Richard Huxton wrote:
> On Tuesday 13 January 2004 09:50, Bernd Helmle wrote:
>
>
>
> I don't think it's that it provides a better plan, just that it comes up with
> a quicker solution. Searching all possible paths is not practical for a large
> number of tables, so you need another approach.
>
Aggreed. That was my opinion, too. Sorry for my unclear statement.
> Google for "travelling salesman problem" for discussion of the sort of
> thinking behind it.
>
That was the first thing i've done. I understand the theoretical
background, but i need a practical scenario, to show:
QUERY A with GEQO
QUERY A without GEQO
And then compare the specific query plan generation efficency.
In this case I have to think about a practical database scenario, to
execute such queries. If i have enough tables i can join against, i
should see an improvement, in theory.
But what means "enough tables"?
So i wonder, if anyone had done such a comparison already.
Thanks for your reply,
Bernd