14.1.1.1.3 FORCE

When the PARALLEL_QUERY option in the FSI_OPTIMIZATION_SETTINGS table and the PARALLEL_DOP parameter are set to values mentioned in the FSI_OPTIMIZATION_SETTINGS table, 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 have been defined as having a specific Degree of Parallelism through 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 CPU's on your server. For details on how the Oracle database determines the default Degree of Parallelism, see Oracle Database VLDB and Partitioning Guide.