InnoDB tables is by using [InnoDB Page Compression](../innodb-page-compression/index). See [Comparison with the COMPRESSED Row Format](../innodb-page-compression/index#comparison-with-the-compressed-row-format). The `COMPRESSED` row format is similar to the `COMPACT` row format, but tables using the `COMPRESSED` row format can store even more data on overflow pages than tables using the `COMPACT` row format. This results in more efficient data storage than tables using the `COMPACT` row format, especially for tables containing columns using the [VARBINARY](../varbinary/index), [VARCHAR](../varchar/index), [BLOB](../blob/index) and [TEXT](../text/index) data types. The `COMPRESSED` row format also supports compression of all data and index pages. Using the `COMPRESSED` Row Format --------------------------------- An InnoDB table that uses the `COMPRESSED` row format can be created by setting the [ROW\_FORMAT](../create-table/index#row_format) table option to `COMPRESSED` and by setting the [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option to one of the following values in a [CREATE TABLE](../create-table/index) or [ALTER TABLE](../alter-table/index) statement, where the units are in `KB`: * `1` * `2` * `4` * `8` * `16` `16k` is the default value of the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) system variable, so using `16` will usually result in minimal compression unless one of the following is true: * The table has many columns that can be stored in overflow pages, such as columns that use the [VARBINARY](../varbinary/index), [VARCHAR](../varchar/index), [BLOB](../blob/index) and [TEXT](../text/index) data types. * The server is using a non-default [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) value that is greater than `16k`. In [MariaDB 10.1](../what-is-mariadb-101/index) and later, the value of the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) system variable can be set to `32k` and `64k`. This is especially useful because the larger page size permits more columns using the [VARBINARY](../varbinary/index), [VARCHAR](../varchar/index), [BLOB](../blob/index) and [TEXT](../text/index) data types. Regardless, even when the value of the [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size) system variable is set to some value higher than `16k`, `16` is still the maximum value for the [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option for InnoDB tables using the `COMPRESSED` row format. The `COMPRESSED` row format cannot be set as the default row format with the [innodb\_default\_row\_format](../innodb-system-variables/index#innodb_default_row_format) system variable. The `COMPRESSED` row format is only supported by the `Barracuda` [file format](../innodb-file-format/index). As a side effect, in [MariaDB 10.1](../what-is-mariadb-101/index) and before, the `COMPRESSED` row format is only supported if the [InnoDB file format](../xtradbinnodb-file-format/index) is `Barracuda`. Therefore, the [innodb\_file\_format](../innodb-system-variables/index#innodb_file_format) system variable must be set to `Barracuda` to use these row formats in those versions. In [MariaDB 10.1](../what-is-mariadb-101/index) and before, the `COMPRESSED` row format is also only supported if the table is in a [file per-table](../innodb-file-per-table-tablespaces/index) tablespace. Therefore, the [innodb\_file\_per\_table](../innodb-system-variables/index#innodb_file_per_table) system variable must be set to `ON` to use this row format in those versions. It is also recommended to set the [innodb\_strict\_mode](../innodb-system-variables/index#innodb_strict_mode) system variable to `ON` when using this row format. InnoDB automatically uses the `COMPRESSED` row format for a table if the [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is set to some value in a [CREATE TABLE](../create-table/index) or [ALTER TABLE](../alter-table/index) statement. For example: ``` SET SESSION innodb_strict_mode=ON; SET GLOBAL innodb_file_per_table=ON; SET GLOBAL innodb_file_format='Barracuda'; CREATE TABLE tab ( id int, str varchar(50) ) ENGINE=InnoDB KEY_BLOCK_SIZE=4; ``` If the [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option is **not** set to some value, but the [ROW\_FORMAT](../create-table/index#row_format) table option is set to `COMPRESSED` in a [CREATE TABLE](../create-table/index) or [ALTER TABLE](../alter-table/index) statement, then InnoDB uses a default value of `8` for the [KEY\_BLOCK\_SIZE](../create-table/index#key_block_size) table option. For example: ``` SET SESSION innodb_strict_mode=ON; SET GLOBAL innodb_file_per_table=ON; SET GLOBAL innodb_file_format='Barracuda'; CREATE TABLE tab ( id int, str varchar(50) ) ENGINE=InnoDB ROW_FORMAT=COMPRESSED; ``` Compression with the `COMPRESSED` Row Format -------------------------------------------- The `COMPRESSED` row format supports compression of all data and index pages. To avoid compressing and uncompressing pages too many times, InnoDB tries to keep both compressed and uncompressed pages in the [buffer pool](../xtradbinnodb-memory-buffer/index) when there is enough room. This results in a bigger cache. When there is not enough room, an adaptive LRU algorithm is used to decide whether compressed or uncompressed pages should be evicted from the buffer: for CPU-bound workloads, the compressed pages are evicted first; for I/O-bound workloads, the uncompressed pages are evicted first. Of course, when necessary, both the compressed and uncompressed version of the same data can be evicted from the buffer. Each compressed page has an uncompressed *modification log*, stored within the page itself. InnoDB writes small changes into it. When the space in the modification log runs out, the page is uncompressed, changes are applied, and the page is recompressed again. This is done to avoid some unnecessary decompression and compression operations. Sometimes a *compression failure* might happen, because the data has grown too much to fit the page. When this happens, the page (and the index node) is split into two different pages. This process can be repeated recursively until the data fit the pages. This can be CPU-consuming on some busy servers which perform many write operations. Before writing a compressed page into a data file, InnoDB writes it into the [redo log](../innodb-redo-log/index). This ensures that the [redo log](../innodb-redo-log/index) can always be used to recover tables after a crash, even if the compression library is updated and some incompatibilities are introduced. But this also means that the [redo log](../innodb-redo-log/index) will grow faster and might need more space, or the frequency of checkpoints might need to increase. Monitoring Performance of the `COMPRESSED` Row Format ----------------------------------------------------- The following `INFORMATION_SCHEMA` tables can be used to monitor the performances of InnoDB compressed tables: * [INNODB\_CMP and INNODB\_CMP\_RESET](../information_schemainnodb_cmp-and-innodb_cmp_reset-tables/index) * [INNODB\_CMP\_PER\_INDEX and INNODB\_CMP\_PER\_INDEX\_RESET](../information_schemainnodb_cmp_per_index-and-innodb_cmp_per_index_reset-table/index) * [INNODB\_CMPMEM and INNODB\_CMPMEM\_RESET](../information_schemainnodb_cmpmem-and-innodb_cmpmem_reset-tables/index) Index Prefixes with the `COMPRESSED` Row Format ----------------------------------------------- The `COMPRESSED` row format supports index prefixes up to 3072 bytes. In [MariaDB 10.2](../what-is-mariadb-102/index) and before, the [innodb\_large\_prefix](../innodb-system-variables/index#innodb_large_prefix) system variable is used to configure the maximum index prefix length. In these versions, if [innodb\_large\_prefix](../innodb-system-variables/index#innodb_large_prefix) is set to `ON`, then the maximum prefix length is 3072 bytes, and if it is set to `OFF`, then the maximum prefix length is 767 bytes. Overflow Pages with the `COMPRESSED` Row Format ----------------------------------------------- All InnoDB row formats can store certain kinds of data in overflow pages. This allows for the maximum row size of an InnoDB table to be larger than the maximum amount of data that can be stored in the row's main data page. See [Maximum Row Size](#maximum-row-size) for more information about the other factors that can contribute to the maximum row size for InnoDB tables. In the `COMPRESSED` row format variable-length columns, such as columns using the [VARBINARY](../varbinary/index), [VARCHAR](../varchar/index), [BLOB](../blob/index) and [TEXT](../text/index) data types, can be completely stored in overflow pages. InnoDB only considers using overflow pages if the table's row size is greater than half of [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size). If the row size is greater than this, then InnoDB chooses variable-length columns to be stored on overflow pages until the row size is less than half of [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size). For [BLOB](../blob/index) and [TEXT](../text/index) columns, only values longer than 40 bytes are considered for storage on overflow pages. For [VARBINARY](../varbinary/index) and [VARCHAR](../varchar/index) columns, only values longer than 255 bytes are considered for storage on overflow pages. Bytes that are stored to track a value's length do not count towards these limits. These limits are only based on the length of the actual column's data. These limits differ from the limits for the `COMPACT` row format, where the limit is 767 bytes for all types. Fixed-length columns greater than 767 bytes are encoded as variable-length columns, so they can also be stored in overflow pages if the table's row size is greater than half of [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size). Even though a column using the [CHAR](../char/index) data type can hold at most 255 characters, a [CHAR](../char/index) column can still exceed 767 bytes in some cases. For example, a `char(255)` column can exceed 767 bytes if the [character set](../character-sets/index) is `utf8mb4`. If a column is chosen to be stored on overflow pages, then the entire value of the column is stored on overflow pages, and only a 20-byte pointer to the column's first overflow page is stored on the main page. Each overflow page is the size of [innodb\_page\_size](../innodb-system-variables/index#innodb_page_size). If a column is too large to be stored on a single overflow page, then it is stored on multiple overflow pages. Each overflow page contains part of the data and a 20-byte pointer to the next overflow page, if a next page exists. This behavior differs from the behavior of the `COMPACT` row format, which always stores the column prefix on the main page. This allows tables using the `COMPRESSED` row format to contain a high number of columns using the [VARBINARY](../varbinary/index), [VARCHAR](../varchar/index), [BLOB](../blob/index) and [TEXT](../text/index) data types. Read-Only --------- **MariaDB starting with [10.6](../what-is-mariadb-106/index)**From [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) until [MariaDB 10.6.5](https://mariadb.com/kb/en/mariadb-1065-release-notes/), tables that are of the `COMPRESSED` row format are read-only by default. This was intended to be the first step towards removing write support and deprecating the feature. This plan has been scrapped, and from [MariaDB 10.6.6](https://mariadb.com/kb/en/mariadb-1066-release-notes/), `COMPRESSED` tables are no longer read-only by default. From [MariaDB 10.6.0](https://mariadb.com/kb/en/mariadb-1060-release-notes/) to [MariaDB 10.6.5](https://mariadb.com/kb/en/mariadb-1065-release-notes/), set the [innodb\_read\_only\_compressed](../innodb-system-variables/index#innodb_read_only_compressed) variable to `OFF` to make the tables writable. See Also -------- * [InnoDB Page Compression](../innodb-page-compression/index) * [Storage-Engine Independent Column Compression](../storage-engine-independent-column-compression/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb mariabackup SST Method mariabackup SST Method ====================== **MariaDB starting with [10.1.26](https://mariadb.com/kb/en/mariadb-10126-release-notes/)**The `mariabackup` SST method was first released in [MariaDB 10.1.26](https://mariadb.com/kb/en/mariadb-10126-release-notes/) and [MariaDB 10.2.10](https://mariadb.com/kb/en/mariadb-10210-release-notes/). The `mariabackup` SST method uses the [Mariabackup](../backup-restore-and-import-clients-mariadb-backup/index) utility for performing SSTs. It is one of the methods that does not block the donor node. [Mariabackup](../backup-restore-and-import-clients-mariadb-backup/index) was originally forked from [Percona XtraBackup](../backup-restore-and-import-clients-percona-xtrabackup/index), and similarly, the `mariabackup` SST method was originally forked from the `[xtrabackup-v2](../xtrabackup-v2-sst-method/index)` SST method. Note that if you use the `mariabackup` SST method, then you also need to have `[socat](#socat-dependency)` installed on the server. This is needed to stream the backup from the donor node to the joiner node. This is a limitation that was inherited from the `[xtrabackup-v2](../xtrabackup-v2-sst-method/index)` SST method. Choosing Mariabackup for SSTs ----------------------------- To use the `mariabackup` SST method, you must set the `[wsrep\_sst\_method=mariabackup](../galera-cluster-system-variables/index#wsrep_sst_method)` on both the donor and joiner node. It can be changed dynamically with `[SET GLOBAL](../set/index#global-session)` on the node that you intend to be a SST donor. For example: ``` SET GLOBAL wsrep_sst_method='mariabackup'; ``` It can be set in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index) prior to starting up a node: ``` [mariadb] ... wsrep_sst_method = mariabackup ``` For an SST to work properly, the donor and joiner node must use the same SST method. Therefore, it is recommended to set `[wsrep\_sst\_method](../galera-cluster-system-variables/index#wsrep_sst_method)` to the same value on all nodes, since any node will usually be a donor or joiner node at some point. Major version upgrades ---------------------- The InnoDB redo log format has been changed in [MariaDB 10.5](../what-is-mariadb-105/index) and [MariaDB 10.8](../what-is-mariadb-108/index) in a way that will not allow the crash recovery or the preparation of a backup from an older major version. Because of this, the `mariabackup` SST method cannot be used for some major version upgrades, unless you temporarily edit the `wsrep_sst_mariabackup` script so that the `--prepare` step on the newer-major-version joiner will be executed using the older-major-version `mariabackup` tool. The default method `wsrep_sst_method=rsync` will work for major version upgrades; see [MDEV-27437](https://jira.mariadb.org/browse/MDEV-27437). Authentication and Privileges ----------------------------- To use the `mariabackup` SST method, [Mariabackup](../backup-restore-and-import-clients-mariadb-backup/index) needs to be able to authenticate locally on the donor node, so that it can create a backup to stream to the joiner. You can tell the donor node what username and password to use by setting the `[wsrep\_sst\_auth](../galera-cluster-system-variables/index#wsrep_sst_auth)` system variable. It can be changed dynamically with `[SET GLOBAL](../set/index#global-session)` on the node that you intend to be a SST donor. For example: ``` SET GLOBAL wsrep_sst_auth = 'mariabackup:mypassword'; ``` It can also be set in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index) prior to starting up a node: ``` [mariadb] ... wsrep_sst_auth = mariabackup:mypassword ``` Some [authentication plugins](../authentication-plugins/index) do not require a password. For example, the `[unix\_socket](../authentication-plugin-unix-socket/index)` and `[gssapi](../authentication-plugin-gssapi/index)` authentication plugins do not require a password. If you are using a user account that does not require a password in order to log in, then you can just leave the password component of `[wsrep\_sst\_auth](../galera-cluster-system-variables/index#wsrep_sst_auth)` empty. For example: ``` [mariadb] ... wsrep_sst_auth = mariabackup: ``` The user account that performs the backup for the SST needs to have [the same privileges as Mariabackup](../mariabackup-overview/index#authentication-and-privileges), which are the `RELOAD` , `PROCESS`, `LOCK TABLES` and `REPLICATION CLIENT` [global privileges](../grant/index#global-privileges). To be safe, you should ensure that these privileges are set on each node in your cluster. [Mariabackup](../backup-restore-and-import-clients-mariadb-backup/index) connects locally on the donor node to perform the backup, so the following user should be sufficient: ``` CREATE USER 'mariabackup'@'localhost' IDENTIFIED BY 'mypassword'; GRANT RELOAD, PROCESS, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'mariabackup'@'localhost'; ``` ### Passwordless Authentication - Unix Socket It is possible to use the `[unix\_socket](../authentication-plugin-unix-socket/index)` authentication plugin for the user account that performs SSTs. This would provide the benefit of not needing to configure a plain-text password in `[wsrep\_sst\_auth](../galera-cluster-system-variables/index#wsrep_sst_auth)`. The user account would have to have the same name as the operating system user account that is running the `mysqld` process. On many systems, this is the user account configured as the `[user](../mysqld-options/index#-user)` option, and it tends to default to `mysql`. For example, if the `[unix\_socket](../authentication-plugin-unix-socket/index)` authentication plugin is already installed, then you could execute the following to create the user account: ``` CREATE USER 'mysql'@'localhost' IDENTIFIED VIA unix_socket; GRANT RELOAD, PROCESS, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'mysql'@'localhost'; ``` And then to configure `[wsrep\_sst\_auth](../galera-cluster-system-variables/index#wsrep_sst_auth)`, you could set the following in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index) prior to starting up a node: ``` [mariadb] ... wsrep_sst_auth = mysql: ``` ### Passwordless Authentication - GSSAPI It is possible to use the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin for the user account that performs SSTs. This would provide the benefit of not needing to configure a plain-text password in `[wsrep\_sst\_auth](../galera-cluster-system-variables/index#wsrep_sst_auth)`. The following steps would need to be done beforehand: * You need a KDC running [MIT Kerberos](http://web.mit.edu/Kerberos/krb5-1.12/doc/index.html) or [Microsoft Active Directory](https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/get-started/virtual-dc/active-directory-domain-services-overview). * You will need to [create a keytab file](../authentication-plugin-gssapi/index#creating-a-keytab-file-on-a-unix-server) for the MariaDB server. * You will need to [install the package](../authentication-plugin-gssapi/index#installing-the-plugins-package) containing the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin. * You will need to [install the plugin](../authentication-plugin-gssapi/index#installing-the-plugin) in MariaDB, so that the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin is available to use. * You will need to [configure the plugin](../authentication-plugin-gssapi/index#configuring-the-plugin). * You will need to [create a user account](../authentication-plugin-gssapi/index#creating-users) that authenticates with the `[gssapi](../authentication-plugin-gssapi/index)` authentication plugin, so that the user account can be used for SSTs. This user account will need to correspond with a user account that exists on the backend KDC. For example, you could execute the following to create the user account in MariaDB: ``` CREATE USER 'mariabackup'@'localhost' IDENTIFIED VIA gssapi; GRANT RELOAD, PROCESS, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'mariabackup'@'localhost'; ``` And then to configure `[wsrep\_sst\_auth](../galera-cluster-system-variables/index#wsrep_sst_auth)`, you could set the following in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index) prior to starting up a node: ``` [mariadb] ... wsrep_sst_auth = mariabackup: ``` Choosing a Donor Node --------------------- When Mariabackup is used to create the backup for the SST on the donor node, Mariabackup briefly requires a system-wide lock at the end of the backup. In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this is done with `[FLUSH TABLES WITH READ LOCK](../flush/index)`. In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this is done with `[BACKUP STAGE BLOCK\_COMMIT](../backup-stage/index)`. If a specific node in your cluster is acting as the *primary* node by receiving all of the application's write traffic, then this node should not usually be used as the donor node, because the system-wide lock could interfere with the application. In this case, you can define one or more preferred donor nodes by setting the `[wsrep\_sst\_donor](../galera-cluster-system-variables/index#wsrep_sst_donor)` system variable. For example, let's say that we have a 5-node cluster with the nodes `node1`, `node2`, `node3`, `node4`, and `node5`, and let's say that `node1` is acting as the *primary* node. The preferred donor nodes for `node2` could be configured by setting the following in a server [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index) prior to starting up a node: ``` [mariadb] ... wsrep_sst_donor=node3,node4,node5, ``` The trailing comma tells the server to allow any other node as donor when the preferred donors are not available. Therefore, if `node1` is the only node left in the cluster, the trailing comma allows it to be used as the donor node. Socat Dependency ---------------- During the SST process, the donor node uses [socat](http://www.dest-unreach.org/socat/doc/socat.html) to stream the backup to the joiner node. Then the joiner node prepares the backup before restoring it. The socat utility must be installed on both the donor node and the joiner node in order for this to work. Otherwise, the MariaDB error log will contain an error like: ``` WSREP_SST: [ERROR] socat not found in path: /usr/sbin:/sbin:/usr//bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin (20180122 14:55:32.993) ``` ### Installing Socat on RHEL/CentOS On RHEL/CentOS, `socat` can be installed from the [Extra Packages for Enterprise Linux (EPEL)](https://fedoraproject.org/wiki/EPEL) repository. TLS --- This SST method supports two different TLS methods. The specific method can be selected by setting the `encrypt` option in the `[sst]` section of the MariaDB configuration file. The options are: * TLS using OpenSSL encryption built into `socat` (`encrypt=2`) * TLS using OpenSSL encryption with Galera-compatible certificates and keys (`encrypt=3`) Note that `encrypt=1` refers to a TLS encryption method that has been deprecated and removed. `encrypt=4` refers to a TLS encryption method in `xtrabackup-v2` that has not yet been ported to `mariabackup`. See [MDEV-18050](https://jira.mariadb.org/browse/MDEV-18050) about that. ### TLS Using OpenSSL Encryption Built into Socat To generate keys compatible with this encryption method, you can follow [these directions](http://www.dest-unreach.org/socat/doc/socat-openssltunnel.html). For example: * First, generate the keys and certificates: ``` FILENAME=sst openssl genrsa -out $FILENAME.key 1024 openssl req -new -key $FILENAME.key -x509 -days 3653 -out $FILENAME.crt cat $FILENAME.key $FILENAME.crt >$FILENAME.pem chmod 600 $FILENAME.key $FILENAME.pem ``` * On some systems, you may also have to add dhparams to the certificate: ``` openssl dhparam -out dhparams.pem 2048 cat dhparams.pem >> sst.pem ``` * Then, copy the certificate and keys to all nodes in the cluster. * Then, configure the following on all nodes in the cluster: ``` [sst] encrypt=2 tca=/etc/my.cnf.d/certificates/sst.crt tcert=/etc/my.cnf.d/certificates/sst.pem ``` But replace the paths with whatever is relevant on your system. This should allow your SSTs to be encrypted. ### TLS Using OpenSSL Encryption with Galera-compatible Certificates and Keys To generate keys compatible with this encryption method, you can follow [these directions](https://galeracluster.com/library/documentation/ssl-cert.html). For example: * First, generate the keys and certificates: ``` # CA openssl genrsa 2048 > ca-key.pem openssl req -new -x509 -nodes -days 365000 \ -key ca-key.pem -out ca-cert.pem # server1 openssl req -newkey rsa:2048 -days 365000 \ -nodes -keyout server1-key.pem -out server1-req.pem openssl rsa -in server1-key.pem -out server1-key.pem openssl x509 -req -in server1-req.pem -days 365000 \ -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 \ -out server1-cert.pem ``` * Then, copy the certificate and keys to all nodes in the cluster. * Then, configure the following on all nodes in the cluster: ``` [sst] encrypt=3 tkey=/etc/my.cnf.d/certificates/server1-key.pem tcert=/etc/my.cnf.d/certificates/server1-cert.pem ``` But replace the paths with whatever is relevant on your system. This should allow your SSTs to be encrypted. Logs ---- The `mariabackup` SST method has its own logging outside of the MariaDB Server logging. ### Logging to SST Logs **MariaDB starting with [10.1.38](https://mariadb.com/kb/en/mariadb-10138-release-notes/)**Starting with [MariaDB 10.1.38](https://mariadb.com/kb/en/mariadb-10138-release-notes/), [MariaDB 10.2.22](https://mariadb.com/kb/en/mariadb-10222-release-notes/), and [MariaDB 10.3.13](https://mariadb.com/kb/en/mariadb-10313-release-notes/), logging for `mariabackup` SSTs works the following way. By default, on the donor node, it logs to `mariabackup.backup.log`. This log file is located in the `[datadir](../server-system-variables/index#datadir)`. By default, on the joiner node, it logs to `mariabackup.prepare.log` and `mariabackup.move.log` These log files are also located in the `[datadir](../server-system-variables/index#datadir)`. By default, before a new SST is started, existing `mariabackup` SST log files are compressed and moved to `/tmp/sst_log_archive`. This behavior can be disabled by setting `sst-log-archive=0` in the `[sst]` [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). Similarly, the archive directory can be changed by setting `sst-log-archive-dir`. For example: ``` [sst] sst-log-archive=1 sst-log-archive-dir=/var/log/mysql/sst/ ``` See [MDEV-17973](https://jira.mariadb.org/browse/MDEV-17973) for more information. **MariaDB until [10.1.38](https://mariadb.com/kb/en/mariadb-10138-release-notes/)**Prior to [MariaDB 10.1.38](https://mariadb.com/kb/en/mariadb-10138-release-notes/), [MariaDB 10.2.22](https://mariadb.com/kb/en/mariadb-10222-release-notes/), and [MariaDB 10.3.13](https://mariadb.com/kb/en/mariadb-10313-release-notes/), logging for `mariabackup` SSTs works the following way. By default, on the donor node, it logs to `innobackup.backup.log`. This log file is located in the `[datadir](../server-system-variables/index#datadir)`. By default, on the joiner node, it logs to `innobackup.prepare.log` and `innobackup.move.log`. These log files are located in the `.sst` directory, which is a hidden directory inside the `[datadir](../server-system-variables/index#datadir)`. These log files are overwritten by each subsequent SST, so if an SST fails, it is best to copy them somewhere safe before starting another SST, so that the log files can be analyzed. ### Logging to Syslog You can redirect the SST logs to the syslog instead by setting the following in the `[sst]` [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index): ``` [sst] sst-syslog=1 ``` You can also redirect the SST logs to the syslog by setting the following in the `[mysqld_safe]` [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index): ``` [mysqld_safe] syslog ``` Performing SSTs with IPv6 Addresses ----------------------------------- If you are performing Mariabackup SSTs with IPv6 addresses, then the `socat` utility needs to be passed the `pf=ip6` option. This can be done by setting the `sockopt` option in the `[sst]` [option group](../configuring-mariadb-with-option-files/index#option-groups) in an [option file](../configuring-mariadb-with-option-files/index). For example: ``` [sst] sockopt=",pf=ip6" ``` See [MDEV-18797](https://jira.mariadb.org/browse/MDEV-18797) for more information. Manual SST with Mariabackup --------------------------- In some cases, if Galera Cluster's automatic SSTs repeatedly fail, then it can be helpful to perform a "manual SST". See the following page on how to do that: * [Manual SST of Galera Cluster node with Mariabackup](../manual-sst-of-galera-cluster-node-with-mariabackup/index) See Also -------- * [Percona XtraBackup SST Configuration](https://www.percona.com/doc/percona-xtradb-cluster/5.7/manual/xtrabackup_sst.html) * [Encrypting PXC Traffic: ENCRYPTING SST TRAFFIC](https://www.percona.com/doc/percona-xtradb-cluster/5.7/security/encrypt-traffic.html#encrypt-sst) * [XTRABACKUP PARAMETERS](https://galeracluster.com/library/documentation/xtrabackup-options.html) * [SSL FOR STATE SNAPSHOT TRANSFERS: ENABLING SSL FOR XTRABACKUP](https://galeracluster.com/library/documentation/ssl-sst.html#ssl-xtrabackup) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb NumGeometries NumGeometries ============= A synonym for [ST\_NumGeometries](../st_numgeometries/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb The maria/5.3-gis tree on Launchpad. The maria/5.3-gis tree on Launchpad. ==================================== **Note:** This page is obsolete. The information is old, outdated, or otherwise currently incorrect. We are keeping the page for historical reasons only. **Do not** rely on the information in this article. The maria/5.3-gis tree on Launchpad. Basic information about the existing spatial features can be found in the [Geographic Features](../geographic-features/index) section of the Knowlegebase. The [Spatial Extensions page of the MySQL manual](http://dev.mysql.com/doc/refman/5.6/en/spatial-extensions.html) also applies to MariaDB. The [maria/5.3-gis tree](https://code.launchpad.net/~maria-captains/maria/5.3-gis), contains recent code improving the spatial functionality in MariaDB. MySQL operates on spatial data based on the OpenGIS standards, particularly the [OpenGIS SFS](http://www.opengeospatial.org/standards/sfs) (Simple feature access, SQL option). Initial support was based on version 05-134 of the standard. MariaDB implements a subset of the 'SQL with Geometry Types' environment proposed by the OGC. And the SQL environment was extended with a set of geometry types. Now we have started to implement the newer 06-104r4 standard. MariaDB supports spatial extensions to operate on spatial features. These features are available for Aria, MyISAM, InnoDB, NDB, and ARCHIVE tables. For spatial columns, Aria and MyISAM supports both SPATIAL and non-SPATIAL indexes. Other storage engines support non-SPATIAL indexes. The most recent changes in the code are aimed at meeting the OpenGIS requirements. One thing missing in the present version is that the functions which check spatial relations don't consider the actual shape of an object, instead they operate only on their bounding rectangles. These legacy functions have been left as they are, and new, properly-working functions are named with an '`ST_`' prefix, in accordance with the last OpenGIS requirements. Also, operations over geometry features were added. The list of new functions: Spatial operators. They produce new geometries. | Name | Description | | --- | --- | | `ST_UNION(A, B)` | union of A and B | | `ST_INTERSECTION(A, B)` | intersection of A and B | | `ST_SYMDIFFERENCE(A, B)` | symdifference, notintersecting parts of A and B | | `ST_BUFFER(A, radius)` | returns the shape of the area that lies in 'radius' distance from the shape A. | Predicates, return boolean result of the relationship | Name | Description | | --- | --- | | `ST_INTERSECTS(A, B)` | if A and B have an intersection | | `ST_CROSSES(A, B)` | if A and B cross | | `ST_EQUAL(A, B)` | if A nad B are equal | | `ST_WITHIN(A, B)` | if A lies within B | | `ST_CONTAINS(A,B)` | if B lies within A | | `ST_DISJOINT(A,B)` | if A and B have no intersection | | `ST_TOUCHES(A,B)` | if A touches B | Geometry metadata views: | | | | --- | --- | | `GEOMETRY_COLUMNS` | *this table describes the available feature tables and their Geometry properties* | | fields: | `F_TABLE_CATALOG VARCHAR(200) NOT NULL,` | | | `F_TABLE_SCHEMA VARCHAR(200) NOT NULL,` | | | `F_TABLE_NAME VARCHAR(200) NOT NULL,` | | | `F_GEOMETRY_COLUMN VARCHAR(200) NOT NULL,` | | | `G_TABLE_CATALOG VARCHAR(200) NOT NULL,` | | | `G_TABLE_SCHEMA VARCHAR(200) NOT NULL,` | | | `G_TABLE_NAME VARCHAR(200) NOT NULL,` | | | `STORAGE_TYPE INTEGER,` | | | `GEOMETRY_TYPE INTEGER,` | | | `COORD_DIMENSION INTEGER,` | | | `MAX_PPR INTEGER,` | | | `SRID INTEGER NOT NULL` | | | | | | | | SPATIAL\_REF\_SYS | *this table describes the coordinate system and transformations for Geometry* | | fields: | `SRID INTEGER NOT NULL PRIMARY KEY,` | | | `AUTH_NAME VARCHAR(200),` | | | `AUTH_SRID INTEGER,` | | | `SRTEXT TEXT` | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb UNLOCK TABLES UNLOCK TABLES ============= Syntax ------ ``` UNLOCK TABLES ``` Description ----------- `UNLOCK TABLES` explicitly releases any table locks held by the current session. See `[LOCK TABLES](../lock-tables/index)` for more information. In addition to releasing table locks acquired by the `[LOCK TABLES](../lock-tables/index)` statement, the `UNLOCK TABLES` statement also releases the global read lock acquired by the `FLUSH TABLES WITH READ LOCK` statement. The `FLUSH TABLES WITH READ LOCK` statement is very useful for performing backups. See `[FLUSH](../flush/index)` for more information about `FLUSH TABLES WITH READ LOCK`. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb CHECK TABLE CHECK TABLE =========== Syntax ------ ``` CHECK TABLE tbl_name [, tbl_name] ... [option] ... option = {FOR UPGRADE | QUICK | FAST | MEDIUM | EXTENDED | CHANGED} ``` Description ----------- `CHECK TABLE` checks a table or tables for errors. `CHECK TABLE` works for [Archive](../archive/index), [Aria](../aria/index), [CSV](../csv/index), [InnoDB](../innodb/index), and [MyISAM](../myisam/index) tables. For Aria and MyISAM tables, the key statistics are updated as well. For CSV, see also [Checking and Repairing CSV Tables](../checking-and-repairing-csv-tables/index). As an alternative, [myisamchk](../myisamchk/index) is a commandline tool for checking MyISAM tables when the tables are not being accessed. For checking [dynamic columns](../dynamic-columns/index) integrity, [COLUMN\_CHECK()](../dynamic-columns-in-mariadb-10/index#column_check) can be used. `CHECK TABLE` can also check views for problems, such as tables that are referenced in the view definition that no longer exist. `CHECK TABLE` is also supported for partitioned tables. You can use `[ALTER TABLE](../alter-table/index) ... CHECK PARTITION` to check one or more partitions. The meaning of the different options are as follows - note that this can vary a bit between storage engines: | | | | --- | --- | | FOR UPGRADE | Do a very quick check if the storage format for the table has changed so that one needs to do a REPAIR. This is only needed when one upgrades between major versions of MariaDB or MySQL. This is usually done by [running mysql\_upgrade](../upgrading-to-mariadb-from-mysql/index). | | FAST | Only check tables that has not been closed properly or are marked as corrupt. Only supported by the MyISAM and Aria engines. For other engines the table is checked normally | | CHANGED | Check only tables that has changed since last REPAIR / CHECK. Only supported by the MyISAM and Aria engines. For other engines the table is checked normally. | | QUICK | Do a fast check. For MyISAM and Aria engine this means we skip checking the delete link chain which may take some time. | | MEDIUM | Scan also the data files. Checks integrity between data and index files with checksums. In most cases this should find all possible errors. | | EXTENDED | Does a full check to verify every possible error. For MyISAM and Aria we verify for each row that all it keys exists and points to the row. This may take a long time on big tables! | For most cases running `CHECK TABLE` without options or `MEDIUM` should be good enough. The [Aria](../aria/index) storage engine supports [progress reporting](../progress-reporting/index) for this statement. If you want to know if two tables are identical, take a look at [CHECKSUM TABLE](../checksum-table/index). InnoDB ------ If `CHECK TABLE` finds an error in an InnoDB table, MariaDB might shutdown to prevent the error propagation. In this case, the problem will be reported in the error log. Otherwise the table or an index might be marked as corrupted, to prevent use. This does not happen with some minor problems, like a wrong number of entries in a secondary index. Those problems are reported in the output of `CHECK TABLE`. Each tablespace contains a header with metadata. This header is not checked by this statement. During the execution of `CHECK TABLE`, other threads may be blocked. