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PI40585: Specific keys can result in incorrect behavior when using eXtremeMemory (XM).

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APAR status

  • Closed as program error.

Error description

  • When using a DataSerializer, and the hash code of a key is -1
    and eXtremeMemory is enabled, the following types of problems
    can occur:
    
    - Get operations can return null when the entry is actually in
    the map.
    
    - Update operations can fail with KeyNotFoundExceptions.
    
    - Upsert operations can get into an infinite loop that does
    not recover.  The client symptom is a message timeout.
    
    - Asynchronous replication can continue to fail to replicate
    due to DuplicateKeyExceptions, until the offending key or
    set of keys are deleted.
    
    - An entry may never be evicted when using time-to-live
    eviction.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of eXtreme Scale who use          *
    *                  eXtremeMemory.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: Keys with a hash code of -1 do not      *
    *                      work correctly when using               *
    *                      eXtremeMemory.                          *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Logic in the native eXtremeMemory code assumed that -1 meant a
    hash code was not provided. Because of this logic, a hash
    algorithm in the native code was used instead.  The native
    code hash algorithm was flawed causing get operations to fail,
    which also caused upsert and update errors.  The logic was
    updated to always use the Java hash code and not do anything
    special for the -1 hash code.
    

Problem conclusion

  • An interim fix is available for this APAR upon request.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PI40585

  • Reported component name

    WS EXTREME SCAL

  • Reported component ID

    5724X6702

  • Reported release

    860

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2015-05-07

  • Closed date

    2015-05-28

  • Last modified date

    2015-05-28

  • 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

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Document Information

Modified date:
28 May 2015