Step 6 should be fun - It is possible to come up with code where plan A is better than plan B in low concurrency systems, but plan B is better than plan A in high concurrency systems.
Similarly, plan X is better than plan Y if no updates are taking place concurrently, and plan Y is better than plan X is you have to compete with updates and the consequent read-consistent costs. There's also the issue of row-level-security (rls / vpd / fgac) which may increase the scale of the investigation quite significantly. It may also have been the problem point that Jeff came up with - outlines store only one plan, but the same (or apparently identical) piece of SQL could have conflicting plans because of a hidden rls predicate. Regards Jonathan Lewis http://www.jlcomp.demon.co.uk Coming soon a new one-day tutorial: Cost Based Optimisation (see http://www.jlcomp.demon.co.uk/tutorial.html ) Next Seminar dates: (see http://www.jlcomp.demon.co.uk/seminar.html ) ____England______January 21/23 The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html -----Original Message----- To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> Date: 23 December 2002 16:31 >We assessed this and discarded the option, and now I can't remember why >(I'll get back to you after I ask Jeff Holt, who did the study). At >best, using stored outlines is a replacement only for steps 2 and 4. The >really hard part is step 1. > > >Cary Millsap >Hotsos Enterprises, Ltd. >http://www.hotsos.com > >Upcoming events: >- Hotsos Clinic 101, Jan 7-9 Knoxville >- Steve Adams's Miracle Master Class, Jan 13-15 Copenhagen >- 2003 Hotsos Symposium, Feb 9-12 Dallas > > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Jonathan Lewis INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
