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bead24b7f3
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
34 lines
875 B
Plaintext
34 lines
875 B
Plaintext
--source include/have_innodb.inc
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--source include/have_debug.inc
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--source include/have_debug_sync.inc
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CREATE TABLE t(a INT PRIMARY KEY, b INT, c INT, UNIQUE KEY `b_c` (`b`,`c`))
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ENGINE=InnoDB, STATS_PERSISTENT=0;
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INSERT INTO t SET a = 1, c = 2;
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--connect con1,localhost,root
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BEGIN;
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INSERT INTO t SET a=2, c=2;
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--connection default
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BEGIN;
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SET DEBUG_SYNC="lock_wait_start SIGNAL select_locked";
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--send SELECT * FROM t FORCE INDEX(b) FOR UPDATE
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--connection con1
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SET DEBUG_SYNC="now WAIT_FOR select_locked";
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ROLLBACK;
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--connection default
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--echo # If the bug is not fixed, and the both unique index key fields are
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--echo # NULL, there will be two (1, NULL, 2) rows in the result,
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--echo # because cursor will be restored to (NULL, 2, 1) position for
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--echo # secondary key instead of "supremum".
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--reap
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COMMIT;
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SET DEBUG_SYNC="RESET";
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--disconnect con1
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DROP TABLE t;
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