Re: Optimizer

On Mon, 15 May 2000 21:50:26 GMT, michael_bialik_at_my-deja.com wrote:

>
> There is a new feature called QUERY OUTLINE from 8.1.5 and up.
> I didn't try it yet, but it's supposed to solve the problem
> of execution plan stability in CBO environment.
>

ORACLE needs to explore the possibility of separately stored and named "execution plans" like DB2 does. That is the way to go. Flexible, and it satisfies EVERY possible situation or combination.

> Anyway RBO can not garantee you anything, because index selection
> is dependant on index creation time ( drop indexes and re-create them
> in different from original sequence and bingo - RBO may select another
> index ). Anothe question is what happens when you add/drop indexes?
>

But CBO with hints will do nearly the same as RBO and take advantage of all the extra latest parallel stuff if enabled. That is IMHO the way to go instead of using RBO. For those who don't like to spend their entire day doing analyze at the drop of a hat.

Cheers
Nuno Souto
nsouto_at_nsw.bigpond.net.au.nospam
http://www.users.bigpond.net.au/the_Den/index.html Received on Tue May 16 2000 - 00:00:00 CDT