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Re: Migrating to cost based optimizer

From: DA Morgan <damorgan_at_psoug.org>
Date: Sat, 23 Sep 2006 09:21:59 -0700
Message-ID: <1159028517.546130@bubbleator.drizzle.com>


hasta_l3_at_hotmail.com wrote:
> Dear group,
>
> Our applications are supporting Oracle 8.1.7 and Oracle 9, for many
> customers with varying level of activity.
> We use the rule based optimizer to ensure the stability of the sql
> statement's execution plans.
>
> We are thinking of moving to the cost based optimizer, at least in
> Oracle 10.
>
> Would you have a strategy to recommand ?

Take Jonathan Lewis' three day Optimising Oracle workshop and buy his book on the CBO.

You can't use it well if you don't understand it.

> What is the first Oracle release with a cost based optimizer working
> reasonably well ?

8.1.7.4.

Well you did say "reasonably."

> How do you check the performances of your applications across oracle
> releases and customers with that optimizer ?

Write a decent SLA and see if you comply with it.

-- 
Daniel Morgan
University of Washington
Puget Sound Oracle Users Group
Received on Sat Sep 23 2006 - 11:21:59 CDT

Original text of this message

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