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IT22284: APPLICATION HEAP CAN BE EXHAUSTED BY REBAL FUNCTION AND THIS CANLEAD TO APPLICATION FAILURE WITH OUT OF MEMORY

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APAR status

  • Closed as program error.

Error description

  • On a database running with INTRA_PARALLEL=YES and DEGREE higher
    than 1, if application is failing with out of memory and
    following
    command
    
    db2pd -alldbs -memblocks appl | grep -A 10  "All memory cons"
    
    shows that one allocation is taking entire application heap:
    
    
    All memory consumers in Application memory set:
    PoolAddr           PoolID     PoolName   SecondID
    TotalSize(Bytes)     %Bytes TotalCount %Count LOC   File
    0x00007FEAEB958CE8 1          apph       15638     7619892696
    89.43  879489     0.29   1102  1984253944
    
    where 7619892696 is the size of entire application heap.
    
    Plan that is taking all this memory has REBAL operator and above
    allocation is coming from REBAL code.
    This fix is needed to control memory consumed by REBAL
    

Local fix

  • db2set DB2_COMPILER_SMP_OVERRIDES=1 (requires instance recycle)
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 version 111m3fp3                              *
    ****************************************************************
    

Problem conclusion

  • APPLICATION HEAP CAN BE EXHAUSTED BY REBAL FUNCTION AND THIS CAN
    LEAD TO APPLICATION FAILURE WITH OUT OF MEMORY
    

Temporary fix

  • see Local Fix
    

Comments

APAR Information

  • APAR number

    IT22284

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-09-06

  • Closed date

    2018-03-15

  • Last modified date

    2018-08-16

  • 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

  • RB10 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":"11.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
16 August 2018