On Fri, Mar 10, 2006 at 08:11:44AM +0100, NbForYou wrote:
> As you can see the query isn't useful anymore because of the
> processtime. Please Also notice that both systems use a different
> query plan.
> Also on the webhost we have a loop of 162409 (403 rows * 403 rows).
> Both systems also use a different postgresql version. But I cannot
> believe that the performance difference between 1 version could be
> this big regarding self outer join queries!
What versions are both servers? I'd guess that the webhost is using
7.3 or earlier and you're using 7.4 or later. I created a table
like yours, populated it with test data, and ran your query on
several versions of PostgreSQL. I saw the same horrible plan on
7.3 and the same good plan on later versions. The 7.4 Release Notes
do mention improvements in query planning; apparently one of those
improvements is making the difference.
--
Michael Fuhr