Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 805759F993A for ; Mon, 10 Sep 2007 18:24:57 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 71120-04 for ; Mon, 10 Sep 2007 18:24:54 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by postgresql.org (Postfix) with ESMTP id 9CC689F98F6 for ; Mon, 10 Sep 2007 18:24:53 -0300 (ADT) X-EthosMedia-Virus-Scanned: no infections found Received: from [64.81.245.111] (account josh@agliodbs.com HELO [192.168.1.27]) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP-TLS id 13178519; Mon, 10 Sep 2007 14:29:13 -0700 From: Josh Berkus Reply-To: josh@agliodbs.com Organization: Aglio Database Solutions To: pgsql-performance@postgresql.org Subject: Re: random_page_costs - are defaults of 4.0 realistic for SCSI RAID 1 Date: Mon, 10 Sep 2007 14:26:40 -0700 User-Agent: KMail/1.8 Cc: "Luke Lonergan" References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200709101426.41424.josh@agliodbs.com> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200709/161 X-Sequence-Number: 26706 Luke, > We (GP) have implemented > something we call "Adaptive Nested Loop" to replace a nested loop + > index scan with a hash join when the selectivity estimates are off in > order to improve this behavior. We also run with a > "random_page_cost=100" because we generally run on machines with fast > sequential I/O. So, when is this getting contributed? ;-) -- --Josh Josh Berkus PostgreSQL @ Sun San Francisco