Commit 6cee60ea authored by unknown's avatar unknown
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Relaxed locking in INSERT...SELECT, single table UPDATE...SELECT and 

single table DELETE...SELECT clauses when innobase_locks_unsafe_for_binlog
is used and isolation level of the transaction is not serializable. 
InnoDB uses consistent read in these cases for a selected table.
Backported from 5.0.x.


sql/ha_innodb.cc:
  Relaxed locking in INSERT...SELECT, single table UPDATE...SELECT and 
  single table DELETE...SELECT clauses when innobase_locks_unsafe_for_binlog
  is used and isolation level of the transaction is not serializable. 
  InnoDB uses consistent read in these cases for a selected table.
parent 5be12eba

sql/ha_innodb.cc

+21 −2
Original line number Diff line number Diff line
@@ -5282,8 +5282,27 @@ ha_innobase::store_lock( 
		are not simple SELECTs; note that select_lock_type in this

		case may get strengthened in ::external_lock() to LOCK_X. */



		if (srv_locks_unsafe_for_binlog &&

		    prebuilt->trx->isolation_level != TRX_ISO_SERIALIZABLE &&

		    (lock_type == TL_READ || lock_type == TL_READ_NO_INSERT) &&

		    thd->lex->sql_command != SQLCOM_SELECT &&

		    thd->lex->sql_command != SQLCOM_UPDATE_MULTI &&

		    thd->lex->sql_command != SQLCOM_DELETE_MULTI ) {



			/* In case we have innobase_locks_unsafe_for_binlog

			option set and isolation level of the transaction

			is not set to serializable and MySQL is doing

			INSERT INTO...SELECT without FOR UPDATE or IN

			SHARE MODE we use consistent read for select. 

			Similarly, in case of DELETE...SELECT and

			UPDATE...SELECT when these are not multi table.*/



			prebuilt->select_lock_type = LOCK_NONE;

			prebuilt->stored_select_lock_type = LOCK_NONE;

		} else {

			prebuilt->select_lock_type = LOCK_S;

			prebuilt->stored_select_lock_type = LOCK_S;

		}



	} else if (lock_type != TL_IGNORE) {