Can HWM values for Db2 threads in the Sysview for Db2 (IDB2) monitor be reset?

Products

• SYSVIEW Performance Management Option for DB2 for z/OS

Issue/Introduction

The following  HIGH WATER MARKS for DDF connections was hit: 

LIMITS Current Max  HWM  HWM
 Users      15   3   35   18
 TSO         9   9   30   11
 Batch       6   6   25    7
 DDF Actv    5   2  200    5
 DDF Inac   68   6 1000   68
 Dataset  5863  97      5863

Can these values be reset without recycling the Sysview Performance Management Option for Db2 for z/OS (IDB2) Data Collector tasks?

Resolution

No, they cannot be reset without the Data Collector being recycled.

HWM is controlled by the SYSPARMS member HWM-SAMP-INT.
HWM-SAMP-INT= nn Controls how often, in hundredths of a second, the high water mark (HWM) collection subtask samples for data.

The HWM subtask samples Db2 control blocks and logs the HWM values for the current statistics interval. In contrast, the statistics
records that Db2 produces contain the HWM values since the Db2 subsystem was last started. When the statistics interval ends,
the HWM values that Sysview for Db2 collects are reset to zero. The HWM values are available online only for the current and
past subsystem history intervals.

Additional Information

DC System Parameters

See HWM-SAMP-INT=nn