Internally Generated Auxiliary Fields
By default, auxiliary fields are generated internally and are not visible in the project. They do not affect metric type configuration or configuration of the compute() function that calculates the values for metric instances.
As a simple example, suppose you define an aggregation field called AvgItemPrice, of type Average. The formula for this type of aggregation requires two auxiliary fields:
SumField/ CountField
TIBCO BusinessEvents internally creates and names a Sum and a Count type field. Each time an event triggers the rule that computes the value, using an event property such as ItemPrice, the Sum and Count type fields are updated based on the value mapped from the event into the AvgItemPrice field. Then an internal process uses those values to calculate the value for the AvgItemPrice metric field.