> From: Nick Upson
> I was under the impression, for example, that the Query optimiser
> had been improved after v4.
>
> I'm trying to 'sell' moving to FB and the best thing I can say is
> something like "we could expect an average 50% improvement over v4 speed".

Optimizer does not perform the query;
it just says the engine how to do it.
(by picking proper indexes, join/sort/merge methods etc.)

"Query optimiser had been improved after v4" just means that there is a chance
that IB6 will choose different plan that IB4. The new plan can be either better, or the same, or worse (!)
than old plan.
It is something you can hardly express in "percents of improvement".


Ivan
http://www.volny.cz/iprenosil/interbase