WLM provides two interfaces to allow resource managers to signal contention situations that need special treatment:

• ENQHOLD: A unit of work waits for a resource which is in use by another unit of work
• ENQRLSE: The situation has been cleared

WLM/SRM promotes the holder (increases DP) for a specified duration to assist in resolving the contention situation. This period is specified through the ERV parameter in the IEAOPT member of SYS1.PARMLIB.

In z/OS 1.3, WLM introduced some significant enhancements to the interfaces for serviceability reasons and to extend promotion if the queue for the resource builds up.

Latch contentions only require a short boost rather than an elongated promotion technique. WLM has now provided promotion that does not require to signal the release.

This 'short time promotion' is an enhancement of the enqueue management function. The enhancement makes DB2 latch contention run smoother and reduces bookkeeping. The new support allows for the DB2 resource manager to resolve DB2 latch contention by consuming the complete short promotion time without issuing an ENQRLSE when the contention ends.