PM54835: CICS REGION HANGS LOOPING READING TDQ WHEN PTF UK63430 FOR APAR PM27536 IS APPLIED. 12/01/10 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• CICS start looping when reading TDQ.
  Additional symptoms:
  You may also see a backup of TD Transient Data
  AID -Automatic  initiate descriptors  control blocks.
  These AID control blocks are orphaned, never freemained.
  

Local fix

• n/a
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Looping occurs when reading TDQ after   *
  *                      applying PTF UK63430 for APAR PM27536   *
  *                      causing CICS region to hang.            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  2 CICS regions are started and connected via a connection.
  A transient data queue (TDQ) is used. An EXEC CICS START TRANSID
  FROM is issued to start TASK1 after EXEC CICS READQ TD QUEUE
  reads the last record on the TDQ and before it reaches QZERO. A
  TD AID is scheduled.
  
  TASK1 issues an EXEC CICS READQ TD QUEUE causing QZERO to be
  reached. Flag AIDSTTSK is turned on to indicate DFHALP to cancel
  the TD AID when DFHALP is called later.
  
  TASK1 terminates and task TCP resumes. It enters ATI and calls
  XMAT ATTACH to attach TASK2 (the task scheduled by the TD AID).
  In DFHALP, the fix added by PM27536 turns on the AIDSTTSK flag
  before the XMAT ATTACH domain call to prevent the AID being
  cancelled when DFHALP loses control. The fix then turns flag
  AIDSTTSK off after the XMAT ATTACH domain call on the assumption
  that flag AIDSTTSK will be set to the appropriate value by later
  code when XMAT ATTACH returns OK. It doesn't consider the
  situation that when it is a TD AID, the later code that sets
  AIDSTTSK is bypassed.
  
  TASK2 enters task termination. Because flag AIDSTTSK is turned
  off by PM27536, DFHALP doesn't cancel the TD AID. Having an AID
  causes TCP to call XMAT ATTACH to attach a new task after TASK2
  terminates. The new task goes through the same process as TASK2
  leading to a loop.
  .
  Another symptom is the build up of AID control blocks for
  transient data trigger tasks.
  .
  

Problem conclusion

• UK63430 UK67848 UK63800
  
  The fix added by PM27536 in DFHALP is changed so that it sets
  AIDSTTSK to its original value after the XMAT ATTACH domain
  call instead of turning it off.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

  PM52558

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

Modules/Macros

•    DFHALP
  

Fix information

• Fixed component name

  CICS TS Z/OS V4

• Fixed component ID

  5655S9700

Applicable component levels

• R600 PSY UK75381

     UP12/01/31 P F201

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.