Received: from localhost (maia-1.hub.org [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 77E469FBB33 for ; Thu, 22 Mar 2007 15:46:39 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-new, port 10024) with ESMTP id 41457-05 for ; Thu, 22 Mar 2007 15:46:25 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from vms042pub.verizon.net (vms042pub.verizon.net [206.46.252.42]) by postgresql.org (Postfix) with ESMTP id 030529FBBC3 for ; Thu, 22 Mar 2007 15:46:24 -0300 (ADT) Received: from osgiliath.mathom.us ([72.66.31.15]) by vms042.mailsrvcs.net (Sun Java System Messaging Server 6.2-6.01 (built Apr 3 2006)) with ESMTPA id <0JFB00LY7ITBJAW0@vms042.mailsrvcs.net> for pgsql-performance@postgresql.org; Thu, 22 Mar 2007 13:46:23 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by osgiliath.mathom.us (Postfix) with ESMTP id 503426FE0C for ; Thu, 22 Mar 2007 14:46:17 -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 T6o5eMXqRu85 for ; Thu, 22 Mar 2007 14:46:15 -0400 (EDT) Received: by osgiliath.mathom.us (Postfix, from userid 1000) id 93712712EB; Thu, 22 Mar 2007 14:46:15 -0400 (EDT) Date: Thu, 22 Mar 2007 14:46:15 -0400 From: Michael Stone Subject: Re: Parallel Vacuum In-reply-to: <200703221924.39278.dimitrik.fr@gmail.com> To: pgsql-performance@postgresql.org Mail-followup-to: pgsql-performance@postgresql.org Message-id: <20070322184613.GJ11402@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: <200703221435.54408.dimitrik.fr@gmail.com> <200703221655.03068.dimitrik.fr@gmail.com> <20070322171007.GH11402@mathom.us> <200703221924.39278.dimitrik.fr@gmail.com> User-Agent: Mutt/1.5.13 (2006-08-11) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200703/354 X-Sequence-Number: 23759 On Thu, Mar 22, 2007 at 07:24:38PM +0100, Dimitri wrote: >you're right until you're using a single disk :) >Now, imagine you have more disks I do have more disks. I maximize the I/O performance by dedicating different sets of disks to different tables. YMMV. I do suggest watching your I/O rates and wallclock time if you try this to see if your aggregate is actually substantially faster than the single case. (I assume that you haven't yet gotten far enough to actually do performance testing.) You may also want to look into tuning your sequential I/O performance. Mike Stone