Define When Measures are Calculated
When you use a calculated measure, you can have the measure calculated before or after rollup. Values for measures calculated before rollup are based on source values instead of summed values, and are rolled up separately.
The following table shows the sequence of operations that take place when calculating measures.
| Timing | Operation sequence |
|---|---|
| After Rollup | 1 Regular rollup takes place on all measures. 2 Time state rollup takes place. 3 Allocated measures are calculated. 4 Calculations are performed on calculated measures. |
| Before Rollup | 1 Calculations are performed as the cube is created. 2 Regular rollup takes place on all measures. 3 Time state rollup takes place. 4 Allocated measures are calculated. |
Although values for measures calculated after rollup require less storage space, time-state rollup cannot be performed on After Rollup calculated measures.
Auto-partitioning is not used when a model contains Before Rollup measures, which can be detrimental to run-time performance. To allow auto-partitioning to proceed, we recommend that you use calculated columns instead of Before Rollup measures wherever possible.
Similarly, although there is no consolidation of Before Rollup measures, you can use calculated columns to perform consolidation instead. The measure data is then consolidated as each row is read into the work file.
Procedure
- Open the property sheet for the calculated measure and click the Rollup tab.
- In the Regular timing box, click Before Rollup or After Rollup and click OK.