On Thu, May 9, 2013 15:25, Robinson, Eric wrote: >> >> > -----Original Message----- >> > From: Robinson, Eric [mailto:eric.robin...@psmnv.com] >> > Sent: Thursday, May 09, 2013 1:58 PM >> > To: mysql@lists.mysql.com >> > Subject: Slow Response -- What Does This Sound Like to You? >> > >> > We have a situation where users complain that the system >> periodically >> > freezes for 30-90 seconds. We check the slow query logs and >> find that >> > one user issued a complex query that did indeed take 30-90 >> seconds to >> > complete. However, NO slow queries are recorded for the other 50 >> > users, before, during, or after the freeze. Note that the complex >> > query in question always shows: "Lock_time: 0". >> > >> > Q: What conditions could cause single query to lock up a >> database for >> > a while for all users (even though it shows "lock time: 0") but no >> > other slow queries would show in the logs for any other >> users who are >> > hitting the database at the same time? >> > >> > OS: RHEL3 x64 >> > CPU: 8 x 2.9GHz Xeon >> > RAM: 32GB >> > Disk: RAID 5 (6 x 512GB SSD) >> > MySQL: 5.0.95 x64 >> > Engine: MyISAM >> > > > >> MyISAM? Or InnoDB? >> Lock_time perhaps applies only to table locks on MyISAM. >> >> SHOW ENGINE InnoDB STATUS; >> You may find some deadlocks. >> >> Is Replication involved? >> >> Anyone doing an ALTER? > > > > MyISAM, no replication involved, and nobody is altering the database. This > happens whenever people run certain reports. > > > --Eric This may be a dumb question, but have you verified that the applications do not issue a "Lock TABLES ..."? Either the big one or one of the others.
------ William R. Mussatto Systems Engineer http://www.csz.com 909-920-9154 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
