Aggregation and Calculation Time for Data
The collection (aggregation) of data and the calculation of data occurs at different times.
With calculated key figures (reusable objects that you can use in multiple queries) and formulas, you can define exception aggregations and determine when the calculation is to be performed. When you execute a query with a calculated key figure and a formula structural component, then the OLAP processor collects the data according to the query definition.
- Key figures are only collected and aggregated for the relevant characteristics, while all others are ignored.
- The calculation of the key figure occurs according to the defined aggregation form before or after the aggregation by means of the OLAP processor.
- The calculation of the local formula occurs after the aggregation but before a configured exception aggregation.
For performance reasons, the evaluation of the calculated key figures occurs partially before and partially after the aggregation of individual data records. In doing so, sums and differences are calculated before the aggregation and all other operators are calculated after the aggregation.
You can make settings in the properties for the calculated key figure so that, for example, a multiplication occurs as an exception before the aggregation. This leads to considerable deterioration of performance, because all affected fact records are read in the OLAP processor and can be aggregated after the calculation.
Note that the calculation of a calculated key figure with exception aggregation or with the setting Calculation Before Aggregation can significantly impede performance in some cases. This is because aggregates cannot be used. For technical reasons, no formula variables are permitted either in calculated key figures that are calculated before the aggregation.
Also note that in a MultiProvider the data records from any InfoProvider can be processed separately. For example, if the formula for the calculated key figure includes key figures that are only available in some of the InfoProviders concerned, then they have the value 0 in the fact records for the other InfoProvider. Analogous to this, non-cumulative InfoCube formulas, which also include non-cumulative and cumulative values, cannot be calculated before the aggregation. Instead of doing this, you need to use the setting Calculation After Aggregation. Alternatively you can simulate the exception aggregation.
We only recommend using the settingCalculation Before Aggregation only for test cases.
You can also carry out a calculation before the aggregation by defining a separate key figure and defining the calculation in the update rules. The calculated key figure then exists as a basic key figure in the InfoCube (and the aggregates).
For a key figure with theCalculation Before Aggregation setting, after an InfoCube has been compressed, additional data can be output since during the compression a request is used for aggregation.
You can make the settings for the aggregation of, and calculation time for, calculated key figures and formulas in the properties dialog for the formula and calculated key figure. You can define whether an exception aggregation is to take place or whether the calculation is to be performed after the aggregation. More information:Selection/Formula/Cell Properties.
You can set the exception aggregation for a simple key figure in the InfoObject maintenance for the key figure.
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