PH63551: MQ Z/OS: ABN=5C6-00C94200 IN CSQIRRSI+00000C80 WITH A MIXTURE OF BATCH AND RRSBATCH STUBS IN A DB2 STORED PROCEDURE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A dump occurred with
  DUMP TITLE=MQS1,ABN=5C6-00C94200,U=xxxxxxx ,C=MQ900.930.DMC -CS
  QIRRSI,M=CSQGFRCV,LOC=CSQILPLM.CSQIRRSI+00000C80
  
  Reason code 00C94200 means there was a bad return code from
  RRS.
  
  In the dump, the thread ends up with a mismatch in between
  BATCH and RRSBATCH:
   Jobname <jobname>  Conntype BATCH    ASID xnnnn  ASCE nnnnnnnn
     EB nnnnnnnn   ACE nnnnnnnn   Jobname RRSBATCH  TCB nnnnnnnn
  
  The abending TCB is the only task in the Db2 job that is
  currently connected to the queue manager, and it was correctly
  linked with the RRS stub CSQBRRSI.  The problem is that another
  stored procedure that ran in the address space was linked with
  the non-RRS batch stub CSQBSTUB.
  
  It should not be possible for stored procedures linked with a
  mix of BATCH and RRSBATCH stubs to be connected to the queue
  manager from the same application address space at the same
  time. Normally any attempt to connect using a different stub
  from that already connected would lead to the later MQCONN
  failing with either MQRC 2012 MQRC_ENVIRONMENT_ERROR or
  MQRC 2058 MQRC_Q_MGR_NAME_ERROR.
  
  If both types of procedure attempt to connect at the same time,
  there is a small timing window that can erroneously allow both
  connections to succeed, resulting in one of these connections
  not matching the connection type. If the mismatched connection
  is for the RRS stored procedure, this leads to the reported
  abend if the same TCB attempts to do transactional work after
  the associated context has ended.
  

Local fix

• Use the same stub for applications running in the same address
  space
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 3 Modification 0 and                 *
  *                 Release 4 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend 5C6-00C94200 occurs in            *
  *                      CSQILPLM.CSQIRRSI when applications     *
  *                      linked with differing stubs connect     *
  *                      from the same address space.            *
  ****************************************************************
  An application was linked with CSQBSTUB connected to the queue
  manager, causing the ASCE to be marked as a BATCH connection to
  the queue manager. At the same time another TCB also connected
  to the same queue manager from an application linked with an RRS
  stub (CSQBRSTB/CSQBRRSI).
  A timing window during identify processing allowed this second
  connection to succeed, rather than failing with
  MQRC_Q_MGR_NAME_ERROR as expected.
  The mismatch between the RRS application's connection type and
  the ASCE connection type meant that interest was not expressed
  in the RRS application's context, leading to incorrect context
  information being used.
  This can result in unpredictable results including, but not
  limited to, abend 5C6-00C94200 when trying to update the context
  interest.
  

Problem conclusion

• Identify processing is changed to remove the timing window that
  allowed a connection with a mismatched connection type to
  erroneously connect successfully.
  

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:

  UO03968 UO03969

Modules/Macros

• CSQ3ID30
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R300 PSY UO03969

     UP25/07/12 P F507 ¢

• R400 PSY UO03968

     UP25/07/12 P F507 ¢

Fix is available

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