# # This test tests a potential race condition in MDL locking # --source include/galera_cluster.inc --source include/have_debug_sync.inc CREATE TABLE t1 (f1 INTEGER PRIMARY KEY, f2 CHAR(1)) engine=innodb; CREATE TABLE t2 (f1 INTEGER PRIMARY KEY, f2 CHAR(1)) engine=innodb; INSERT INTO t1 VALUES (1, 'a'); INSERT INTO t1 VALUES (2, 'a'); --connection node_1 SET AUTOCOMMIT=ON; START TRANSACTION; UPDATE t1 SET f2 = 'b' WHERE f1 = 1; # block access to t2 --connect node_1a, 127.0.0.1, root, , test, $NODE_MYPORT_1 --connection node_1a LOCK TABLE t2 WRITE; # Block before MLD lock wait --connection node_1 SET @@debug_dbug = "d,sync.wsrep_before_mdl_wait"; --send SELECT * FROM t2; # Wait for SELECT to be blocked --connection node_1a #--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIS WHERE STATE = 'System lock'; #--source include/wait_condition.inc #--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE STATE = 'init' AND INFO = 'COMMIT'; #--source include/wait_condition.inc # block applier to wait after BF victim is locked SET @@debug_dbug = "d,sync.wsrep_after_BF_victim_lock"; # Issue a conflicting update on node #2 --connection node_2 UPDATE t1 SET f2 = 'c' WHERE f1 = 1; # Unblock the SELECT, to enter wsrep_thd_is_BF --connection node_1a SET @@debug_dbug = ""; SET DEBUG_SYNC = "now SIGNAL signal.wsrep_before_mdl_wait"; # unblock applier to try to BF the SELECT SET DEBUG_SYNC = "now SIGNAL signal.wsrep_after_BF_victim_lock"; # table lock is not needed anymore UNLOCK TABLES; # SELECT succeeds --connection node_1 --error ER_LOCK_DEADLOCK --reap SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'a'; SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'c'; --connection node_2 SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'a'; SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'c'; DROP TABLE t1; DROP TABLE t2; --connection node_1a SET DEBUG_SYNC = "RESET";