In a specific case, the CA-IDMS SQL Optimizer is not using the CALC location mode when it logically has enough information to do so.
For example, assume a record or table with a concatenated CALC key consisting of fields C1 and C2.
A query with the following WHERE clause has enough information to retrieve the required records with three CALC accesses:-
WHERE C1=1 AND C2 IN (1, 2, 3)
However, such a query does not use the CALC location mode and instead resorts to an area sweep or any other indexes or indirect access methods that may exist for that record/table.