# --source include/galera_cluster.inc # --source include/have_debug_sync.inc # # This test attempts to catch a race condition between autocommit # transaction and transaction which is rolling back due to # deadlock. # # Test outline: # * Trx 1a makes updates # * SR trx 1b writes a row 3, then makes updates # * AC trx 1c will attempt to write row 3 and will wait for lock # held by 1b # * Sync point is set for 1b to delay SR rollback # * SR trx 1b makes an update which makes it conflict with trx 1a # * Slave shows BF - BF conflict and fails in applying write event --connection node_1 CREATE TABLE t1 (f1 INTEGER PRIMARY KEY, f2 VARCHAR(1)) ENGINE=InnoDB; INSERT INTO t1 VALUES (1, 'x'), (2, 'x'), (4, 'x'), (5, 'x'); # --connect node_1a, 127.0.0.1, root, , test, $NODE_MYPORT_1 # --connect node_1b, 127.0.0.1, root, , test, $NODE_MYPORT_1 # --connect node_1c, 127.0.0.1, root, , test, $NODE_MYPORT_1 --connection node_1a START TRANSACTION; UPDATE t1 SET f2 = 'a' WHERE f1 = 1; UPDATE t1 SET f2 = 'a' WHERE f1 = 4; UPDATE t1 SET f2 = 'a' WHERE f1 = 5; --connection node_1b START TRANSACTION; SET SESSION wsrep_trx_fragment_size = 1; INSERT INTO t1 VALUES (3, 'b'); UPDATE t1 SET f2 = 'b' WHERE f1 = 2; --connection node_2 SELECT * FROM t1; # Will block, waiting for 1b --connection node_1c SET AUTOCOMMIT=ON; --send INSERT INTO t1 VALUES (3, 'c') --connection node_2 SELECT * FROM t1; # Will block, waiting for 1b --connection node_1a --send UPDATE t1 SET f2 = 'a' WHERE f1 = 2 # Will deadlock --connection node_1b SET DEBUG_SYNC = 'wsrep_before_SR_rollback SIGNAL wait WAIT_FOR continue'; --send UPDATE t1 SET f2 = 'b' WHERE f1 = 1 # Wait until 1b hits rollback --connection node_1 SET DEBUG_SYNC = 'now WAIT_FOR wait'; # UPDATE 12.06.2016: as of recent wsrep API changes, rollbacking thread no # longer queues ROLLBACKs and blocks on ROLLBACK replication before performing # the actual rollback. As a result this test is moot as both node_1a and node_1c # connections are hanging now until sync point is released. Thus sync point # release had to be moved above to release the connections. However it is not # impossible that further changes in the code may reintroduce the race, so # leaving the test as close to original as possible. # # --connection node_1a # --reap # COMMIT; # # --connection node_1c # --reap # # UPDATE t1 SET f2 = 'x' WHERE f1 = 3; --connection node_1 SET DEBUG_SYNC = 'now SIGNAL continue'; --connection node_1c --reap UPDATE t1 SET f2 = 'x' WHERE f1 = 3; --connection node_1a --reap COMMIT; --connection node_1b --error ER_LOCK_DEADLOCK --reap --connection node_1 SELECT * FROM t1; --connection node_2 SELECT * FROM t1; --connection node_1 DROP TABLE t1;