IT23218: Delay observed during strmqm when starting queue manager with many message on the SYSTEM.DURABLE.SUBSCRIBER.QUEUE

APAR status

• Closed as program error.

Error description

• strmqm takes a long time to complete if there are thousands of
  messages on the SYSTEM.DURABLE.SUBSCRIBER.QUEUE.
  
  From AMQERR01.LOG the delay is observed between the following
  two messages:
  
  AMQ5051: The queue manager task 'DUR-SUBS-MGR' has started.
  AMQ5037: The queue manager task 'MARKINTSCAN' has started.
  

Local fix

• na
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users with queue managers that serve many applications that
  create durable subscriptions.  These queue managers can validly
  have thousands of messages on their
  SYSTEM.DURABLE.SUBSCRIBER.QUEUE.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A long delay (several minutes) during execution of the strmqm
  command, due to the large amount of processing required for the
  SYSTEM.DURABLE.SUBSCRIBER.QUEUE.
  
  The activity taking place on this queue during strmqm was
  "reconciling durable subscribers". This task involved reading
  back state information for each subscriber, and reconciling
  these into an active status record for each subscriber. To do
  this MQ has to access the queue many times, which may cause a
  delay if the number of messages on the queue is large.
  Efficiencies were identified which could reduce the overhead of
  this necessary processing.
  

Problem conclusion

• A more efficient hashing mechanism has been implemented in order
  to reduce the amount of work required at this stage in queue
  manager startup.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.9
  v9.0 CD    9.0.5
  v9.0 LTS   9.0.0.3
  
  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

  5724H7251

Applicable component levels

• R800 PSY

     UP