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IDB2 Data collector tasks recycle for Clock Change

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Article ID: 237057

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Updated On:

Products

SYSVIEW Performance Management Option for DB2 for z/OS Database Management for DB2 for z/OS - Administration Suite Database Management for DB2 for z/OS - Performance Suite Database Management for DB2 for z/OS - Recovery Suite Database Management for DB2 for z/OS - SQL Performance Suite Database Management for DB2 for z/OS - Utilities Suite

Issue/Introduction

During every clock change activity during March and November,  the  data collector tasks are recycled. The tasks are kept down for one hour to avoid date duplicity. Is there any PTF's that needs to be applied to avoid date duplicity and keep the tasks active during automatic clock change period ?

Environment

Release : 20.0

Component : SYSVIEW Performance Management Option for DB2 for z/OS

Resolution

When you change the clock time for daylight savings time(DST), the following data collector concerns apply:

When you change the clock time during an IPL, there are no concerns for the datacollector. The data collector is brought down and restarted after the IPL.

When you change the clock time dynamically using the operator SET CLOCK command, there are no know issues with leaving the datacollector active during the clock-changing. But it's recommended to stop the data collector first, issue the command, and restart the data collector. This process ensures correct data collection during overlapping time periods or during a skip in a time period.

The DB2 trace records contain timestamps in the Greenwich Mean Time(GMT) format. When Db2 records are reported, the time values are converted to the local time using the time zone at the moment of request processing. When you select the data that is written before the time change and run the report after the change, the data is converted to the local time zone and the reported time values look shifted in comparison with the reports run before the time change. When you run the reports in batch, you can use the report writer SYSPARMs GMT-ADJUSTMENT and DST-LOCATION to override the current local time setting offset. If you use GSS services for SYSVIEW for Db2, GSS also recommends restarting the ISERVE address space around the SET CLOCK command similar to what is recommended for the SYSVIEW for Db2 data collector.