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LI73700: TABLE DESCRIPTOR FOR XML COLUMN STATS MAY GET CORRUPTION DURING 32BIT<->64BIT INSTANCE MIGRATION

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APAR status

  • Closed as program error.

Error description

  • When users migrate instance between 32 bit <-> 64 bit, the table
    descriptor for XML column statistics may get corruption.
    
    A typeical symptom is db2look failed with -101 because the
    corrupted descriptor may ask for unexpected amount of statement
    heap memory for the table.
    
    In order to validate that, db2cat is required to be run against
    the problematic table, and the last area for XML column
    statistics may show unexpected value for ColumnID or path counts
    
    ++++++++++++++++++++++++++++++++++++++++
    XML column statistics
    ++++++++++++++++++++++++++++++++++++++++
    Column ID            = 0
    No. NULL XML docs    = 0
    No. non-NULL XML docs = 0
    ----------------------------------------
    Catch All Pathid Bucket
    ----------------------------------------
    Distinct Pathid count = 0
    Sum Node Counts       = 0
    Sum Doc Counts        = 0
    ----------------------------------------
    Top-k Pathid node counts
    ----------------------------------------
    Max no. of path counts = -169592440
    Cur no. of path counts = 0
    ----------------------------------------
    Top-k Pathid doc counts
    ----------------------------------------
    Max no. of path counts = -169592440
    Cur no. of path counts = 0
    ----------------------------------------
    Top-k Pathid-Value node counts
    ----------------------------------------
    Max no. of path-value counts = -169592440
    Cur no. of path-value counts = 0
    ----------------------------------------
    Top-k Pathid-Value doc counts
    ----------------------------------------
    Max no. of path-value counts = -169592440
    Cur no. of path-value counts = 0
    ----------------------------------------
    Catch All Pathid-Value Bucket
    ----------------------------------------
    Max no. of buckets = -169592440
    Cur no. of buckets = 0
    ----------------------------------------
    

Local fix

  • RUNSTATS against the problematic table will update the corrupted
    XML column statistics information in descriptor
    db2 "RUNSTATS ON TABLE SYSIBM.SYSXSROBJECTS ON ALL COLUMNS WITH
    DISTRIBUTION AND SAMPLED DETAILED INDEXES ALL"
    

Problem summary

  • User Affected:
    All
    Problem Description:
    TABLE DESCRIPTOR FOR XML COLUMN STATS MAY GET CORRUPTION DURING
    32BIT<->64BIT INSTANCE MIGRATION
    Problem Summary:
    When users migrate instance between 32 bit <-> 64 bit, the table
    
    descriptor for XML column statistics may get corruption.
    
    A typeical symptom is db2look failed with -101 because the
    corrupted descriptor may ask for unexpected amount of statement
    heap memory for the table.
    
    In order to validate that, db2cat is required to be run against
    the problematic table, and the last area for XML column
    statistics may show unexpected value for ColumnID or path counts
    
    ++++++++++++++++++++++++++++++++++++++++
    XML column statistics
    ++++++++++++++++++++++++++++++++++++++++
    Column ID            = 0
    No. NULL XML docs    = 0
    No. non-NULL XML docs = 0
    ----------------------------------------
    Catch All Pathid Bucket
    ----------------------------------------
    Distinct Pathid count = 0
    Sum Node Counts       = 0
    Sum Doc Counts        = 0
    ----------------------------------------
    Top-k Pathid node counts
    ----------------------------------------
    Max no. of path counts = -169592440
    Cur no. of path counts = 0
    ----------------------------------------
    Top-k Pathid doc counts
    ----------------------------------------
    Max no. of path counts = -169592440
    Cur no. of path counts = 0
    ----------------------------------------
    Top-k Pathid-Value node counts
    ----------------------------------------
    Max no. of path-value counts = -169592440
    Cur no. of path-value counts = 0
    ----------------------------------------
    Top-k Pathid-Value doc counts
    ----------------------------------------
    Max no. of path-value counts = -169592440
    Cur no. of path-value counts = 0
    ----------------------------------------
    Catch All Pathid-Value Bucket
    ----------------------------------------
    Max no. of buckets = -169592440
    Cur no. of buckets = 0
    ----------------------------------------
    

Problem conclusion

  • Problem was first fixed in Version 9.1 Fix Pack 8
    

Temporary fix

  • RUNSTATS against the problematic table will update the corrupted
    
    XML column statistics information in descriptor
    db2 "RUNSTATS ON TABLE SYSIBM.SYSXSROBJECTS ON ALL COLUMNS WITH
    DISTRIBUTION AND SAMPLED DETAILED INDEXES ALL"
    

Comments

APAR Information

  • APAR number

    LI73700

  • Reported component name

    DB2 UDE ESE LIN

  • Reported component ID

    5765F4104

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-08-09

  • Closed date

    2009-10-26

  • Last modified date

    2009-10-26

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

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

    LI74507

Fix information

  • Fixed component name

    DB2 UDE ESE LIN

  • Fixed component ID

    5765F4104

Applicable component levels

  • R910 PSY

       UP

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Document Information

Modified date:
15 October 2021