From: Andrew Sullivan <ajs@crankycanuck.ca>
To: pgsql-performance@postgresql.org
Subject: Re: Occasional Slow Commit
Date: Tue, 28 Oct 2008 08:47:16 -0400
Message-ID: <20081028124716.GE13363@crankycanuck.ca> (raw)
In-Reply-To: <72dbd3150810271723w57859013v9c4e3718ae86fba@mail.gmail.com>
References: <72dbd3150810271723w57859013v9c4e3718ae86fba@mail.gmail.com>
On Mon, Oct 27, 2008 at 05:23:37PM -0700, David Rees wrote:
> However, occasionally, processing time will jump up significantly -
> the average processing time is around 20ms with the maximum processing
> time taking 2-4 seconds for a small percentage of transactions. Ouch!
>
> Turning on statement logging and analyzing the logs of the application
> itself shows that step #4 is the culprit of the vast majority of the
> slow transactions.
My bet is that you're waiting on checkpoints. Given that you're on
8.3, start fiddling with the checkpoint_completion_target parameter.
0.7 might help.
A
--
Andrew Sullivan
ajs@commandprompt.com
+1 503 667 4564 x104
http://www.commandprompt.com/
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: ajs@crankycanuck.ca
Subject: Re: Occasional Slow Commit
In-Reply-To: <20081028124716.GE13363@crankycanuck.ca>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox