use db.add_documents([docs])

app.py

@@ -100,10 +100,11 @@ def merge_split_docs_to_db(split_docs,db,progress,progress_step=0.1):
   batch = 10
   for i in range(0, len(split_docs), batch):
     progress(i/len(split_docs),desc=f"added {i} chunks of {len(split_docs)} chunks")
-    db1 = FAISS.from_documents(split_docs[i:i+batch], embeddings)
+    #db1 = FAISS.from_documents(split_docs[i:i+batch], embeddings)
     #db.merge_from(db1)
-    db1.merge_from(db)
-  return db1
+    #db1.merge_from(db)
+    db.add_documents(split_docs[i:i+batch])
+  return db
 
 def merge_pdf_to_db(filename,db,progress,progress_step=0.1):
   progress_step+=0.05