IT35443: Queue manager hangs and becomes unresponsive. An FDC record is generated which reports xecS_E_NO_MEM

APAR status

• Closed as program error.

Error description

• Queue manager hangs and becomes unresponsive.
  
  The following failure data capture (FDC) records can be
  observed:
  
  amqzlaa0 33584.6898 KN369026 ksiDynBuf_new xecS_E_NO_MEM
  amqzlaa0 5232.5     XY388001 xcsConnectSharedMemSet
  xecS_E_MEM_SET_NOT_FOUND
  amqzlaa0 5232.4     KN028004 kpiInitialise xecF_E_UNEXPECTED_RC
  

Local fix

• Restart the queue manager
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of selectors may be more likely to hit this problem.  The
  issue has only been seen in IBM MQ version 8 and so this version
  of IBM MQ may be more vulnerable to the problem.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A bad return code is received when trying to extend a selector
  shared memory block.  This results in a shared memory set being
  incorrectly removed, leading to queue manager instability.
  

Problem conclusion

• The problem has not been seen on IBM MQ after release version 8.
   Definitive root cause for the problem was not found but there
  is a suspicion that the default size of the shared memory set
  for selectors was too small.
  
  A fix has been added which applies to IBM MQ version 8 and
  version 9 and increases the default selector set size.  This fix
  is not needed in version 9.1 or higher as the selector set size
  was already larger in those releases.
  
  Extra diagnostics have also been added to the code for all
  releases in order to assist IBM Support should the problem occur
  again.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.12
  v9.1 LTS   9.1.0.10
  v9.2 LTS   9.2.0.4
  v9.x CD    9.2.4
  
  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:

  PH40142

Fix information

• Fixed component name

  IBM MQ BASE M/P

• Fixed component ID

  5724H7261

Applicable component levels