To clear the user trace log for the default execution group, on
distributed systems, enter the command 
mqsichangetrace WBRK_BROKER -u -e default -r
where: - WBRK_BROKER
- specifies the name of the broker
- -u
- specifies user trace
- -e
- specifies the execution group (in this case the default execution group)
- -r
- clears the trace log