IT44251: Queue manager trace temporarily disables itself when trace is started with the '-m' switch

APAR status

• Closed as program error.

Error description

• When starting queue manager trace with IBM MQ 9.3, using the
  command:
  
  strmqtrc -t all -t detail -m <MY_QMGR_NAME>
  
  trace of the queue manager starts to be collected, as normal.
  
  However when the data is uploaded and analysed by IBM MQ
  support, it is report that trace keeps stopping and starting
  intermittently, resulting in gaps in the captured trace data
  which may miss trace data critical to the problem which is being
  reported and investigated.
  

Local fix

• Do not specify the '-m' option on the 'strmqtrc' command, so
  that trace data is captured for all queue managers and MQ C
  applications running on the system.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of an IBM MQ queue manager or MQ C client application, who
  are attempting to collect trace, where the trace start command
  ('strmqtrc') specified the '-m' flag to trace data for a
  specific queue manager.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  Trace data for a queue manager or MQ C application can be
  enabled for a specific queue manager, by specifying the -m
  switch, such as with the command:
  
    strmqtrc -t detail -m <MY_QMGR_NAME>
  
  When this is done, it was observed by the IBM MQ support teams
  that on occasion, trace stopped recording data into the trace
  files, and then started again some time later.
  
  The time interval between trace stopping and starting might have
  been small, for example 2 milliseconds. However a lot of data
  can be missed in that non-traced time period, resulting in the
  IBM MQ support teams being unable to complete diagnosis of
  reported problems using the trace data alone.
  

Problem conclusion

• When tracing a specific queue manager, an internal data store is
  used to keep track of when a specific queue manager or MQ C
  application functions associated with a queue manager should be
  recording trace data.
  
  The algorithm which maintains the state of the internal data
  store contained a code defect which resulted in trace being
  stopped for a period of time, until other code functions
  re-enabled trace for that specific queue manager at a later
  point in time.
  
  The problem with this algorithm has been corrected such that
  trace data associated with a specific queue manager will
  continue to be output until requested to be stopped with the
  'endmqtrc' command.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.3 LTS   9.3.0.15
  v9.x CD    9.3.4
  
  The latest available maintenance can be obtained from
  'IBM MQ Recommended Fixes'
  https://www.ibm.com/support/pages/recommended-fixes-ibm-mq
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'IBM MQ
  Planned Maintenance Release Dates'
  https://www.ibm.com/support/pages/ibm-mq-planned-maintenance-rel
  
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  MQ BASE V9.3

• Fixed component ID

  5724H7291

Applicable component levels