Received: from maia.hub.org (maia-4.hub.org [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 4C78F632CF2 for ; Mon, 10 May 2010 21:23:23 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 44816-03 for ; Tue, 11 May 2010 00:23:16 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from glacier.frostconsultingllc.com (glacier.frostconsultingllc.com [69.36.227.170]) by mail.postgresql.org (Postfix) with ESMTP id 0EA30632D85 for ; Mon, 10 May 2010 21:23:16 -0300 (ADT) Received: from dsl081-245-111.sfo1.dsl.speakeasy.net ([64.81.245.111] helo=Sidney-Stratton.local) by glacier.frostconsultingllc.com with esmtpsa (TLSv1:CAMELLIA256-SHA:256) (Exim 4.69) (envelope-from ) id 1OBdFf-0006O8-AB for pgsql-hackers@postgresql.org; Mon, 10 May 2010 17:23:14 -0700 Message-ID: <4BE8A36E.2050301@agliodbs.com> Date: Mon, 10 May 2010 17:23:10 -0700 From: Josh Berkus User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20090223 Thunderbird/3.0b2 MIME-Version: 1.0 To: pgsql-hackers@postgresql.org Subject: Re: no universally correct setting for fsync References: <4BE3D3930200002500031382@gw.wicourts.gov> <4BE425F7.30804@dunslane.net> <4BE3E205020000250003138F@gw.wicourts.gov> <4BE82D6602000025000314D6@gw.wicourts.gov> <4BE87892.5060409@agliodbs.com> <4BE890C6.5010907@2ndquadrant.com> In-Reply-To: <4BE890C6.5010907@2ndquadrant.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-5 required=5 tests=BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201005/488 X-Sequence-Number: 162151 > The real question is how much of a speed-up fsync provides compared to > the same workload with synchronous_commit disabled. The only case for > fsync=off is one where that number is much faster. I can't say I've tested this. Most of my head-to-heads on fsync were before asych existed. -- -- Josh Berkus PostgreSQL Experts Inc. http://www.pgexperts.com