MDX query performance on ASO cube with dynamic members

Question

We have an ASO cube and we are using MDX queries to extract data from that cube. We are doing some performance testing on the MDX data extract.
Recently we made around 15-20 account dimension members dynamic in the ASO cube, and it is taking around 1 and a half hour for the query to run on an empty cube. Earlier the query was running in 1 minute on the empty cube when there were no dynamic members in the cube.
Am not clear why it takes so much time to extract data from MDX on an empty cube when there is nothing to extract. The performance has also degraded while extracting data on the cube with data in it.
Does dynamic members in the outline affect the MDX performance? Is there a way to exclude dynamic members from the MDX extract?
I appreciate any insights on this issue.

Answer 1

I guess it depends on what the formulas of those members in the dynamic hierarchy are doing.
As an extreme example, I can write a member formula to count every unique member combination in the cube and assign it to multiple members, regardless if I have any data in the database or not, that function is going to resolve itself when you query it and it is going to take a lot of time. You are probably somewhere in between there and a simple function that doesn't require any over head. So without seeing the MDX it is hard to say what about it might be causing an issue.
As far as excluding members there are various function in MDX to narrow down the set you are querying
Filter(), Contains(), Except(), Is(), Subset(), UDA(), etc.
Keep in mind you did not make members dynamic, you made a hierarchy dynamic, that is not the same thing and it does impact the way Essbase internally optimizes the database based on Stored vs dynamic hierarchies. So that alone can have an impact as well.