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IC86520: HEALTH MONITOR ACTIVITIES AND AUTOMATIC MAINTENANCE MAY FAIL DUE TO MEMORY LEAK/EXHAUSTION

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • On instances with volatile databases (frequently
    deactivating/activating), and with health monitoring and/or
    automatic maintenance enabled, a memory leak may occur in the
    memory segment supporting health monitor and automatic
    maintenance activities.  The memory segment is a relatively
    small fixed size, so the concern is not the amount of memory
    consumed, but that these activities will start failing once the
    memory insides the segment becomes exhausted (it is being
    managed/assigned internally by DB2).
    
    A variety of symptoms may occur, such as tables statistics not
    being updated, which can negatively affect optimizer
    plans/performance.  The following db2diag.log entry is an
    indication that the memory inside the segment is exhausted:
    
    2011-08-19-14.18.41.245798+330 I29615875A490      LEVEL: Severe
    PID     : 1126558              TID  : 772         PROC : db2acd
    0
    INSTANCE: db2inst1             NODE : 000
    EDUID   : 772                  EDUNAME: db2acd 0
    FUNCTION: DB2 UDB, Health Monitor, hmonTreeResizeRequest,
    probe:10
    MESSAGE : The health monitor shared memory segment is full.
    Current size
              100663296, free 36800
    DATA #1 : Hexdump, 4 bytes
    0x0000000110518DB0 : 0000 0000
    ....
    

Local fix

  • If possible, explicitly activate databases.  This prevents the
    memory leak by avoiding volatility in the metadata maintained by
    health monitoring and automatic maintenance activities, and may
    generally improve performance.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * systems with health monitor or automatic maintenance enabled *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * upgrade to DB2 Version 9.7 Fix Pack 8                        *
    ****************************************************************
    

Problem conclusion

  • Problem first fixed in DB2 Version 9.7 Fix Pack 8
    

Temporary fix

  • see local fix
    

Comments

APAR Information

  • APAR number

    IC86520

  • 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

    2012-09-12

  • Closed date

    2013-07-11

  • Last modified date

    2013-07-11

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

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

    IC86534

Modules/Macros

  • sqmh
    

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP

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Document Information

Modified date:
11 July 2013