OA58507: JOB HUNG IFCC ASYNCXI CFLEVEL 22 DB2 DSNB5SCM after PTFs UA97982 or UA97985 are applied 19/11/08 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When using asynchronous XI and connector specifies IXLCONN
  ASYNCXI=1, the connection information is updated to indicate
  connector understanding of the async protocol:
  Async XI support : YES
  If the CF is not at CFLEVEL 23 (which is required to support
  async XIs) then the if the request fails (i.e. IFCC on outbound
  chpid) recovery will redrive the request, which causes the
  request to be suspended and the job hangs.
  VERIFICATION:
  XESDATA DETAIL can be checked:
  1. Asynchronous XI Requests:
  Lowest active AXISN................. 00000000_00000000
  Highest issued AXISN................ 00000000_00000000
  Suspendee Info...................... 02AF6020
  Requestor home ASCB address...... 00F3B580
  Requestor home ASID.............. X'010C'
  Suspend token.................... 80198452 04EB6AE0
  Waiting for AXISN................ 00000000_00000000
  Confirm connectors support for async XI in XESDATA CONNECTION
  Confirm CFLEVEL
  
  
  PE Information:
  
  Users Affected:
  
  All Db2 12 for z/OS data sharing users with APAR PH10577
  (PERFORMANCE OPTIMIZATION OF ASYNCHRONOUS CROSS-INVALIDATION
  EXPLOITATION ) PTF UI62802,  which enables the use of  Coupling
  Facility (CF) asynchronous cross-invalidation (XI)  -AND-
  z/OS APAR OA54688 ( NEW FUNCTION - ASYNCHRONOUS
  CROSS-INVALIDATION FOR COUPLING FACILITY CACHE STRUCTURES)
  applied at one of the following z/OS levels:
  
  z/OS V2R2 (HBB77A0) with PTF UA97985
  z/OS V2R3 (HBB77B0 ) with PTF UA97982
  
  or base z/OS V2R4 installed.
  
  APAR OA54688 for z/OS V2R2 and V2R3 and base z/OS V2R4
  introduces support for asynchronous cross-invalidation.
  In this protocol made available at CFLEVEL 23 and introduced by
  GA2 of z14 models 3906 and 3907,
  the CF's communication to notify connectors of data invalidation
  can be initiated asynchronously with respect
  to the IXLCACHE request. In a transaction involving multiple
  cache requests, the parallelism obtained by allowing XI
  notifications to execute asynchronously may reduce both request
  service time and transaction elapsed time, thus improving
  overall application throughput.  Db2 12 for z/OS enables CF
  asynchronous cross-invalidation via APAR PH10577.
  
  
  The problem described by this APAR can only occur if the
  following three (3) conditions are present:
  
  1. DB2 12 for z/OS is installed with the PTF for APAR PH10577
  applied.
  2. z/OS V2R2 or V2R3 is installed with the PTF(s) for APAR
  OA54688 applied or z/OS V2R4 is installed.
  3. Your DB2 data sharing group buffer pool structures are
  allocated in a CF at CFLEVEL 22 or lower.
  
  
  User Impact:
  
  APAR OA54688 at the available z/OS levels and z/OS V2R4 provided
  the intended new function but contains an error that
  can cause IXLCACHE requests to hang indefinitely waiting for
  asynchronous cross-invalidations to complete when a cache
  structure resides
  in a CF at CFLEVEL 22 or lower. The z/OS asynchronous
  cross-invalidation support incorrectly looks for asynchronous
  cross-invalidation completions
  in a CF that does not support the asynchronous
  cross-invalidation protocol.
  

Local fix

• Eliminate cause of IFCCs.
  
  ++APARs  for all affected z/OS releases are available on the
  testcase.boulder.ibm.com website under
   fromibm/mvs subdirectory and named as follows:
  
  BA58507.HBB77B0
  CA58507.HBB77C0
  KA58507.HBB77A0
  
  The files should be retrieved with FB, 80, 3200 in Binary.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 12 for z/OS data sharing users with                  *
  * APAR PH10577 (PERFORMANCE OPTIMIZATION OF                    *
  * ASYNCHRONOUS CROSS-INVALIDATION                              *
  * EXPLOITATION) PTF UI62802, which enables the                 *
  * use of Coupling Facility (CF) asynchronous                   *
  * cross-invalidation (XI) -AND- z/OS APAR                      *
  * OA54688 (NEW FUNCTION - ASYNCHRONOUS                         *
  * CROSS-INVALIDATION FOR COUPLING FACILITY                     *
  * CACHE STRUCTURES) applied at one of the                      *
  * following z/OS levels:                                       *
  *                                                              *
  * z/OS V2R2 (HBB77A0) with PTF UA97985                         *
  * z/OS V2R3 (HBB77B0) with PTF UA97982                         *
  *                                                              *
  * or Base z/OS V2R4 (No APAR).                                 *
  *                                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * IXLCACHE requests can hang indefinitely                      *
  * waiting for asynchronous                                     *
  * cross-invalidations to complete when a                       *
  * cache structure resides in a CF at                           *
  * CFLEVEL 22 or lower. The z/OS                                *
  * asynchronous cross-invalidation support                      *
  * incorrectly looks for asynchronous                           *
  * cross-invalidation completions from a                        *
  * CF that does not support the                                 *
  * asynchronous cross-invalidation                              *
  * protocol.                                                    *
  *                                                              *
  * SYSPLEXDS                                                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Install PTF via rolling IPL on each system                   *
  * in the sysplex.                                              *
  ****************************************************************
  APAR OA54688 for z/OS V2R2 and V2R3 and base z/OS V2R4
  introduces support for asynchronous cross-invalidations of cache
  structure data. The support provides the capability for cache
  structure connectors to be notified of data cross-invalidations
  asynchronously with respect to an IXLCACHE request. Under
  certain error conditions, the IXLCACHE service routine may have
  to suspend on behalf of the IXLCACHE requestor until completion
  of asynchronous cross-invalidations associated with a request
  complete. OA54688 contains an error where suspend processing is
  performed when no asynchronous cross-invalidations were
  initiated due to the cache structure residing in a CF LEVEL that
  does not support asynchronous cross-invalidations. The user
  request remains suspended (hung) indefinitely
  in the IXLCACHE service routine.
  

Problem conclusion

• The IXLCACHE service routine was updated to correctly determine
  when there is a need to suspend on behalf of the IXLCACHE
  requestor to wait for asynchronous cross-invalidations to
  complete.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UJ01330 UJ01331 UJ01335

Modules/Macros

• IXLM2DIE IXLM2TAM IXLM2DR  IXLR1CAC
  

Fix information

• Fixed component name

  CROSS SYS.EXT.S

• Fixed component ID

  5752SCIXL

Applicable component levels

• R7A0 PSY UJ01335

     UP19/11/20 P F911 ­

• R7B0 PSY UJ01330

     UP19/11/20 P F911 ­

• R7C0 PSY UJ01331

     UP19/11/20 P F911 ­

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.