To: "Joshua D. Drake" <jd@commandprompt.com>
Cc: "Campbell\, Lance" <lance@uiuc.edu>,  <pgsql-performance@postgresql.org>
Subject: Re: Suggestions on an update query
In-Reply-To: <20071026141547.70c9c1e0@scratch> (Joshua D. Drake's message of
	"Fri\, 26 Oct 2007 14\:15\:47 -0700")
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	<20071026141547.70c9c1e0@scratch>
From: Gregory Stark <stark@enterprisedb.com>
Organization: EnterpriseDB
Date: Sat, 27 Oct 2007 03:04:47 +0100
Message-ID: <87odel1feo.fsf@oxford.xeocode.com>
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"Joshua D. Drake" <jd@commandprompt.com> writes:

> On Fri, 26 Oct 2007 15:31:44 -0500
> "Campbell, Lance" <lance@uiuc.edu> wrote:
>
>> I forgot to include an additional parameter I am using in
>> Postgresql.conf: 
>> 
>
> O.k. first, just to get it out of the way (and then I will try and
> help). Please do not top post, it makes replying contextually very
> difficult.
>
>> PostgreSql version 8.2.4
>> 
>> Memory = 8 Gig
>> 
>> CPUs 1 dual core Zeon running at 3.0
>> 
>
> O.k. first you might be grinding through your 20 checkpoint segments
> but in reality what I think is happening is you are doing foreign key
> checks against all of it and slowing things down.

If you're going to berate someone about top-posting perhaps you should attach
your own commentary to relevant bits of context :P

But the original post didn't include any foreign key constraints. I suspect
you've guessed it right though. In fact I suspect what's happening is he
doesn't have an index on the referencing column so the foreign key checks are
doing sequential scans of.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com