set global innodb_table_locks=1; select @@innodb_table_locks; @@innodb_table_locks 1 set @@innodb_table_locks=1; connect con1,localhost,root,,; create table t1 (id integer, x integer) engine=INNODB; insert into t1 values(0, 0); set autocommit=0; SELECT * from t1 where id = 0 FOR UPDATE; id x 0 0 connect con2,localhost,root,,; set autocommit=0; lock table t1 write; connection con1; update t1 set x=1 where id = 0; select * from t1; id x 0 1 commit; connection con2; update t1 set x=2 where id = 0; commit; unlock tables; connection con1; select * from t1; id x 0 2 commit; drop table t1; # # Old lock method (where LOCK TABLE was ignored by InnoDB) no longer # works when LOCK TABLE ... WRITE is used due to fix for bugs #46272 # "MySQL 5.4.4, new MDL: unnecessary and bug #37346 "innodb does not # detect deadlock between update and alter table". # After WL#6671 "Improve scalability by not using thr_lock.c locks # for InnoDB tables" was implemented it no longer works for LOCK TABLES # ,,, READ as well. # LOCK TABLES locks are now completely handled by MDL subsystem. # set @@innodb_table_locks=0; create table t1 (id integer primary key, x integer) engine=INNODB; insert into t1 values(0, 0),(1,1),(2,2); commit; SELECT * from t1 where id = 0 FOR UPDATE; id x 0 0 connection con2; set autocommit=0; set @@innodb_table_locks=0; # The following statement should block because SQL-level lock # is taken on t1 which will wait until concurrent transaction # is commited. # Sending: lock table t1 write;; connection con1; # Wait until LOCK TABLE is blocked on SQL-level lock. # We should be able to do UPDATEs and SELECTs within transaction. update t1 set x=1 where id = 0; select * from t1; id x 0 1 1 1 2 2 # Unblock LOCK TABLE. commit; connection con2; # Reap LOCK TABLE. unlock tables; connection con1; select * from t1 where id = 0 for update; id x 0 1 connection con2; # The following statement should block because SQL-level lock # is taken on t1 which will wait until concurrent transaction # is commited. # Sending: lock table t1 read;; connection con1; # Wait until LOCK TABLE is blocked on SQL-level lock. # We should be able to do UPDATEs and SELECTs within transaction. update t1 set x=2 where id = 0; select * from t1; id x 0 2 1 1 2 2 # Unblock LOCK TABLE. commit; connection con2; # Reap LOCK TABLE. unlock tables; connection default; drop table t1; # #Bug#12842206 INNODB LOCKING REGRESSION FOR INSERT IGNORE #fixed by re-fixing Bug#7975 #aka Bug#11759688 52020: InnoDB can still deadlock on just INSERT... # connection default; CREATE TABLE t1 (a INT PRIMARY KEY, b INT NOT NULL) ENGINE=InnoDB; INSERT INTO t1 VALUES(3,1); BEGIN; INSERT IGNORE INTO t1 VALUES(3,14); Warnings: Warning 1062 Duplicate entry '3' for key 'PRIMARY' connection con1; BEGIN; INSERT IGNORE INTO t1 VALUES(3,23); Warnings: Warning 1062 Duplicate entry '3' for key 'PRIMARY' SELECT * FROM t1 FOR UPDATE; connection con2; disconnect con2; connection default; COMMIT; connection con1; a b 3 1 COMMIT; connection default; DROP TABLE t1; # # MDEV-11080 InnoDB: Failing assertion: # table->n_waiting_or_granted_auto_inc_locks > 0 # CREATE TABLE t1 (pk INTEGER AUTO_INCREMENT PRIMARY KEY) ENGINE=InnoDB; INSERT INTO t1 VALUES (NULL),(NULL); CREATE TABLE t2 LIKE t1; BEGIN; connection con1; BEGIN; DELETE FROM t2; connection default; LOCK TABLE t2 READ;; connection con1; SET innodb_lock_wait_timeout= 1, lock_wait_timeout= 2; INSERT INTO t2 SELECT * FROM t1; COMMIT; connection default; UNLOCK TABLES; DROP TABLE t1, t2; # # MDEV-16709 InnoDB: Error: trx already had an AUTO-INC lock # CREATE TABLE t1 (pk INT AUTO_INCREMENT PRIMARY KEY) ENGINE=InnoDB PARTITION BY key (pk) PARTITIONS 2; INSERT INTO t1 VALUES(100); INSERT INTO t1 VALUES(101); CREATE TABLE t2 (a INT) ENGINE=InnoDB; INSERT INTO t2 VALUES (1),(2),(3),(4),(5),(6); CREATE TABLE t3 (b INT) ENGINE=InnoDB; INSERT INTO t3 VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9); connection con1; INSERT t1 SELECT NULL FROM t2; connection default; INSERT t1 SELECT NULL FROM t3; connection con1; disconnect con1; connection default; DROP TABLE t1, t2, t3;