X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 9D7E311F647B for ; Fri, 28 Apr 2006 02:18:23 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 59048-04 for ; Fri, 28 Apr 2006 02:18:12 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from ns2.nec.com.au (ns2.nec.com.au [147.76.180.2]) by postgresql.org (Postfix) with ESMTP id EFCFC11F6477 for ; Fri, 28 Apr 2006 02:18:11 -0300 (ADT) Received: from ns2.nec.com.au ([127.0.0.1]) by localhost (ns2.nec.com.au [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 30500-01-77 for ; Fri, 28 Apr 2006 15:18:10 +1000 (EST) Received: from smtp1.nec.com.au (unknown [172.31.8.18]) by ns2.nec.com.au (Postfix) with ESMTP id 4E0C73B7A4 for ; Fri, 28 Apr 2006 15:18:10 +1000 (EST) Received: from eddy (eddy.ssd.neca.nec.com.au [147.76.48.116]) by warp.ssd.neca.nec.com.au (8.12.10+Sun/8.12.10) with SMTP id k3S5I9uP026964; Fri, 28 Apr 2006 15:18:09 +1000 (EST) Reply-To: From: "Guoping Zhang" To: "'Guillaume Smet'" Cc: , "'Guoping Zhang (E-mail)'" Subject: Re: how unsafe (or worst scenarios) when setting fsync OFF for postgresql Date: Fri, 28 Apr 2006 15:18:08 +1000 Message-ID: <004301c66a83$234bd470$74304c93@eddy> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook CWS, Build 9.0.2416 (9.0.2911.0) Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 In-Reply-To: <1d4e0c10604270226s53e261e9m943bf44766c880bf@mail.gmail.com> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200604/662 X-Sequence-Number: 18746 Hi, Guillaume, Thanks for the reply. I am using wal_sync_methods be open_datasync, which appear much faster than 'fdatasync'. Regards, Guoping -----Original Message----- From: Guillaume Smet [mailto:guillaume.smet@gmail.com] Sent: 2006Äê4ÔÂ27ÈÕ 19:26 To: guoping.zhang@nec.com.au Cc: pgsql-performance@postgresql.org; Guoping Zhang (E-mail) Subject: Re: [PERFORM] how unsafe (or worst scenarios) when setting fsync OFF for postgresql Guoping, On 4/27/06, Guoping Zhang wrote: > We have to looking at setting fsync OFF option for performance reason, Did you try the other wal sync methods (fdatasync in particular)? I saw a few posts lately explaining how changing sync method can affect performances in specific cases. -- Guillaume