[rt-users] One Performance problem identified

[Ruslan Zakirov]

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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-- 
Best regards, Ruslan.