Yeah, actually, I mean the cost based optimization.
I think in general they were based on System-R model in calculating
the execuation cost.
that is: Total cost = i/o cost + cpu cost

but Is there anything different when to implement this formula?
I read this article below
Cost Control: Inside the Oracle Optimizer
and I am looking for similar articles about other dbms...
=========
Anyway, 3x for your reply~


Carl Kayser wrote:
> "Steven" <songxin328@gmail.com> wrote in message
> news:1176977151.318652.95400@b75g2000hsg.googlegro ups.com...
> > Anybody knows this?
> > Thanks a lot.....
> > orz~
> >
>
> 43
>
>
> In all seriousness your question is near the level of "What is the meaning
> of life?" What do you mean by cost? License cost? Site license cost (for
> how many servers with how many CPUs, etc)? Over what time span? Or perhaps
> you are asking about cost based optimizers?