Re: Optimizer Question

I think it's going to depend on where you are setting the optimization rule. By default, the rule is set to CHOOSE, meaning it will use Cost Based if you have done any statistics computations; otherwise it will use Rule Based. I believe the only way to change it at the statement level is with hints - I don't think Oracle will change the optimization method on it's own.

In article <758s58$q7h$1_at_nnrp1.dejanews.com>,   imrad_at_icubed.com wrote:
> I'm using a Oracle 8.0.4. Database on a Unix system and using the Cost Based
> Optimizer. When I submit a select statement does Oracle use only the Cost
> Based Optimizer OR does it use a combination of the Cost Based and Rule Bases
> Optimizers without any hints?
>
> I was told that Oracle uses both Cost Based and Rule Based Optimizers on the
> select statement at the same time with the database running in Cost Based
> mode.
>
> I'm trying to confirm if the above statement is true or just B.S.
>
> Thanks
>
> Russ
> imrad_at_icubed.com
>
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-----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own Received on Wed Dec 16 1998 - 12:59:02 CST