X-Original-To: pgsql-docs-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 3692F52A16 for ; Thu, 7 Jul 2005 12:05:55 -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 24649-10 for ; Thu, 7 Jul 2005 15:05:49 +0000 (GMT) Received: from mr2.surnet.cl (smtp2.surnet.cl [216.155.73.163]) by svr1.postgresql.org (Postfix) with ESMTP id 0B7BD528CE for ; Thu, 7 Jul 2005 12:05:46 -0300 (ADT) Received: from smtp2.surnet.cl (216.155.73.169) by mr2.surnet.cl (7.0.031.3) id 4259ADFA013B78BA; Thu, 7 Jul 2005 11:05:32 -0400 Received: from smtp2.surnet.cl (mr2.surnet.cl []) by mr2.surnet.cl ([216.155.73.169]); Thu, 07 Jul 2005 15:05:32 +0000 Received: from cluster.surnet.cl (216.155.73.164) by smtp2.surnet.cl (7.0.031.3) id 4259ADE300C07A9A; Thu, 7 Jul 2005 11:05:32 -0400 Received: from alvh.no-ip.org (200.85.217.230) by cluster.surnet.cl (7.0.043) (authenticated as alvherre@surnet.cl) id 42B3EF60002B34D0; Thu, 7 Jul 2005 11:05:43 -0400 Received: by alvh.no-ip.org (Postfix, from userid 1000) id 9EF9BC2D425; Thu, 7 Jul 2005 11:05:43 -0400 (CLT) Date: Thu, 7 Jul 2005 11:05:43 -0400 From: Alvaro Herrera To: Halley Pacheco de Oliveira Cc: pgsql-docs@postgresql.org Subject: Re: buffer freelist Message-ID: <20050707150543.GC7157@alvh.no-ip.org> References: <20050707102933.40007.qmail@web52710.mail.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20050707102933.40007.qmail@web52710.mail.yahoo.com> User-Agent: Mutt/1.5.9i X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=1.413 tagged_above=0 required=5 tests=AWL, DNS_FROM_RFC_ABUSE, FORGED_RCVD_HELO, RCVD_IN_NJABL_PROXY X-Spam-Level: * X-Archive-Number: 200507/7 X-Sequence-Number: 3133 On Thu, Jul 07, 2005 at 07:29:33AM -0300, Halley Pacheco de Oliveira wrote: > PostgreSQL 8.0.3 Documentation > Chapter 16. Server Run-time Environment > 16.4. Run-time Configuration > > debug_shared_buffers (integer) > > Number of seconds between buffer freelist reports. If set greater than > zero, emit freelist statistics to the log every so many seconds. Zero > (the default) disables reporting. > > What is a buffer freelist? I can't find a definition, and I can't > translate if I don't understand. > > Is it a list of free buffers as it seems to be? What is a free buffer? Yes, a list of free buffers. A free buffer is a buffer that's not used :-) This is mainly a debugging option -- I don't think it would have much use for regular users. Then again, you may want to know how well is your shared_buffers setting defined -- if too low, then freelists will be short. I doubt this can really be used to improve performance. Note that this option disappeared in current in-development code ... -- Alvaro Herrera () "La realidad se compone de muchos sueños, todos ellos diferentes, pero en cierto aspecto, parecidos..." (Yo, hablando de sueños eróticos)