Re: Overriding the optimizer

> > Yeah it would - an implementation I have seen that I like is where the
> > developer can supply the *entire* execution plan with a query. This is
> > complex enough to make casual use unlikely :-), but provides the ability
> > to try out other plans, and also fix that vital query that must run
> > today.....
>
> Being able to specify an exact plan would also provide for query plan
> stability; something that is critically important in certain
> applications. If you have to meet a specific response time requirement
> for a query, you can't afford to have the optimizer suddenly decide that
> some other plan might be faster when in fact it's much slower.

Plan stability doesn't mean time response stability...
The plan that today is almost instantaneous tomorrow can take hours...

--
regards,
Jaime Casanova
(DBA: DataBase Aniquilator ;)