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.


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