PK14799: TOPOLOGY JOINS ARE SLOW DUE TO CMAS MAXTASK CONDITION XLST TSG2

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Topology joins may not occur immediately in all CMASes due to
  the CMAS being in a maxtask condition.  The maxtask is due to
  hundreds of XLST tasks waiting for work.  These XLST tasks
  will remain waiting until work arrives for them or they timeout
  after 10 minutes.  The TSSJ (Topology CICS System Join Event)
  transactions are waiting on MXT and cannot run until the XLST
  tasks timeout and free up a task slot.
  .
  Additional Symptom(s) Search Keyword(s): EENDJOIN TSLG TSG2
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICSPlex/SM V3R1M0 Users                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: Various errors may occur when a CMAS    *
  *                      encounters a MAXTASK condition.         *
  *                                                              *
  *                      An external symptom of this may be an   *
  *                      approximately 10 minute delay for other *
  *                      connected CMASes to JOIN MASes that are *
  *                      connected to the CMAS that incurs the   *
  *                      MAXTASK condition.                      *
  ****************************************************************
  * RECOMMENDATION: After applying the PTF that resolves this    *
  *                 APAR, all CMASes must be restarted.  Note    *
  *                 that the restarts do not need to occur at    *
  *                 the same time.                               *
  ****************************************************************
  A CMAS keeps a pool of XLST tasks to handle most requests that
  are received by the CMAS.  After processing a request, an XLST
  task will go into a wait state for 10 minutes.  If no
  subsequent request is received by the task, it will terminate.
  
  When a request is made, module EYU9XLCI (EUI requests) or method
  EYU0XLNC (all other requests) will look for a waiting XLST task,
  and if found will associate the request with that task.  If no
  XLST task is available when a request is made, module EYU9XLEV
  (EUI requests) or method EYU0XLNC (all other requests) will
  request that an XLST task be STARTed to handle a request.
  
  There is no limit to the number of XLST tasks a CMAS will START.
  If a large number of concurrent requests are received by a CMAS
  it is possible that some of the XLST tasks started will be
  placed in a MAXTASK wait.  When XLST tasks that were able to
  execute complete processing their request, they will go into
  their wait.  This will result in the XLST tasks waiting on
  MAXTASK to wait at least 10 minutes for other XLST tasks to end.
  

Problem conclusion

• Updates have been made such that when an XLST task completes
  processing a request, it will determine if another non-EUI
  request is waiting because its XLST task did not start due to
  MAXTASK (EUI requests remain tied to the XLST task that was
  started to process that request).  If so, the active XLST task
  will process the waiting request.  When the MAXTASK held task
  does start, it will recognize that its request was satisfied by
  another XLST task and terminate.  If there are no additional
  requests for a completing XLST task to process, it will
  determine if the CMAS is at or near MAXTASK.  If so, the XLST
  task will terminate.  Otherwise, the XLST task will enter its
  wait for work.
  
  To affect these changes, the following updates have been made:
  
  -  the parameter list (MAL - method argument list) for method
     EYU0XLST (XLST), EYUZXLST, has been updated to allow the
     caller to indicate whether the request being made is for the
     EUI or for other processing.
  
  -  module EYU9XLEV has been updated to indicate in the XLST MAL
     that the request is an EUI request.
  
  -  method EYU0XLNC has been updated to indicate in the XLST MAL
     that the request is not an EUI request.
  
  -  method EYU0XLST (XLST), which is the controlling method for
     the XLST task, will check the request type on entry.  If it
     is an EUI request, XLST will process it immediately.  If it
     is not an EUI request, XLST will determine if the request has
     already been processed, and if so, it will terminate.
  
     After XLST processes a request, whether it was an EUI request
     or not, it will determine if there are any non-EUI requests
     available to process, and if so, it will process the request.
     If there are no non-EUI requests to process, XLST will
     determine if the CMAS is at or near MAXTASK.  If so, XLST
     will terminate.  If not, XLST will go into its wait for work.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

• Various errors may occur when a CMAS
  encounters a MAXTASK condition.
  
  An external symptom of this may be an
  approximately 10 minute delay for other
  connected CMASes to JOIN MASes that are
  connected to the CMAS that incurs the
  MAXTASK condition.
  
  
  A CMAS keeps a pool of XLST tasks to handle most requests that
  are received by the CMAS.  After processing a request, an XLST
  task will go into a wait state for 10 minutes.  If no
  subsequent request is received by the task, it will terminate.
  
  When a request is made, module EYU9XLCI (EUI requests) or method
  EYU0XLNC (all other requests) will look for a waiting XLST task,
  and if found will associate the request with that task.  If no
  XLST task is available when a request is made, module EYU9XLEV
  (EUI requests) or method EYU0XLNC (all other requests) will
  request that an XLST task be STARTed to handle a request.
  
  There is no limit to the number of XLST tasks a CMAS will START.
  If a large number of concurrent requests are received by a CMAS
  it is possible that some of the XLST tasks started will be
  placed in a MAXTASK wait.  When XLST tasks that were able to
  execute complete processing their request, they will go into
  their wait.  This will result in the XLST tasks waiting on
  MAXTASK to wait at least 10 minutes for other XLST tasks to end.
  
  
  Updates have been made such that when an XLST task completes
  processing a request, it will determine if another non-EUI
  request is waiting because its XLST task did not start due to
  MAXTASK (EUI requests remain tied to the XLST task that was
  started to process that request).  If so, the active XLST task
  will process the waiting request.  When the MAXTASK held task
  does start, it will recognize that its request was satisfied by
  another XLST task and terminate.  If there are no additional
  requests for a completing XLST task to process, it will
  determine if the CMAS is at or near MAXTASK.  If so, the XLST
  task will terminate.  Otherwise, the XLST task will enter its
  wait for work.
  
  To affect these changes, the following updates have been made:
  
  -  the parameter list (MAL - method argument list) for method
     EYU0XLST (XLST), EYUZXLST, has been updated to allow the
     caller to indicate whether the request being made is for the
     EUI or for other processing.
  
  -  module EYU9XLEV has been updated to indicate in the XLST MAL
     that the request is an EUI request.
  
  -  method EYU0XLNC has been updated to indicate in the XLST MAL
     that the request is not an EUI request.
  
  -  method EYU0XLST (XLST), which is the controlling method for
     the XLST task, will check the request type on entry.  If it
     is an EUI request, XLST will process it immediately.  If it
     is not an EUI request, XLST will determine if the request has
     already been processed, and if so, it will terminate.
  
     After XLST processes a request, whether it was an EUI request
     or not, it will determine if there are any non-EUI requests
     available to process, and if so, it will process the request.
     If there are no non-EUI requests to process, XLST will
     determine if the CMAS is at or near MAXTASK.  If so, XLST
     will terminate.  If not, XLST will go into its wait for work.
  

APAR Information

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

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

  PK15080 UK10708 PK25861

Modules/Macros

•    EYUQXLST EYURXLEB EYURXLST EYUTRKNL EYUTXLPD
  EYUUXLST EYUYXLST EYUZXLST EYU0XLBV EYU0XLNC EYU0XLST EYU9XLEV
  EYU9XLRU EYU9XLR3 EYU9XLR4 EYU9XLR5 EYU9XLR6
  

Fix information

• Fixed component name

  CPSM CICS 3.1

• Fixed component ID

  5655M1501

Applicable component levels

• R100 PSY UK10708

     UP06/01/13 P F601

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.