IBM Support

IT07948: DB2 MEMORY LEAK IN APPLICATION HEAP WHEN QUERYING FOR LOB DATA USING PERSISTENT CONNECTIONS

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • If connections are persistent, under certain conditions of
    querying  for LOB data, you may find a memory leak in
    application heap.
    
    To isolate this issue, you may monitor with monitoring tools
    such as MON_GET_MEMORY_SET which will show high levels of
    "Application" memory set, and
    MON_GET_MEMORY_POOL which will show a high/growing level of
    memory usage within specific "Application" heap memory pools.
    
    After isolating to Application heap being the cause of growth,
    you may isolate to a specific block which is leaking using the
    db2pd below:
    
    db2pd -db <dbname> -memblocks top
    
    Top memory consumers in Appl memory set:
    PoolID     PoolName   TotalSize(Bytes)     %Bytes TotalCount
    %Count  LOC    File
    1               apph          353395680            8.48
    11043615    0.18       4199   925998910
    1               apph          352491840            8.46
    11015370    0.18       4199   925998910
    
    You will see high number of allocations from 925998910 block.
    
    As the connection stays persistent, the above block allocations
    will keep growing in number.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * DB2 Version 9.7 Fixpack 10 and below                         *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 9.7 Fixpack 11                        *
    ****************************************************************
    

Problem conclusion

  • Fixed in DB2 Version 9.7 Fixpack 11
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT07948

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-03-26

  • Closed date

    2015-10-28

  • Last modified date

    2015-10-28

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

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

    IT13327 IT13367

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 #: IT07948

Modified date: 28 October 2015