Re: Migrating to cost based optimizer

Thanks for all answers so far.
They are very appreciated.

Brian Peasland wrote :

> > How do you check the performances of your applications across oracle
> > releases and customers with that optimizer ?
>
> How do you check the performances of your applications with any
> optimizer or any version? The fact that you are using CBO does not
> change this, neither does the Oracle version. The application has to
> perform well enough to meet any defined SLA performance metrics and
> eliminate user pain.

Our current strategy - with the rule based optimizer - is to (1) check all statement's execution plan and test while developping, then (2) test on a test database which we hope is representative of demanding customers, then (3) test on a real customer site, which again we hope is representative, then (4) deliver to (hundreds of) customers.

We wonder whether the cost based optimizer may one day decide to use a suboptimal plan at a customer site thousand kilometers away, and how to make sure this won't happen...

BTW, we have exactly zero experience with CBO :-) Received on Sat Sep 23 2006 - 12:41:47 CDT