Sorry, again... I have been looking forward too early.
I am now up to a certain point...
Did the following:
Copying the original database for test purposes, upgraded it to 90% comp....
Basically I am now able to simulate productive mode.
I did what GilaMonster said:
After updating statistics and defragmentating indexes, I ran the same script again, and again whithout no significant success.
How is it possible that the same script has better perfomances running under SQL 2000 ????
The goal is to achieve a query time less than 30 seconds.
Within the productive database, the query time is about at 3-5 mins.
Refreshing views does not make much sense, because the certain script does not refer to one.
Any other idea ?