X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id A45F29DC867 for ; Wed, 1 Mar 2006 07:58:19 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 63491-09 for ; Wed, 1 Mar 2006 07:58:21 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from peufeu.com (unknown [82.67.9.10]) by postgresql.org (Postfix) with ESMTP id D03869DCB51 for ; Wed, 1 Mar 2006 07:58:16 -0400 (AST) Received: (qmail 32384 invoked from network); 1 Mar 2006 12:58:22 +0100 Received: from unknown (HELO apollo13) (82.67.9.10) by boutiquenumerique.com with SMTP; 1 Mar 2006 12:58:22 +0100 To: pgsql-performance@postgresql.org Subject: Re: wal sync method References: <200602280114.k1S1EAQ17159@candle.pha.pa.us> <3867.1141170306@sss.pgh.pa.us> Message-ID: Date: Wed, 01 Mar 2006 12:58:21 +0100 From: PFC Content-Type: text/plain; format=flowed; delsp=yes; charset=utf-8 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In-Reply-To: <3867.1141170306@sss.pgh.pa.us> User-Agent: Opera M2/8.51 (Linux, build 1462) X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.105 required=5 tests=[AWL=0.105] X-Spam-Score: 0.105 X-Spam-Level: X-Archive-Number: 200603/3 X-Sequence-Number: 17440 Hm, i seem to have mixed fwrite() (which buffers data in userspace) and write() (which apparently doesnt !) Sorry ! > PFC writes: >> Just a stupid question about the various fsync settings. >> There is fsync=off, but is there fsync=fflush ? >> fflush would mean only an OS crash could cause data loss, >> I think.it could be useful for some applications where you need a speed >> boost (like testing database import scripts...) without being as scary >> as >> fsync=off... > > I think you misunderstand. There aren't any scenarios where a PG crash > (without hardware/OS crash) risks data, because we always at least > write() data before commit. The only issue is how hard do we try to get > the OS+hardware to push that data down to disk. > > regards, tom lane