IT35809: MQ MFT resource monitor runs on multiple threads at the same time after its config

APAR status

• Closed as program error.

Error description

• A resource monitor has been defined on an MQ Managed File
  Transfer (MFT) agent, and has been configured to monitor a
  source directory. The configuration of the monitor is updated
  using the fteCreateMonitor command, specifying the -f parameter.
  After this happens:
  
  - The agent starts receiving multiple transfer requests for the
  same transfer items, instead of just one.
  - The agent's resource monitor event log (resmonevent0.log)
  shows that the monitor is running on different threads within
  the agent at the same time.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of IBM MQ Managed File Transfer who are
  using resource monitors, and want to update the configuration of
  those monitors.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  IBM MQ 9.1.5.0 Managed File Transfer changed the way in which
  resource monitor threads ran. Prior to MQ 9.1.5.0, resource
  monitor threads ran as Java TimerTask - this meant that if a
  monitor's poll took took longer than its specified poll
  interval, the next poll would start as soon as the previous one
  had finished with no gap in between. In MQ 9.1.5.0, this was
  changed so that monitor threads were started using the Java
  ScheduledExecutorService. As a result of this change, once a
  monitor thread had completed its poll, it would wait for the
  specified poll interval before starting the next one.
  
  When a resource monitor's configuration changed, either by
  running the fteCreateMonitor command specifying the -f parameter
  or by using the MQ Explorer Managed File Transfer plugin, the
  agent didn't stop the current resource monitor thread that had
  been started by the ScheduledExecutorService. As a result, there
  were multiple threads within the agent running the same resource
  monitor. The number of resource monitor threads would be equal
  to the number of times the monitor's configuration had been
  changed since the agent hosting the monitor had restarted.
  
  When this issue occurred, an agent's resource monitor event log
  (resmonevent0.log) would contain multiple entries for a single
  resource monitor, where the entries were generated by different
  threads, as shown in the example below:
  
  [25/01/2021 13:05:57:664 IST] 00000073  TESTM
  Start Poll     New poll cycle started
  [25/01/2021 13:05:57:696 IST] 00000073  TESTM               End
  Poll      Poll cycle completed in 32 milliseconds. Trigger items
  matched [ 0 ]
  [25/01/2021 13:06:16:117 IST] 00000082  TESTM
  Start Poll     New poll cycle started
  [25/01/2021 13:06:16:164 IST] 00000082  TESTM               End
  Poll      Poll cycle completed in 47 milliseconds. Trigger items
  matched [ 0 ]
  [25/01/2021 13:06:27:711 IST] 00000073  TESTM
  Start Poll     New poll cycle started
  [25/01/2021 13:06:27:742 IST] 00000073  TESTM               End
  Poll      Poll cycle completed in 31 milliseconds. Trigger items
  matched [ 0 ]
  [25/01/2021 13:06:46:180 IST] 00000082  TESTM
  Start Poll     New poll cycle started
  [25/01/2021 13:06:46:242 IST] 00000082  TESTM               End
  Poll      Poll cycle completed in 62 milliseconds. Trigger items
  matched [ 0 ]
  

Problem conclusion

• To resolve this issue, MQ Managed File Transfer has been updated
  to ensure that if a resource monitor's configuration has been
  updated, using:
  
  - Either by running the fteCreateMonitor command specifying the
  -f parameter
  - Or by using the MQ Explorer Managed File Transfer plugin
  
  then the existing resource monitor thread is stopped before the
  new thread is started.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.2 LTS   9.2.0.2
  v9.x CD    9.2.2
  
  The latest available MQ maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

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

  IBM MQ MFT V9.1

• Fixed component ID

  5724H7272

Applicable component levels