Re: CBO calculates lower cost, but runs slower...

Jonathan Lewis doodled thusly:

>
>(and I think that covers all the bases - and perhaps

yup, pretty much! :-)
Sorry if I sounded pedantic, but:

>
>then the path with the lowest cost if the one
>which the cost-based optimizer thinks will be the
>fastest way to satisfy the query according to the
>specific requirements of the optimizer goal.

that's what I thought. I like to be absolutely specific on this: I've had this same discussion with other people in Australia and there is a lot of confusion out there in the ORACLE community.

It's a relative estimate of the weight of execution, as you pointed out.

I've had quite a few tell me that "plans with higher costs cannot possibly execute faster". No qualification of the statement whatsoever. Oh well...

Thanks, Jonathan. As usual, a great help.

Cheers
Nuno Souto
nsouto_at_optushome.com.au.nospam Received on Tue Nov 20 2001 - 05:31:26 CST