PI15808: A ClassCastException exception can occur when removing a non-existing entry and using the write-behind loader function.

APAR status

• Closed as program error.

Error description

• When processing a remove request of an entry that is not in
  the data grid or the back-end server, transactions fail with an
  exception similar to following example:
  
  java.lang.ClassCastException:
  com.ibm.websphere.objectgrid.plugins.Loader$SpecialValue
  incompatible with
  com.ibm.ws.objectgrid.plugins.io.dataobject.SerializedEntryExten
  sions
  at
  com.ibm.ws.objectgrid.writebehind.QueueMapValueSerializer.serial
  izeDataObject(QueueMapValueSerializer.java:64)
  at
  com.ibm.ws.objectgrid.plugins.io.dataobject.values.ValueDataImpl
  .autoSerialize(ValueDataImpl.java:234)
  at
  com.ibm.ws.objectgrid.plugins.io.dataobject.values.ValueDataImpl
  .checkBufferAndSerialize(ValueDataImpl.java:156)
  at
  com.ibm.ws.objectgrid.plugins.io.dataobject.values.ValueDataImpl
  .isIndirectHeapBuffer(ValueDataImpl.java:149)
  at
  com.ibm.ws.objectgrid.DiffMapValue.getCurrentBytesSerialized(Dif
  fMapValue.java:1199)
  at
  com.ibm.ws.objectgrid.DiffMapValue.getCurrentBytes(DiffMapValue.
  java:1102)
  at
  com.ibm.ws.objectgrid.DiffMapValue.getCurrentBytes(DiffMapValue.
  java:1080)
  at
  com.ibm.ws.objectgrid.map.BaseMap.getValueToCommit(BaseMap.java:
  3917)
  at
  com.ibm.ws.objectgrid.map.BaseMap.insertCacheEntry(BaseMap.java:
  3331)
  at
  com.ibm.ws.objectgrid.map.BaseMap.applyPMap(BaseMap.java:2186)
  at
  com.ibm.ws.objectgrid.SessionImpl.commit(SessionImpl.java:1771)
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  Users of eXtreme Scale who run with the     *
  *                  write-behind loader function.               *
  ****************************************************************
  * PROBLEM DESCRIPTION: The value that is trying to be          *
  *                      persisted to the queue map is           *
  *                      Loader.KEY_NOT_FOUND when it should     *
  *                      be null.                                *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  LogElement.getBeforeImage and getAfterImage were updated to
  return null if the stored value is currently
  Loader.KEY_NOT_FOUND.  A previous defect fix stored it as
  Loader.KEY_NOT_FOUND to make sure a non-existing remove
  followed by a put operation in the same transaction
  resulted in an insert operation instead of an update
  operation.  This APAR is a side effect of that change.
  

Problem conclusion

• An interim fix is available for this APAR.
  

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

• Fixed component name

  WS EXTREME SCAL

• Fixed component ID

  5724X6702

Applicable component levels

• R860 PSY

     UP