PH59397: CICS SHUTDOWN HANGS BECAUSE CKAM TASK DOES NOT END.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The CICS region comes up with SIT parameter, WLMHEALTH=OFF.
  Sometime during the run, the region reaches MXT very briefly.
  This can, if the timing is right, result in a bit being left on
  invalidly.  This bit is used by the CKAM transaction and it
  means that a MXT event is happening.
  
  
  
  The CKAM task does not wakeup again until CICS is shutdown
  (which could be days later). During shutdown, CKAM is posted to
  wakeup to begin shutting itself down.  But the presence of that
  iMXT bit causes CKAM to not realize that it was called to begin
  shutting down, and instead just suspends itself. This causes
  CICS shutdown to hang (unless the shutdown assist task purges
  it).
  
  When WLMHEALTH is on, CKAM is called earlier during shutdown to
  deal with WLMHEALTH things.  That call to CKAM clears out the
  iMXT bit that was left on invalidly. When CKAM is later called
  to begin shutting itself down, the bit is not on and it begins
  shutting itself down as expected.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CICS Shutdown may not complete when     *
  *                      WLMHEALTH=OFF is specified and CICS     *
  *                      uses MQMON.                             *
  ****************************************************************
  CICS Shutdown may never complete when WLMHEALTH=OFF and the CICS
  system has previously hit MXT.
  
  A small window exists when the CICS region hits the MAXTASK
  limit and quickly releases it. This can mean that the MXT flag
  is left on in DFHMQMON. When the CICS region is shutdown, code
  in DFHMQMON to stop the CKAM transaction is bypassed because the
  ECB it is relying on has already been cleared. The CKAM
  transaction does not then get purged by CESD.
  

Problem conclusion

• DFHMQMON has been changed to not clear the ECB when the CICS
  region is in shutdown.
  

Temporary fix

Comments

APAR Information

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

  PH59359

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

  UI95655

Modules/Macros

• DFHMQMON
  

Fix information

• Fixed component name

  CICS TS Z/OS V6

• Fixed component ID

  5655YA100

Applicable component levels

• R400 PSY UI95655

     UP24/02/16 P F402

Fix is available

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