Utility throttling

Utility throttling regulates the performance impact of maintenance utilities so that they can run concurrently during production periods. Although the impact policy, a setting that allows utilities to run in throttled mode, is defined by default, you must set the impact priority, a setting that each cleaner has indicating its throttling priority, when you run a utility if you want to throttle it.

The throttling system ensures that the throttled utilities are run as frequently as possible without violating the impact policy. You can throttle statistics collection, backup operations, rebalancing operations, and asynchronous index cleanups.

You define the impact policy by setting the util_impact_lim configuration parameter.

Cleaners are integrated with the utility throttling facility. By default, each (index) cleaner has a utility impact priority of 50 (acceptable values are between 1 and 100, with 0 indicating no throttling). You can change the priority by using the SET UTIL_IMPACT_PRIORITY command or the db2UtilityControl API.