Before Strategy 10.7, when performing In-Memory calculations for simple and aggregation functions, Strategy will ignore null values while still treating nulls as 0 for scalar operations.
Since Strategy 10.7, New value for Null checking for Analytical Engine VLDB is introduced: “Scalar operations treat nulls as zero; aggregation calculations ignore nulls” as shown below:
The new calculation behavior is applied by default to new projects created after upgrading the metadata.
For users with environments and metadata updated to Strategy 10.7, the Analytical Engine will ignore null values for aggregation functions in new projects by default. Any existing projects will retain the null checking behavior that was applied before the upgrade. Default null check behavior is applied to function types as follows:
Aggregation: Ignore nulls
Use scenario:
When counting of averaging values, treating nulls as zeros gives unexpected results as shown below:
With the new VLDB value, nulls are ignored in aggregation calculations as shown below:
The old default Analytical Engine “Null checking for Analytical Engine” VLDB property for versions 10.6 and below is still available in version 10.7, but is option two - "Scalar and aggregation calculations treat nulls as zero (Deprecated)". Users can revert back to this option if they which to regress the metric calculation to the old results.
NOTE:
The internal reference number for this is KB440562 and KB440562
