…values (1,’Mysql‘),(2,’Solid’),(3,’MyISAM‘); mysql> begin; mysql> update test2 set names=’mysql‘ where id=1; Session 2: mysql> begin; mysql> update …locking reads (SELECT FOR UPDATE/LOCK IN SHARE MODE) as only actual row versions can be locked. With Innodb we would get “SolidDB2″ as result. mysql…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…lock_wait_timeoutblogpercona.commanual locked_in…
Post: INSERT INTO ... SELECT Performance with Innodb tables.
July 12, 2006 By 21 Comments
… perform non locking reads, meaning unless you use some modifiers such as LOCK IN SHARE MODE or FOR UPDATE, SELECT statements will not lock any rows… are done in MyISAM table. So why was this done, being pretty bad for MySQL Performance and concurrency ? The reason is – replication. In MySQL before…
Post: Paul McCullagh answers your questions about PBXT
November 20, 2009 By 2 Comments
… somewhere between MyISAM and InnoDB in both performance and…in this manner. I should also mention that the consequence of this is that SELECT … LOCK IN SHARE MODE…MySQL calls the engine “init” method on startup it is holding the global LOCK_plugin lock. In init, the engine needs to do recovery. In…
Post: The perils of InnoDB with Debian and startup scripts
January 28, 2009 By 13 Comments
…mysql start it runs this script, which runs mysqlcheck, which can destroy performance. It can happen on a server with MyISAM…in mode exclusive number of readers 0, waiters flag 1 Last time read locked in file btr0sea.c line 746 Last time write locked in…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… the operating mode you expect us to work in. Maybe…mysql –user=mysql –pid-file=/var/run/mysqld/mysqld.pid –skip-external-locking –port=3306 –socket=/var/db/mysql/mysql…in Locked status, which might be an indication that it’s time to convert MyISAM… and mailing list. We share all sorts of dirty…
