Message-ID: <473326D2.6030600@usit.uio.no>
Date: Thu, 08 Nov 2007 16:10:10 +0100
From: Rafael Martinez <r.m.guerrero@usit.uio.no>
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To: Rafael Martinez <r.m.guerrero@usit.uio.no>,
	pgsql-performance@postgresql.org
Subject: Re: Need to run CLUSTER to keep performance
References: <4732E6B4.1030907@usit.uio.no>
	<20071108145646.GI2938@alvh.no-ip.org>
In-Reply-To: <20071108145646.GI2938@alvh.no-ip.org>
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Alvaro Herrera wrote:
> Rafael Martinez wrote:

>> The 'problem' is that performance decrease during the day and the only
>> thing that helps is to run CLUSTER on the table with problems. VACUUM
>> ANALYZE does not help.
> 
> Probably because all the live tuples are clustered at the end of the
> table, and the initial pages are polluted with dead tuples.  Try
> vacuuming the table much more often, say every few minutes.
> 
> Your table is 2536 pages long, but it could probably be in the vicinity
> of 700 ...
> 

We run VACUUM ANALYZE every 10 minuttes during 2-3 days to see if it
helped, but when it didn't we when back to the old configuration (1 time
everyday)

Yes, after a CLUSTER we are using 517 pages. But the table does not grow
much, it is always around 12-20MB, it looks like vacuum works without
problems.

regards,
-- 
 Rafael Martinez, <r.m.guerrero@usit.uio.no>
 Center for Information Technology Services
 University of Oslo, Norway

 PGP Public Key: http://folk.uio.no/rafael/