From oracle-l-bounce@freelists.org Fri Apr 22 17:51:10 2005 Return-Path: Received: from air891.startdedicated.com (root@localhost) by orafaq.com (8.12.10/8.12.10) with ESMTP id j3MMpAxO014827 for ; Fri, 22 Apr 2005 17:51:10 -0500 X-ClientAddr: 206.53.239.180 Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by air891.startdedicated.com (8.12.10/8.12.10) with ESMTP id j3MMpA4Z014823 for ; Fri, 22 Apr 2005 17:51:10 -0500 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 9B92218633C; Fri, 22 Apr 2005 16:48:48 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 30998-03; Fri, 22 Apr 2005 16:48:48 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 1D9FE18634E; Fri, 22 Apr 2005 16:48:48 -0500 (EST) Message-ID: <426970D3.1030206@centrexcc.com> Date: Fri, 22 Apr 2005 15:46:59 -0600 From: Wolfgang Breitling Organization: Centrex Consulting Corporation User-Agent: Mozilla Thunderbird 0.7.2 (Windows/20040707) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Robyn Cc: oracle-l@freelists.org Subject: Re: optimizer_ ??? References: <42695CD9.6020801@centrexcc.com> In-Reply-To: Content-type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit X-UCIT-MailScanner-Information: Please contact IT Help Desk at (403) 220-5555 for more information X-UCIT-MailScanner: Found to be clean X-UCIT-MailScanner-From: breitliw@centrexcc.com X-archive-position: 18889 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-To: oracle-l-bounce@freelists.org X-original-sender: breitliw@centrexcc.com Precedence: normal Reply-To: breitliw@centrexcc.com X-list: oracle-l X-Virus-Scanned: by amavisd-new-20030616-p9 (Debian) at avenirtech.net X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on air891.startdedicated.com X-Spam-Status: No, hits=0.0 required=5.0 tests=AWL autolearn=ham version=2.63 Robyn, I would say that the use of the system statistics this way is valid. Those are the real numbers Oracle is seeing while you collect the system statistics. You want to make sure the numbers are consistent before drawing conclusions (what you did) and not a one-time aberration because of special circumstances. But you want to do that anyways and not let the optimizer make decisions based on an erratic spike. What EMC system did you have and what did you swap it for? If you don't mind me asking. You can e-mail me privately if you don't want to blast that information to the world. Robyn wrote: > Wolfgang, > > I don't know if this is an 'acceptable' use of system stats, but I had > gathered them on several different systems and noted that singleblock > and multiblock read times were consistently and noticeably slower on our > EMC systems. I'd been arguing that our performance issues were related > to the durations of the reads, so I turned the numbers over to my boss > and the systems guys. When I got back to work, I realized I hadn't > gathered new system stats after the recent storage upgrade and I > recollected the numbers. The post SAN swap numbers did get much better > which I think proved the original point: > -- Regards Wolfgang Breitling Centrex Consulting Corporation www.centrexcc.com -- http://www.freelists.org/webpage/oracle-l