Return-Path: Received: from ensim.rackshack.net (root@localhost) by orafaq.net (8.11.6/8.11.6) with ESMTP id h0DL0q225080 for ; Mon, 13 Jan 2003 15:00:52 -0600 X-ClientAddr: 209.68.248.164 Received: from newsfeed.cts.com (newsfeed.cts.com [209.68.248.164]) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id h0DL0pc25075 for ; Mon, 13 Jan 2003 15:00:51 -0600 Received: from fatcity.UUCP (uucp@localhost) by newsfeed.cts.com (8.9.3/8.9.3) with UUCP id JAA40064; Mon, 13 Jan 2003 09:42:19 -0800 (PST) Received: by fatcity.com (26-Feb-2001/v1.0g-b72/bab) via UUCP id 0052DDAC; Mon, 13 Jan 2003 09:25:27 -0800 Message-ID: Date: Mon, 13 Jan 2003 09:25:27 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: Rajesh.Rao@jpmchase.com Sender: root@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: Rajesh.Rao@jpmchase.com Subject: Re: BCHR Tuning Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0g, build 72; ListGuru (c) 1996-2001 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit I too think the BCHR has its place, as a problem indicator. It can tell me theres something wrong with my database. Say, I have this database performing well, the users are happy, the BHR is mostly at 90%, and now it suddenly shoots down to 70%, or it suddenly increases to 98. Somethings amiss. Its less tasking, to code for scripts that query v$sysstat to indicate me of some problems, rather than querying v$sqlarea. Or I need to code for some intelligent scripts to query v$session_wait or V$system_event. Or I need to look at the statspack reports every hour. The point is when do I look at wait events? When the user calls me up? All the papers out there, asking us rightly, to look at wait events, trash the BCHR. I think what the authors intended was to tell us that increasing DB_BLOCK_BUFFERS was not the solution to a low BCHR, and that a BCHR of 99% does not mean a highly efficient database. Vice Versa, a BCHR of 50% does not indicate a poorly performing database. Give me a database with a 45% BHR, and I can get it to 99% by running a few queries. Point well understood. It does not mean in any way that I should now ignore PIO's and start tuning LIO's. I still use BCHR. "What you infer from the BCHR is what counts". Raj "Yechiel Adar" To: Multiple recipients of list ORACLE-L Subject: Re: BCHR Tuning Sent by: root@fatcity. com January 13, 2003 10:58 AM Please respond to ORACLE-L Hello Anjo I just had a tuning session with Dov Hit, from ACS in Israel. He used some of the scripts that you showed him 2 years ago when you did some work for Amdocs. Anyway, after doing some search on the waits, he checked the BCHR and found out that this database has only 40%. That led us on further checks and we found more offending SQL's. The BCHR has it's place. Just do not measure yourself JUST by it. Yechiel Adar Mehish ----- Original Message ----- To: Multiple recipients of list ORACLE-L Sent: Monday, January 13, 2003 3:03 AM > Hmm, > > Lately? That actually started publicly in 1998 as far as I am concerned ;-) > And acutally long before that. > > Anjo. > > ----- Original Message ----- > To: "Multiple recipients of list ORACLE-L" > Sent: Sunday, January 12, 2003 11:43 PM > > > > On Friday 10 January 2003 14:48, Mogens Nørgaard wrote: > > > Obviously, we don't know what we're talking about. I can see there's a > > > presentation by Rich Niemich at IOUG-A where he'll address all those > > > idiots who are saying you should ignore the Cash Hit Ratio (and who are > > > all just after making big money on their products - I loved that one). > > > > Or modify the set up of these tools to take action when BCHR > falls...... > > > > > > > > Here's the session info: > > > > Date: Mon, Apr 28, 2003 @ 11:45 AM - 12:15 PM > > Venue: Southern Hemisphere 2, Walt Disney World > > Dolphin, Lake Buena Vista, FL > > > > Abstract: Lately, there has been a big push to ignore your > > hit ratio with claims that it is meaningless. This shallow > > minded view (usually by people who sell a tuning tool) ignores > > why people look at hit ratios and what they are looking for. > > This quick tip talk will show you what to look for and why. > > You will definitely know when, where & why to look at your > > hit ratio in the future. > > > > Show you why your hit ratio matters. How to analyze the > > hit ratio. Fallacies by those who want to sell you products > > and tools instead. > > > > > > Shallow Minded ?! > > > > Jared > > -- -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: Rajesh.Rao@jpmchase.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).