The columns should always be part of the primary index if this does not result in other performance disadvantages. The advantage when partition columns are in the primary index: Each primary index value can only be present in exactly one partition. Therefore the query is more performant as no partition probing is needed to locate the rows. Here is an example where it is a disadvantage to include the partition column in the primary index: CREATE TABLE Sales ( SalesId NOT NULL, SalesDate DATE NOT NULL, Price DECIMAL(18,2) NOT NULL ) PRIMARY INDEX (SalesId,SalesDate) PARTITION BY RANGE_N ( SalesDate BETWEEN DATE '2019-01-01' AND '2019-12-31' EACH INTERVAL '1' DAY ); The following kind of tactical query is mainly executed: SELECT * FROM Sales WHERE SalesId = ; In this case, the Table cannot be queried using the primary index. Therefore, SalesDate should not be in the primary index.