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IC75916: MONITOR HEAP LEAKING IN SIZE 16 AND 24 BYTES MAY OCCUR IF THERE ARE MANY TASKS RUN LIKE RESET MONITOR AND INSTANCE DETACH.

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APAR status

  • Closed as program error.

Error description

  • If there are many tasks like "db2 reset monitor all" and "db2
    detach" run in the background, from the the db2pd -memblock
    output, it could be perceived that db2 is leaking 16 and 24
    bytes monitor memory at a stretch, like below:
    
    Address            PoolID PoolName BlockAge Size I LOC File
    0x0780000003694AC8 11     monh     7195      24  1 146
    3254716357
    0x0780000003694B08 11     monh     43116     16  1 146
    3254716357
    0x0780000003694B48 11     monh     43117     24  1 146
    3254716357
    0x078000000369D8C8 11     monh     63753     16  1 146
    3254716357
    0x078000000369D908 11     monh     63754     24  1 146
    3254716357
    0x078000000369DA28 11     monh     27486     16  1 146
    3254716357
    0x078000000369DA68 11     monh     27487     24  1 146
    3254716357
    0x078000000369DDA8 11     monh     19330     16  1 146
    3254716357
    0x078000000369DE68 11     monh     30457     16  1 146
    3254716357
    0x078000000369DF68 11     monh     55378     16  1 146
    3254716357
    ...
    
    Under such condition, the monitor memory heap will NOT be
    released all the while and the error DIA8300C will be come up
    with in the db2diag.log at the end as below:
    
    2011-04-11-13.52.10.204659+480 I1287415A500   LEVEL: Severe
    PID     : 2150452      TID  : 1       PROC : db2agent(instance)
    0
    INSTANCE: db2inst1     NODE : 000
    APPHDL  : 0-298        APPID:*LOCAL.db2inst1.2007070720080708
    AUTHID  : hujinpei
    FUNCTION: DB2 UDB, database monitor, sqm_object::new, probe:100
    RETCODE : ZRC=0x8B0F000B=-1961951221=SQLO_NOMEM_MONH
              "No memory available in 'Database Monitor Heap'"
              DIA8300C A memory heap error has occurred.
    

Local fix

  • The memory lack only happen when detaching the instance
    attachment. Keep using the same instance attachment to do the
    "reset monitor" and snapshot could avoid the memory leak.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * If there are many tasks like "db2 reset monitor all" and     *
    * "db2 detach" run in the background, from the the db2pd       *
    * -memblock output, it could be perceived that db2 is leaking  *
    * 16 and 24 bytes monitor memory at a stretch, like below:     *
    *                                                              *
    * Address            PoolID     PoolName     BlockAge          *
    * Size(Bytes)  I LOC   File                                    *
    * 0x0780000003694AC8 11         monh         7195       24     *
    * 1 146   3254716357                                           *
    * 0x0780000003694B08 11         monh         43116      16     *
    * 1 146   3254716357                                           *
    * 0x0780000003694B48 11         monh         43117      24     *
    * 1 146   3254716357                                           *
    * 0x078000000369D8C8 11         monh         63753      16     *
    * 1 146   3254716357                                           *
    * 0x078000000369D908 11         monh         63754      24     *
    * 1 146   3254716357                                           *
    * 0x078000000369DA28 11         monh         27486      16     *
    * 1 146   3254716357                                           *
    * 0x078000000369DA68 11         monh         27487      24     *
    * 1 146   3254716357                                           *
    * 0x078000000369DDA8 11         monh         19330      16     *
    * 1 146   3254716357                                           *
    * 0x078000000369DE68 11         monh         30457      16     *
    * 1 146   3254716357                                           *
    * 0x078000000369DF68 11         monh         55378      16     *
    * 1 146   3254716357                                           *
    * ...                                                          *
    *                                                              *
    * Under such condition, the monitor memory heap will NOT be    *
    * released all the while and the error DIA8300C will be come   *
    * up with in the db2diag.log at the end as below:              *
    *                                                              *
    * 2011-04-11-13.52.10.204659+480 I1287415A500       LEVEL:     *
    * Severe                                                       *
    * PID     : 2150452              TID  : 1           PROC :     *
    * db2agent                                                     *
    * (instance) 0                                                 *
    *                                                              *
    * INSTANCE: db2inst1             NODE : 000                    *
    *                                                              *
    * APPHDL  : 0-298                APPID:                        *
    * *LOCAL.db2inst1.2007070720080708                             *
    * AUTHID  : hujinpei                                           *
    *                                                              *
    * FUNCTION: DB2 UDB, database monitor, sqm_object::new,        *
    * probe:100                                                    *
    * RETCODE : ZRC=0x8B0F000B=-1961951221=SQLO_NOMEM_MONH         *
    *                                                              *
    * "No memory available in 'Database Monitor Heap'"             *
    *                                                              *
    * DIA8300C A memory heap error has occurred.                   *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to v9.7 FP5                                          *
    ****************************************************************
    

Problem conclusion

  • The memory lack only happen when detaching the instance
    attachment. Keep using the same instance attachment to do the
    "reset monitor" and snapshot could avoid the memory leak.
    
    This defect will be fixed in v9.7 FP5
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC75916

  • 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

    2011-04-20

  • Closed date

    2011-12-10

  • Last modified date

    2012-06-01

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

    IC75872

  • 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

  • R910 PSN

       UP

  • R950 PSN

       UP

  • R970 PSN

       UP

[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSEPGG","label":"DB2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.7","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
01 June 2012