PARALLEL_ADAPTIVE_MULTI_USER

Parameter type	Boolean
Default value	Derived from the value of PARALLEL_AUTOMATIC_TUNING
Parameter class	Dynamic: ALTER SYSTEM
Range of values	true | false

PARALLEL_ADAPTIVE_MULTI_USER, when set to true, enables an adaptive algorithm designed to improve performance in multiuser environments that use parallel execution. The algorithm automatically reduces the requested degree of parallelism based on the system load at query startup time. The effective degree of parallelism is based on the default degree of parallelism, or the degree from the table or hints, divided by a reduction factor.

The algorithm assumes the following:

• The system has been tuned for optimal performance in a single-user environment

• The parameter PARALLEL_AUTOMATIC_TUNING parameter is set to TRUE

Tables and hints use the default degree of parallelism.

See Also: Oracle9i Database Performance Guide and Reference for more information on tuning parallel execution and on the algorithm described here