IT28091: Application intermittently receives MQRC_HOST_NOT_AVAILABLE error while connecting to the queue manager.

APAR status

• Closed as program error.

Error description

• Attempts by an application to connect to a queue manager using
  a server connection SVRCONN channel with SHARECNV > 1
  specified, unexpectedly receives
  MQRC 2538 MQRC_HOST_NOT_AVAILABLE.
  .
  Application has several threads with working connections to the
  queue manager. Client connections in the application work fine
  for some time, then start to fail.
  

Local fix

• Set SHARECNV(1) on the SVRCONN channel definition
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All MQ client application users who use SVRCONN channels with
  SHARECNV value greater than 1.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When shared conversation(SHARECNV) is set to any value greater
  than 1 then it means multiple logical connections
  (conversations) use the same channel instance. The channel
  instance is closed if all the conversations sharing the channel
  are disconnected.  A small timing window allowed a new
  conversation to pick the same channel instance  that was being
  ended by another thread and this results in the
  MQRC_HOST_NOT_AVAILABLE error.
  

Problem conclusion

• The code has been modified to ensure that a new conversation
  request does not pick a channel instance that is being
  terminated.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.8
  v9.0 CD    9.1.0.0
  
  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