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql_waitpid mysql\_waitpid ============== **MariaDB starting with [10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/)**From [MariaDB 10.4.6](https://mariadb.com/kb/en/mariadb-1046-release-notes/), `mariadb-waitpid` is a symlink to `mysql_waitpid`. **MariaDB starting with [10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/)**From [MariaDB 10.5.2](https://mariadb.com/kb/en/mariadb-1052-release-notes/), `mysql_waitpid` is the symlink, and `mariadb-waitpid` the binary name. `mysql_pid` is a utility for terminating processes. It runs on Unix-like systems, making use of the `kill()` system call. Usage ----- ``` mysql_waitpid [options] pid time ``` Description ----------- `mysql_pid` sends signal 0 to the process *pid* and waits up to *time* seconds for the process to terminate. *pid* and *time* must be positive integers. Returns 0 if the process terminates in time, or does not exist, and 1 otherwise. Signal 1 is used if the kill() system call cannot handle signal 0 Options ------- | Option | Description | | --- | --- | | `-?`, `--help` | Display help and exit | | `-I`, `--help` | Synonym for -? | | `-v`, `--verbose` | Be more verbose. Give a warning, if kill can't handle signal 0 | | `-V`, `--version` | Print version information and exit | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Optimizer Trace Optimizer Trace ================ | Title | Description | | --- | --- | | [Optimizer Trace Overview](../optimizer-trace-overview/index) | Produces a JSON trace with decision info taken by the optimizer during the optimization phase. | | [Optimizer Trace Guide](../optimizer-trace-guide/index) | Guide to the structured log file showing what actions were taken by the query optimizer. | | [Basic Optimizer Trace Example](../basic-optimizer-trace-example/index) | MariaDB> select \* from information\_schema.optimizer\_trace limit 1\G \*\*\*\*\* 1. row \*\*\*\*\* | | [Optimizer Trace Resources](../optimizer-trace-resources/index) | Optimizer Trace Walkthrough talk at MariaDB Fest 2020: https://mariadb.org/... | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb POSITION POSITION ======== Syntax ------ ``` POSITION(substr IN str) ``` Description ----------- POSITION(substr IN str) is a synonym for [LOCATE(substr,str)](../locate/index). It's part of ODBC 3.0. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb mysql.table_stats Table mysql.table\_stats Table ======================== The `mysql.table_stats` table is one of three tables storing data used for [Engine-independent table statistics](../engine-independent-table-statistics/index). The others are [mysql.column\_stats](../mysqlcolumn_stats-table/index) and [mysql.index\_stats](../mysqlindex_stats-table/index). **MariaDB starting with [10.4](../what-is-mariadb-104/index)**In [MariaDB 10.4](../what-is-mariadb-104/index) and later, this table uses the [Aria](../aria/index) storage engine. **MariaDB until [10.3](../what-is-mariadb-103/index)**In [MariaDB 10.3](../what-is-mariadb-103/index) and before, this table uses the [MyISAM](../myisam-storage-engine/index) storage engine. The `mysql.table_stats` table contains the following fields: | Field | Type | Null | Key | Default | Description | | --- | --- | --- | --- | --- | --- | | `db_name` | `varchar(64)` | NO | PRI | `NULL` | Database the table is in . | | `table_name` | `varchar(64)` | NO | PRI | `NULL` | Table name. | | `cardinality` | `bigint(21) unsigned` | YES | | `NULL` | Number of records in the table. | It is possible to manually update the table. See [Manual updates to statistics tables](../engine-independent-table-statistics/index#manual-updates-to-statistics-tables) for details. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Sample storagemanager.cnf Sample storagemanager.cnf ========================= ``` # Sample storagemanager.cnf [ObjectStorage] service = S3 object_size = 5M metadata_path = /var/lib/columnstore/storagemanager/metadata journal_path = /var/lib/columnstore/storagemanager/journal max_concurrent_downloads = 21 max_concurrent_uploads = 21 common_prefix_depth = 3 [S3] region = us-west-1 bucket = my_columnstore_bucket endpoint = s3.amazonaws.com aws_access_key_id = AKIAR6P77BUKULIDIL55 aws_secret_access_key = F38aR4eLrgNSWPAKFDJLDAcax0gZ3kYblU79 [LocalStorage] path = /var/lib/columnstore/storagemanager/fake-cloud fake_latency = n max_latency = 50000 [Cache] cache_size = 2g path = /var/lib/columnstore/storagemanager/cache ``` ***Note**: A region is required even when using an on-prem solution like [ActiveScale](https://qsupport.quantum.com/kb/flare/Content/ActiveScale/PDFs/ActiveScale_OS_S3_API_Reference.pdf) due to header expectations within the API.* Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB ColumnStore software upgrade 1.1.5 GA to 1.1.6 GA MariaDB ColumnStore software upgrade 1.1.5 GA to 1.1.6 GA ========================================================= MariaDB ColumnStore software upgrade 1.1.5 GA to 1.1.6 GA --------------------------------------------------------- Additional Dependency Packages exist for 1.1.6, so make sure you install those based on the "Preparing for ColumnStore Installation" Guide. Note: Columnstore.xml modifications you manually made are not automatically carried forward on an upgrade. These modifications will need to be incorporated back into .XML once the upgrade has occurred. The previous configuration file will be saved as /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave. If you have specified a root database password (which is good practice), then you must configure a .my.cnf file with user credentials for the upgrade process to use. Create a .my.cnf file in the user home directory with 600 file permissions with the following content (updating PASSWORD as appropriate): ``` [mysqladmin] user = root password = PASSWORD ``` ### Choosing the type of upgrade As noted on the Preparing guide, you can installing MariaDB ColumnStore with the use of soft-links. If you have the softlinks be setup at the Data Directory Levels, like mariadb/columnstore/data and mariadb/columnstore/dataX, then your upgrade will happen without any issues. In the case where you have a softlink at the top directory, like /usr/local/mariadb, you will need to upgrade using the binary package. If you updating using the rpm package and tool, this softlink will be deleted when you perform the upgrade process and the upgrade will fail. #### Root User Installs #### Upgrading MariaDB ColumnStore using RPMs tar package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Download the package mariadb-columnstore-1.1.6-1-centos#.x86\_64.rpm.tar.gz to the PM1 server where you are installing MariaDB ColumnStore.** Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate a set of RPMs that will reside in the /root/ directory. ``` # tar -zxf mariadb-columnstore-1.1.6-1-centos#.x86_64.rpm.tar.gz ``` * Upgrade the RPMs. The MariaDB ColumnStore software will be installed in /usr/local/. ``` # rpm -e --nodeps $(rpm -qa | grep '^mariadb-columnstore') # rpm -ivh mariadb-columnstore-*1.1.6*rpm ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml.rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` For RPM Upgrade, the previous configuration file will be saved as: /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave #### Upgrading MariaDB ColumnStore using RPM Package Repositories The system can be upgrade when it was previously installed from the Package Repositories. This will need to be run on each module in the system Additional information can be found in this document on how to setup and install using the 'yum' package repo command: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Shutdown the MariaDB ColumnStore system:** ``` # mcsadmin shutdownsystem y ``` * Uninstall MariaDB ColumnStore Packages ``` # yum remove mariadb-columnstore* ``` * Install MariaDB ColumnStore Packages ``` # yum --enablerepo=mariadb-columnstore clean metadata # yum install mariadb-columnstore* ``` NOTE: On the non-pm1 module, start the columnstore service ``` # /usr/local/mariadb/columnstore/bin/columnstore start ``` * Run postConfigure using the upgrade and non-distributed options, which will utilize the configuration from the Columnstore.xml.rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u -n ``` For RPM Upgrade, the previous configuration file will be saved as: /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /usr/local directory -mariadb-columnstore-1.1.6-1.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Run pre-uninstall script ``` # /usr/local/mariadb/columnstore/bin/pre-uninstall ``` * Unpack the tarball, in the /usr/local/ directory. ``` # tar -zxvf mariadb-columnstore-1.1.6-1.x86_64.bin.tar.gz ``` * Run post-install scripts ``` # /usr/local/mariadb/columnstore/bin/post-install ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` ### Upgrading MariaDB ColumnStore using the DEB package A DEB upgrade would be done on a system that supports DEBs like Debian or Ubuntu systems. Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /root directory mariadb-columnstore-1.1.6-1.amd64.deb.tar.gz (DEB 64-BIT) to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Unpack the tarball, which will generate DEBs. ``` # tar -zxf mariadb-columnstore-1.1.6-1.amd64.deb.tar.gz ``` * Remove and install all MariaDB ColumnStore debs ``` # cd /root/ # dpkg -r $(dpkg --list | grep 'mariadb-columnstore' | awk '{print $2}') # dpkg --install mariadb-columnstore-*1.1.6-1*deb ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u ``` #### Upgrading MariaDB ColumnStore using DEB Package Repositories The system can be upgrade when it was previously installed from the Package Repositories. This will need to be run on each module in the system Additional information can be found in this document on how to setup and install using the 'apt-get' package repo command: [https://mariadb.com/kb/en/library/installing-mariadb-ax-from-the-package-repositories](../library/installing-mariadb-ax-from-the-package-repositories) Upgrade MariaDB ColumnStore as user root on the server designated as PM1: **Shutdown the MariaDB ColumnStore system:** ``` # mcsadmin shutdownsystem y ``` * Uninstall MariaDB ColumnStore Packages ``` # apt-get remove mariadb-columnstore* ``` * Install MariaDB ColumnStore Packages ``` # apt-get update # sudo apt-get install mariadb-columnstore* ``` NOTE: On the non-pm1 module, start the columnstore service ``` # /usr/local/mariadb/columnstore/bin/columnstore start ``` * Run postConfigure using the upgrade and non-distributed options, which will utilize the configuration from the Columnstore.xml.rpmsave ``` # /usr/local/mariadb/columnstore/bin/postConfigure -u -n ``` For RPM Upgrade, the previous configuration file will be saved as: /usr/local/mariadb/columnstore/etc/Columnstore.xml.rpmsave #### Non-Root User Installs ### Initial download/install of MariaDB ColumnStore binary package Upgrade MariaDB ColumnStore as user root on the server designated as PM1: * Download the package into the /home/'non-root-user" directory mariadb-columnstore-1.1.6-1.x86\_64.bin.tar.gz (Binary 64-BIT)to the server where you are installing MariaDB ColumnStore. * Shutdown the MariaDB ColumnStore system: ``` # mcsadmin shutdownsystem y ``` * Run pre-uninstall script ``` # $HOME/mariadb/columnstore/bin/pre-uninstall --installdir=/home/guest/mariadb/columnstore ``` * Unpack the tarball, which will generate the $HOME/ directory. ``` # tar -zxvf mariadb-columnstore-1.1.6-1.x86_64.bin.tar.gz ``` * Run post-install scripts ``` # $HOME/mariadb/columnstore/bin/post-install --installdir=/home/guest/mariadb/columnstore ``` * Run postConfigure using the upgrade option, which will utilize the configuration from the Columnstore.xml,rpmsave ``` # $HOME/mariadb/columnstore/bin/postConfigure -u -i /home/guest/mariadb/columnstore ``` ### Running the mysql\_upgrade script As part of the upgrade process, the user is required to run the mysql\_upgrade script on all of the following nodes. * User Modules on a system configured with separate User and Performance Modules * Performance Modules on a system configured with separate User and Performance Modules and Local Query Feature is enabled * Performance Modules on a system configured with combined User and Performance Modules mysql\_upgrade should be run once the