Re: Really really slow select count(*)

From: Shaun Thomas <sthomas(at)peak6(dot)com>
To: Greg Smith <greg(at)2ndquadrant(dot)com>
Cc: felix <crucialfelix(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Really really slow select count(*)
Date: 2011-02-04 15:03:49
Message-ID: 4D4C1555.40209@peak6.com
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On 02/04/2011 08:56 AM, Greg Smith wrote:

> PostgreSQL version? If you're running on 8.3 or earlier, I would be
> suspicous that your Free Space Map has been overrun.

That's my first inclination. If he says autovacuum is running, there's
no way it should be bloating the table that much.

Felix, If you're running a version before 8.4, what is your
max_fsm_pages setting? If it's too low, autovacuum won't save you, and
your tables will continue to grow daily unless you vacuum full
regularly, and I wouldn't recommend that to my worst enemy. ;)

--
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas(at)peak6(dot)com

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