From: Gregory Stark <stark@enterprisedb.com>
To: "Greg Smith" <gsmith@gregsmith.com>
Cc: <pgsql-performance@postgresql.org>
Subject: Re: PostgreSQL 8.0 occasionally slow down
In-Reply-To: <Pine.GSO.4.64.0706280942320.6275@westnet.com> (Greg Smith's
	message of "Thu, 28 Jun 2007 09:52:54 -0400 (EDT)")
Organization: EnterpriseDB
References: <97e6e20f0706272354m5e42c91em177c8b80abb2ea52@mail.gmail.com>
	<468361A9.1040308@archonet.com>
	<97e6e20f0706280101y543b871ao4cbf85e57f07f7e9@mail.gmail.com>
	<Pine.GSO.4.64.0706280942320.6275@westnet.com>
Date: Thu, 28 Jun 2007 15:16:49 +0100
Message-ID: <876458b1v2.fsf@oxford.xeocode.com>
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"Greg Smith" <gsmith@gregsmith.com> writes:

> On Thu, 28 Jun 2007, Ho Fat Tsang wrote:
>
>> I have tuned the checkpoint_timeout to 30 second which is ten times less than
>> default and the issue is still reproduced.
>
> Your problem looks exactly like a pause at every checkpoint, and I'm not
> sure what Richard was thinking when he suggested having them more often
> would improve things.

Having frequent checkpoints is bad for overall performance but should reduce
the severity of the checkpoint impact. I interpreted his comment as saying he
lowered it just as an experiment to test if it was checkpoint causing the
problems not as a permanent measure.

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