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IC75246: Log Replay of Update LOB Field Concatenation Can Cause Corruption

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • If a LOB field has been appended with an update command (e.g.
    using the || operator or the CONCAT scalar operator), it may
    become corrupted if either of the following scenarios occur:
    
    1. If a LOB is appended after a backup is taken, restoring from
    the backup and rolling forward such that the concatenation is
    replayed can corrupt the LOB.
    2. In HADR scenarios, a LOB concatenation operation on the
    primary can be incorrectly replayed on the secondary, corrupting
    the LOB.
    
    In both cases, the target LOB to be updated must contain the
    original version of itself as one of the concatenation
    arguments. The concatenation of other values written to the
    target LOB will not result in corruption.
    
    If corruption did occur, the LOB will appear to be truncated.
    Although the length as indicated by LENGTH(column) will report
    the non-corrupted size of the concatenated LOB, the actual LOB
    will appear to be shorter than what it should be.
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * An error in LOB concatenation in log replay can cause the    *
    * LOB to be concatenated to overwrite portions of the previous *
    * LOB.                                                         *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 V9.7 Fix Pack 4.                              *
    ****************************************************************
    

Problem conclusion

  • This problem was first fixed in DB2 V9.7 Fix Pack 4.
    

Temporary fix

  • n/a
    

Comments

APAR Information

  • APAR number

    IC75246

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-03-23

  • Closed date

    2011-05-05

  • Last modified date

    2011-05-12

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

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

    IC75313 IC83438

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSY

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC75246

Modified date: 12 May 2011