IT29978: IBM MQ Console creates multiple non-durable subscriptions for the same chart widgets.

APAR status

• Closed as program error.

Error description

• An "MQCONN/MQCONNX count" chart widget is added to the IBM MQ
  Console dashboard in order to monitor the number of MQCONN and
  MQCONNX calls made on the queue manager QM1. After the chart
  widget has been added, the runmqsc command:
  
    display sub(*)
  
  is run on QM1, to generate a list of subscriptions on that queue
  manager. The output from the command contains the following
  entry:
  
     SUBID(414D51207061756C745639314C5453206EEF965D23F7001A)
     SUB(JMS:ND:QM1::Monitor.STATMQI.CONNDISC.1570436072474)
  
  which represents the non-durable subscription associated by the
  chart widget.
  
  After a few days, the runmqsc command:
  
    display sub(*)
  
  is run on one of QM1 again. This time, the output from the
  command shows that there are two non-durable subscriptions
  associated by the chart widget. as shown below:
  
     SUBID(414D51207061756C745639314C5453206EEF965D23F6E073)
     SUB(JMS:ND:QM1::Monitor.STATMQI.CONNDISC.1570436072474)
  
      SUBID(414D51207061756C745639314C5453206EEF965D23F6E073)
      SUB(JMS:ND:QM1::Monitor.STATMQI.CONNDISC.1570449605614)
  
  This is incorrect - a chart widget should only have one
  non-durable subscription associated with it.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of the IBM MQ Console who use chart
  widgets to monitor resources.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  IBM MQ provides a number of system topics that can be used to
  monitor resources on a queue manager. Information about these
  topics can be found in the System topics for monitoring and
  activity trace topic in the IBM MQ sections of IBM Knowledge
  Center. The URI for this topic in the IBM MQ V9.1 section of IBM
  Knowledge Center is
  https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.1.0/com.
  ibm.mq.mon.doc/mo00040_.htm.
  
  The chart widgets provided by the IBM MQ Console subscribe to
  these system topics in order to get the information that needs
  to be displayed to the user. The first time a chart widget is
  added to the IBM MQ Console, the user interface will create a
  shared, non-durable subscription to the appropriate system topic
  for the resource being monitored. The non-durable subscription
  is shared by all users of the IBM MQ Console - this means that:
  
  - If user1 adds a chart widget to their IBM MQ Console
  dashboard, to monitor the CPU usage of the queue manager QM1.
  - And then user2 adds the same chart widget to their IBM MQ
  Console dashboard
  
  then both chart widgets will use the same non-durable
  subscription to the system topic on QM1. The non-durable
  subscription will exist until the mqweb server hosting the IBM
  MQ Console is stopped.
  
  The IBM MQ Console periodically checked if all of the chart
  widgets that had been added were currently collecting monitoring
  data. If it found a chart widget that was not collecting data,
  it would:
  
  - Reconnect the chart widget to the queue manager, if it had
  been disconnected.
  - Create a shared, non-durable subscription to the appropriate
  system topic, specifying a unique subscription name.
  
  This meant that if a chart widget stopped collecting data for
  some reason, and was successfully restarted, then a new shared,
  non-durable subscription with a different subscription name was
  created to the system topic and associated with the chart
  widget.
  

Problem conclusion

• To resolve this issue, the IBM MQ Console has been updated so
  that a unique subscription name for the chart widget is
  generated the first time a chart widget is added to a user's
  dashboard. If the chart widget stops collecting data for some
  reason, then it will use this subscription name when recreating
  the non-durable subscription.
  
  This ensures that chart widgets will always use the same shared,
  non-durable subscription if they stop collecting data and are
  subsequently restarted.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.1 CD    9.1.4
  v9.1 LTS   9.1.0.4
  
  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

  IBM MQ BASE MP

• Fixed component ID

  5724H7271

Applicable component levels