[rt-users] One Performance problem identified

Mathew theillien at yahoo.com
Tue Nov 6 20:17:15 EST 2007


But the slow query log only lists the "SELECT GET_LOCK..." queries.  How do I get to the underlying query?

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Ruslan Zakirov wrote:
> One possible reason is previous lock that is there from another
> request, so you really have to look for other slow queries that take
> too much time so users don't wait and click on links or restart
> requests.
> 
> On 11/7/07, Mathew Snyder <theillien at yahoo.com> wrote:
>> The sessions table is a mess (well, *was* a mess).  Why this doesn't get cleaned
>> out regularly by RT is beyond me.  That said, we had more than 21000 records in
>> there.  I ran "DELETE * FROM sessions WHERE LastUpdated < (now() - INTERVAL 24
>> HOUR)" as is laid out in the wiki-page for clearing sessions.  This cleaned out
>> the table but, it still takes too long to load a ticket.  Looking at the slow
>> queries log I see
>>
>> # Time: 071106 17:56:13
>> # User at Host: rt_user[rt_user] @ localhost []
>> # Query_time: 14  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
>> SELECT GET_LOCK('Apache-Session-d279953494e7dcbbaca2e566a94002f2', 3600);
>>
>> Why is it taking so long to get a lock on a table?  I know it isn't taking
>> forever to actually query the database because the page loaded almost
>> immediately after the above query completed.  We're using InnoDB as opposed to
>> MyISAM.  Might that have something to do with it?
>>
>> Any thoughts on this?
>>
>> Mathew
>> --
>> Keep up with me and what I'm up to: http://theillien.blogspot.com
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> 
> 



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