Received: from localhost (maia-1.hub.org [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 104C39FB8C5 for ; Thu, 26 Apr 2007 14:49:46 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 39746-09 for ; Thu, 26 Apr 2007 14:49:35 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 2189D9FB7C0 for ; Thu, 26 Apr 2007 14:49:35 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.6/8.13.6) with ESMTP id l3QHnWXH026943; Thu, 26 Apr 2007 13:49:32 -0400 (EDT) To: Gregory Stark cc: "Craig A. James" , "Bill Moran" , "Heikki Linnakangas" , "Postgresql list Performance" Subject: Re: Filesystem fragmentation (Re: Fragmentation of WAL files) In-reply-to: <87wszz6q1q.fsf@oxford.xeocode.com> References: <3BD44C5D-E402-43EB-8FFD-1A4BC97AFD0C@decibel.org> <20070426080050.522ef7b5.wmoran@collaborativefusion.com> <463096AD.4020707@enterprisedb.com> <20070426091432.274977fe.wmoran@collaborativefusion.com> <4630D4B6.9040802@modgraph-usa.com> <87wszz6q1q.fsf@oxford.xeocode.com> Comments: In-reply-to Gregory Stark message dated "Thu, 26 Apr 2007 17:47:29 +0100" Date: Thu, 26 Apr 2007 13:49:32 -0400 Message-ID: <26942.1177609772@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200704/433 X-Sequence-Number: 24310 Gregory Stark writes: > In the case of a performance-critical file like the WAL that's always read > sequentially it may be to our advantage to defeat this technique and force it > to be allocated sequentially. I'm not sure whether any filesystems provide any > option to do so. We more or less do that already by filling the entire file in one go when it's created ... regards, tom lane