An additional MON trace Class 29 being started by Sysview for Db2

Products

• SYSVIEW Performance Management Option for DB2 for z/OS

Issue/Introduction

Recently upgraded Sysview for Db2 for z/OS (IDB2) and noticed that when we do a Display Trace command, that we now see a MON trace class 29 active.

We found in the Systems Guide where:
If your Data Collector is using IFI=NO or IFI=READS, you will see a performance trace active with class 29.
Class 29 has no trace records currently defined for it.

Use IFI=YES. Why MON trace Class 29 is used for when IFI=YES?

Resolution

IBM has changed the way it handles the start of unqualified class 2 or 3 traces that include explicit IFCID records under DB2 v8 and higher.
As a result, the Sysview Performance Monitor for DB2 now uses a second Monitor Class 29 trace in order to get data for specific IFCID records that are used by IQL requests at start-up.