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------------------------------------------------------------ revno: 3035.4.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 39897-6.0 timestamp: Thu 2009-01-15 12:17:57 -0200 message: Bug#39897: lock_multi fails in pushbuild: timeout waiting for processlist The problem is that relying on the "Table lock" thread state in its current position to detect that a thread is waiting on a lock is race prone. The "Table lock" state change happens before the thread actually tries to grab a lock on a table. The solution is to move the "Table lock" state so that its set only when a thread is actually going to wait for a lock. The state change happens after the thread fails to grab the lock (because it is owned by other thread) and proceeds to wait on a condition. This is considered part of work related to WL#4284 "Transactional DDL locking" Warning: this patch contains an incompatible change. When waiting on a lock in thr_lock.c, the server used to display "Locked" processlist state. After this patch, the state is "Table lock". The new state was actually intended to be display since year 2002, when Monty added it. But up until removal of thd->locked boolean member, this state was ignored by SHOW PROCESSLIST code.
118 lines
4.6 KiB
Text
118 lines
4.6 KiB
Text
#
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# Locking related tests which use DEBUG_SYNC facility.
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#
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--source include/have_debug_sync.inc
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# We need InnoDB to be able use TL_WRITE_ALLOW_WRITE type of locks in our tests.
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--source include/have_innodb.inc
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# Until bug#41971 'Thread state on embedded server is always "Writing to net"'
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# is fixed this test can't be run on embedded version of server.
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--source include/not_embedded.inc
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# Save the initial number of concurrent sessions.
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--source include/count_sessions.inc
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--echo #
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--echo # Test for bug #45143 "All connections hang on concurrent ALTER TABLE".
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--echo #
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--echo # Concurrent execution of statements which required weak write lock
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--echo # (TL_WRITE_ALLOW_WRITE) on several instances of the same table and
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--echo # statements which tried to acquire stronger write lock (TL_WRITE,
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--echo # TL_WRITE_ALLOW_READ) on this table might have led to deadlock.
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--disable_warnings
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drop table if exists t1;
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--enable_warnings
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--echo # Create auxiliary connections used through the test.
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connect (con_bug45143_1,localhost,root,,test,,);
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connect (con_bug45143_3,localhost,root,,test,,);
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connect (con_bug45143_2,localhost,root,,test,,);
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connection default;
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--echo # Reset DEBUG_SYNC facility before using it.
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set debug_sync= 'RESET';
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--echo # Turn off logging so calls to locking subsystem performed
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--echo # for general_log table won't interfere with our test.
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set @old_general_log = @@global.general_log;
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set @@global.general_log= OFF;
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create table t1 (i int) engine=InnoDB;
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insert into t1 values (1);
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--echo # Prepare user lock which will be used for resuming execution of
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--echo # the first statement after it acquires TL_WRITE_ALLOW_WRITE lock.
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select get_lock("lock_bug45143_wait", 0);
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--echo # Switch to connection 'con_bug45143_1'.
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connection con_bug45143_1;
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--echo # Sending:
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--send insert into t1 values (get_lock("lock_bug45143_wait", 100));
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--echo # Switch to connection 'con_bug45143_2'.
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connection con_bug45143_2;
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--echo # Wait until the above INSERT takes TL_WRITE_ALLOW_WRITE lock on 't1'
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--echo # and then gets blocked on user lock 'lock_bug45143_wait'.
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let $wait_condition= select count(*)= 1 from information_schema.processlist
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where state= 'User lock' and
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info='insert into t1 values (get_lock("lock_bug45143_wait", 100))';
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--source include/wait_condition.inc
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--echo # Ensure that upcoming SELECT waits after acquiring TL_WRITE_ALLOW_WRITE
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--echo # lock for the first instance of 't1'.
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set debug_sync='thr_multi_lock_after_thr_lock SIGNAL parked WAIT_FOR go';
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--echo # Sending:
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--send select count(*) > 0 from t1 as a, t1 as b for update;
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--echo # Switch to connection 'con_bug45143_3'.
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connection con_bug45143_3;
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--echo # Wait until the above SELECT ... FOR UPDATE is blocked after
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--echo # acquiring lock for the the first instance of 't1'.
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set debug_sync= 'now WAIT_FOR parked';
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--echo # Send LOCK TABLE statement which will try to get TL_WRITE lock on 't1':
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--send lock table t1 write;
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--echo # Switch to connection 'default'.
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connection default;
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--echo # Wait until this LOCK TABLES statement starts waiting for table lock.
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let $wait_condition= select count(*)= 1 from information_schema.processlist
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where state= 'Table lock' and
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info='lock table t1 write';
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--source include/wait_condition.inc
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--echo # Allow SELECT ... FOR UPDATE to resume.
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--echo # Since it already has TL_WRITE_ALLOW_WRITE lock on the first instance
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--echo # of 't1' it should be able to get lock on the second instance without
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--echo # waiting, even although there is another thread which has such lock
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--echo # on this table and also there is a thread waiting for a TL_WRITE on it.
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set debug_sync= 'now SIGNAL go';
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--echo # Switch to connection 'con_bug45143_2'.
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connection con_bug45143_2;
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--echo # Reap SELECT ... FOR UPDATE
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--reap
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--echo # Switch to connection 'default'.
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connection default;
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--echo # Resume execution of the INSERT statement.
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select release_lock("lock_bug45143_wait");
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--echo # Switch to connection 'con_bug45143_1'.
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connection con_bug45143_1;
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--echo # Reap INSERT statement.
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--reap
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--echo # Switch to connection 'con_bug45143_3'.
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connection con_bug45143_3;
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--echo # Reap LOCK TABLES statement.
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--reap
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unlock tables;
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--echo # Switch to connection 'default'.
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connection default;
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--echo # Do clean-up.
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disconnect con_bug45143_1;
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disconnect con_bug45143_2;
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disconnect con_bug45143_3;
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set debug_sync= 'RESET';
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set @@global.general_log= @old_general_log;
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drop table t1;
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# Check that all connections opened by test cases in this file are really
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# gone so execution of other tests won't be affected by their presence.
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--source include/wait_until_count_sessions.inc
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