- the evaluation of flow node frequency reports returns null for all flow nodes that have never been executed
The heatmap in the front-end distinguishes between three states:
- a flow node has a number larger than 0
- a flow node value is 0
- a flow node has never been executed and is therefore null
This is because in a duration heatmap a flow node can have a duration of zero but still has been executed. For those flow nodes with zero duration we still show a heat so that users know that those have been executed with a small duration. Hence, we need those three states. If we now return also zero for flow node frequency reports, those flow nodes will also have a heat, which is actually not what we want.