upgrade has been completed. This is an example of how it run on a root user install: ``` /usr/local/mariadb/columnstore/mysql/bin/mysql_upgrade --defaults-file=/usr/local/mariadb/columnstore/mysql/my.cnf --force ``` This is an example of how it run on a non-root user install, assuming ColumnStore is installed under the user's home directory: ``` $HOME/mariadb/columnstore/mysql/bin/mysql_upgrade --defaults-file=$HOME/mariadb/columnstore/mysql/my.cnf --force ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb SETVAL SETVAL ====== **MariaDB starting with [10.3.1](https://mariadb.com/kb/en/mariadb-1031-release-notes/)**SEQUENCEs were introduced in [MariaDB 10.3](../what-is-mariadb-103/index). Syntax ------ ``` SETVAL(sequence_name, next_value, [is_used, [round]]) ``` Description ----------- Set the next value to be returned for a `SEQUENCE`. This function is compatible with PostgreSQL syntax, extended with the `round` argument. If the `is_used` argument is not given or is `1` or `true`, then the next used value will one after the given value. If `is_used` is `0` or `false` then the next generated value will be the given value. If `round` is used then it will set the `round` value (or the internal cycle count, starting at zero) for the sequence. If `round` is not used, it's assumed to be 0. `next_value` must be an integer literal. For `SEQUENCE` tables defined with `CYCLE` (see [CREATE SEQUENCE](../create-sequence/index)) one should use both `next_value` and `round` to define the next value. In this case the current sequence value is defined to be `round`, `next_value`. The result returned by `SETVAL()` is `next_value` or NULL if the given `next_value` and `round` is smaller than the current value. `SETVAL()` will not set the `SEQUENCE` value to a something that is less than its current value. This is needed to ensure that `SETVAL()` is replication safe. If you want to set the SEQUENCE to a smaller number use [ALTER SEQUENCE](../alter-sequence/index). If `CYCLE` is used, first `round` and then `next_value` are compared to see if the value is bigger than the current value. Internally, in the MariaDB server, `SETVAL()` is used to inform slaves that a `SEQUENCE` has changed value. The slave may get `SETVAL()` statements out of order, but this is ok as only the biggest one will have an effect. `SETVAL` requires the [INSERT privilege](../grant/index). Examples -------- ``` SELECT setval(foo, 42); -- Next nextval will return 43 SELECT setval(foo, 42, true); -- Same as above SELECT setval(foo, 42, false); -- Next nextval will return 42 ``` SETVAL setting higher and lower values on a sequence with an increment of 10: ``` SELECT NEXTVAL(s); +------------+ | NEXTVAL(s) | +------------+ | 50 | +------------+ SELECT SETVAL(s, 100); +----------------+ | SETVAL(s, 100) | +----------------+ | 100 | +----------------+ SELECT NEXTVAL(s); +------------+ | NEXTVAL(s) | +------------+ | 110 | +------------+ SELECT SETVAL(s, 50); +---------------+ | SETVAL(s, 50) | +---------------+ | NULL | +---------------+ SELECT NEXTVAL(s); +------------+ | NEXTVAL(s) | +------------+ | 120 | +------------+ ``` Example demonstrating `round`: ``` CREATE OR REPLACE SEQUENCE s1 START WITH 1 MINVALUE 1 MAXVALUE 99 INCREMENT BY 1 CACHE 20 CYCLE; SELECT SETVAL(s1, 99, 1, 0); +----------------------+ | SETVAL(s1, 99, 1, 0) | +----------------------+ | 99 | +----------------------+ SELECT NEXTVAL(s1); +-------------+ | NEXTVAL(s1) | +-------------+ | 1 | +-------------+ ``` The following statement returns NULL, as the given `next_value` and `round` is smaller than the current value. ``` SELECT SETVAL(s1, 99, 1, 0); +----------------------+ | SETVAL(s1, 99, 1, 0) | +----------------------+ | NULL | +----------------------+ SELECT NEXTVAL(s1); +-------------+ | NEXTVAL(s1) | +-------------+ | 2 | +-------------+ ``` Increasing the round from zero to 1 will allow `next_value` to be returned. ``` SELECT SETVAL(s1, 99, 1, 1); +----------------------+ | SETVAL(s1, 99, 1, 1) | +----------------------+ | 99 | +----------------------+ SELECT NEXTVAL(s1); +-------------+ | NEXTVAL(s1) | +-------------+ | 1 | +-------------+ ``` See Also -------- * [Sequence Overview](../sequence-overview/index) * [ALTER SEQUENCE](../alter-sequence/index) * [CREATE SEQUENCE](../create-sequence/index) * [NEXT VALUE FOR](../next-value-for-sequence_name/index) * [PREVIOUS VALUE FOR](../previous-value-for-sequence_name/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_BOUNDARY ST\_BOUNDARY ============ **MariaDB starting with [10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/)**The ST\_BOUNDARY function was introduced in [MariaDB 10.1.2](https://mariadb.com/kb/en/mariadb-1012-release-notes/) Syntax ------ ``` ST_BOUNDARY(g) BOUNDARY(g) ``` Description ----------- Returns a geometry that is the closure of the combinatorial boundary of the geometry value *`g`*. BOUNDARY() is a synonym. Examples -------- ``` SELECT ST_AsText(ST_Boundary(ST_GeomFromText('LINESTRING(3 3,0 0, -3 3)'))); +----------------------------------------------------------------------+ | ST_AsText(ST_Boundary(ST_GeomFromText('LINESTRING(3 3,0 0, -3 3)'))) | +----------------------------------------------------------------------+ | MULTIPOINT(3 3,-3 3) | +----------------------------------------------------------------------+ SELECT ST_AsText(ST_Boundary(ST_GeomFromText('POLYGON((3 3,0 0, -3 3, 3 3))'))); +--------------------------------------------------------------------------+ | ST_AsText(ST_Boundary(ST_GeomFromText('POLYGON((3 3,0 0, -3 3, 3 3))'))) | +--------------------------------------------------------------------------+ | LINESTRING(3 3,0 0,-3 3,3 3) | +--------------------------------------------------------------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb MariaDB Optimization for MySQL Users MariaDB Optimization for MySQL Users ==================================== MariaDB contains many new options and optimizations which, for compatibility or other reasons, are not enabled in the default install. Enabling them helps you gain extra performance from the same hardware when upgrading from MySQL to MariaDB. This article contains information on options and settings which you should enable, or at least look in to, when making the switch. ``` aria-pagecache-buffer-size=## ``` If you are using a log of on-disk temporary tables, increase the above to as much as you can afford. See [Aria Storage Engine](../aria-storage-engine/index) for more details. ``` key-cache-segments=8 ``` If you use/have a lot of MyISAM files, increase the above to 4 or 8. See [Segmented Key Cache](../segmented-key-cache/index) and [Segmented Key Cache Performance](../segmented-key-cache-performance/index) for more information. ``` thread-handling=pool-of-threads ``` Threadpool is a great way to increase performance in situations where queries are relatively short and the load is CPU bound (e.g. OLTP workloads). To enable it, add the above to your my.cnf file. See [Threadpool in 5.5](../threadpool-in-55/index) for more information. ``` innodb-buffer-pool-instances= ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb OLD_PASSWORD OLD\_PASSWORD ============= Syntax ------ ``` OLD_PASSWORD(str) ``` Description ----------- `OLD_PASSWORD()` was added to MySQL when the implementation of [PASSWORD()](../password/index) was changed to improve security. `OLD_PASSWORD()` returns the value of the old (pre-MySQL 4.1) implementation of PASSWORD() as a string, and is intended to permit you to reset passwords for any pre-4.1 clients that need to connect to a more recent MySQL server version, or any version of MariaDB, without locking them out. As of [MariaDB 5.5](../what-is-mariadb-55/index), the return value is a nonbinary string in the connection [character set and collation](../data-types-character-sets-and-collations/index), determined by the values of the [character\_set\_connection](../server-system-variables/index#character_set_connection) and [collation\_connection](../server-system-variables/index#collation_connection) system variables. Before 5.5, the return value was a binary string. The return value is 16 bytes in length, or NULL if the argument was NULL. See Also -------- * [PASSWORD()](../password/index) * [MySQL manual on password hashing](http://dev.mysql.com/doc/refman/5.1/en/password-hashing.html) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Installing System Tables (mysql_install_db) Installing System Tables (mysql\_install\_db) ============================================= `mysql_install_db` initializes the MariaDB data directory and creates the [system tables](../system-tables/index) in the [mysql](../the-mysql-database-tables/index) database, if they do not exist. MariaDB uses these tables to manage [privileges](../grant/index#privilege-levels), [roles](../roles/index), and [plugins](../plugins/index). It also uses them to provide the data for the [help](../help-command/index) command in the [mysql](../mysql-command-line-client/index) client. [mysql\_install\_db](../mysql_install_db/index) works by starting MariaDB Server's `mysqld` process in [--bootstrap](../mysqld-options/index#-bootstrap) mode and sending commands to create the [system tables](../system-tables/index) and their content. There is a version specifically for Windows, [mysql\_install\_db.exe](../mysql_install_dbexe/index). To invoke `mysql_install_db`, use the following syntax: ``` mysql_install_db --user=mysql ``` For the options supported by [mysql\_install\_db](../mysql_install_db/index), see [mysql\_install\_db: Options](../mysql_install_db/index#options). For the option groups read by [mysql\_install\_db](../mysql_install_db/index), see [mysql\_install\_db: Option Groups](../mysql_install_db/index#option-groups). See [mysql\_install\_db: Installing System Tables](../mysql_install_db/index#installing-system-tables) for information on the installation process. See [mysql\_install\_db: Troubleshooting Issues](../mysql_install_db/index#troubleshooting-issues) for information on how to troubleshoot the installation process. See Also -------- * [mysql\_install\_db](../mysql_install_db/index) * The Windows version of `mysql_install_db`: [mysql\_install\_db.exe](../mysql_install_dbexe/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema INNODB_UNDO_LOGS Table Information Schema INNODB\_UNDO\_LOGS Table =========================================== **MariaDB [5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/) - [10.0](../what-is-mariadb-100/index)**The `INNODB_UNDO_LOGS` are a Percona enhancement, introduced in version [MariaDB 5.5.27](https://mariadb.com/kb/en/mariadb-5527-release-notes/) and removed in 10.0. The [Information Schema](../information_schema/index) `INNODB_UNDO_LOGS` table is a Percona enchancement, and is only available for XtraDB, not InnoDB (see [XtraDB and InnoDB](../xtradb-and-innodb/index)). It contains information about the the InnoDB [undo log](../undo-log/index), with each record being an undo log segment. It was removed in [MariaDB 10.0](../what-is-mariadb-100/index). It has the following columns: | Column | Description | | --- | --- | | `TRX_ID` | Unique transaction ID number, matching the value from the [information\_schema.INNODB\_TRX](../information-schema-innodb_trx-table/index) table. | | `RSEG_ID` | Rollback segment ID, matching the value from the `information_schema.INNODB_RSEG` table. | | `USEG_ID` | Undo segment ID. | | `SEGMENT_TYPE` | Indicates the operation type, for example `INSERT` or `UPDATE`. | | `STATE` | Segment state; one of `ACTIVE` (contains active transaction undo log), `CACHED`, `TO_FREE` (insert undo segment can be freed), `TO_PURGE` (update undo segment won't be re-used and can be purged when all undo data is removed) or `PREPARED` (segment of a prepared transaction). | | `SIZE` | Size in pages of the segment. | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Dynamic Columns Dynamic Columns =============== Dynamic columns allow one to store different sets of columns for each row in a table. It works by storing a set of columns in a blob and having a small set of functions to manipulate it. Dynamic columns should be used when it is not possible to use regular columns. A typical use case is when one needs to store items that may have many different attributes (like size, color, weight, etc), and the set of possible attributes is very large and/or unknown in advance. In that case, attributes can be put into