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IC74036: DB2STOP FORCE MAY HANG IF WRITE SUSPEND IS ISSUED IN PARALLEL

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • A DB2 instance may hang if db2stop force and set write suspend
    are issued in parallel.
    
    There exists a timing hole such that a write suspend operation
    may successfully suspend a database during a stop force
    (deactivate phase). If this happens, the database will enter
    write suspend mode, and it will hang.
    
    This may happen in a case where an event monitor attempts to
    commit but is unable to because no writing is allowed. The event
    monitor then hangs and will refuse to shut down. Here is a stack
    of such an example:
    
    <StackTrace>
    sqloxconflict_LONG
    sqloXLatchNoSpin_track
    sqlpxcm1
    sqlrrcom_dps
    sqlrrcom
    sqm_evmon_ttarget::commitInserts
    sqm_evmon_ttarget::write_data
    sqmEvmonBuffer::write_data
    sqmEvmonWriter::flushBuffers
    sqmEvmonWriter::cleanupEvmonWriter
    sqmEvmonWriter::evmonWriter
    sqleIndCoordProcessRequest
    sqeAgent::RunEDU
    sqlzRunEDU
    sqloEDUEntry
    </StackTrace>
    

Local fix

  • Do not attempt to stop the instance in parallel with setting
    write suspend on a database within the instance.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * DB2 LUW                                                      *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * The instance is hung when db2stop force is issued.           *
    *                                                              *
    * There exists a timing hole such that a write suspend         *
    * operation may successfully suspend a database during a stop  *
    * force (deactivate phase). If this happens, the database will *
    * enter write suspend mode, and it will hang.                  *
    *                                                              *
    * This may happen in a case where an event monitor attempts to *
    * commit but is unable to because no writing is allowed. The   *
    * event monitor then hangs and will refuse to shut down.       *
    *                                                              *
    * sqloxconflict_LONG                                           *
    * sqloXLatchNoSpin_track                                       *
    * sqlpxcm1                                                     *
    * sqlrrcom_dps                                                 *
    * sqlrrcom                                                     *
    * sqm_evmon_ttarget::commitInserts                             *
    * sqm_evmon_ttarget::write_data                                *
    * sqmEvmonBuffer::write_data                                   *
    * sqmEvmonWriter::flushBuffers                                 *
    * sqmEvmonWriter::cleanupEvmonWriter                           *
    * sqmEvmonWriter::evmonWriter                                  *
    * sqleIndCoordProcessRequest                                   *
    * sqeAgent::RunEDU                                             *
    * sqlzRunEDU                                                   *
    * sqloEDUEntry                                                 *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 v9.7 fp4 or later.                            *
    ****************************************************************
    

Problem conclusion

  • db2_v97fp4 will contain the fix for the timing hole.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC74036

  • 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

    2011-01-21

  • Closed date

    2012-11-08

  • Last modified date

    2012-11-08

  • 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

  • R970 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC74036

Modified date: 08 November 2012