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Oracle® Database Reference
11g Release 2 (11.2)

E40402-12
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PARALLEL_IO_CAP_ENABLED

Property Description
Parameter type Boolean
Default value false
Modifiable ALTER SESSION, ALTER SYSTEM
Range of values true | false
Basic No
Oracle RAC Multiple instances can have different values.

Note:

The PARALLEL_IO_CAP_ENABLED parameter is deprecated. It is retained for backward compatibility only. It is replaced by the PARALLEL_DEGREE_LIMIT parameter when set to IO.

PARALLEL_IO_CAP_ENABLED specifies whether or not Oracle caps the default degree of parallelism to no greater than what the I/O system can support. This new value is calculated based on the results of the resource manager's I/O calibration package.

If PARALLEL_IO_CAP_ENABLED is set to true and the database I/O capacity has been calibrated, then Oracle will reduce the default degree of parallelism if the I/O capacity cannot support the available number of CPUs. To calibrate the I/O capacity, use the DBMS_RESOURCE_MANAGER.CALIBRATE_IO procedure to measure the system's I/O capacity. Oracle then computes the degree of parallelism so as not to exceed the system's I/O capacity.

See Also:

Oracle Database Data Warehousing Guide for information on initializing and tuning parameters for parallel execution