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MDEV-33172 : Galera test case galera_mdl_race unstable
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Add wait_condition between debug sync SIGNAL points and other
expected state conditions and refactor actual sync point for
easier to use in test case.

Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
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@janlindstrom @sysprg
janlindstrom authored and sysprg committed Jan 29, 2024
1 parent 5b4456b commit ddb27a2
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Showing 3 changed files with 80 additions and 41 deletions.
50 changes: 37 additions & 13 deletions mysql-test/suite/galera/r/galera_mdl_race.result
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Original file line number Diff line number Diff line change
@@ -1,44 +1,68 @@
connection node_2;
connection node_1;
connection node_1;
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;
connect node_1a, 127.0.0.1, root, , test, $NODE_MYPORT_1;
connection node_1a;
SET SESSION wsrep_sync_wait=0;
LOCK TABLE t2 WRITE;
connection node_1;
SET @@debug_dbug = "d,sync.wsrep_before_mdl_wait";
SET DEBUG_SYNC= 'wsrep_before_mdl_wait SIGNAL before_mdl_wait WAIT_FOR mdl_wait_continue';
SELECT * FROM t2;;
connection node_1a;
# Wait until select is blocked before MDL lock wait
SET DEBUG_SYNC= 'now WAIT_FOR before_mdl_wait';
connection node_1a;
SET @@debug_dbug = "d,sync.wsrep_after_BF_victim_lock";
connection node_2;
UPDATE t1 SET f2 = 'c' WHERE f1 = 1;
connection node_1a;
SET @@debug_dbug = "";
SET DEBUG_SYNC = "now SIGNAL signal.wsrep_before_mdl_wait";
connect node_1b, 127.0.0.1, root, , test, $NODE_MYPORT_1;
connection node_1b;
SET SESSION wsrep_sync_wait=0;
# Wait for conflicting update to block
SET DEBUG_SYNC = "now SIGNAL signal.wsrep_after_BF_victim_lock";
connect node_1c, 127.0.0.1, root, , test, $NODE_MYPORT_1;
connection node_1c;
connection node_1a;
SET DEBUG_SYNC = "now SIGNAL BF_victim_continue";
UNLOCK TABLES;
connection node_1;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'a';
COUNT(*) = 1
connection node_1;
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'a';
EXPECT_1
1
SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'c';
COUNT(*) = 1
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'c';
EXPECT_1
1
SELECT * FROM t1;
f1 f2
1 c
2 a
connection node_2;
SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'a';
COUNT(*) = 1
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'a';
EXPECT_1
1
SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'c';
COUNT(*) = 1
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'c';
EXPECT_1
1
SELECT * FROM t1;
f1 f2
1 c
2 a
DROP TABLE t1;
DROP TABLE t2;
connection node_1a;
SET DEBUG_SYNC = "RESET";
connection node_1b;
SET DEBUG_SYNC = "RESET";
connection node_1;
disconnect node_1a;
disconnect node_1b;
disconnect node_1c;
60 changes: 41 additions & 19 deletions mysql-test/suite/galera/t/galera_mdl_race.test
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Original file line number Diff line number Diff line change
Expand Up @@ -3,70 +3,92 @@
#

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

--connection node_1
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
SET SESSION wsrep_sync_wait=0;
--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 't2'
--let $wait_condition_on_error_output = SELECT * FROM INFORMATION_SCHEMA.TABLES
--source include/wait_condition_with_debug.inc
LOCK TABLE t2 WRITE;

# Block before MLD lock wait
# Block before MDL lock wait
--connection node_1
SET @@debug_dbug = "d,sync.wsrep_before_mdl_wait";
SET DEBUG_SYNC= 'wsrep_before_mdl_wait SIGNAL before_mdl_wait WAIT_FOR mdl_wait_continue';
--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
--echo # Wait until select is blocked before MDL lock wait
SET DEBUG_SYNC= 'now WAIT_FOR before_mdl_wait';

# block applier to wait after BF victim is locked
--connection node_1a
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;

--connect node_1b, 127.0.0.1, root, , test, $NODE_MYPORT_1
--connection node_1b
SET SESSION wsrep_sync_wait=0;
--echo # Wait for conflicting update to block
--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE STATE LIKE 'Update_rows_log_event:%';
--source include/wait_condition.inc

# 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";
SET DEBUG_SYNC = "now SIGNAL signal.wsrep_after_BF_victim_lock";

--connect node_1c, 127.0.0.1, root, , test, $NODE_MYPORT_1
--connection node_1c
--let $wait_condition = SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE STATE LIKE 'Update_rows_log_event:%';
--source include/wait_condition.inc

--connection node_1a
# unblock applier to try to BF the SELECT
SET DEBUG_SYNC = "now SIGNAL signal.wsrep_after_BF_victim_lock";
SET DEBUG_SYNC = "now SIGNAL BF_victim_continue";

# table lock is not needed anymore
UNLOCK TABLES;

# SELECT succeeds
# SELECT returns deadlock
--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_1
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'a';
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'c';
SELECT * FROM t1;

--connection node_2
SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'a';
SELECT COUNT(*) = 1 FROM t1 WHERE f2 = 'c';
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'a';
SELECT COUNT(*) AS EXPECT_1 FROM t1 WHERE f2 = 'c';
SELECT * FROM t1;

DROP TABLE t1;
DROP TABLE t2;

--connection node_1a
SET DEBUG_SYNC = "RESET";
--connection node_1b
SET DEBUG_SYNC = "RESET";

--connection node_1
--disconnect node_1a
--disconnect node_1b
--disconnect node_1c

11 changes: 2 additions & 9 deletions sql/mdl.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1176,15 +1176,8 @@ MDL_wait::timed_wait(MDL_context_owner *owner, struct timespec *abs_timeout,
{
#ifdef WITH_WSREP
# ifdef ENABLED_DEBUG_SYNC
// Allow tests to block the applier thread using the DBUG facilities
DBUG_EXECUTE_IF("sync.wsrep_before_mdl_wait",
{
const char act[]=
"now "
"wait_for signal.wsrep_before_mdl_wait";
DBUG_ASSERT(!debug_sync_set_action((owner->get_thd()),
STRING_WITH_LEN(act)));
};);
// Allow tests to block thread before MDL-wait
DEBUG_SYNC(owner->get_thd(), "wsrep_before_mdl_wait");
# endif
if (WSREP_ON && wsrep_thd_is_BF(owner->get_thd(), false))
{
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