dynamic columns. Dynamic Columns Basics ---------------------- The table should have a blob column which will be used as storage for dynamic columns: ``` create table assets ( item_name varchar(32) primary key, -- A common attribute for all items dynamic_cols blob -- Dynamic columns will be stored here ); ``` Once created, one can access dynamic columns via dynamic column functions: Insert a row with two dynamic columns: color=blue, size=XL ``` INSERT INTO assets VALUES ('MariaDB T-shirt', COLUMN_CREATE('color', 'blue', 'size', 'XL')); ``` Insert another row with dynamic columns: color=black, price=500 ``` INSERT INTO assets VALUES ('Thinkpad Laptop', COLUMN_CREATE('color', 'black', 'price', 500)); ``` Select dynamic column 'color' for all items: ``` SELECT item_name, COLUMN_GET(dynamic_cols, 'color' as char) AS color FROM assets; +-----------------+-------+ | item_name | color | +-----------------+-------+ | MariaDB T-shirt | blue | | Thinkpad Laptop | black | +-----------------+-------+ ``` It is possible to add and remove dynamic columns from a row: ``` -- Remove a column: UPDATE assets SET dynamic_cols=COLUMN_DELETE(dynamic_cols, "price") WHERE COLUMN_GET(dynamic_cols, 'color' as char)='black'; -- Add a column: UPDATE assets SET dynamic_cols=COLUMN_ADD(dynamic_cols, 'warranty', '3 years') WHERE item_name='Thinkpad Laptop'; ``` You can also list all columns, or get them together with their values in JSON format: ``` SELECT item_name, column_list(dynamic_cols) FROM assets; +-----------------+---------------------------+ | item_name | column_list(dynamic_cols) | +-----------------+---------------------------+ | MariaDB T-shirt | `size`,`color` | | Thinkpad Laptop | `color`,`warranty` | +-----------------+---------------------------+ SELECT item_name, COLUMN_JSON(dynamic_cols) FROM assets; +-----------------+----------------------------------------+ | item_name | COLUMN_JSON(dynamic_cols) | +-----------------+----------------------------------------+ | MariaDB T-shirt | {"size":"XL","color":"blue"} | | Thinkpad Laptop | {"color":"black","warranty":"3 years"} | +-----------------+----------------------------------------+ ``` Dynamic Columns Reference ------------------------- The rest of this page is a complete reference of dynamic columns in MariaDB ### Dynamic Columns Functions #### COLUMN\_CREATE ``` COLUMN_CREATE(column_nr, value [as type], [column_nr, value [as type]]...); COLUMN_CREATE(column_name, value [as type], [column_name, value [as type]]...); ``` Return a dynamic columns blob that stores the specified columns with values. The return value is suitable for * + storing in a table + further modification with other dynamic columns functions The **`as type`** part allows one to specify the value type. In most cases, this is redundant because MariaDB will be able to deduce the type of the value. Explicit type specification may be needed when the type of the value is not apparent. For example, a literal `'2012-12-01'` has a CHAR type by default, one will need to specify `'2012-12-01' AS DATE` to have it stored as a date. See the [Datatypes](#Datatypes) section for further details. Note also [MDEV-597](https://jira.mariadb.org/browse/MDEV-597). Typical usage: ``` -- MariaDB 5.3+: INSERT INTO tbl SET dyncol_blob=COLUMN_CREATE(1 /*column id*/, "value"); -- MariaDB 10.0.1+: INSERT INTO tbl SET dyncol_blob=COLUMN_CREATE("column_name", "value"); ``` #### COLUMN\_ADD ``` COLUMN_ADD(dyncol_blob, column_nr, value [as type], [column_nr, value [as type]]...); COLUMN_ADD(dyncol_blob, column_name, value [as type], [column_name, value [as type]]...); ``` Adds or updates dynamic columns. * + **`dyncol_blob`** must be either a valid dynamic columns blob (for example, `COLUMN_CREATE` returns such blob), or an empty string. + **`column_name`** specifies the name of the column to be added. If `dyncol_blob` already has a column with this name, it will be overwritten. + **`value`** specifies the new value for the column. Passing a NULL value will cause the column to be deleted. + **`as type`** is optional. See <#datatypes> section for a discussion about types. The return value is a dynamic column blob after the modifications. Typical usage: ``` -- MariaDB 5.3+: UPDATE tbl SET dyncol_blob=COLUMN_ADD(dyncol_blob, 1 /*column id*/, "value") WHERE id=1; -- MariaDB 10.0.1+: UPDATE t1 SET dyncol_blob=COLUMN_ADD(dyncol_blob, "column_name", "value") WHERE id=1; ``` Note: `COLUMN_ADD()` is a regular function (just like `[CONCAT()](../concat/index)`), hence, in order to update the value in the table you have to use the `UPDATE ... SET dynamic_col=COLUMN_ADD(dynamic_col, ....)` pattern. #### COLUMN\_GET ``` COLUMN_GET(dyncol_blob, column_nr as type); COLUMN_GET(dyncol_blob, column_name as type); ``` Get the value of a dynamic column by its name. If no column with the given name exists, `NULL` will be returned. **`column_name as type`** requires that one specify the datatype of the dynamic column they are reading. This may seem counter-intuitive: why would one need to specify which datatype they're retrieving? Can't the dynamic columns system figure the datatype from the data being stored? The answer is: SQL is a statically-typed language. The SQL interpreter needs to know the datatypes of all expressions before the query is run (for example, when one is using prepared statements and runs `"select COLUMN_GET(...)"`, the prepared statement API requires the server to inform the client about the datatype of the column being read before the query is executed and the server can see what datatype the column actually has). See the [Datatypes](#datatypes) section for more information about datatypes. #### COLUMN\_DELETE ``` COLUMN_DELETE(dyncol_blob, column_nr, column_nr...); COLUMN_DELETE(dyncol_blob, column_name, column_name...); ``` Delete a dynamic column with the specified name. Multiple names can be given. The return value is a dynamic column blob after the modification. #### COLUMN\_EXISTS ``` COLUMN_EXISTS(dyncol_blob, column_nr); COLUMN_EXISTS(dyncol_blob, column_name); ``` Check if a column with name `column_name` exists in `dyncol_blob`. If yes, return `1`, otherwise return `0`. #### COLUMN\_LIST ``` COLUMN_LIST(dyncol_blob); ``` Return a comma-separated list of column names. The names are quoted with backticks. ``` SELECT column_list(column_create('col1','val1','col2','val2')); +---------------------------------------------------------+ | column_list(column_create('col1','val1','col2','val2')) | +---------------------------------------------------------+ | `col1`,`col2` | +---------------------------------------------------------+ ``` #### COLUMN\_CHECK ``` COLUMN_CHECK(dyncol_blob); ``` Check if `dyncol_blob` is a valid packed dynamic columns blob. Return value of 1 means the blob is valid, return value of 0 means it is not. **Rationale:** Normally, one works with valid dynamic column blobs. Functions like `COLUMN_CREATE`, `COLUMN_ADD`, `COLUMN_DELETE` always return valid dynamic column blobs. However, if a dynamic column blob is accidentally truncated, or transcoded from one character set to another, it will be corrupted. This function can be used to check if a value in a blob field is a valid dynamic column blob. **Note:** It is possible that a truncation cut a Dynamic Column "clearly" so that COLUMN\_CHECK will not notice the corruption, but in any case of truncation a warning is issued during value storing. #### COLUMN\_JSON ``` COLUMN_JSON(dyncol_blob); ``` Return a JSON representation of data in `dyncol_blob`. Example: ``` SELECT item_name, COLUMN_JSON(dynamic_cols) FROM assets; +-----------------+----------------------------------------+ | item_name | COLUMN_JSON(dynamic_cols) | +-----------------+----------------------------------------+ | MariaDB T-shirt | {"size":"XL","color":"blue"} | | Thinkpad Laptop | {"color":"black","warranty":"3 years"} | +-----------------+----------------------------------------+ ``` Limitation: `COLUMN_JSON` will decode nested dynamic columns at a nesting level of not more than 10 levels deep. Dynamic columns that are nested deeper than 10 levels will be shown as BINARY string, without encoding. ### Nesting Dynamic Columns It is possible to use nested dynamic columns by putting one dynamic column blob inside another. The `COLUMN_JSON` function will display nested columns. ``` SET @tmp= column_create('parent_column', column_create('child_column', 12345)); Query OK, 0 rows affected (0.00 sec) SELECT column_json(@tmp); +------------------------------------------+ | column_json(@tmp) | +------------------------------------------+ | {"parent_column":{"child_column":12345}} | +------------------------------------------+ SELECT column_get(column_get(@tmp, 'parent_column' AS char), 'child_column' AS int); +------------------------------------------------------------------------------+ | column_get(column_get(@tmp, 'parent_column' as char), 'child_column' as int) | +------------------------------------------------------------------------------+ | 12345 | +------------------------------------------------------------------------------+ ``` If you are trying to get a nested dynamic column as a string use 'as BINARY' as the last argument of COLUMN\_GET (otherwise problems with character set conversion and illegal symbols are possible): ``` select column_json( column_get( column_create('test1', column_create('key1','value1','key2','value2','key3','value3')), 'test1' as BINARY)); ``` ### Datatypes In SQL, one needs to define the type of each column in a table. Dynamic columns do not provide any way to declare a type in advance ("whenever there is a column 'weight', it should be integer" is not possible). However, each particular dynamic column value is stored together with its datatype. The set of possible datatypes is mostly the same as that used by the SQL `[CAST](../cast/index)` and `[CONVERT](../convert/index)` functions. However, note that there are currently some differences - see [MDEV-597](https://jira.mariadb.org/browse/MDEV-597). | type | dynamic column internal type | description | | --- | --- | --- | | `BINARY[(N)]` | `DYN_COL_STRING` | (variable length string with binary charset) | | `CHAR[(N)]` | `DYN_COL_STRING` | (variable length string with charset) | | `DATE` | `DYN_COL_DATE` | (date - 3 bytes) | | `DATETIME[(D)]` | `DYN_COL_DATETIME` | (date and time (with [microseconds](../microseconds-in-mariadb/index)) - 9 bytes) | | `DECIMAL[(M[,D])]` | `DYN_COL_DECIMAL` | (variable length binary decimal representation with MariaDB limitation) | | `DOUBLE[(M,D)]` | `DYN_COL_DOUBLE` | (64 bit double-precision floating point) | | `INTEGER` | `DYN_COL_INT` | (variable length, up to 64 bit signed integer) | | `SIGNED [INTEGER]` | `DYN_COL_INT` | (variable length, up to 64 bit signed integer) | | `TIME[(D)]` | `DYN_COL_TIME` | (time (with [microseconds](../microseconds-in-mariadb/index), may be negative) - 6 bytes) | | `UNSIGNED [INTEGER]` | `DYN_COL_UINT` | (variable length, up to 64bit unsigned integer) | #### A Note About Lengths If you're running queries like ``` SELECT COLUMN_GET(blob, 'colname' as CHAR) ... ``` without specifying a maximum length (i.e. using #as CHAR#, not `as CHAR(n)`), MariaDB will report the maximum length of the resultset column to be `53,6870,911` (bytes or characters?) for [MariaDB 5.3](../what-is-mariadb-53/index)-10.0.0 and `16,777,216` for [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/)+. This may cause excessive memory usage in some client libraries, because they try to pre-allocate a buffer of maximum resultset width. If you suspect you're hitting this problem, use `CHAR(n)` whenever you're using `COLUMN_GET` in the select list. ### [MariaDB 5.3](../what-is-mariadb-53/index) vs [MariaDB 10.0](../what-is-mariadb-100/index) The dynamic columns feature was introduced into MariaDB in two steps: 1. [MariaDB 5.3](../what-is-mariadb-53/index) was the first version to support dynamic columns. Only numbers could be used as column names in this version. 2. In [MariaDB 10.0.1](https://mariadb.com/kb/en/mariadb-1001-release-notes/), column names can be either numbers or strings. Also, the `COLUMN_JSON` and `COLUMN_CHECK` functions were added. See also [Dynamic Columns in MariaDB 10](../dynamic-columns-in-mariadb-10/index). ### Client-side API It is also possible to create or parse dynamic columns blobs on the client side. `libmysql` client library now includes an API for writing/reading dynamic column blobs. See [dynamic-columns-api](../dynamic-columns-api/index) for details. ### Limitations | Description | Limit | | --- | --- | | Max number of columns | 65535 | | Max total length of packed dynamic column | [max\_allowed\_packet](../server-system-variables/index#max_allowed_packet) (1G) | See Also -------- * [Dynamic Columns from MariaDB 10](../dynamic-columns-from-mariadb-10/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
