IBM Support

IT28060: LOAD OPERATION MAY TRAP OR CAUSE DATA OR INDEX PAGE CORRUPTION IN V11.1.4.4, WHEN READING PAGES FROM 9.7 OR PRIOR RELEASE

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APAR status

  • Closed as program error.

Error description

  • Regression starting in Version 11.1.4.4.
    
    When performing a LOAD operation, some pages are read by Load
    while bypassing the bufferpool (we refer to this as a
    'direct-read'). This is common in all Load operations, and most
    predominant in Load operations using INDEXING MODE REBUILD.
    
    In v9.7 and prior releases, a consistency bit was embedded at
    pre-defined intervals within data and index pages.  In 9.8 and
    later releases, this was replaced with a checksum field. The
    purpose and differences between the consistency bit and checksum
    field are beyond the scope of this APAR description.
    
    In Db2 Version 11.1.4.4, when a Load operation performs a
    direct-read of a data or index page that still contains the v9.7
    consistency bit format, it may not handle the consistency bit
    correctly. This will result in an in-memory page
    corruption at x200 offsets within the page, which may lead to
    different error symptoms.  This corruption could potentially
    even persist to disk if load writes the page back out (as it
    does for some meta table pages).
    
    Note, a data or index page will still contain the v9.7
    consistency bit format if the table and page was created on a
    9.7 or earlier release, and the data or index pages was never
    previously updated (inserted/updated/deleted) in a 9.8 or later
    release.
    
    Exposure to this issue will be most common in scenarios where a
    9.7 or earlier database is upgraded directly to v11.1.4.4 and
    Load operations performed.
    
    Due to the nature of data or index page corruptions, symptoms
    will vary, including: the potential for Load to fail with an
    unexpected error; or for the Load operation to trap (especially
    during the INDEX REBUILD phase, if one exists) and bring down
    the database instance; or unexpected failures or traps in the
    future when these corrupt pages are accessed by non-Load
    operations, such as select, insert, update, delete operations.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 11.1 Mod 4 Fixpack 5 or higher                *
    ****************************************************************
    

Problem conclusion

  • First fixed in Db2 11.1 Mod 4 Fixpack 5
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT28060

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-02-11

  • Closed date

    2020-01-16

  • Last modified date

    2020-01-16

  • 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

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RB10 PSN

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
16 January 2020