Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id B743AB5DC07 for ; Fri, 12 Aug 2011 21:19:00 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 62684-03 for ; Sat, 13 Aug 2011 00:18:54 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mail-vw0-f46.google.com (mail-vw0-f46.google.com [209.85.212.46]) by mail.postgresql.org (Postfix) with ESMTP id 6BE0BB5DBFC for ; Fri, 12 Aug 2011 21:18:54 -0300 (ADT) Received: by vws1 with SMTP id 1so2861745vws.19 for ; Fri, 12 Aug 2011 17:18:54 -0700 (PDT) Received: by 10.52.71.197 with SMTP id x5mr1423080vdu.305.1313194734368; Fri, 12 Aug 2011 17:18:54 -0700 (PDT) Received: from [10.1.1.8] (124-169-181-228.dyn.iinet.net.au [124.169.181.228]) by mx.google.com with ESMTPS id bp11sm1543668vcb.24.2011.08.12.17.18.52 (version=SSLv3 cipher=OTHER); Fri, 12 Aug 2011 17:18:53 -0700 (PDT) Message-ID: <4E45C2E8.5070701@ringerc.id.au> Date: Sat, 13 Aug 2011 08:18:48 +0800 From: Craig Ringer User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:5.0) Gecko/20110624 Thunderbird/5.0 MIME-Version: 1.0 To: Tomas Vondra CC: pgsql-performance@postgresql.org Subject: Re: strange pgbench results (as if blocked at the end) References: <2f9ba8ed6e4ed11d9a6d236cb4d2a2ec.squirrel@sq.gransy.com> In-Reply-To: <2f9ba8ed6e4ed11d9a6d236cb4d2a2ec.squirrel@sq.gransy.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-10 required=5 tests=BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201108/156 X-Sequence-Number: 44603 On 13/08/2011 7:37 AM, Tomas Vondra wrote: > I'd understand a slowdown, but why does it block? My first guess is that you're having checkpoint issues. Try enabling logging of checkpoints and checkpoint timings and see if anything there lines up with the pause you encounter. -- Craig Ringer