MAX DEGREE FOR DPSI (PARAMDEG_DPSI subsystem parameter)
The PARAMDEG_DPSI subsystem parameter specifies the maximum degree of parallelism that you can specify for a parallel group in which a data partitioned secondary index (DPSI) is used to drive parallelism.
A DPSI is a nonpartitioning index that is physically partitioned according to the partitioning scheme of the table. When you specify a value of greater than 0 for this parameter, you limit the degree of parallelism for DPSIs so that Db2 does not create too many parallel tasks that use virtual storage.
| Acceptable values: | 0-254, DISABLE |
|---|---|
| Default: | 0 |
| Update: | option 30 on panel DSNTIPB |
| DSNZPxxx: | DSN6SPRM PARAMDEG_DPSI |
| Data sharing scope: | All members use the same setting |
- 0
- Specifies that Db2 uses the value that is specified for the PARAMDEG subsystem parameter, instead of PARAMDEG_DPSI, to control the degree of parallelism when DPSI is used to drive parallelism. This is the default value for the field.
- 1
- Specifies that Db2 creates multiple child tasks but works on one task at a time when DPSI is used to drive parallelism.
- 2-254
- Specifies that Db2 creates multiple child tasks and works concurrently on the tasks that are specified. The number of specified tasks may be larger or smaller than the number of tasks as specified in PARAMDEG. When PARAMDEG is set to 1, the rest of the query does not have any parallelism.
- DISABLE
- Specifies that Db2 does not use DPSI to drive parallelism. Parallelism might still occur for the query if PARAMDEG is greater than 1.