mariadb/mysql-test/suite/galera/t/galera_mdl_race.test

#
# This test tests a potential race condition in MDL locking
#

--source include/galera_cluster.inc
--source include/have_innodb.inc
--source include/have_debug_sync.inc

CREATE TABLE t1 (f1 INTEGER PRIMARY KEY, f2 CHAR(1));
CREATE TABLE t2 (f1 INTEGER PRIMARY KEY, f2 CHAR(1));
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 GLOBAL DEBUG = "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 GLOBAL DEBUG = "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;

--sleep 3

# Unblock the SELECT, to enter wsrep_thd_is_BF
--connection node_1a
SET GLOBAL DEBUG = "";
SET DEBUG_SYNC = "now SIGNAL signal.wsrep_before_mdl_wait";

--sleep 3

# 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
--sleep 3
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";