IT38770: fteListMonitors can display monitor details twice if the monitor configuration is being updated when it is run

APAR status

• Closed as program error.

Error description

• At the same time as the fteListMonitors command is run (to get
  information about all of the resource monitors defined in an MQ
  Managed File Transfer topology), a monitor's configuration is
  updated. This results in the output from the fteListMonitors
  command containing two entries for that resource monitor, as
  shown below:
  
  Agent Name:      Monitor Name:     Resource Type:
  AGENT1           MONITOR1          Queue
  AGENT2           MONITOR2          Queue
  AGENT3           MONITOR3          Queue
  AGENT4           MONITOR4          Queue
  AGENT5           MONITOR5          Queue
  AGENT1           MONITOR1          Queue
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of IBM MQ Managed File Transfer, who
  are using the fteListMonitors command.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  The coordination queue manager for an MQ Managed File Transfer
  topology holds information about all of the resource monitors
  that are defined. When a monitor is created, it publishes a
  retained publication to the SYSTEM.FTE topic on the queue
  manager, using the topic string:
  
  Monitors/<monitor name>
  
  If the monitor's configuration is updated, then it publishes a
  new retained publication using the same topic string. When the
  monitor is deleted, the retained publication is removed.
  
  The fteListMonitors command is used to list all of the resource
  monitors defined in an MQ Managed File Transfer topology. When
  this command is run, it performs the following steps:
  
  - Connect to the coordination queue manager.
  - Issue an MQSUB API call, to subscribe to the SYSTEM.FTE topic
  using the topic string Monitors/#
  - Issue a series of MQGET API calls, to get the retained
  publications stored on the topic.
  - For each message that is returned:
    - Add the message to an internal list.
  - End for.
  - For each message in the internal list.
      - Process the message, and display the monitor details.
  - End for
  - Disconnect from the coordination queue manager.
  
  [For more information about these topic strings, see the
  SYSTEM.FTE topic topic in the MQ sections of IBM Knowledge
  Center. The URI for the topic in the MQ 9.2.x section of IBM
  Knowledge Center is
  https://www.ibm.com/support/knowledgecenter/SSFKSJ_9.2.0/com.ibm
  .mq.ref.con.doc/system_fte.htm]
  
  
  Now, when the issue reported in this APAR occurred, a monitor
  definition was updated at the same time as the fteListMonitors
  command was run. This resulted in the following sequence of
  events occurring:
  
  - The fteListMonitors command was run.
  - After subscribing to the SYSTEM.FTE topic on the coordination
  queue manager using the topic string Monitors/#, the command
  started to receive the retained publications.
  - The command received the retained publication for Monitor1,
  and added it to its internal list of messages.
  
  - While the command was still getting the retained publications,
  the configuration for Monitor1 was updated.
  - As a result, the retained publication for Monitor1 was
  updated.
  
  - The command now received another retained publication for
  Monitor 1. This message was also added to the command's internal
  list. As a result, the list now contained two entries for
  Monitor 1.
  
  - After receiving the last retained publication from the queue
  manager, the command started to process the messages stored in
  the list.
  - Because the internal list contained two entries for Monitor1,
  the command displayed information about this monitor twice in
  its output.
  

Problem conclusion

• To resolve this issue, the fteListMonitors command has been
  updated to:
  
  - Create the subscription to the coordination queue manager by
  issuing an MQSUB API call with the MQSO_PUBLICATIONS_ON_REQUEST
  option specified.
  - And get the retained publications by making an MQSUBREQ API
  call specifying the MQSR_ACTION_PUBLICATION option.
  
  When the MQSUBREQ API call is made, the queue manager's
  Publish/Subscribe Engine makes a copy of the current retained
  publications, and then makes that available to the
  fteListMonitors command. This means that if a retained
  publication containing a monitor definition is updated after the
  copy is made, then the updated publication won't be delivered to
  fteListMonitors and so that monitor will only appear once in the
  command output.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.2 LTS   9.2.0.7
  v9.3 LTS   9.3.0.1
  v9.x CD    9.3.1
  
  The latest available 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

  MQ BASE V9.2

• Fixed component ID

  5724H7281

Applicable component levels