Received: from magus.postgresql.org (magus.postgresql.org [87.238.57.229]) by mail.postgresql.org (Postfix) with ESMTP id D96D91AB353A for ; Wed, 18 Jul 2012 09:18:41 -0300 (ADT) Received: from mail.kickstone.com ([46.37.63.75]) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1SrTDD-0004g2-4v for pgsql-performance@postgresql.org; Wed, 18 Jul 2012 12:18:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=kickstone.com; s=mail; h=Content-Transfer-Encoding:Content-Type:Subject:To:MIME-Version:From:Date:Message-ID; bh=Qz1a57UHQxNqhrT1/QSUhhXWG3a0l6kCVoq69+IdO3o=; b=hqUgYOEdcVqbl+sOHsPZBuDigyTMaG5WOE5/B80+SwYEZ9MEx2nE0UUMs5hdxgCYqtrftfsCSqtuTYt6CCGKMvpZ6fYZuUGqLWPhVYDva9S6Enleq+aqXmXaDaP+fY+v; Received: from host86-171-128-101.range86-171.btcentralplus.com ([86.171.128.101]:53405 helo=[192.168.1.123]) by mail.kickstone.com with esmtpa (Exim 4.76) (envelope-from ) id 1SrTCz-0004N7-3q for pgsql-performance@postgresql.org; Wed, 18 Jul 2012 13:18:25 +0100 Message-ID: <5006A991.3020504@kickstone.com> Date: Wed, 18 Jul 2012 13:18:25 +0100 From: John Lister User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: pgsql-performance@postgresql.org Subject: postgresql query cost values/estimates Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -0.1 (/) X-Archive-Number: 201207/221 X-Sequence-Number: 47402 Hi, I was wondering if there are any recommended ways or tools for calculating the planner cost constants? Also, do the absolute values matter or is it simply the ratio between them? I'm about to configure a new server and can probably do a rough job of calculating them based on supposed speeds of the various components but wondered if anyone uses more accurate methods? Thanks John