H.2.1.2.2 ENABLE

When the PARALLEL_DML option in the FSI_PARALLEL_PARAMETERS table is set to ENABLE, the engine will begin each rule by issuing the following statement:

ALTER SESSION ENABLE PARALLEL DML;

When the Parallel DML is enabled, the database may elect to execute a DML statement in parallel if it is run against an object (table or index) that has been declared (or altered) using the PARALLEL clause.

The database may also elect to execute a DML statement in parallel if a parallel SQL hint is included in the DML statement. A parallel SQL hint will override the Degree of Parallelism assigned to a table or index through the PARALLEL clause. If the tables and indexes against which a SELECT statement is executed have not been defined using the PARALLEL clause and if the SELECT statement does not include a parallel hint, then the SQL statement will always run serially (in a single thread).