CURRENT DEGREE field (CDSSRDEF subsystem parameter)
The CDSSRDEF subsystem parameter determines the default value that is to be used for the CURRENT DEGREE special register. The default value is used when a degree is not explicitly set in the SQL statement SET CURRENT DEGREE.
| Acceptable values: | 1, ANY |
|---|---|
| Default: | 1 |
| Update: | option 30 on panel DSNTIPB |
| DSNZPxxx: | DSN6SPRM CDSSRDEF |
- 1
- Specifies that when a query is dynamically prepared, the execution
of that query will not use parallelism.
If this value is specified, Db2 does not use any optimization hints for parallelism.
- ANY
- Specifies that when a query is dynamically prepared, the execution of that query can involve parallelism.
Recommendation: In almost
all situations, accept the default value of 1. You should use parallelism
selectively where it provides value, rather than globally. Although
parallelism can provide a substantial reduction in elapsed time for
some queries with only a modest overhead in processing time, parallelism
does not always provide the intended benefit. For some queries and
in many other situations, query parallelism does not provide an improvement,
or it uses too many resources. If you are using nearly all of your
CPU, I/O, or storage resources, parallelism is more likely to cause
degradation of performance. Use parallelism only where it is most
likely to provide benefits.