PK89459: SYSPLEX OPTIMISED WLM ROUTING CHANGES

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• - Changing RSPOOLID on CPLEXDEF once workload is created affects
  running wokloads, leading to incorrect routing.
  - Message EYUWM0504I and EYUWM0503I repeatedly issued in a
    router when a target is outside of the sysplex.
  - High coupling facility update rates may occur with an
    optimized workload when a target region is at MAXTASKs
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICSPlex SM V4R1M0 Users                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: -  When a Sysplex optimized routing     *
  *                         region includes within its routing   *
  *                         scope a Sysplex optimized target     *
  *                         region that is active on a different *
  *                         Sysplex, the routing region will     *
  *                         repeatedly go in and out of          *
  *                         optimized state, issuing messages    *
  *                         EYUWM0504I and EYUWM0503I each time  *
  *                         it switches.  (26673)                *
  *                                                              *
  *                         The text of the messages will be     *
  *                         similar to the following:            *
  *                                                              *
  *                         EYUWM0504I Routing region (<name>)   *
  *                                    is not running in Sysplex *
  *                                    Optimized WLM state.      *
  *                                                              *
  *                         EYUWM0503I Routing region (<name>)   *
  *                                    is running in Sysplex     *
  *                                    Optimized WLM state       *
  *                                                              *
  *                      -  Various errors will occur if the     *
  *                         CPLEXDEF RSPOOLID value is changed   *
  *                         while any workloads associated with  *
  *                         the CICSplex are active.  (26673)    *
  *                                                              *
  *                      -  Excessive coupling facility updates  *
  *                         may occur when target regions reach  *
  *                         maxtask (MXT). (26813)               *
  ****************************************************************
  * RECOMMENDATION: After applying the PTF that resolves this    *
  *                 APAR, all CMASes, WUI servers and MASes must *
  *                 be restarted.  Note that the restarts do not *
  *                 need to occur at the same time.              *
  *                                                              *
  *                 Additionally, users of the CICSPlex SM       *
  *                 supplied starter set viewsets and menus must *
  *                 re-import the updated starter set viewset    *
  *                 and menu definitions into each Web User      *
  *                 Interface (WUI) server's repository in order *
  *                 to pick up the changes.                      *
  *                                                              *
  *                 The starter set viewsets and menus can be    *
  *                 re-imported either via the AUTOIMPORTDSN and *
  *                 AUTOIMPORTMEM WUI server initialization      *
  *                 parameters or the IMPORT (from a dataset)    *
  *                 function of the COVC WUI transaction.        *
  *                                                              *
  *                 If COVC is used to re-import the starter     *
  *                 set, ensure that the OVERWRITE import option *
  *                 is specified if the WUI server's repository  *
  *                 previously contained that starter set        *
  *                 viewsets and menus.                          *
  *                                                              *
  *                 For details on the COVC IMPORT function see  *
  *                 'The CICSPlex SM Web User Interface          *
  *                 transaction (COVC)' in the CICS Transaction  *
  *                 Server for z/OS Version 4 Release 1 CICSPlex *
  *                 SM Web User Interface Guide (SC34-7045).     *
  *                                                              *
  *                 The updated starter set member name that     *
  *                 needs to be imported is:                     *
  *                                                              *
  *                 View: EYUxA240                               *
  *                                                              *
  *                 Replace x with the required language version *
  *                 to be imported: E - English, K - Japanese, S *
  *                 - Chinese.                                   *
  ****************************************************************
  -  When an optimized routing region encounters an active
     optimized target region in a routing scope, method EYU0WNAL
     (WNAL) running in the routing region will call module DFHRSSR
     to perform a lookup of the target region's optimization
     block.  Sysplex optimization only occurs when both the
     routing and target regions reside within the same Sysplex.
     If the target region is in another Sysplex, the block will
     not be found, and DFHRSSR returns a SERVER_FAILED return code
     to WNAL.  WNAL will then issue message EYUWM0504I and mark
     itself inactive for optimization.
  
