Monday, March 26, 2007

Cure to Distinct Counts in SQL AS 2000

So I have had a chance to work with aggregation settings to optimize performance in SQL AS 2000 of distinct counts. So far tweaking the aggregations has gotten me the best performance. Dare I say I have the cure to the distinct count blues in SQL 2000? Well give it a try. You will notice significant cube processing times. Basically here is the rundown:

Aggregations:
1. Start at a lower aggregation level like 15% or even no aggregations level.
(Lower aggregation levels will also save the space needed for the cubes.)
2. Let users query the cubes (also known as Warm Caching). Once the queries are warm and toasty you get incredible query performance even though in step 1 above you created very low aggregations.
3. Use the usage-based optimization (UBO) wizard to build aggregates that support those queries.

Reference:
OLAP Distinct Counts and Performance Analysis

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