X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 9018352968 for ; Fri, 1 Jul 2005 22:59:43 -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 53668-08 for ; Sat, 2 Jul 2005 01:59:42 +0000 (GMT) Received: from mail.baymountain.com (mail.baymountain.com [8.7.96.19]) by svr1.postgresql.org (Postfix) with SMTP id 8274C528C1 for ; Fri, 1 Jul 2005 22:59:40 -0300 (ADT) Received: (qmail 2314 invoked by uid 504); 2 Jul 2005 01:59:43 -0000 Received: from emil@baymountain.com by mail.baymountain.com by uid 501 with qmail-scanner-1.16 (spamassassin: 2.53. Clear:SA:0(0.0/7.0):. Processed in 0.246783 secs); 02 Jul 2005 01:59:43 -0000 Received: from unknown (HELO briggspack.com) (emil@briggspack.com@24.211.148.77) by mail.baymountain.com with SMTP; 2 Jul 2005 01:59:43 -0000 From: Emil Briggs Reply-To: emil@baymountain.com Organization: Baymountain, Inc. To: pgsql-performance@postgresql.org Subject: Planner constants for RAM resident databases Date: Fri, 1 Jul 2005 21:59:38 -0400 User-Agent: KMail/1.7.1 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200507012159.39041.emil@baymountain.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.038 tagged_above=0 required=5 tests=AWL, FORGED_RCVD_HELO X-Spam-Level: X-Archive-Number: 200507/8 X-Sequence-Number: 13249 I'm working with an application where the database is entirely resident in RAM (the server is a quad opteron with 16GBytes of memory). It's a web application and handles a high volume of queries. The planner seems to be generating poor plans for some of our queries which I can fix by raising cpu_tuple_cost. I have seen some other comments in the archives saying that this is a bad idea but is that necessarily the case when the database is entirely resident in RAM? Emil