     When the COIE heartbeat task next runs in the routing region
     (this task runs every 15 seconds), method EYU0NLHD (NLHD)
     will call method EYU0WNHD (WNHD) to verify the region's
     status.  WNHD will determine that the region is marked
     inactive for optimization, when it should be active for
     optimization.  As a result, WNHD will mark it active for
     optimization and issue message EYUWM0503I.
  
     This process will continue as long as an active optimized
     target region that resides on a different Sysplex remains in
     the routing region's routing scope.
  
  -  Sysplex optimization uses a CICS coupling facility data table
     (CFDT) to store information about target regions.  The CFDT
     is associated with a coupling facility pool ID, which is
     defined in the CPLEXDEF record.  This data is accessed from
     the target region, routing regions, and CMASes.  The first
     time a specific region accesses the data, the CFDT is opened
     with the current pool ID.  If the pool ID is changed, active
     systems that have already opened the CFDT will continue to
     use the old pool ID, while systems that first access the CFDT
     after the pool ID change will open the file with the new pool
     ID.  This will result in regions accessing different data.
  
  -  To reduce coupling facility activity, Sysplex optimization
     has been tuned so that an optimized target region updates its
     optimization block in the CFDT when certain active task count
     thresholds are met.  Normally, the threshold is a task
     increment based upon the UPDATERS attribute for the target.
     A secondary value, based upon the TOPRSUPD attribute for
     the target, is used when the target approaches maxtask.
     Since it is important to update more frequently as the region
     goes in and out of maxtask, this increment value is normally
     lower than the UPDATERS value, resulting in more frequent
     updates of the CFDT.  This lower increment value is also used
     to determine further CFDT updates as tasks become queued for
     maxtask in the target.  Since the target is unlikely to
     receive work as it is already at maxtask, these frequent
     updates cause unnecessary coupling facility activity.
  

Problem conclusion

• -  DFHRSSR has been updated to return TARGET_NOT_KNOWN when it
     cannot find the optimization block for a target region.  WNAL
     has been updated to check for this return code, and if found,
     will correctly treat the target region as inactive for
     optimization and will not issue message EYUWM0504I and will
     not mark the routing region inactive for optimization.
  
  -  To ensure that all regions access the same CFDT data, if the
     CPLEXDEF pool ID is changed while workloads are active within
     the CICSplex, the following will now occur:
  
     -  all CMASes that have opened the CFDT file with the old
        pool ID will CLOSE and DISABLE the CFDT, associate the
        CFDT with the new pool ID, and then will OPEN and ENABLE
        the CFDT.
  
     -  all active routing and target regions that have opened the
        CFDT with the old pool ID, will be marked inactive for
        optimization until they are restarted.  Note that stopping
        and restarting the MAS agent is not sufficient.  The
        regions must be terminated and restarted.
  
        The distributed WUI starter set CPLEXDEF viewset has been
        modified to include a warning to this effect on the UPDATE
        view.
  
        The CPLEXDEF viewset help for attribute RSPOOLID has also
        been modified to indicate what will occur if the attribute
        is modified.
  
  -  DFHRSSR has been updated to not update a target region's
     optimization block after updating it to indicate that the
     target is at maxtask, until the maxtask condition ends.
  

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:

  UK49986

Modules/Macros

• CPLEXDEF DESRSFD  DESRSSR  DESRSXM  DFHRSFD
  DFHRSSR  DFHRSSRA DFHRSSRM DFHRSSRT DFHRSXM  EYUEA240 EYUE2736
  EYUKA240 EYUK2736 EYUMCWMC EYUMCWME EYUMCWMK EYUQCCPU EYURCCPU
  EYURWAOR EYURWTOR EYUSA240 EYUS2736 EYUUCMEQ EYUUWMEQ EYUYCCPU
  EYUZCCPU EYU0CCPU EYU0WARS EYU0WMAA EYU0WMAD EYU0WMWD EYU0WNAL
  EYU0WNHD EYU0WNRS EYU0WNWK EYU0WPUD HCI6600J
  

Fix information

• Fixed component name

  CICS TS Z/OS V4

• Fixed component ID

  5655S9700

Applicable component levels

• R60M PSY UK49986

     UP09/09/25 P F909

• R600 PSY UK49985

     UP09/09/25 P F909

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.