Received: from localhost (unknown [200.46.204.182]) by postgresql.org (Postfix) with ESMTP id C8C2E2E3FC0 for ; Thu, 17 Jan 2008 02:50:29 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.182]) (amavisd-maia, port 10024) with ESMTP id 40690-08 for ; Thu, 17 Jan 2008 02:50:22 -0400 (AST) Received: from cptwks26.careerjunction.local (unknown [196.212.105.173]) by postgresql.org (Postfix) with ESMTP id C626B2E3B76 for ; Thu, 17 Jan 2008 02:50:22 -0400 (AST) Received: from [127.0.0.1] (localhost [127.0.0.1]) by cptwks26.careerjunction.local (Postfix) with ESMTP id 35F41B7A4A; Thu, 17 Jan 2008 08:50:29 +0200 (SAST) Message-ID: <478EFAB0.30205@careerjunction.co.za> Date: Thu, 17 Jan 2008 08:50:24 +0200 From: Adrian Moisey User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: Greg Smith CC: pgsql-performance@postgresql.org Subject: Re: strange pauses References: <478DDF83.8070106@careerjunction.co.za> <478DE16F.50308@archonet.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200801/136 X-Sequence-Number: 28375 Hi >> Search this list for references to "checkpoints". If you run >> vmstat/iostat for a bit you should see bursts of disk activity at >> those times. > > The most straightforward way to prove or disprove that the slow queries > line up with checkpoints is to set to checkpoint_warning to a high value > (3600 should work), which should log every checkpoint, and then see if > they show up at the same time in the logs. You guys were spot on. During these pauses the IO goes up high. I've got the following set: checkpoint_timeout = 5min checkpoint_warning = 3600s log_min_messages = info But I see nothing in the logs about checkpoints -- Adrian Moisey System Administrator | CareerJunction | Your Future Starts Here. Web: www.careerjunction.co.za | Email: adrian@careerjunction.co.za Phone: +27 21 686 6820 | Mobile: +27 82 858 7830 | Fax: +27 21 686 6842