PI54396: CPSM MESSAGE TO EXTERNALIZE XDATLOST "NO BUCKETS" CONDITION

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• CPSM uses message buckets to communicate certain information
  between regions (CMAS-to-CMAS or CMAS-to-MAS.) If CPSM goes to
  retrieve an empty bucket and none are available, it will write
  an exception trace entry and keep a count of how many times
  this 'No Buckets' situation occurs during the region run. This
  trace entry though may be overwritten if the trace wraps.
  This APAR is being opened to add additional external messages
  when the XDATLOST condition occurs, so that it can be made
  available for problem determination if needed.
  .
  Additional Symptom(s) Search Keyword(s): KIXREVGJT
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICSPlex SM V4R2M0 Users                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: Your CICSplex occasionally fails to     *
  *                      capture CICS notifications, which       *
  *                      in turn give rise to other issues       *
  *                      within the CICSplex. Such errors        *
  *                      may include (but are not limited to):   *
  *                                                              *
  *                      - failure to recognise instances of     *
  *                        newly defined CICS resources,         *
  *                      - failure to recognise an Operator      *
  *                        Sign-off, causing WLM affinities to   *
  *                        persist for too long.                 *
  *                                                              *
  *                      These conditions can occur without any  *
  *                      visible warning to the normal message   *
  *                      logs, and are only detectable if a      *
  *                      CICS auxiliary trace is available       *
  *                      that has not wrapped back over itself.  *
  *                                                              *
  ****************************************************************
  * RECOMMENDATION: After applying the PTF that resolves         *
  *                 this APAR, all MASes and WUI regions         *
  *                 must be recycled to pick up the new          *
  *                 code.  Note that regions do not need         *
  *                 to be brought down and restarted at          *
  *                 the same time.                               *
  *                                                              *
  ****************************************************************
  Notifications of events from CICS to CPSM are captured via
  CPSM provided GLUE modules.  These modules capture CICS
  data into predefined data "buckets", which are swapped from
  a free chain to an in-use chain. The elements in the in-use
  chain are gathered and emptied by CPSM long running task
  processes, which then make the appropriate adjustments to
  the CPSM operating environment commensurate with the
  original CICS notification. The "used" bucket is then
  swapped from the in-use chain to the free chain, ready for
  subsequent re-use.
  
  On occasions of intense CICS notification activity, for
  instance - if a large number of CICS resources are being
  installed or discarded simultaneously - then it is possible
  for the free bucket chain to be emptied, meaning some
  notifications are lost. CPSM registers this occurrence by
  taking special exception traces, but these will be lost as
  soon as the auxiliary trace dataset wraps around, leaving
  no clue as to why CPSM is possibly behaving erroneously.
  
  In addition, if a lost bucket involves the notification of
  a new (or updated) CICS connection, then the GLUE module will
  set a flag to inform the CPSM MAS heartbeat process to
  initiate a scan of all SNA and IP connections defined to the
  CICS region. This should cause CPSM's Topology data for the
  region to be consistent with what is actually installed.
  If the SNA connection scan should fail unexpectedly, it can
  cause the IP connection scan to be skipped. In turn, this
  will prevent consistency between CPSM Topology data and the
  actual IP connections active in the MAS. One spin off effect
  of this will be that Workload Manager may choose an
  inappropriate dynamic routing target region, when an
  acceptable IP connected target is available.
  

Problem conclusion

• Changes were made to MAS exit data processor (EYU0NLXD) to
  issue a new CPSM message on the first occasion that a "no
  buckets" condition arises:
  
  EYUNL0144W -applid- MAS notifications have been lost -
                      no free message buckets.
  
  The message explanation will advise customers that see this
  message to extract and print the auxiliary trace datasets of
  the reporting region as soon as possible, and consider
  increasing the value of the MSGBUCKETS EYUPARM in the MAS
  if the condition persists.
  
  The CPSM XRSINDI Exit module (EYU9NLID) and the XMEOUT Exit
  module (EYU9NLME) have been modified to employ separate flags
  for notifying of SNA and IP connection notification failures.
  Correspondingly, the Topology Resource synchronizer (EYU0NLT1)
  has been modified to use both of the flags to control the
  scanning of installed SNA and IP connections in a MAS.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

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

  PI54986 UI36561

Modules/Macros

• CJA9NLID CJA9NLME CJB9NLID CJB9NLME CJC9NLID CJC9NLME EYUMCNLC
  EYUMCNLE EYUMCNLK EYU0NLT1 EYU0NLXD EYU9NLID EYU9NLME
  

Fix information

• Fixed component name

  CICS TS Z/OS V4

• Fixed component ID

  5655S9700

Applicable component levels

• R70M PSY UI36561

     UP16/03/31 P F603

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.