Filter the trace for user IDs matching the filter_name pattern.
If the user ID matches the filter at the time the client logs in, then tracing options will be set to the current value of the options. Otherwise, there
will be no tracing options set. The client might use the SITE command to set options after login if the initial ones are not appropriate. An example for
the USERID filter is
MODIFY jobname,DUMP=(21,USERID(USER33))
which will activate the dumpID 21 trace for a user if the user ID is USER33.