IBM Support

LI73319: DATA CORRUPTION WHEN A LOB OBJECT ASSOCIATED WITH A TABLE GROWS LARGER THAN 2 TB

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • When a large object (BLOB, CLOB, or DBCLOB data type) object
    that is associated with a table crosses the 2 terabyte (TB) size
    boundary, there is a problem in the space allocation algorithm
    that can lead to corruption of the table space.  For example a
    previously allocated extent might be erroneously reused.  One
    occurrence of this problem resulted in the beginning pages of
    the LOB table space being overwritten when the LOB object grew
    larger than 2 terabytes.
    

Local fix

  • Use a range partitioned table to split LOBs for a column into
    separate LOB objects to avoid crossing the 2TB threshold for a
    single LOB object.
    
    The size of the LOB object can be determined using the following
    command:
    
    db2pd -db dbname -tcbstats
    
    One of the columns that is generated in this report is LobSize
    (which is shown as number of pages).  A quick calculation
    (number of pages * page size) will give the size of the LOB
    object.
    
    If the LOB object has already crossed the 2TB boundary just
    applying the fix will not correct the issue, the table will
    still need to be rebuilt.
    

Problem summary

  • User affected: Any using large > 2TB LOB objects in a table for
    LOB storage.
    Problem description: Corruption of the LOB object can occur if
    it crosses the 2TB size boundary.
    Problem Summary: see above
    

Problem conclusion

  • Problem was first fixed in Version 9.1 FixPak 5 (s080512).
    

Temporary fix

  • Use a range partitioned table to split LOBs for a column into
    separate LOB objects to avoid crossing the 2TB threshold for a
    single LOB object.
    
    Note: If the LOB object has already crossed the 2TB boundary
    just
    applying the fix will not correct the issue, the table will
    still need to be rebuilt.
    

Comments

APAR Information

  • APAR number

    LI73319

  • Reported component name

    DB2 UDB WSE LIN

  • Reported component ID

    5765F3504

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-03-28

  • Closed date

    2008-07-12

  • Last modified date

    2008-09-04

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

    LI73318

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

Fix information

  • Fixed component name

    DB2 UDB WSE LIN

  • Fixed component ID

    5765F3504

Applicable component levels

  • R910 PSN

       UP

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"910","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
15 October 2021