X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id F283EDA1F8 for ; Wed, 5 Oct 2005 10:23:45 -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 27932-06 for ; Wed, 5 Oct 2005 13:23:41 +0000 (GMT) Received: from mailhost.intellivid.com (mailhost.intellivid.com [64.32.200.11]) by svr1.postgresql.org (Postfix) with ESMTP id 0821BDA1F5 for ; Wed, 5 Oct 2005 10:23:40 -0300 (ADT) Received: from [192.168.2.68] (spectre.intellivid.com [192.168.2.68]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by newmail.intellivid.com (Postfix) with ESMTP id 325D0F18107 for ; Wed, 5 Oct 2005 09:23:45 -0400 (EDT) Subject: wal_buffers From: Ian Westmacott To: pgsql-performance@postgresql.org Content-Type: text/plain Organization: Intellivid Corp. Message-Id: <1128518624.15795.28.camel@spectre.intellivid.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Wed, 05 Oct 2005 09:23:45 -0400 Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0 required=5 tests=[none] X-Spam-Level: X-Archive-Number: 200510/98 X-Sequence-Number: 14866 Can anyone tell me what precisely a WAL buffer contains, so that I can compute an appropriate setting for wal_buffers (in 8.0.3)? I know the documentation suggests there is little evidence that supports increasing wal_buffers, but we are inserting a large amount of data that, I believe, easily exceeds the default 64K in a single transaction. We are also very sensitive to write latency. As background, we are doing a sustained insert of 2.2 billion rows in 1.3 million transactions per day. Thats about 1700 rows per transaction, at (roughly) 50 bytes per row.