Diagnosis
V1 fields are selected as grouping keys (the data record number isalways a grouping key).
A database index can only contain 16 fields.

System Response
This function is terminated since generating the error stack may causeerrors.

Procedure
Reduce the number grouping keys you have selected to 15.
Deselect fields with a low cardinality since these have little use withregard to grouping.
You access this function in the maintenance of data transfer processeson the "Extraction" tab page behind the "semantic groups" pushbutton.