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 2455452AA9 for ; Sun, 8 May 2005 13:49:32 -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 02524-04 for ; Sun, 8 May 2005 16:49:23 +0000 (GMT) Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by svr1.postgresql.org (Postfix) with ESMTP id C714C53A40 for ; Sun, 8 May 2005 13:49:22 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id j48GnJoK012304; Sun, 8 May 2005 12:49:19 -0400 (EDT) To: Jeroen van Iddekinge Cc: pgsql-performance@postgresql.org Subject: Re: sequence scan on PK In-reply-to: <427E5130.7020702@lycos.com> References: <427E2941.9070105@lycos.com> <427E17BC.7050407@arbash-meinel.com> <427E5130.7020702@lycos.com> Comments: In-reply-to Jeroen van Iddekinge message dated "Sun, 08 May 2005 17:49:36 -0000" Date: Sun, 08 May 2005 12:49:19 -0400 Message-ID: <12303.1115570959@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.006 tagged_above=0 required=5 tests=AWL X-Spam-Level: X-Archive-Number: 200505/81 X-Sequence-Number: 12245 Jeroen van Iddekinge writes: >> You could tweak with several settings to get it to do an index scan >> earlier, but these would probably break other queries. You don't need to >> tune for 100 rows, morelike 100k or 100M. > Which settings shoud I change for this? I'd agree with John's response: if you change any settings based on just this one test case, you're a fool. But usually random_page_cost is the best knob to twiddle if you wish to encourage indexscans. regards, tom lane