X-Original-To: pgsql-performance-postgresql.org@postgresql.org Received: from localhost (wm.hub.org [200.46.204.128]) by postgresql.org (Postfix) with ESMTP id 5427E9FB28C for ; Tue, 15 Aug 2006 17:53:35 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.128]) (amavisd-new, port 10024) with ESMTP id 65192-08 for ; Tue, 15 Aug 2006 20:53:23 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey- Received: from vms048pub.verizon.net (vms048pub.verizon.net [206.46.252.48]) by postgresql.org (Postfix) with ESMTP id 33C379FB274 for ; Tue, 15 Aug 2006 17:53:22 -0300 (ADT) Received: from osgiliath.mathom.us ([72.66.19.42]) by vms048.mailsrvcs.net (Sun Java System Messaging Server 6.2-4.02 (built Sep 9 2005)) with ESMTPA id <0J42001614OLKYR2@vms048.mailsrvcs.net> for pgsql-performance@postgresql.org; Tue, 15 Aug 2006 15:53:10 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by osgiliath.mathom.us (Postfix) with ESMTP id EBA356FBD1; Tue, 15 Aug 2006 16:53:05 -0400 (EDT) Received: from osgiliath.mathom.us ([127.0.0.1]) by localhost (osgiliath.home.mathom.us [127.0.0.1]) (amavisd-new, port 10024) with LMTP id HavoX9sQauBg; Tue, 15 Aug 2006 16:53:04 -0400 (EDT) Received: by osgiliath.mathom.us (Postfix, from userid 1000) id 9CE596FC71; Tue, 15 Aug 2006 16:53:03 -0400 (EDT) Date: Tue, 15 Aug 2006 16:53:03 -0400 From: Michael Stone Subject: Re: Postgresql Performance on an HP DL385 and In-reply-to: <20060815191505.GH21363@pervasive.com> To: "Jim C. Nasby" Cc: mark@mark.mielke.cc, pgsql-performance@postgresql.org Mail-followup-to: "Jim C. Nasby" , mark@mark.mielke.cc, pgsql-performance@postgresql.org Message-id: <20060815205300.GX2900@mathom.us> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed Content-disposition: inline X-Virus-Scanned: Debian amavisd-new at mathom.us X-Pgp-Fingerprint: 53 FF 38 00 E7 DD 0A 9C 84 52 84 C5 EE DF 7C 88 References: <20060810110935.GF2900@mathom.us> <20060814153841.GF27928@pervasive.com> <721b21dc0608140851v2332cdf9g59808004c983540f@mail.gmail.com> <20060814170545.GG27928@pervasive.com> <20060814170902.GN2900@mathom.us> <20060815162926.GS27928@pervasive.com> <20060815172645.GU2900@mathom.us> <20060815183327.GC12834@mark.mielke.cc> <20060815190254.GW2900@mathom.us> <20060815191505.GH21363@pervasive.com> User-Agent: Mutt/1.5.12-2006-07-14 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0.134 tagged_above=0 required=5 tests=FORGED_RCVD_HELO, SPF_PASS X-Spam-Level: X-Archive-Number: 200608/250 X-Sequence-Number: 20435 On Tue, Aug 15, 2006 at 02:15:05PM -0500, Jim C. Nasby wrote: >Now, if >fsync'ing a file also ensures that all the metadata is written, then >we're probably fine... ...and it does. Unclean shutdowns cause problems in general because filesystems operate asynchronously. postgres (and other similar programs) go to great lengths to make sure that critical operations are performed synchronously. If the program *doesn't* do that, metadata journaling isn't a magic wand which will guarantee data integrity--it won't. If the program *does* do that, all the metadata journaling adds is the ability to skip fsck and start up faster. Mike Stone