Re: Quad Opteron stuck in the mud - Mailing list pgsql-performance

From Alvaro Herrera
Subject Re: Quad Opteron stuck in the mud
Date
Msg-id 20050713201817.GA5450@alvh.no-ip.org
Whole thread Raw
In response to Re: Quad Opteron stuck in the mud  (Dan Harris <fbsd@drivefaster.net>)
List pgsql-performance
On Wed, Jul 13, 2005 at 01:16:25PM -0600, Dan Harris wrote:

> On Jul 13, 2005, at 1:11 PM, John A Meinel wrote:
>
> >I might be wrong, but there may be something much more substantially
> >wrong than slow i/o.
>
> Yes, I'm afraid of that too.  I just don't know what tools I should
> use to figure that out.  I have some 20 other databases on this
> system, same schema but varying sizes, and the small ones perform
> very well.  It feels like there is an O(n) increase in wait time that
> has recently become very noticeable on the largest of them.

I'd guess it's stuck on some lock.  Try that EXPLAIN, and when it
blocks, watch the pg_locks view for locks not granted to the process
executing the EXPLAIN.  Then check what else is holding the locks.

--
Alvaro Herrera (<alvherre[a]alvh.no-ip.org>)
"La rebeldía es la virtud original del hombre" (Arthur Schopenhauer)

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