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
