Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id 89A811337B6C for ; Tue, 16 Nov 2010 20:05:16 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 88562-08 for ; Wed, 17 Nov 2010 00:05:09 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from lpo-relay-04.vmsinfo.com (lpo-relay-04.vmsinfo.com [216.169.137.115]) by mail.postgresql.org (Postfix) with ESMTP id 657BD1337B67 for ; Tue, 16 Nov 2010 20:05:08 -0400 (AST) X-IronPort-AV: E=Sophos;i="4.59,208,1288584000"; d="scan'208";a="27045742" Received: from unknown (HELO lpo-mailbox-02.vmsinfo.com) ([216.169.137.251]) by lpo-relay-04.vmsinfo.com with ESMTP; 16 Nov 2010 19:05:06 -0500 Received: from [10.101.43.35] (lpo-autonomy-p03.vmsinfo.com [216.169.135.234]) by lpo-mailbox-02.vmsinfo.com (Postfix) with ESMTP id F1BC256258; Tue, 16 Nov 2010 19:05:05 -0500 (EST) Message-ID: <4CE31C31.6090108@vmsinfo.com> Date: Tue, 16 Nov 2010 19:05:05 -0500 From: Mladen Gogala Organization: VMS User-Agent: Thunderbird 2.0.0.24 (X11/20101027) MIME-Version: 1.0 To: Josh Berkus CC: "pgsql-performance@postgresql.org" Subject: Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1? References: <4CCDCAA3.4050805@2ndquadrant.com> <201011010010.28724.andres@anarazel.de> <4CD472CC.80006@2ndquadrant.com> <4CE2EBF8.4040602@2ndquadrant.com> <4CE312D9.6030503@agliodbs.com> In-Reply-To: <4CE312D9.6030503@agliodbs.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=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201011/272 X-Sequence-Number: 41296 Josh Berkus wrote: > On 11/16/10 12:39 PM, Greg Smith wrote: > >> I want to next go through and replicate some of the actual database >> level tests before giving a full opinion on whether this data proves >> it's worth changing the wal_sync_method detection. So far I'm torn >> between whether that's the right approach, or if we should just increase >> the default value for wal_buffers to something more reasonable. >> > > We'd love to, but wal_buffers uses sysV shmem. > > Speaking of the SYSV SHMEM, is it possible to use huge pages? -- Mladen Gogala Sr. Oracle DBA 1500 Broadway New York, NY 10036 (212) 329-5251 http://www.vmsinfo.com The Leader in Integrated Media Intelligence Solutions