Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id 5F3701337B97 for ; Mon, 8 Nov 2010 14:40:53 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 61335-07 for ; Mon, 8 Nov 2010 18:40:46 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 349CC1337B49 for ; Mon, 8 Nov 2010 14:40:46 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id oA8IeZcZ027403; Mon, 8 Nov 2010 13:40:35 -0500 (EST) To: Scott Carey cc: Marti Raudsepp , Greg Smith , Andres Freund , "pgsql-performance@postgresql.org" Subject: Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1? In-reply-to: <9D7DB2F2-683B-480C-B781-8D282A280E35@richrelevance.com> References: <4CCDCAA3.4050805@2ndquadrant.com> <201011010010.28724.andres@anarazel.de> <4CD472CC.80006@2ndquadrant.com> <4CD47FCD.6010106@2ndquadrant.com> <4CD737C1.9070502@2ndquadrant.com> <9D7DB2F2-683B-480C-B781-8D282A280E35@richrelevance.com> Comments: In-reply-to Scott Carey message dated "Mon, 08 Nov 2010 10:13:43 -0800" Date: Mon, 08 Nov 2010 13:40:34 -0500 Message-ID: <27402.1289241634@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201011/108 X-Sequence-Number: 41132 Scott Carey writes: > No matter how you slice it, the default on Linux is implicitly changing and the choice is to either: > * Return the default to fdatasync > * Let it implicitly change to O_DSYNC > The latter choice is the one that requires testing to prove that it is the proper and preferred default from the performance and data reliability POV. And, in fact, the game plan is to do that testing and see which default we want. I think it's premature to argue further about this until we have some test results. regards, tom lane