X-Original-To: pgsql-docs@postgresql.org Received: from spampd.localdomain (postgresql.org [64.49.215.8]) by postgresql.org (Postfix) with ESMTP id 79CF047580B for ; Mon, 12 May 2003 13:26:31 -0400 (EDT) Received: from sss.pgh.pa.us (unknown [192.204.191.242]) by postgresql.org (Postfix) with ESMTP id B203F474E42 for ; Mon, 12 May 2003 13:26:30 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.12.9/8.12.9) with ESMTP id h4CHQTU6010151; Mon, 12 May 2003 13:26:29 -0400 (EDT) To: Nailah Ogeer Cc: pgsql-docs@postgresql.org Subject: Re: Multiple Buffer pools In-reply-to: References: Comments: In-reply-to Nailah Ogeer message dated "Mon, 12 May 2003 12:45:12 -0400" Date: Mon, 12 May 2003 13:26:28 -0400 Message-ID: <10150.1052760388@sss.pgh.pa.us> From: Tom Lane X-Spam-Status: No, hits=-32.3 required=5.0 tests=BAYES_00,EMAIL_ATTRIBUTION,IN_REP_TO,QUOTED_EMAIL_TEXT, REFERENCES,REPLY_WITH_QUOTES autolearn=ham version=2.50 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) X-Archive-Number: 200305/7 X-Sequence-Number: 1777 Nailah Ogeer writes: > I am currently undergoing the project of making postgres's single buffer > pool into multiple buffer pools hopefully to decrease the number of > physical reads. Just wondering if anyone has done some work on this > before. To be honest, I think this is a complete waste of effort, as the optimal buffering scheme for Postgres relies on OS-level caching more than PG-internal caching. But yes, it's been discussed before. See the archives for pgsql-performance and pgsql-hackers. > Also, I need some information on where the number of relations in > the system is defined. There is no very practical way to determine that. Any one backend can only see one database, not the entire cluster; and at the time shared memory is sized, you don't have any database access capability at all. regards, tom lane