Re: CBO irregularity

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Mon, 7 Jun 2004 22:03:28 +0100
Message-ID: <01a601c44cd2$e35506e0$7102a8c0@Primary>

Note in-line

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk

http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/seminar.html Optimising Oracle Seminar - schedule updated May 1st

:----- Original Message -----
:From: "Daniel Fink" <Daniel.Fink_at_Sun.COM>
:To: <oracle-l_at_freelists.org>
:Sent: Monday, June 07, 2004 9:23 PM
:Subject: Re: CBO irregularity
:

:Continuing on, examine the relevant parameters for the system and, most
importantly, the session. Is optimizer_mode set the same?
:db_file_multiblock_read_count impacts full table scans and full index
scans. For a definitive list of parameters that influence the
:CBO, read Wolfgang's paper at www.centrexcc.com titled "What's New in the
Cost-Based Optimizer in 9i" (or variation thereof, my
:memory is not as good as it used to be). BTW, according to 10053 trace, the
number of CBO parameters increases to over 150 in 10g!
:
:
:For a more detailed explanation of the CBO and it's care and feeding, check
Wolfgang's paper library and Jonathan Lewis's site
:(http://www.jlcomp.demon.co.uk). Both gentleman are amongst the elite of
Oracle scientists, especially in the area of the CBO.
:

I think Tim Gorman's paper on www.evdbt.com is important as well (The search for Intelligent Life in the CBO)
as well as one I sent to www.dbazine.com called "Oh! I see a problem."

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Received on Mon Jun 07 2004 - 16:00:38 CDT