H.2.1.1.3 FORCE

When the PARALLEL_QUERY option in the FSI_PARALLEL_PARAMETERS table is set to FORCE and the PARALLEL_DEGREE parameter is set to NULL, the engine will begin each rule by issuing the following statement:

ALTER SESSION FORCE PARALLEL QUERY;

After this ALTER SESSION statement, subsequent SELECT statements are executed with a default Degree of Parallelism unless (a) the objects against which the SELECT statement operates is defined as having a specific Degree of Parallelism with the use of the PARALLEL clause or (b) the SELECT statement includes a parallel hint. Again, a parallel hint will override the Degree of Parallelism specified through a PARALLEL clause.

The default Degree of Parallelism is determined by the database and is generally a function of the number of CPUs on your server. For details on how the Oracle database determines the default Degree of Parallelism, see Oracle Database VLDB and Partitioning Guide.