wlm_disp_concur - Workload manager dispatcher thread concurrency configuration parameter
This parameter specifies how the Db2® workload manager (WLM) dispatcher sets the thread concurrency level. You can also manually set the thread concurrency level to a fixed value.
- Configuration type
- Database manager
- Applies to
- Database server with local and remote clients
- Database server with local clients
- Partitioned database server with local and remote clients
- Parameter type
- Configurable Online
- Propagation class
- Default [range]
- COMPUTED [COMPUTED; manually_set_value]
When upgrading Db2 database manager, the value of the wlm_disp_concur database manager configuration parameter is COMPUTED.
- Db2 database manager computes a fixed thread concurrency level based upon the value of 4 times the number of logical CPUs available to the Db2 database manager.
- You can manually set the thread concurrency level to a fixed value (1 - 32767). The optimal value depends on the specific hardware used and the operating system level; generally, in the range of 2 to 4 times the number of logical CPUs on the host or LPAR.
- Unit of measure
- Number of concurrent threads
The setting of this database manager configuration parameter controls the number of threads that the WLM dispatcher allows to be dispatched to the operating system run queues in parallel. The value is set as a low multiple of the number of logical CPUs available to the Db2 database manager. In general, you can set the value to 4 times the number of available logical CPUs to take into account possible scheduling latencies that result when threads switch in and out of the active state. An optimal value is just large enough to ensure that there are an adequate numbers of threads for the Db2 database manager to fully use the CPUs on the host or LPAR and no larger. This optimal value ensures maximum efficiency and gives the Db2 WLM dispatcher maximum control over CPU allocation.