X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id B1ADBD7DBD; Mon, 29 Aug 2005 17:19:06 -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 83627-08; Mon, 29 Aug 2005 20:19:05 +0000 (GMT) Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by svr1.postgresql.org (Postfix) with ESMTP id C5E0BD7CC1; Mon, 29 Aug 2005 17:19:03 -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 j7TKJ5Nv012791; Mon, 29 Aug 2005 16:19:05 -0400 (EDT) To: "Marc G. Fournier" Cc: pgsql-performance@postgresql.org Subject: Re: getting an index to work with partial indices ... In-reply-to: <20050829165335.X1044@ganymede.hub.org> References: <20050829165335.X1044@ganymede.hub.org> Comments: In-reply-to "Marc G. Fournier" message dated "Mon, 29 Aug 2005 16:56:15 -0300" Date: Mon, 29 Aug 2005 16:19:05 -0400 Message-ID: <12790.1125346745@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.006 required=5 tests=[AWL=0.006] X-Spam-Level: X-Archive-Number: 200508/500 X-Sequence-Number: 14247 "Marc G. Fournier" writes: > But, ti will if I try 'priority = -2' ... what is teh threshhold for using > the index? obviously 10% of the records is too high ... Depends on a lot of factors, but usually somewhere between 1% and 10%. (The new bitmap index scan code in 8.1 should be workable for higher percentages.) If this doesn't seem to square with reality for you, you might try reducing random_page_cost. regards, tom lane