X-Original-To: pgsql-performance-postgresql.org@postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id E84439FB1D2 for ; Tue, 19 Sep 2006 00:45:56 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 32040-04 for ; Tue, 19 Sep 2006 00:45:49 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.envysolutions.com (mark.mielke.cc [206.248.142.186]) by postgresql.org (Postfix) with ESMTP id DE79F9FA372 for ; Tue, 19 Sep 2006 00:45:48 -0300 (ADT) Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.envysolutions.com (Postfix) with ESMTP id 7D3165403B; Mon, 18 Sep 2006 23:45:47 -0400 (EDT) X-Virus-Scanned: amavisd-new at mail.envysolutions.com Received: from mail.envysolutions.com ([127.0.0.1]) by localhost (mark.mielke.cc [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VvUROhYqxquG; Mon, 18 Sep 2006 23:45:47 -0400 (EDT) Received: by mail.envysolutions.com (Postfix, from userid 500) id 443505403C; Mon, 18 Sep 2006 23:45:47 -0400 (EDT) Date: Mon, 18 Sep 2006 23:45:47 -0400 From: mark@mark.mielke.cc To: Luke Lonergan Cc: Bucky Jordan , "Spiegelberg, Greg" , Joshua Drake , "Craig A. James" , pgsql-performance@postgresql.org Subject: Re: Large tables (was: RAID 0 not as fast as expected) Message-ID: <20060919034547.GA24692@mark.mielke.cc> References: <78ED28FACE63744386D68D8A9D1CF5D42099C7@MAIL.corp.lumeta.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=1.143 tagged_above=0 required=5 tests=AWL, FORGED_RCVD_HELO, NO_REAL_NAME, SPF_HELO_PASS, SPF_PASS X-Spam-Level: * X-Archive-Number: 200609/246 X-Sequence-Number: 20932 On Mon, Sep 18, 2006 at 06:10:13PM -0700, Luke Lonergan wrote: > Also be sure to set the random_page_cost parameter in > postgresql.conf to 100 or even higher when you use indexes, as the actual > seek rate for random access ranges between 50 and 300 for modern disk > hardware. If this parameter is left at the default of 4, indexes will often > be used inappropriately. Does a tool exist yet to time this for a particular configuration? Cheers, mark -- mark@mielke.cc / markm@ncf.ca / markm@nortel.com __________________________ . . _ ._ . . .__ . . ._. .__ . . . .__ | Neighbourhood Coder |\/| |_| |_| |/ |_ |\/| | |_ | |/ |_ | | | | | | \ | \ |__ . | | .|. |__ |__ | \ |__ | Ottawa, Ontario, Canada One ring to rule them all, one ring to find them, one ring to bring them all and in the darkness bind them... http://mark.mielke.cc/