At 11:36 AM 5/22/02 +0200, Mirza Hadzic wrote:

>Helo,
>
>Is it really possible for any optimizer to make (at least almost) perfect
>plan for every query?
>

Because the Interbase/Firebird optimizer never has go chose between
two alternative indexes, it has a much easier problem to solve than
other database optimizers. The only tricky thing is join order
optimization, made more complicated by the unreasonable requirement
to complete in a feasible amount of time.

The problem with the optimizer isn't that it's dumb. It's broken.
It should be fixed. When it's fixed, it should do a better job
than you can because it knows more about the internal costs of
executing a query.

It hasn't been fixed because there's a workaround -- plans. And,
most likely, as long as plans exist and are extended, it won't
get fixed.

Jim Starkey