>bad development. You had to put these primary keys into a temporary table and use this temporary table for filtering...

Yes, as I have a few situations like these, this was the next step to do. It is already under way since a while but I need to find the clean line here. It is of higher performance up to a certain number of keys. I also need to find how much de-optimization I would have to deal with with this new approach. As, we had a performance issue before, I just need to make sure it will not bring me to the same point.