PH44469: ABENDAAL8 AND UNPREDICTABLE RESULTS FOLLOWING DFHPI0731

APAR status

• Closed as program error.

Error description

• For a WS-AT transaction that times out waiting for the WS-AT
  Registration process to complete, CICS issues message DFHPI0731
  " An attempt to register unit of work - X'DB1D123456789ABC' with
  a remote WSAT coordinating transaction has failed. "  Following
  that, unpredictable problems occur.
  
  In a configuration where the DFHPIDIR file is remote, each
  transaction that gets DFHPI0731 does not clean up its MRO Send
  link that was used to go to the FOR.  After the transaction is
  over, the transaction's TCA and its task# remain in the MRO Send
  link TCTTE at +x'10' ( TCTTECA ) and +x'14' (  TCTE_TRANNUM ).
  This causes that MRO Send link to be unusable, un-allocatable,
  for the rest of that run of CICS.  If there are 20 MRO Send
  links, then after 20 DFHPI0731 messages, all Send links are
  unusable and subsequent atomic transactions hang in an Allocate
  wait trying access DFHPIDIR in the FOR.  That can lead to
  abendAAL8.  These atomic transactions that get stuck and abend
  accessing DFHPIDIR do not send a registration request to the
  coordinator and they do not run the atomic transaction.
  
  If DFHPIDIR is local, then a task that gets DFHPI0731 could have
  one of its TRUEs (Task Related User Exits) not called for task
  termination.  That will lead to unpredictable results.
  
  Additional keywords: AAL8
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: A web services request that is making   *
  *                      use of WS-AT (Web Services Atomic       *
  *                      Transactions) arrives in CICS. For any  *
  *                      number of reasons the WS-AT             *
  *                      registration fails. During clean up     *
  *                      processing an incorrect RM link is      *
  *                      deleted when attempting to remove the   *
  *                      link that would have been added had the *
  *                      registration been successful.           *
  *                                                              *
  *                      Depending on what the RM link was for   *
  *                      this can result in unexpected behaviour *
  *                      in CICS.                                *
  ****************************************************************
  A web services request that is making use of WS-AT (Web Services
  Atomic Transactions) arrives in CICS. A RegisterRequest is sent
  to the coordinator and the backend task waits for the
  RegisterResponse to be returned. For any number of reasons, the
  RegisterResponse message never gets processed by CICS and
  eventually the WS-AT backend task times out waiting.
  
  Message DFHPI0731 gets issued to report the failure to register.
  As part of clean up processing. CICS removes the RM link that
  would have been created if the register was successful.
  As the register failed, a link has not been created so there is
  no link to remove in this case. The browse for an associated RM
  link token does not find one of interest, however the link token
  variable is not cleared in the parameter list. This means that
  the last RM link token that the browse found is passed back to
  DFHPIRS. This link token is then incorrectly removed. In the
  customers case this was the MRO link token to the FOR which
  owned the DFHPIDIR file. This meant the session to the FOR was
  left allocated to the abending transaction and never released.
  
  Depending on what the RM link was for, this can cause an unknown
  number of issues.
  

Problem conclusion

• DFHPIRS has been changed so that a call to delete an RM link is
  only made if registration was successful.
  

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:

  UI80357 UI80358

Modules/Macros

• DFHPIRS
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels