You can use either Administration Services Aggregation Design Wizard or MaxL statements to perform an aggregation. The aggregation process has two phases:
During the aggregate view selection phase, Essbase analyzes how calculating and storing various combinations of aggregate views might affect average query response time. As input to the analysis, you can define physical storage and performance requirements. You can also track data usage and provide the information to the analysis process. See Selecting Views Based on Usage.
Based on their usefulness and resource requirements, Essbase creates a list of aggregate views. Included with each view in the list is storage and performance information that applies when that aggregate view plus all other aggregate views listed above it are stored. You can choose to aggregate the listed views, select and aggregate a subset of the listed views, or rerun the selection process with different input criteria. You can also add to an aggregation the materialization of new views that are based on new selection criteria. See Fine-Tuning Aggregate View Selection.
Whether or not you materialize the selection, you can save the selection of aggregate views as an aggregation script. Aggregation scripts provide flexibility and can save time because they enable you to bypass the selection process if the same selection is needed again. See Working with Aggregation Scripts.
After the selection process is finished, the selected aggregate views are calculated when you materialize the selected aggregate views into an aggregation.
The following process is recommended for defining and materializing aggregations:
Perform the default aggregation.
Optional: Specify a storage stopping point.
Materialize the suggested aggregate views and save the default selection in an aggregation script.
Run the types of queries for which the aggregation is designed.
If query time or aggregation time is too long, consider fine-tuning the aggregation. See Fine-Tuning Aggregate View Selection.
Optional: Save the aggregation selection as an aggregation script. See Working with Aggregation Scripts.
To perform a database aggregation selection or materialization, use a tool:
Aggregation Design Wizard enables running aggregation processes in the background. When you run an Administration Services process in the background, you can continue to use Administration Services Console for other activities simultaneously as the background process is running. |
Also see Optimizing Aggregation Performance.