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 A5E3752896 for ; Sat, 2 Jul 2005 00:15:06 -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 76535-06 for ; Sat, 2 Jul 2005 03:15:01 +0000 (GMT) Received: from sccmmhc92.asp.att.net (sccmmhc92.asp.att.net [204.127.203.212]) by svr1.postgresql.org (Postfix) with ESMTP id E2C8352801 for ; Sat, 2 Jul 2005 00:14:58 -0300 (ADT) Received: from juju.arbash-meinel.com ([12.214.18.81]) by sccmmhc92.asp.att.net (sccmmhc92) with ESMTP id <20050702031454m92008hqove>; Sat, 2 Jul 2005 03:14:54 +0000 Received: by juju.arbash-meinel.com (Postfix, from userid 505) id CBD85560B3; Fri, 1 Jul 2005 22:14:53 -0500 (CDT) Received: from [192.168.1.11] (liliana.arbash-meinel.com [192.168.1.11]) by juju.arbash-meinel.com (Postfix) with ESMTP id 70BFA56070; Fri, 1 Jul 2005 22:14:50 -0500 (CDT) Message-ID: <42C606AA.8060406@arbash-meinel.com> Date: Fri, 01 Jul 2005 22:14:50 -0500 From: John A Meinel User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317) X-Accept-Language: en-us, en MIME-Version: 1.0 To: emil@baymountain.com, Postgresql Performance Subject: Re: Planner constants for RAM resident databases References: <200507012159.39041.emil@baymountain.com> <42C5FFB9.9050302@arbash-meinel.com> <200507012311.37942.emil@baymountain.com> In-Reply-To: <200507012311.37942.emil@baymountain.com> X-Enigmail-Version: 0.92.0.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig6532213C64F4D9578C5667D0" X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.048 tagged_above=0 required=5 tests=AWL, FORGED_RCVD_HELO X-Spam-Level: X-Archive-Number: 200507/11 X-Sequence-Number: 13252 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig6532213C64F4D9578C5667D0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Emil Briggs wrote: >>I just mentioned random_page_cost, but you should also tune >>effective_cache_size, since that is effectively most of your RAM. It >>depends what else is going on in the system, but setting it as high as >>say 12-14GB is probably reasonable if it is a dedicated machine. With >>random_page_cost 1.5-2, and higher effective_cache_size, you should be >>doing pretty well. >>John >>=:-> >> >> > >I tried playing around with these and they had no effect. It seems the only >thing that makes a difference is cpu_tuple_cost. > > > I'm surprised. I know cpu_tuple_cost can effect it as well, but usually the recommended way to get indexed scans is the above two parameters. When you do "explain analyze" of a query that you have difficulties with, how are the planner's estimates. Are the estimated number of rows about equal to the actual number of rows? If the planner is mis-estimating, there is a whole different set of tuning to do to help it estimate correctly. John =:-> PS> Use reply-all so that your comments go to the list. --------------enig6532213C64F4D9578C5667D0 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (Cygwin) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFCxgaqJdeBCYSNAAMRAv9IAJ9KadS2PKPBL2jSFouJJcaG86+A8QCdGKdz Ivx8YqiiBA+DUJ14kL+P3Ww= =a9/R -----END PGP SIGNATURE----- --------------enig6532213C64F4D9578C5667D0--