I have a question about the priority between reflections ! how the optimizer do choose when there multiple reflections that can respond !
I have a PDS with a reflection on it
I created a VDS (based on the previous PDS), and I added some calculated columns on it, then I created a reflections on this VDS (with included the derived columns)
the good thing, is that the VDS reflection is accelerated by the PDS reflections
and when I do a select from the VDS, the query is accelerated by the VDS reflection
But, when I do a select from the VDS join another PDS (no reflection defined on it)
the query is not accelerated by the VDS reflections any more but by the PDS reflection ?
And I can’t understand why is it so ?