Aggregation Design Wizard: functionality questions

Hi,
As an example, I use the Aggregation Design Wizard to specify MOLAP 20% for a partition - this is based on 20 products, 40 sub-products, 100 sub-sub-products. What if my product dimension table increases substantially in size so that I now have 200 products, 400 sub-products and 1000 sub-sub-products - do I need to rerun the aggregation wizard to maintain this "20% performance gain"? Or does MSAS know that I always want 20% performance gain, and design new aggregations when it sees new dimensions data? The main question is: do I have to keep running the aggregation wizard whenever new data arrives to be sure to maintain my desired level of performance increase?

The next question is what setting is recommended for performance gain: why wouldn't I want 100% performance gain? Is this just a matter of disk storage (which I have plenty of), or could too high a performance gain actually mean decreased performance? (then why call it 100% performance gain? :) )

Thanks for your help!
-cf

I can begin from the 2nd question. which solves your problem. Yes, performance costs disk space. So keep it %100 where it is possible.

If you use the Agg Des Wiz it saves the aggregation amounts. When you run the test it tells you how many aggregations it has designed. And these aggregations are saved and applied every time you process the cube or database.

|||"When you run the test it tells you how many aggregations it has designed" - correct, but what if the underlying data has changed? Won't the number of aggregations designed then vary based on data - so I need to run the Aggregation Design Wizard every time I have new data or it will just use the aggregations from the last time I ran the wizard?
Thanks for your help.
|||

Refer to the Books Online --> Index --> Aggregations --> overview.

Aggregation is precalculated structure. If is says "3 aggregations" This doesn't mean it calculated 3 data. It means it calculated 3 fields in a structure. So no matter if you add new data it will again be calculating that data too for the same aggregation as you process it.