PARALLEL_BROADCAST_ENABLED

Parameter type	Boolean
Default value	false
Parameter class	Dynamic: ALTER SESSION
Range of values	true | false

Note: This parameter refers to parallel execution, not to Oracle9i Real Application Clusters.

PARALLEL_BROADCAST_ENABLED lets you improve performance of hash and merge join operations in which a very large join result set is joined with a very small result set (size being measured in bytes, rather than number of rows).

When this parameter is set to true, the optimizer can choose to copy all the source rows of the small result set and broadcast a copy to each cluster database that is processing some rows of the larger set.