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?
> -----Original Message-----
> From: Robinson, Eric [mailto:eric.robinson@stripped]
> Sent: Thursday, May 09, 2013 1:58 PM
> To: mysql@stripped
> 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
> Eric Robinson
> Disclaimer - May 9, 2013
> This email and any files transmitted with it are confidential and
> intended solely for mysql@stripped. If you are not the named
> addressee you should not disseminate, distribute, copy or alter this
> email. Any views or opinions presented in this email are solely those
> of the author and might not represent those of Physicians' Managed Care
> or Physician Select Management. Warning: Although Physicians' Managed
> Care or Physician Select Management has taken reasonable precautions to
> ensure no viruses are present in this email, the company cannot accept
> responsibility for any loss or damage arising from the use of this
> email or attachments.
> This disclaimer was added by Policy Patrol: