IT25290: Clean Session Record was not removed from the SYSTEM.MQTT.PERSISTENT.STATE queue during a client takeover

APAR status

• Closed as program error.

Error description

• A Clean Session Record message which contains only a client ID
  is put to the SYSTEM.MQTT.PERSISTENT.STATE queue every time a
  MQTT client connects and requests a clean session.
  This Clean Session Record message should get removed from the
  queue when either the client disconnects or during a client
  takeover.  However, this message was not removed during a client
  takeover, leading to a buildup of messages on the
  SYSTEM.MQTT.PERSISTENT.STATE queue.
  

Local fix

• NA
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects MQTT Clients connecting with same client ID
  as an existing connected MQTT client, and also specifying clean
  session true in the connect options.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  MQTT Client takeover is a situation in which a MQTT client
  connects to the MQXR service, specifying the same client ID as a
  client that is already connected. If the original client
  connected specifying clean session true, it would have put a
  clean session record message to the SYSTEM.MQTT.PERSISTENT.STATE
  queue. The new client taking over this client's session did not
  remove the previous client's clean session record message from
  the SYSTEM.MQTT.PERSISTENT.STATE queue before putting its own
  message, leading to a buildup of these messages on that queue.
  

Problem conclusion

• This fix ensures that during a MQTT client takeover, the
  previous client's clean session record is deleted and the clean
  session record from the newly connected client is saved to the
  SYSTEM.MQTT.PERSISTENT.STATE queue.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.6
  v9.1 LTS   9.1.0.2
  
  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 M/P

• Fixed component ID

  5724H7261

Applicable component levels