Technical Blog Post
DB2 RUNSTATS may be slow due to UTIL_IMPACT_PRIORITY option
RUNSTATS has an option UTIL_IMPACT_PRIORITY which as its name suggests, specifies the priority of RUNSTATS utility.
However, be aware of the following implications
|Option Specified||RUNSTATS Priority|
|Option UTIL_IMPACT_PRIORITY not specified||Unthrottled|
|Option UTIL_IMPACT_PRIORITY used, no value specified||Throttled, Priority is 50 (Default)|
|Option UTIL_IMPACT_PRIORITY used, value 1 to 100 specified||Throttled, Priority is 1 to 100 as specified|
When RUNSTATS is throttled, the overall performance impact is controlled by UTIL_IMPACT_LIM:
The DBM config parameter limits the performance degradation of a throttled utility on the workload and
it has 10% as default impact value.
The above means, even if you specify UTIL_IMPACT_PRIORITY 100 with RUNSTATS, it may still
run slow because the overall utility(which includes RUNSTATS) impact is limited to 10%.