mirror of
https://github.com/MariaDB/server.git
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116 lines
3.6 KiB
Text
116 lines
3.6 KiB
Text
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let $initial_timeout=`select @@innodb_lock_wait_timeout`;
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set global innodb_lock_wait_timeout=42;
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connect (a,localhost,root,,);
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connect (b,localhost,root,,);
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connection a;
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select @@innodb_lock_wait_timeout;
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set innodb_lock_wait_timeout=1;
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select @@innodb_lock_wait_timeout;
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connection b;
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let $connection_b_id=`SELECT CONNECTION_ID()`;
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select @@innodb_lock_wait_timeout;
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set global innodb_lock_wait_timeout=347;
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select @@innodb_lock_wait_timeout;
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set innodb_lock_wait_timeout=10;
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select @@innodb_lock_wait_timeout;
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connect (c,localhost,root,,);
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connection c;
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select @@innodb_lock_wait_timeout;
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disconnect c;
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--source include/wait_until_disconnected.inc
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connection a;
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--replace_result $connection_b_id <connection_b_id>
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eval SET @connection_b_id = $connection_b_id;
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create table t1(a int primary key)engine=innodb;
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begin;
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insert into t1 values(1),(2),(3);
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connection b;
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--send
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select * from t1 for update;
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# Observation on information_schema.processlist (2010-12 mysql-5.5)
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# -----------------------------------------------------------------
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# As soon as the server started the execution of the
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# connection a: --send select ... for update
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# High parallel load could delay this up to two seconds.
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# and before either
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# - the innodb_lock_wait_timeout was exceeded
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# -> connection b reap gets ER_LOCK_WAIT_TIMEOUT
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# or
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# - connection a commits, the lock disappears and the statement
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# of connection b finishes
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# -> connection b reap gets success + result set
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# we see within information_schema.processlist for connection b a row
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# command state info
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# Query Sending data select * from t1 for update
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# The highest time value seen was @@innodb_lock_wait_timeout + 1.
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# Please note that there is unfortunately nothing which says
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# that we are just waiting for a lock.
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connection a;
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# In order to ensure that the execution of
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# connection b: select * from t1 for update
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# has really started and is most probably waiting for the lock now we poll on
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# information_schema.processlist.
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# Also our current session innodb_lock_wait_timeout of 10 seconds should big
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# enough to prevent that connection b ends up with getting ER_LOCK_WAIT_TIMEOUT.
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#
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let $wait_timeout= 10;
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let $wait_condition= SELECT COUNT(*) = 1 FROM information_schema.processlist
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WHERE id = @connection_b_id AND INFO = 'select * from t1 for update';
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--source include/wait_condition.inc
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commit;
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connection b;
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reap;
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connection a;
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begin;
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insert into t1 values(4);
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connection b;
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set innodb_lock_wait_timeout=3;
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# 3 seconds should be big enough that the wait routine of connection a will
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# hit the time span where our next statement is visible within the
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# information_schema.processlist.
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--send
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select * from t1 for update;
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connection a;
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# Wait till the execution of the connection b statement was started.
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let $wait_timeout= 10;
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let $wait_condition= SELECT COUNT(*) = 1 FROM information_schema.processlist
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WHERE id = @connection_b_id AND INFO = 'select * from t1 for update';
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--source include/wait_condition.inc
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# Wait till the execution of the connection b statement has ended.
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let $wait_timeout= 10;
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let $wait_condition= SELECT COUNT(*) = 1 FROM information_schema.processlist
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WHERE id = @connection_b_id AND INFO IS NULL;
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--source include/wait_condition.inc
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# Give "commit" though this must be too late for the statement of connection b.
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commit;
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connection b;
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--error ER_LOCK_WAIT_TIMEOUT
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reap;
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disconnect b;
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--source include/wait_until_disconnected.inc
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connection a;
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disconnect a;
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--source include/wait_until_disconnected.inc
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connection default;
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drop table t1;
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--replace_result $initial_timeout <initial_timeout>
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eval set global innodb_lock_wait_timeout=$initial_timeout;
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