X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id E31A0D881A for ; Thu, 1 Sep 2005 18:52:49 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 33241-08 for ; Thu, 1 Sep 2005 21:52:47 +0000 (GMT) Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [129.241.93.19]) by svr1.postgresql.org (Postfix) with ESMTP id B7172D8792 for ; Thu, 1 Sep 2005 18:52:45 -0300 (ADT) Received: from trofast.ipv6.sesse.net ([2001:700:300:dc03:20e:cff:fe36:a766] helo=trofast.sesse.net) by cassarossa.samfundet.no with esmtp (Exim 4.50) id 1EAwzG-0003DY-AG for pgsql-performance@postgresql.org; Thu, 01 Sep 2005 23:52:47 +0200 Received: from sesse by trofast.sesse.net with local (Exim 3.36 #1 (Debian)) id 1EAwzF-0001Ji-00 for ; Thu, 01 Sep 2005 23:52:45 +0200 Date: Thu, 1 Sep 2005 23:52:45 +0200 From: "Steinar H. Gunderson" To: pgsql-performance@postgresql.org Subject: Re: Massive performance issues Message-ID: <20050901215245.GA4242@uio.no> Mail-Followup-To: pgsql-performance@postgresql.org References: <20050901174231.GE23970@pongo.lshift.net> <43176A95.70506@tweakers.net> <20050901211359.GD7131@pongo.lshift.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20050901211359.GD7131@pongo.lshift.net> X-Operating-System: Linux 2.6.11.8 on a i686 X-Message-Flag: Outlook? --> http://www.mozilla.org/products/thunderbird/ User-Agent: Mutt/1.5.10i X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.014 required=5 tests=[AWL=0.014] X-Spam-Level: X-Archive-Number: 200509/29 X-Sequence-Number: 14337 On Thu, Sep 01, 2005 at 10:13:59PM +0100, Matthew Sackman wrote: > Well that's the thing - on the queries where it decides to use the index > it only reads at around 3MB/s and the CPU is maxed out, whereas when it > doesn't use the index, the disk is being read at 60MB/s. So when it > decides to use an index, I don't seem to be IO bound at all. Or at least > that's the way it seems to me. You are I/O bound; your disk is doing lots and lots of seeks. The SATA interface is not the bottleneck; the disk's ability to rotate and move its heads is. /* Steinar */ -- Homepage: http://www.sesse.net/