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OA24071: LOSS OF SERIALIZATION OF VSAM WORKING STORAGE

A fix is available

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APAR status

  • Closed as program error.

Error description

  • VSAM Record Management has a header block to keep track of
    storage that is acquired by VSAM for internal processing. The
    routine that assigns this storage has a small timing hole that
    can enable two requests to think they own the same storage. This
    causes overlay type symptoms.
    SYMPTOMS:
    ABEND0C4 in IDA019L1 WSHD
    Garbage in RPL feedback word
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of VSAM Record Management that     *
    *                 utilize VSAM Compressed data sets or data    *
    *                 sets that have alternate indexes.            *
    ****************************************************************
    * PROBLEM DESCRIPTION: A failure to serialize access to        *
    *                      work storage used by VSAM requests      *
    *                      can result in 2 requests using the      *
    *                      same storage simultaneously.            *
    *                      Unpredictable results can occur         *
    *                      including apparent overlays, ABENDS     *
    *                      and incorrect RPL feedback codes.       *
    ****************************************************************
    * RECOMMENDATION: Apply PTFs.                                  *
    ****************************************************************
    A header control block is used to serialize the assignment of
    internal work storage used by VSAM.  A small window exists
    that can cause two requests to be assigned the same storage.
    

Problem conclusion

  • The procedure in IDA019RX that assigns this work storage has
    been changed to utilize only registers when setting up for a
    Compare and Swap on the assignment of the block of storage.
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    OA24071

  • Reported component name

    DFSMS VSAM MEDA

  • Reported component ID

    5695DF106

  • Reported release

    1K0

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2008-02-15

  • Closed date

    2008-03-19

  • Last modified date

    2010-11-17

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

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

    UA40125 UA40126 UA40127

Modules/Macros

  •    IDA019RX
    

Fix information

  • Fixed component name

    DFSMS VSAM MEDA

  • Fixed component ID

    5695DF106

Applicable component levels

  • R1K0 PSY UA40125

       UP08/06/27 P F806 Ž

  • R180 PSY UA40126

       UP08/06/27 P F806 Ž

  • R190 PSY UA40127

       UP08/06/27 P F806 Ž

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.

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Document Information

Modified date:
09 January 2021