Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id DA3299FB631 for ; Fri, 25 May 2007 16:56:43 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 12077-01 for ; Fri, 25 May 2007 16:56:35 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id B689D9FB5DA for ; Fri, 25 May 2007 16:56:37 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l4PJuZPJ021072; Fri, 25 May 2007 15:56:35 -0400 (EDT) To: Dave Pirotte cc: pgsql-performance@postgresql.org Subject: Re: Performance problem on 8.2.4, but not 8.2.3 In-reply-to: <2C91A79B-6AFD-4734-B245-2ED81F4F15D4@mediamatters.org> References: <2C91A79B-6AFD-4734-B245-2ED81F4F15D4@mediamatters.org> Comments: In-reply-to Dave Pirotte message dated "Fri, 25 May 2007 14:08:52 -0400" Date: Fri, 25 May 2007 15:56:35 -0400 Message-ID: <21071.1180122995@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200705/537 X-Sequence-Number: 24927 Dave Pirotte writes: > We have two servers running pgsql -- an older server running 8.2.3, > and a newer (far superior) one running 8.2.4. One of our reporting > queries is running painfully slowly on 8.2.4, but it executes in a > reasonable timeframe on 8.2.3. Are you sure you've analyzed all these tables in the 8.2.4 database? Some of the rowcount estimates seem a bit far off. I looked through the CVS logs and didn't find any planner changes between 8.2.3 and 8.2.4 that seem likely to affect your query, so I'm thinking it must be a statistical discrepancy. regards, tom lane