Jonathan, I thought your article was very positive. "It's a great improvement on the Oracle 7/8 version," and "Overall - it's definitely a good thing." I'm just wondering why is Connor suggesting that these only be collected for a few hours? In 10 it sounds like we won't have that choice. "We run a job once per month to gather system stats for a couple of hours. It checks to make sure that sessions/processes are within 75% of their high water mark before commencing to (hopefully) ensure that the stats are representative. Cheers Connor" Thanks Larry Wolfson -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Jonathan Lewis Sent: Friday, April 23, 2004 3:23 AM To: oracle-l@xxxxxxxxxxxxx Subject: Re: CPU COSTING Re-reading my post, it's not obvious that I approve of CPU costing and think it should be enabled as part of the migration plan from 8 to 9; so I'll just say it clearly: "I approve of CPU costing and think it should be enabled as part of the migration plan from 8 to 9" The fact that it will cause some surprises and confusion occasionally is unfortunate. One guideline when you've got some system statistics gathered. If you've adjusted optimizer_index_cost_adj, set it back to default, otherwise you've effectively told Oracle twice that single block reads are cheaper than multiblock reads. (This was the point of the throwaway comment I made about Oracle 9 in my DBAZine article on OICA). Regards Jonathan Lewis http://www.jlcomp.demon.co.uk The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html April 2004 Iceland http://www.index.is/oracleday.php June 2004 UK - Optimising Oracle Seminar July 2004 USA West Coast, Optimising Oracle Seminar August 2004 Charlotte NC, Optimising Oracle Seminar September 2004 USA East Coast, Optimising Oracle Seminar September2004 UK - Optimising Oracle Seminar ----- Original Message ----- From: "Wolfson Larry - lwolfs" <lawrence.wolfson@xxxxxxxxxx> To: <oracle-l@xxxxxxxxxxxxx> Sent: Friday, April 23, 2004 12:38 AM Subject: RE: CPU COSTING Jonathan, thanks for heads up. Tanel, by freaked out, I assume you mean performing at warp speed. Thanks Larry Wolfson. ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ********************************************************************** The information contained in this communication is confidential, is intended only for the use of the recipient named above, and may be legally privileged. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please re-send this communication to the sender and delete the original message or any copy of it from your computer system. Thank You. ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------