Received: from maia.hub.org (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id C396F633E3C for ; Thu, 25 Mar 2010 14:16:26 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 43460-02 for ; Thu, 25 Mar 2010 17:16:13 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mail-ww0-f46.google.com (mail-ww0-f46.google.com [74.125.82.46]) by mail.postgresql.org (Postfix) with ESMTP id 264DF63219F for ; Thu, 25 Mar 2010 14:16:14 -0300 (ADT) Received: by wwe15 with SMTP id 15so6039291wwe.19 for ; Thu, 25 Mar 2010 10:16:13 -0700 (PDT) MIME-Version: 1.0 Received: by 10.216.88.212 with SMTP id a62mr1566782wef.72.1269537373599; Thu, 25 Mar 2010 10:16:13 -0700 (PDT) In-Reply-To: <645d9d71003250801o246439a0j93c7b568786e98de@mail.gmail.com> References: <645d9d71003250801o246439a0j93c7b568786e98de@mail.gmail.com> From: Jaime Casanova Date: Thu, 25 Mar 2010 13:15:58 -0400 Message-ID: <3073cc9b1003251015x590e962ata59dadbb58b42ce5@mail.gmail.com> Subject: Re: Why Wal_buffer is 64KB To: Tadipathri Raghu Cc: pgsql-performance@postgresql.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-0.278 tagged_above=-10 required=5 tests=AWL=-0.279, BAYES_50=0.001 X-Spam-Level: X-Archive-Number: 201003/320 X-Sequence-Number: 38145 On Thu, Mar 25, 2010 at 11:01 AM, Tadipathri Raghu w= rote: > Hi All, > > Can anybody clarify on this, why wal_buffer is 64kb and what is advantage= s > and disadvantages in increasing or decreasing the wal_buffer. > is 64kb just because by default we have low values in almost everything :) and the advantages is that if your average transaction is more than 64kb large all wal data will be in memory until commit, actually i thing it should be large enough to accomodate more than one transaction but i'm not sure about that one... i usually use 1Mb for OLTP systems --=20 Atentamente, Jaime Casanova Soporte y capacitaci=C3=B3n de PostgreSQL Asesor=C3=ADa y desarrollo de sistemas Guayaquil - Ecuador Cel. +59387171157