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IC74968: ABEND WHEN DROPPING SMALL TABLE OR REORGANIZING LOB OBJECT WHEN DB2_MEMORY_PROTECT ENABLED ON AIX WITH STORAGE KEY SUPPORT

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • The DB2_MEMORY_PROTECT registry variable is enabled, and DB2 is
    running on AIX with storage key support, which is one of the
    pre-conditions for DB2_MEMORY_PROTECT to take effect (please
    refer to Information Center for more detail). When these
    conditions are met, the DB2 instance may abend during one of the
    following actions. The common denominator is the presence of the
    sqlbPurgeOrFlushEMPs routine in the trap file.
    
    1) Small Table Drop
    ===================
    This problem can only happen if the table to be dropped has
    dirty pages in one of the bufferpools defined on the current
    database, and the size of the table is relatively small compared
    to the size of the dirty lists for the bufferpool (the exact
    threshold is IBM Confidential and subject to change). In this
    case the table will qualify for fast dirty page purging, and the
    attempt to purge its dirty pages during DROP TABLE will cause an
    instance abend. The trap file will be similar to:
    
    EDU name     : db2agent (SAMPLE)
    Signal #11
    
    sqlpflog or sqlbGetPageLSN
    sqlpflog or sqlbCheckAndForceLogs
    sqlbPurgeOrFlushAllPagesInSmallRange
    sqlbPurgeOrFlushEMPs
    sqlbDMSDeleteObject
    
    2) LOB Reorg
    ============
    A similar trap may happen during a lob object reorganization.
    The trap file will be similar to:
    
    EDU name     : db2agent (SAMPLE)
    Signal #11
    
    sqlbAddToHateList_IUO
    sqlbPurgeAllPagesCommon
    sqlbPurgeOrFlushEMPs
    sqldReorgReplaceDMS
    sqldReorgCopyPhase
    
    Both problems only exist in DB2 UDB 9.7 FixPak 1 or newer.
    

Local fix

  • Disable DB2_MEMORY_PROTECT.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ABEND WHEN DROPPING SMALL TABLE OR REORGANIZING LOB OBJECT   *
    * WHEN DB2_MEMORY_PROTECT ENABLED ON AIX WITH STORAGE KEY      *
    * SUPPORT                                                      *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * The DB2_MEMORY_PROTECT registry variable is enabled, and DB2 *
    * is running on AIX with storage key support, which is one of  *
    * the pre-conditions for DB2_MEMORY_PROTECT to take effect     *
    * (please refer to Information Center for more detail). When   *
    * these conditions are met, the DB2 instance may abend during  *
    * one of the following actions. The common denominator is the  *
    * presence of the sqlbPurgeOrFlushEMPs routine in the trap     *
    * file.                                                        *
    *                                                              *
    * 1) Small Table Drop                                          *
    * ===================                                          *
    * This problem can only happen if the table to be dropped has  *
    * dirty pages in one of the bufferpools defined on the current *
    * database, and the size of the table is relatively small      *
    * compared to the size of the dirty lists for the bufferpool   *
    * (the exact threshold is IBM Confidential and subject to      *
    * change). In this case the table will qualify for fast dirty  *
    * page purging, and the attempt to purge its dirty pages       *
    * during DROP TABLE will cause an instance abend. The trap     *
    * file will be similar to:                                     *
    *                                                              *
    * EDU name    : db2agent (SAMPLE)                              *
    * Signal #11                                                   *
    *                                                              *
    * sqlpflog or sqlbGetPageLSN                                   *
    * sqlpflog or sqlbCheckAndForceLogs                            *
    * sqlbPurgeOrFlushAllPagesInSmallRange                         *
    * sqlbPurgeOrFlushEMPs                                         *
    * sqlbDMSDeleteObject                                          *
    *                                                              *
    * 2) LOB Reorg                                                 *
    * ============                                                 *
    * A similar trap may happen during a lob object                *
    * reorganization.                                              *
    * The trap file will be similar to:                            *
    *                                                              *
    * EDU name    : db2agent (SAMPLE)                              *
    * Signal #11                                                   *
    *                                                              *
    * sqlbAddToHateList_IUO                                        *
    * sqlbPurgeAllPagesCommon                                      *
    * sqlbPurgeOrFlushEMPs                                         *
    * sqldReorgReplaceDMS                                          *
    * sqldReorgCopyPhase                                           *
    *                                                              *
    * Both problems only exist in DB2 UDB 9.7 FixPak 1 or newer.   *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 UDB 9.7 FixPak 5.                             *
    ****************************************************************
    

Problem conclusion

  • This APAR is first fixed in DB2 UDB 9.7 FixPak 5.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC74968

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-03-10

  • Closed date

    2011-12-23

  • Last modified date

    2011-12-23

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

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

    IC75711

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC74968

Modified date: 23 December 2011