X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 29BBC9FA3CD for ; Mon, 1 May 2006 20:35:14 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 93254-09 for ; Mon, 1 May 2006 20:35:04 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 1B0339FA2BE for ; Mon, 1 May 2006 20:35:03 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.6/8.13.6) with ESMTP id k41NZ255020935; Mon, 1 May 2006 19:35:02 -0400 (EDT) To: Nolan Cafferky cc: pgsql-performance@postgresql.org Subject: Re: Cluster vs. non-cluster query planning In-reply-to: <445678B1.9050908@rbsinteractive.com> References: <445644F9.2020708@rbsinteractive.com> <44566612.8020709@rbsinteractive.com> <8044.1146515444@sss.pgh.pa.us> <445678B1.9050908@rbsinteractive.com> Comments: In-reply-to Nolan Cafferky message dated "Mon, 01 May 2006 14:08:01 -0700" Date: Mon, 01 May 2006 19:35:02 -0400 Message-ID: <20934.1146526502@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/23 X-Sequence-Number: 18810 Nolan Cafferky writes: > But, I'm guessing that random_page_cost = 1 is not a realistic value. Well, that depends. If all your data can be expected to fit in memory then it is a realistic value. (If not, you should be real careful not to make performance decisions on the basis of test cases that *do* fit in RAM...) In any case, if I recall your numbers correctly you shouldn't need to drop it nearly that far to get the thing to make the right choice. A lot of people run with random_page_cost set to 2 or so. regards, tom lane