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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
84 lines
2.5 KiB
Plaintext
84 lines
2.5 KiB
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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SET @old_innodb_enable_xap_unlock_unmodified_for_primary_debug=
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@@GLOBAL.innodb_enable_xap_unlock_unmodified_for_primary_debug;
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SET GLOBAL innodb_enable_xap_unlock_unmodified_for_primary_debug= 1;
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SET @saved_dbug = @@GLOBAL.debug_dbug;
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CREATE TABLE t(id INT PRIMARY KEY) ENGINE=InnoDB STATS_PERSISTENT=0;
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--let $i = 2
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while ($i) {
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--source include/wait_all_purged.inc
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INSERT INTO t VALUES (10), (20), (30);
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--connect(prevent_purge,localhost,root,,)
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start transaction with consistent snapshot;
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--connection default
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DELETE FROM t WHERE id = 20;
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SET @@GLOBAL.debug_dbug=
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"+d,enable_row_purge_remove_clust_if_poss_low_sync_point";
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# Cover both lock_release_on_prepare() and lock_release_on_prepare_try()
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# functions
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if ($i == 1) {
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SET @@GLOBAL.debug_dbug="+d,skip_lock_release_on_prepare_try";
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}
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XA START '1';
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UPDATE t SET id=40 WHERE id=30;
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XA END '1';
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--connection prevent_purge
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COMMIT;
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# stop purge worker after it requested page X-latch, but before
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# lock_update_delete() call
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SET DEBUG_SYNC=
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'now WAIT_FOR row_purge_remove_clust_if_poss_low_before_delete';
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SET @@GLOBAL.debug_dbug=
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"-d,enable_row_purge_remove_clust_if_poss_low_sync_point";
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--connection default
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# lock_rec_unlock_unmodified() is executed either under lock_sys.wr_lock() or
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# under a combination of lock_sys.rd_lock() + record locks hash table cell
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# latch. Stop it before page latch request.
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SET DEBUG_SYNC=
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"lock_rec_unlock_unmodified_start SIGNAL lock_sys_latched WAIT_FOR cont";
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--send XA PREPARE '1'
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--connection prevent_purge
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# let purge thread to continue execution and invoke lock_update_delete(),
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# which, in turns, requests locks_sys related latches.
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SET DEBUG_SYNC= 'now SIGNAL row_purge_remove_clust_if_poss_low_cont';
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SET DEBUG_SYNC= 'now SIGNAL cont';
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--disconnect prevent_purge
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--connection default
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# deadlock if the bug is not fixed, as lock_rec_unlock_unmodified() requests
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# page latch acquired by purge worker, and the purge worker requests lock_sys
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# related latches in lock_update_delete() call, acquired by the current XA
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# in lock_rec_unlock_unmodified() caller.
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--reap
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XA COMMIT '1';
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SET DEBUG_SYNC="RESET";
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TRUNCATE TABLE t;
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--dec $i
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}
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SET @@GLOBAL.debug_dbug = @saved_dbug;
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DROP TABLE t;
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SET GLOBAL innodb_enable_xap_unlock_unmodified_for_primary_debug=
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@old_innodb_enable_xap_unlock_unmodified_for_primary_debug;
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