programming_docs
mariadb Compiling OQGRAPH Compiling OQGRAPH ================= To compile OQGraph v2 you need to have the boost library with the versions not earlier than 1.40 and not later than 1.55 and gcc version not earlier than 4.5. **MariaDB starting with [10.0.7](https://mariadb.com/kb/en/mariadb-1007-release-notes/)**OQGraph v3 compiles fine with the newer boost libraries, but it additionally needs the Judy library installed. When all build prerequisites are met, OQGraph is enabled and compiled automatically. To enable or disable OQGRAPH explicitly, see the generic [plugin build instructions](../specifying-what-plugins-to-build/index). ### Finding Out Why OQGRAPH Didn't Compile If OQGRAPH gets compiled properly, there should be a file like: ``` storage/oqgraph/ha_oqgraph.so ``` If this is not the case, then you can find out if there is any modules missing that are required by OQGRAPH by doing: ``` cmake . -LAH | grep -i oqgraph ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Information Schema CHARACTER_SETS Table Information Schema CHARACTER\_SETS Table ======================================== The [Information Schema](../information_schema/index) `CHARACTER_SETS` table contains a list of supported [character sets](../data-types-character-sets-and-collations/index), their default collations and maximum lengths. It contains the following columns: | Column | Description | | --- | --- | | `CHARACTER_SET_NAME` | Name of the character set. | | `DEFAULT_COLLATE_NAME` | Default collation used. | | `DESCRIPTION` | Character set description. | | `MAXLEN` | Maximum length. | The [SHOW CHARACTER SET](../show-character-set/index) statement returns the same results (although in a different order), and both can be refined in the same way. For example, the following two statements return the same results: ``` SHOW CHARACTER SET WHERE Maxlen LIKE '2'; ``` and ``` SELECT * FROM information_schema.CHARACTER_SETS WHERE MAXLEN LIKE '2'; ``` See [Setting Character Sets and Collations](../setting-character-sets-and-collations/index) for details on specifying the character set at the server, database, table and column levels, and [Supported Character Sets and Collations](../supported-character-sets-and-collations/index) for a full list of supported characters sets and collations. Example ------- ``` SELECT CHARACTER_SET_NAME FROM information_schema.CHARACTER_SETS WHERE DEFAULT_COLLATE_NAME LIKE '%chinese%'; +--------------------+ | CHARACTER_SET_NAME | +--------------------+ | big5 | | gb2312 | | gbk | +--------------------+ ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Buildbot Setup for Virtual Machines - Debian 6 amd64 Buildbot Setup for Virtual Machines - Debian 6 amd64 ==================================================== Create the VM: ``` cd /kvm/vms qemu-img create -f qcow2 vm-debian6-amd64-serial.qcow2 8G kvm -m 2047 -hda /kvm/vms/vm-debian6-amd64-serial.qcow2 -cdrom /kvm/debian-6a1-amd64-netinst.iso -redir 'tcp:2244::22' -boot d -smp 2 -cpu qemu64 -net nic,model=virtio -net user ``` Serial console and account setup -------------------------------- From base install, setup for serial port, and setup accounts for passwordless ssh login and sudo: ``` kvm -m 2047 -hda /kvm/vms/vm-debian6-amd64-serial.qcow2 -redir 'tcp:2244::22' -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user su apt-get install sudo openssh-server visudo # Add: %sudo ALL=NOPASSWD: ALL # add user account to group sudo `addgroup <USER> sudo`. # Copy in public ssh key. # Add in /etc/inittab: S0:2345:respawn:/sbin/getty -L ttyS0 19200 vt100 ``` Editing /etc/default/grub: ``` sudo vi /etc/default/grub # Add/edit these entries: GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8" GRUB_TERMINAL="serial" GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1" sudo update-grub ``` Add user buildbot, with disabled password. Add as sudo, and add ssh key. ``` sudo adduser --disabled-password buildbot sudo adduser buildbot sudo sudo su - buildbot mkdir .ssh # Add all necessary keys. cat >.ssh/authorized_keys chmod -R go-rwx .ssh ``` VM for building .deb -------------------- ``` qemu-img create -b vm-debian6-amd64-serial.qcow2 -f qcow2 vm-debian6-amd64-build.qcow2 kvm -m 2047 -hda /kvm/vms/vm-debian6-amd64-build.qcow2 -redir 'tcp:2244::22' -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user -nographic sudo apt-get build-dep mysql-server-5.1 sudo apt-get install devscripts hardening-wrapper doxygen texlive-latex-base ghostscript libevent-dev libssl-dev zlib1g-dev libreadline-dev ``` VM for install testing ---------------------- ``` qemu-img create -b vm-debian6-amd64-serial.qcow2 -f qcow2 vm-debian6-amd64-install.qcow2 kvm -m 2047 -hda /kvm/vms/vm-debian6-amd64-install.qcow2 -redir 'tcp:2244::22' -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user -nographic ``` See the [General Principles](../buildbot-setup-for-virtual-machines-general-principles/index) article for how to make the '`my.seed`' file. ``` # No packages mostly! sudo apt-get install debconf-utils cat >>/etc/apt/sources.list <<END deb file:///home/buildbot/buildbot/debs binary/ deb-src file:///home/buildbot/buildbot/debs source/ END sudo debconf-set-selections /tmp/my.seed ``` VM for upgrade testing ---------------------- ``` qemu-img create -b vm-debian6-amd64-install.qcow2 -f qcow2 vm-debian6-amd64-upgrade.qcow2 kvm -m 2047 -hda /kvm/vms/vm-debian6-amd64-upgrade.qcow2 -redir 'tcp:2244::22' -boot c -smp 2 -cpu qemu64 -net nic,model=virtio -net user -nographic sudo apt-get install mysql-server-5.1 mysql -uroot -prootpass -e "create database mytest; use mytest; create table t(a int primary key); insert into t values (1); select * from t" ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema setup_objects Table Performance Schema setup\_objects Table ======================================= Description ----------- The `setup_objects` table determines whether objects are monitored by the performance schema or not. By default limited to 100 rows, this can be changed by setting the [performance\_schema\_setup\_objects\_size](../performance-schema-system-variables/index#performance_schema_setup_objects_size) system variable when the server starts. It contains the following columns: | Column | Description | | --- | --- | | `OBJECT_TYPE` | Type of object to instrument, currently only . Currently, only `TABLE'`, for base table. | | `OBJECT_SCHEMA` | Schema containing the object, either the literal or `%` for any schema. | | `OBJECT_NAME` | Name of the instrumented object, either the literal or `%` for any object. | | `ENABLED` | Whether the object's events are instrumented or not. Can be disabled, in which case monitoring is not enabled for those objects. | | `TIMED` | Whether the object's events are timed or not. Can be modified. | When the Performance Schema looks for matches in the `setup_objects`, there may be more than one row matching, with different `ENABLED` and `TIMED` values. It looks for the most specific matches first, that is, it will first look for the specific database and table name combination, then the specific database, only then falling back to a wildcard for both. Rows can be added or removed from the table, while for existing rows, only the `TIMED` and `ENABLED` columns can be updated. By default, all tables except those in the `performance_schema`, `information_schema` and `mysql` databases are instrumented. Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ST_LineStringFromText ST\_LineStringFromText ====================== A synonym for [ST\_LineFromText](../st_linefromtext/index). Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb ColumnStore Data Definition Statements ColumnStore Data Definition Statements ======================================= You can use most normal statements from the [MariaDB data definition language](../data-definition/index) (DDL) with ColumnStore tables. This section lists DDL that differs for ColumnStore compared to normal MariaDB usage. | Title | Description | | --- | --- | | [DDL statements that differ for ColumnStore](../ddl-statements-that-differ-for-columnstore/index) | Lists of data definition statements (DDL) that differ from normal MariaDB DDL | | [ColumnStore Alter Table](../columnstore-alter-table/index) | Modifies existing tables including adding, deleting and renaming columns | | [ColumnStore Create Procedure](../columnstore-create-procedure/index) | Creates a stored routine in ColumnStore | | [ColumnStore Create Table](../columnstore-create-table/index) | Create multiple columns | | [ColumnStore Drop Table](../columnstore-drop-table/index) | Deletes a table from ColumnStore | | [ColumnStore Alter View](../columnstore-alter-view/index) | Alters the definition of a view. CREATE OR REPLACE VIEW may also be used t... | | [ColumnStore Create View](../columnstore-create-view/index) | Creates a stored query in the MariaDB ColumnStore Syntax CREATE [OR REPLACE] VIEW | Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Performance Schema events_statements_summary_by_account_by_event_name Table Performance Schema events\_statements\_summary\_by\_account\_by\_event\_name Table ================================================================================== The [Performance Schema](../performance-schema/index) events\_statements\_summary\_by\_account\_by\_event\_name table contains statement events summarized by account and event name. It contains the following columns: | Column | Description | | --- | --- | | `USER` | User. Used together with `HOST` and `EVENT_NAME` for grouping events. | | `HOST` | Host. Used together with `USER` and `EVENT_NAME` for grouping events. | | `EVENT_NAME` | Event name. Used together with `USER` and `HOST` for grouping events. | | `COUNT_STAR` | Number of summarized events | | `SUM_TIMER_WAIT` | Total wait time of the summarized events that are timed. | | `MIN_TIMER_WAIT` | Minimum wait time of the summarized events that are timed. | | `AVG_TIMER_WAIT` | Average wait time of the summarized events that are timed. | | `MAX_TIMER_WAIT` | Maximum wait time of the summarized events that are timed. | | `SUM_LOCK_TIME` | Sum of the `LOCK_TIME` column in the `events_statements_current` table. | | `SUM_ERRORS` | Sum of the `ERRORS` column in the `events_statements_current` table. | | `SUM_WARNINGS` | Sum of the `WARNINGS` column in the `events_statements_current` table. | | `SUM_ROWS_AFFECTED` | Sum of the `ROWS_AFFECTED` column in the `events_statements_current` table. | | `SUM_ROWS_SENT` | Sum of the `ROWS_SENT` column in the `events_statements_current` table. | | `SUM_ROWS_EXAMINED` | Sum of the `ROWS_EXAMINED` column in the `events_statements_current` table. | | `SUM_CREATED_TMP_DISK_TABLES` | Sum of the `CREATED_TMP_DISK_TABLES` column in the `events_statements_current` table. | | `SUM_CREATED_TMP_TABLES` | Sum of the `CREATED_TMP_TABLES` column in the `events_statements_current` table. | | `SUM_SELECT_FULL_JOIN` | Sum of the `SELECT_FULL_JOIN` column in the `events_statements_current` table. | | `SUM_SELECT_FULL_RANGE_JOIN` | Sum of the `SELECT_FULL_RANGE_JOIN` column in the `events_statements_current` table. | | `SUM_SELECT_RANGE` | Sum of the `SELECT_RANGE` column in the `events_statements_current` table. | | `SUM_SELECT_RANGE_CHECK` | Sum of the `SELECT_RANGE_CHECK` column in the `events_statements_current` table. | | `SUM_SELECT_SCAN` | Sum of the `SELECT_SCAN` column in the `events_statements_current` table. | | `SUM_SORT_MERGE_PASSES` | Sum of the `SORT_MERGE_PASSES` column in the `events_statements_current` table. | | `SUM_SORT_RANGE` | Sum of the `SORT_RANGE` column in the `events_statements_current` table. | | `SUM_SORT_ROWS` | Sum of the `SORT_ROWS` column in the `events_statements_current` table. | | `SUM_SORT_SCAN` | Sum of the `SORT_SCAN` column in the `events_statements_current` table. | | `SUM_NO_INDEX_USED` | Sum of the `NO_INDEX_USED` column in the `events_statements_current` table. | | `SUM_NO_GOOD_INDEX_USED` | Sum of the `NO_GOOD_INDEX_USED` column in the `events_statements_current` table. | The `*_TIMER_WAIT` columns only calculate results for timed events, as non-timed events have a `NULL` wait time. Example ------- ``` SELECT * FROM events_statements_summary_by_account_by_event_name\G ... *************************** 521. row *************************** USER: NULL HOST: NULL EVENT_NAME: statement/com/Error COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 SUM_LOCK_TIME: 0 SUM_ERRORS: 0 SUM_WARNINGS: 0 SUM_ROWS_AFFECTED: 0 SUM_ROWS_SENT: 0 SUM_ROWS_EXAMINED: 0 SUM_CREATED_TMP_DISK_TABLES: 0 SUM_CREATED_TMP_TABLES: 0 SUM_SELECT_FULL_JOIN: 0 SUM_SELECT_FULL_RANGE_JOIN: 0 SUM_SELECT_RANGE: 0 SUM_SELECT_RANGE_CHECK: 0 SUM_SELECT_SCAN: 0 SUM_SORT_MERGE_PASSES: 0 SUM_SORT_RANGE: 0 SUM_SORT_ROWS: 0 SUM_SORT_SCAN: 0 SUM_NO_INDEX_USED: 0 SUM_NO_GOOD_INDEX_USED: 0 *************************** 522. row *************************** USER: NULL HOST: NULL EVENT_NAME: statement/com/ COUNT_STAR: 0 SUM_TIMER_WAIT: 0 MIN_TIMER_WAIT: 0 AVG_TIMER_WAIT: 0 MAX_TIMER_WAIT: 0 SUM_LOCK_TIME: 0 SUM_ERRORS: 0 SUM_WARNINGS: 0 SUM_ROWS_AFFECTED: 0 SUM_ROWS_SENT: 0 SUM_ROWS_EXAMINED: 0 SUM_CREATED_TMP_DISK_TABLES: 0 SUM_CREATED_TMP_TABLES: 0 SUM_SELECT_FULL_JOIN: 0 SUM_SELECT_FULL_RANGE_JOIN: 0 SUM_SELECT_RANGE: 0 SUM_SELECT_RANGE_CHECK: 0 SUM_SELECT_SCAN: 0 SUM_SORT_MERGE_PASSES: 0 SUM_SORT_RANGE: 0 SUM_SORT_ROWS: 0 SUM_SORT_SCAN: 0 SUM_NO_INDEX_USED: 0 SUM_NO_GOOD_INDEX_USED: 0 ``` Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party. mariadb Upgrading from MariaDB 10.2 to MariaDB 10.3 Upgrading from MariaDB 10.2 to MariaDB 10.3 =========================================== ### How to Upgrade For Windows, see [Upgrading MariaDB on Windows](../upgrading-mariadb-on-windows/index) instead. For MariaDB Galera Cluster, see [Upgrading from MariaDB 10.2 to MariaDB 10.3 with Galera Cluster](../upgrading-from-mariadb-102-to-mariadb-103-with-galera-cluster/index) instead. Before you upgrade, it would be best to take a backup of your database. This is always a good idea to do before an upgrade. We would recommend [Mariabackup](../mariabackup/index). The suggested upgrade procedure is: 1. Modify the repository configuration, so the system's package manager installs [MariaDB 10.3](../what-is-mariadb-103/index). For example, * On Debian, Ubuntu, and other similar Linux distributions, see [Updating the MariaDB APT repository to a New Major Release](../installing-mariadb-deb-files/index#updating-the-mariadb-apt-repository-to-a-new-major-release) for more information. * On RHEL, CentOS, Fedora, and other similar Linux distributions, see [Updating the MariaDB YUM repository to a New Major Release](../yum/index#updating-the-mariadb-yum-repository-to-a-new-major-release) for more information. * On SLES, OpenSUSE, and other similar Linux distributions, see [Updating the MariaDB ZYpp repository to a New Major Release](../installing-mariadb-with-zypper/index#updating-the-mariadb-zypp-repository-to-a-new-major-release) for more information. 2. [Stop MariaDB](../starting-and-stopping-mariadb-automatically/index). The server should be cleanly shut down, with no incomplete transactions remaining. [innodb\_fast\_shutdown](../innodb-system-variables/index#innodb_fast_shutdown) must be set to `0` or `1` and [innodb\_force\_recovery](../innodb-system-variables/index#innodb_force_recovery) must be less than `3`. 3. Uninstall the old version of MariaDB. * On Debian, Ubuntu, and other similar Linux distributions, execute the following: `sudo apt-get remove mariadb-server` * On RHEL, CentOS, Fedora, and other similar Linux distributions, execute the following: `sudo yum remove MariaDB-server` * On SLES, OpenSUSE, and other similar Linux distributions, execute the following: `sudo zypper remove MariaDB-server` 4. Install the new version of MariaDB. * On Debian, Ubuntu, and other similar Linux distributions, see [Installing MariaDB Packages with APT](../installing-mariadb-deb-files/index#installing-mariadb-packages-with-apt) for more information. * On RHEL, CentOS, Fedora, and other similar Linux distributions, see [Installing MariaDB Packages with YUM](../yum/index#installing-mariadb-packages-with-yum) for more information. * On SLES, OpenSUSE, and other similar Linux distributions, see [Installing MariaDB Packages with ZYpp](../installing-mariadb-with-zypper/index#installing-mariadb-packages-with-zypp) for more information. 5. Make any desired changes to configuration options in [option files](../configuring-mariadb-with-option-files/index), such as `my.cnf`. This includes removing any options that are no longer supported. 6. [Start MariaDB](../starting-and-stopping-mariadb-automatically/index). 7. Run `[mysql\_upgrade](../mysql_upgrade/index)`. * `mysql_upgrade` does two things: 1. Ensures that the system tables in the `[mysq](../the-mysql-database-tables/index)l` database are fully compatible with the new version. 2. Does a very quick check of all tables and marks them as compatible with the new version of MariaDB . ### Incompatible Changes Between 10.2 and 10.3 On most servers upgrading from 10.2 should be painless. However, there are some things that have changed which could affect an upgrade: #### Options That Have Changed Default Values | Option | Old default value | New default value | | --- | --- | --- | | [innodb\_flush\_method](../innodb-system-variables/index#innodb_flush_method) | (empty) | fsync | | [innodb\_spin\_wait\_delay](../innodb-system-variables/index#innodb_spin_wait_delay) | 6 | 4 | | [performance\_schema\_max\_stage\_classes](../performance-schema-system-variables/index#performance_schema_max_stage_classes) | 150 | 160 | | [plugin\_maturity](../server-system-variables/index#plugin_maturity) | unknown | One less than the server maturity | #### Options That Have Been Removed or Renamed The following options should be removed or renamed if you use them in your [option files](../configuring-mariadb-with-option-files/index): | Option | Reason | | --- | --- | | [innodb\_buffer\_pool\_populate](../innodb-system-variables/index#innodb_buffer_pool_populate) | Used in XtraDB-only | | [innodb\_cleaner\_lsn\_age\_factor](../innodb-system-variables/index#innodb_cleaner_lsn_age_factor) | Used in XtraDB-only | | [innodb\_corrupt\_table\_action](../innodb-system-variables/index#innodb_corrupt_table_action) | Used in XtraDB-only | | [innodb\_empty\_free\_list\_algorithm](../innodb-system-variables/index#innodb_empty_free_list_algorithm) | Used in XtraDB-only | | [innodb\_fake\_changes](../innodb-system-variables/index#innodb_fake_changes) | Used in XtraDB-only | | [innodb\_file\_format](../innodb-system-variables/index#innodb_file_format) | The [InnoDB file format](../xtradbinnodb-file-format/index) is now Barracuda, and the old Antelope file format is no longer supported. | | [innodb\_file\_format\_check](../innodb-system-variables/index#innodb_file_format_check) | No longer necessary as the Antelope [InnoDB file format](../xtradbinnodb-file-format/index) is no longer supported. | | [innodb\_file\_format\_max](../innodb-system-variables/index#innodb_file_format_max) | No longer necessary as the Antelope [InnoDB file format](../xtradbinnodb-file-format/index) is no longer supported. | | [innodb\_foreground\_preflush](../innodb-system-variables/index#innodb_foreground_preflush) | Used in XtraDB-only | | [innodb\_instrument\_semaphores](../innodb-system-variables/index#innodb_instrument_semaphores) | | | [innodb\_kill\_idle\_transaction](../innodb-system-variables/index#innodb_kill_idle_transaction) | Used in XtraDB-only | | [innodb\_large\_prefix](../innodb-system-variables/index#innodb_large_prefix) | Large index key prefixes were made default from [MariaDB 10.2](../what-is-mariadb-102/index), and limiting tables to small prefixes is no longer permitted in [MariaDB 10.3](../what-is-mariadb-103/index). | | [innodb\_locking\_fake\_changes](../innodb-system-variables/index#innodb_locking_fake_changes) | Used in XtraDB-only | | [innodb\_log\_arch\_dir](../innodb-system-variables/index#innodb_log_arch_dir) | Used in XtraDB-only | | [innodb\_log\_arch\_expire\_sec](../innodb-system-variables/index#innodb_log_arch_expire_sec) | Used in XtraDB-only | | [innodb\_log\_archive](../innodb-system-variables/index#innodb_log_archive) | Used in XtraDB-only | | [innodb\_log\_block\_size](../innodb-system-variables/index#innodb_log_block_size) | Used in XtraDB-only | | [innodb\_log\_checksum\_algorithm](../innodb-system-variables/index#innodb_log_checksum_algorithm) | Translated to [innodb\_log\_checksums](../innodb-system-variables/index#innodb_log_checksums) (NONE to OFF, everything else to ON); only existed to allow easier upgrade from earlier XtraDB versions. | | [innodb\_mtflush\_threads](../innodb-system-variables/index#innodb_mtflush_threads) | Replaced by the [innodb\_page\_cleaners](../innodb-system-variables/index#innodb_page_cleaners) system variable. | | [innodb\_sched\_priority\_cleaner](../innodb-system-variables/index#innodb_sched_priority_cleaner) | Used in XtraDB-only | | [innodb\_show\_locks\_held](../innodb-system-variables/index#innodb_show_locks_held) | Used in XtraDB-only | | [innodb\_show\_verbose\_locks](../innodb-system-variables/index#innodb_show_verbose_locks) | Used in XtraDB-only | | [innodb\_support\_xa](../innodb-system-variables/index#innodb_support_xa) | XA transactions are always supported. | | [innodb\_use\_fallocate](../innodb-system-variables/index#innodb_use_fallocate) | | | [innodb\_use\_global\_flush\_log\_at\_trx\_commit](../innodb-system-variables/index#innodb_use_global_flush_log_at_trx_commit) | Used in XtraDB-only | | [innodb\_use\_mtflush](../innodb-system-variables/index#innodb_use_mtflush) | Replaced by the [innodb\_page\_cleaners](../innodb-system-variables/index#innodb_page_cleaners) system variable. | | [innodb\_use\_stacktrace](../innodb-system-variables/index#innodb_use_stacktrace) | Used in XtraDB-only | | [innodb\_use\_trim](../innodb-system-variables/index#innodb_use_trim) | | #### Reserved Words * New [reserved words](../reserved-words/index): EXCEPT and INTERSECT. These can no longer be used as [identifiers](../identifier-names/index) without being quoted. #### SQL\_MODE=ORACLE * [MariaDB 10.3](../what-is-mariadb-103/index) has introduced major new Oracle compatibility features. If you upgrade and are using this setting, please check the [changes carefully](../what-is-mariadb-103/index). #### Functions * As a result of implementing Table Value Constructors, the [VALUES function](../values/index) has been renamed to VALUE(). * Functions that used to only return 64-bit now can return 32-bit results ([MDEV-12619](https://jira.mariadb.org/browse/MDEV-12619)). This could cause incompatibilities with strongly-typed clients. #### mysqldump * [mysqldump](../mysqldump/index) in [MariaDB 10.3](../what-is-mariadb-103/index) includes logic to cater for the [mysql.transaction\_registry table](../mysqltransaction_registry-table/index). `mysqldump` from an earlier MariaDB release cannot be used on [MariaDB 10.3](../what-is-mariadb-103/index) and beyond. #### MariaDB Backup and Percona XtraBackup * [Percona XtraBackup](../percona-xtrabackup/index) is not compatible with [MariaDB 10.3](../what-is-mariadb-103/index). Installations currently using XtraBackup should upgrade to [MariaDB Backup](../mariadb-backup/index) before upgrading to [MariaDB 10.3](../what-is-mariadb-103/index). #### Privileges * If a user has the [SUPER privilege](../grant/index) but not the `DELETE HISTORY` privilege, running [mysql\_upgrade](../mysql_upgrade/index) will grant `DELETE HISTORY` as well. ### Major New Features To Consider You might consider using the following major new features in [MariaDB 10.3](../what-is-mariadb-103/index): * [System-versioned tables](../system-versioned-tables/index) * [Sequences](../sequences/index) * See also [System Variables Added in MariaDB 10.3](../system-variables-added-in-mariadb-103/index). ### See Also * [The features in MariaDB 10.3](../what-is-mariadb-103/index) * [Upgrading from MariaDB 10.2 to MariaDB 10.3 with Galera Cluster](../upgrading-from-mariadb-102-to-mariadb-103-with-galera-cluster/index) * [Upgrading from MariaDB 10.1 to MariaDB 10.2](../upgrading-from-mariadb-101-to-mariadb-102/index) * [Upgrading from MariaDB 10.0 to MariaDB 10.1](../upgrading-from-mariadb-100-to-mariadb-101/index) Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
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