Received: from localhost (unknown [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 78A982E00E0 for ; Sat, 8 Mar 2008 16:08:52 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 04377-03 for ; Sat, 8 Mar 2008 16:08:37 -0400 (AST) 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 9BD2F2E00C3 for ; Sat, 8 Mar 2008 16:08:49 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id m28K8kbI006360; Sat, 8 Mar 2008 15:08:46 -0500 (EST) To: "Kynn Jones" cc: "Heikki Linnakangas" , pgsql-performance@postgresql.org Subject: Re: Joins and DELETE FROM In-reply-to: References: <47D2D485.9040103@enterprisedb.com> Comments: In-reply-to "Kynn Jones" message dated "Sat, 08 Mar 2008 14:02:03 -0500" Date: Sat, 08 Mar 2008 15:08:46 -0500 Message-ID: <6359.1205006926@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200803/185 X-Sequence-Number: 29139 "Kynn Jones" writes: > So it seems like turning off ENABLE_SEQSCAN is the way to go. Try reducing random_page_cost a bit instead. Also, have you got effective_cache_size set to something that's realistic for your machine? One problem with this test is that your smaller tables probably fit in memory whereas the big ones may not, so it's not a given that your test accurately reflects how the real query will go down. regards, tom lane