PM43691: LOOP IN DFHEMT56 AFTER CEMT I TAS TRAN(XXXX) REQUEST WHEN THOUSANDS OF TASKS ARE QUEUED

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible.

Error description

• Loop occurs following a CEMT I TAS TRAN(xxxx) request. The dump
  shows that CICS is at MAXTASK with 55,000+ tasks queued for
  TCLASS reasons. CICS trace shows that the CEMT task is looping
  doing EXEC CICS INQUIRE TASK commands, passing a transaction
  number of zeroes. The INQUIRE TASK request is issued out of
  module DFHEMT56.
  .
  Additional Symptom(s) Search Keyword(s):
  KIXREVrer  UNKNOWN_TRANSACTION_NUMBER LISTNUM REALLNUM TASKIDERR
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CEMT INQUIRE TASK TRANSACTION command   *
  *                      becomes stuck in an infinite loop if a  *
  *                      large number of tasks (over 55,000)     *
  *                      queued up in a CICS region due to       *
  *                      TClass reasons.                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A CICS user issues a CEMT I TASK TRANSACTION command when there
  are a large number of tasks (over 55,000) queued up in the CICS
  region due to TClass reasons. Module DFHEMT56 is used to do the
  inquire task action and the variable used to control the loop
  is defined as signed half word which means the maximum value it
  can hold is 32767.As a result, when the loop which is going
  through each task on the system exceeds 32767, the value of the
  variable becomes negative and therefore does not increment the
  task number issued by the DFHXMIQ INQUIRE TRANSACTION which
  remains zero.
  

Problem conclusion

Temporary fix

•             *********
              * HIPER *
              *********
  FIX AVAILABLE BY PTF ONLY
  

Comments

• DFHEIN56 and DFHEMT56 have been updated to create a variable
  which is a full-word version of original half-word version  that
  is used to control the loops in the GENTASK procedure. Doing so
  allows the loop to iterate up to the value of LISTNUM since now
  both variables have the same definitions.
  

APAR Information

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

  PM41417

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

  UK70645

Modules/Macros

•    DFHEIN56 DFHEMT56
  

Fix information

• Fixed component name

  CICS TS Z/OS V4

• Fixed component ID

  5655S9700

Applicable component levels

• R600 PSY UK70645

     UP11/08/16 P F108

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.