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 08B93D7FE7; Wed, 5 Oct 2005 06:41:28 -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 67500-09; Wed, 5 Oct 2005 09:41:23 +0000 (GMT) Received: from vms042pub.verizon.net (vms042pub.verizon.net [206.46.252.42]) by svr1.postgresql.org (Postfix) with ESMTP id 43669D6F63; Wed, 5 Oct 2005 06:41:24 -0300 (ADT) Received: from osgiliath.mathom.us ([70.108.61.78]) by vms042.mailsrvcs.net (Sun Java System Messaging Server 6.2 HotFix 0.04 (built Dec 24 2004)) with ESMTPA id <0INV005W0S92ASA6@vms042.mailsrvcs.net>; Wed, 05 Oct 2005 04:41:26 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by osgiliath.mathom.us (Postfix) with ESMTP id B86D060849A; Wed, 05 Oct 2005 05:41:25 -0400 (EDT) Received: from osgiliath.mathom.us ([127.0.0.1]) by localhost (osgiliath [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 01195-04-3; Wed, 05 Oct 2005 05:41:25 -0400 (EDT) Received: by osgiliath.mathom.us (Postfix, from userid 1000) id 9C4D3608468; Wed, 05 Oct 2005 05:41:25 -0400 (EDT) Date: Wed, 05 Oct 2005 05:41:25 -0400 From: Michael Stone Subject: Re: [HACKERS] A Better External Sort? In-reply-to: <20051001161936.GE13830@svana.org> To: Martijn van Oosterhout Cc: pgsql-hackers@postgresql.org, pgsql-performance@postgresql.org Mail-Followup-To: Martijn van Oosterhout , pgsql-hackers@postgresql.org, pgsql-performance@postgresql.org Message-id: <20051005094125.GW2241@mathom.us> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed Content-disposition: inline X-Pgp-Fingerprint: 53 FF 38 00 E7 DD 0A 9C 84 52 84 C5 EE DF 7C 88 X-Virus-Scanned: by amavisd-new-20030616-p10 (Debian) at mathom.us References: <25552174.1128176560482.JavaMail.root@elwamui-polski.atl.sa.earthlink.net> <20051001161936.GE13830@svana.org> User-Agent: Mutt/1.5.10i X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.004 required=5 tests=[AWL=0.004] X-Spam-Level: X-Archive-Number: 200510/93 X-Sequence-Number: 14861 On Sat, Oct 01, 2005 at 06:19:41PM +0200, Martijn van Oosterhout wrote: >COPY TO /dev/null WITH binary >13MB/s 55% user 45% system (ergo, CPU bound) [snip] >the most expensive. But it does point out that the whole process is >probably CPU bound more than anything else. Note that 45% of that cpu usage is system--which is where IO overhead would end up being counted. Until you profile where you system time is going it's premature to say it isn't an IO problem. Mike Stone