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IT21211: SLOW DATABASE ACTIVATION, CREATE/ALTER BUFFERPOOL, LOAD OPERATIONS ON LARGE WINDOWS SYSTEMS

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • On Windows, allocating memory may be
    significantly slower for databases with larger memory footprints
    ( many GBs ).  Because DB2's memory allocations on Windows are
    typically small and incremental, coalesce checks end up being
    performed on a very large number of OS allocations.  Activities
    which are intense in terms of allocating memory (such as
    bufferpool activation, creation, or increase, or initializing
    LOAD operations), may suffer some degradation as a result
    
    The call stack will contain the following :
    SMemSet::checkRecommitable
    SMemSet::recommitChunksUntilTargetReached
    SMemSet::getChunksFromTree
    SMemSet::getContiguousChunks
    SMemBasePool::getNewChunkSubgroup
    

Local fix

  • Consider using
       db2set DB2MEMDISCLAIM=NO
    followed by db2stop; db2start, which avoids the need for any
    coalesce check.
    
    Note that DB2MEMDISCLAIM=NO disables STMM-tuning of
    database_memory, though STMM will still tune the main consumers
    (bufferpools, locklist, package cache, shared sort) inside the
    existing database_memory size.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Larger Windows systems                                       *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 11.1 Mod 3 Fix Pack 3                 *
    ****************************************************************
    

Problem conclusion

  • Problem first fixed in DB2 Version 11.1 Mod 3 Fix pack 3
    

Temporary fix

  • see Local Fix
    

Comments

APAR Information

  • APAR number

    IT21211

  • 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

    2017-06-27

  • Closed date

    2018-03-15

  • Last modified date

    2018-03-15

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

    IT21209

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

Modules/Macros

  • sqo
    

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RB10 PSN

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"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:
15 March 2018