PM49561: IMS IFP REGION ABENDS IN DB2 WITH AN ABEND04E AND REASON CODE 00D91001.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• AbendU004E in DB2 with reason code 00D91001 is issued for an
  IFP region when it is processing a protected message that was
  rescheduled after a U0777 in IMS. The U0777 in IMS is due to
  a deadlock for a DB2 resource. DB2 has notified IMS and has
  not received an abort request when the new schedule occurs.
  This causes a DB2 to have the 2 threads active for the same
  UR and results in the 04E abend.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS V11 users of protected conversations *
  *                 and DB2/ESAF                                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: ABENDU004E in DB2 with reason code      *
  *                      00D91001 is issued for an IFP region    *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  An ABENDU0777 first occurs for a protected message being
  processed by an IFP that is connected to DB2.  When the
  protected message reschedules as part of U777 processing, a
  U004E abend in DB2 with reason code 00D91001 occurs for the IFP
  region in which the rescheduled protected message processes.
  
  The U777 in IMS is due to a deadlock for a DB2 resource.  DB2
  has notified IMS, but does not receive an abort request for the
  U777 thread before the message reschedules.  This causes a DB2
  to have the two threads active for the same UR with RRS XID and
  results in the U004E abend.
  
  The only abort notification DB2 (or any ESS) receives for a U777
  abend or equivalent is the JES EOT broadcast notification for
  the abending task.  The JES EOT notification is the trigger for
  DB2 to clean up its thread which would have included cleaning up
  the RRS XID information in this case.  However, the JES EOT
  broadcast can happen after IMS performs its requeue/reschedule
  process for the input message, thus forming a timing window in
  which the input message can reschedule before the JES EOT
  notification is received by DB2.
  
  JES EOT is the only notification for the ESS for a U777 or
  equivalent (ie.  hard abend that terminates the TCB) because IMS
  cannot drive any ESS exits while processing the hard abend due
  to IMS abterm processing occuring in the IMS control region
  under the CTL TCB.  ESS exits can only be driven from the
  dependent region.
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  IPST:
  A new syncpoint subfunction for field PSTSYNFC has been added to
  request special ESS abort processing:
  
  SFESSABT EQU   48  Special ESS abort
  
  
  DFSASK00:
  Code has been added to invoke syncpoint processing (DFSFXC30)
  while still executing in the dependent region, requesting this
  new special ESS abort processing for a U777 abend.  This new
  code is added to the abterm path.
  
  
  DFSFXC30:
  Code has been added to invoke the ESS Syncpoint Manager
  (DFSFESP0) for this special ESS abort processing.
  
  
  DFSFESP0:
  Code has been added to support this new syncpoint subfunction,
  SFESSABT, and invoke ABORT processing which will in turn invoke
  the ESS Term Thread exit for abterm processing.
  
  
  DFSRRSI0:
  Code has been added to the APPLICATION_ABEND routine to skip the
  ATRSUSI2 call for a U777 abend because the transaction will
  reschedule, so we should not mark it BACKOUT required for RRS.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  PM48456

• APAR is sysrouted TO one or more of the following:

  PM49562 UK78583

Modules/Macros

• DFSASK00 DFSFESP0 DFSFXC30 DFSRRSI0 IPST
  

Fix information

• Fixed component name

  IMS V11

• Fixed component ID

  5635A0200

Applicable component levels

• R100 PSY UK78583

     UP12/05/15 P F205

Fix is available

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