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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
38 lines
901 B
PHP
38 lines
901 B
PHP
#
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# TRANSACTION WITH CONSISTENT SNAPSHOT
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#
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--source ../have_engine.inc
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connect (con1,localhost,root,,);
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connect (con2,localhost,root,,);
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connection con1;
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let $create_definition = a $int_col;
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--source ../create_table.inc
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eval SET SESSION TRANSACTION ISOLATION LEVEL $trx_isolation;
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# While a consistent snapshot transaction is executed,
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# no external inserts should be visible to the transaction.
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# But it should only work this way for REPEATABLE-READ and SERIALIZABLE
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START TRANSACTION WITH CONSISTENT SNAPSHOT;
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connection con2;
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INSERT INTO t1 (a) VALUES (1);
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if ($mysql_errname)
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{
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--echo # INSERT finished with error $mysql_errname
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}
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connection con1;
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--echo # If consistent read works on this isolation level ($trx_isolation), the following SELECT should not return the value we inserted (1)
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SELECT a FROM t1;
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COMMIT;
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connection default;
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disconnect con1;
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disconnect con2;
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DROP TABLE t1;
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