II06463: GDG DUPLICATE GENERATIONS GDGALL REQUEST

APAR status

• Closed as canceled.

Error description

• ALSO SEE:  II08285
  Symptoms: Multiple copies of the same generation allocated on
            a GDG all request.
            Duplicate MSGIEF285I IEF285I for the same data set
            name
  
  Cause: Programs cataloging new generations of the same GDG while
         the failing step is going through allocation.
  
     In this case a user program that catalogs new generations of
  a GDG using SVC99 was running.  The program calculates its own
  GxxxxVxx number and issues the SVC99 (Dynamic Allocation) for
  the fully qualified name with a disposition of NEW CATALOG :
  
       SVC99 PARM DALSTATS = x'04' (NEW)
       SVC99 PARM DALNDISP = x'02' (CATLG)
  
     This user application program does not use the relative
  generation number.  This causes a problem because the proper
  serialization is not obtained for the GDG base.  Normally
  allocation enqueues (ENQ) on the base GDG name plus the fully
  qualified name.  The base enqueue prevents multiple updates to
  the catalog.  The base GDG name must be enqueued prior to the
  catalog being updated to insure proper serialization.
     If the proper serialization is not maintained when
  updating the catalog you could have duplicate generations for a
  GDGALL request.  This occurs due to the way allocation
  processes GDGALL requests.  A locate is done for the base and
  catalog will return the number of generations.  Allocation will
  then issue locates for each of the generations.  If while doing
  this, a new generation (GDS) is cataloged, the next locate by
  allocation will give the same data set name as the previous
  locate.  This is because the generations have now shifted and
  the previous generation is now the current.
     For information regarding the use and operation of the
  GDG ALL (GDGALL) request see the GDG appendix B. of the
  MVS/ESA JCL USER's GUIDE.  A GDGALL request will retrieve
  all generations (GDS) of a GDG as a single data set.  This is
  done by specifying the GDG name without a generation number
  in the DSNAME parameter (DALDSNAM).
  
  VSAMINFO : more information related to overall GDG functions
             can be found in the DFP 'Using Data Sets' manual.
  
  CATKEYS: CATINFO CATGDG
  

Local fix

• none
  ALSO SEE:   II08285
  

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

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

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

Fix information

Applicable component levels