14.1.1.1.9 FORCE with PARALLEL_DOP

When the PARALLEL_DML option in the FSI_OPTIMIZATION_SETTINGS table is set to FORCE and the PARALLEL_DOP parameter is set to a non-NULL integer value (4 in this example), the engine will begin each rule by issuing the following statement:

ALTER SESSION FORCE PARALLEL DML PARALLEL 4;

The subsequent behavior of Parallel DML is the same as where no specific Degree of Parallelism has been specified except that the database will employ the Degree of Parallelism you have set in your PARALLEL_DOP parameter instead of using the database's default Degree of Parallelism. Your PARALLEL_DOP parameter will override any Degree of Parallelism stemming from a PARALLEL clause associated with a table or index, but a Degree of Parallelism specified in a parallel hint will override your PARALLEL_DOP parameter setting.

Regardless of its value, the PARALLEL_DOP parameter is ignored when the PARALLEL_QUERY parameter is set to either DISABLE or ENABLE.