mariadb/mysql-test/suite/innodb/t/lock_deleted.test
Sergei Golubchik bead24b7f3 mariadb-test: wait on disconnect
Remove one of the major sources of race condiitons in mariadb-test.
Normally, mariadb_close() sends COM_QUIT to the server and immediately
disconnects. In mariadb-test it means the test can switch to another
connection and sends queries to the server before the server even
started parsing the COM_QUIT packet and these queries can see the
connection as fully active, as it didn't reach dispatch_command yet.

This is a major source of instability in tests and many - but not all,
still less than a half - tests employ workarounds. The correct one
is a pair count_sessions.inc/wait_until_count_sessions.inc.
Also very popular was wait_until_disconnected.inc, which was completely
useless, because it verifies that the connection is closed, and after
disconnect it always is, it didn't verify whether the server processed
COM_QUIT. Sadly the placebo was as widely used as the real thing.

Let's fix this by making mariadb-test `disconnect` command _to wait_ for
the server to confirm. This makes almost all workarounds redundant.

In some cases count_sessions.inc/wait_until_count_sessions.inc is still
needed, though, as only `disconnect` command is changed:

 * after external tools, like `exec $MYSQL`
 * after failed `connect` command
 * replication, after `STOP SLAVE`
 * Federated/CONNECT/SPIDER/etc after `DROP TABLE`

and also in some XA tests, because an XA transaction is dissociated from
the THD very late, after the server has closed the client connection.

Collateral cleanups: fix comments, remove some redundant statements:
 * DROP IF EXISTS if nothing is known to exist
 * DROP table/view before DROP DATABASE
 * REVOKE privileges before DROP USER
 etc
2025-07-16 09:14:33 +07:00

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Text

--source include/have_innodb.inc
--source include/have_debug.inc
--source include/have_debug_sync.inc
connect(stop_purge, localhost, root,,);
START TRANSACTION WITH CONSISTENT SNAPSHOT;
connect(delete, localhost, root,,);
connection default;
CREATE TABLE t1(a INT PRIMARY KEY, b INT UNIQUE) ENGINE=InnoDB;
INSERT INTO t1 VALUES(1,1);
DELETE FROM t1;
let $i=2;
while ($i) {
let $iso= `SELECT CASE $i WHEN 1 THEN 'UNCOMMITTED' ELSE 'COMMITTED' END`;
SET DEBUG_SYNC='row_ins_sec_index_unique SIGNAL inserted WAIT_FOR locked';
BEGIN;
send INSERT INTO t1 VALUES(1,1);
connection delete;
SET DEBUG_SYNC='now WAIT_FOR inserted';
SET DEBUG_SYNC='innodb_row_search_for_mysql_exit SIGNAL locked';
eval SET SESSION TRANSACTION ISOLATION LEVEL READ $iso;
BEGIN;
send DELETE FROM t1 WHERE b=1;
connection default;
reap;
connection delete;
reap;
COMMIT;
connection default;
SET DEBUG_SYNC='RESET';
ROLLBACK;
dec $i;
}
SET DEBUG_SYNC='row_ins_sec_index_unique SIGNAL inserted WAIT_FOR locked';
BEGIN;
SET innodb_lock_wait_timeout=1;
send INSERT INTO t1 VALUES(1,1);
connection delete;
SET DEBUG_SYNC='now WAIT_FOR inserted';
SET DEBUG_SYNC='innodb_row_search_for_mysql_exit SIGNAL locked';
SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ;
BEGIN;
send DELETE FROM t1 WHERE b=1;
connection default;
--error ER_LOCK_WAIT_TIMEOUT
reap;
COMMIT;
SET DEBUG_SYNC='RESET';
connection delete;
reap;
COMMIT;
disconnect delete;
disconnect stop_purge;
connection default;
DROP TABLE t1;