PM51938: IN SQ ENVIRONMENT, IMS DISPLAY TRANSACTION COMMAND INDICATES A MESSAGE EXITS FOR A TRANSACTION WHEN IT REALLY DOESN'T

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• IMS is processing an input message in a shared queues
  environment. The IMS code determines that there is a region
  ready to run and process the message so it is flagged as
  local=yes and enqueued to the SMB.  Before the region completes
  scheduling, a QCF job that is processing the local queues does
  a GU and retrieves the message.  QCF issues a reject for the
  message and it is deleted.  During this process the DEQ count
  is incremented and the result is that any display indicates
  there IS a message for this transaction but no message exists
  because now the DEQ count is one more than the ENQ count.
  
  For QCF V210 fix, install IMS APAR PM52013.
  
  Keywords: CMD /DIS TRAN QCNT QCT QUEUE 0 ZERO
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS systems using Shared Queues          *
  *                 (SQ) and Queue Control Facility (QCF)        *
  *                 version 3.1                                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: A QCF UNLOAD AREA=(ALL),QUEUETYPE=(ALL) *
  *                      was running and dequeued a transaction  *
  *                      message that was scheduled in a MPP     *
  *                      region to run local.  This caused the   *
  *                      dequeue count of the transaction, field *
  *                      SMBDQCT, to be incremented one count    *
  *                      greater than the enqueue count, field   *
  *                      SMBNQCT, which causes the command       *
  *                      /DISPLAY TRAN to show one message       *
  *                      enqueued when there are none (i.e. QCF  *
  *                      deleted it).                            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  There is a timing window where QCF can unload a message and
  increment the transaction dequeue count, while the transaction
  has been scheduled to run locally, and the SMBDQCT and
  SMBNQCT fields have been incremented by one, then QCF dequeues
  the message and increments SMBDQCT by one, causing the
  dequeue count to be one greater than the enqueue count (i.e.
  this is an invalid condition) which causes the /DISPLAY TRAN
  command to show a queue count (QCNT) value of one.
  Retro fit is   APAR PM52013, IMS 10.1 for QCF2.1.
  

Problem conclusion

• INSTALL CORRECTIVE SERVICE FOR APAR/PTF
  

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:

  PM52013 UK74652

Modules/Macros

• IQCQMR5A IQCQMR5B IQCQMR5C IQCQMR58 IQCQMR59
  

Fix information

• Fixed component name

  IMS QUEUE CNTL

• Fixed component ID

  5697E9900

Applicable component levels

• R310 PSY UK74652

     UP11/12/11 P F112

Fix is available

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