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IC90556: STMM BUFFERPOOL MINIMUM NORMAL PAGE AREA AND CONFIGURED BLOCK PAGE AREA ARE NOT MAINTAINED ON ACTIVATION WITH SCALE BACK

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • STMM normally maintains a minimum number of normal bufferpool
    pages (1000 at this time).  This is on top of any configured
    block page area, which STMM does not tune.  On database
    activation, scaling back may occur when memory is constrained.
    This process only attempts to maintain an overall size of 1000
    for a bufferpool, which may compromise the configuration when
    there is a block page area configured.  The following conditions
    may result in performance degradation and SQL1218 errors.
    
    1. The bufferpool may initialize with a very small number of
    normal pages (as low as 32).  STMM will try to increase this to
    the normal minimum size on the next tuning cycle.
    2. The block page area may be initialized with less than the
    configured value.  This condition will persist during the
    current activation as STMM does not tune the block page area.
    3. In an STMM/HADR environment, STMM does not actively tune the
    secondary.  If the scaling back occurs on the secondary, the
    condition of having a small number of normal pages will persist,
    potentially leading to failures hadr replay processing,
    resulting in the secondary database marked bad.  Since STMM is
    not tuning, any scaling back on the secondary will also be
    persistent (configuration changes are written to disk and will
    be effective on the next activation).
    
    Example db2diag.log messages showing scaling back with a block
    page area configured:
    
    2012-10-30-10.03.31.350919-240 I31939A505         LEVEL: Info
    PID     : 8585406              TID  : 1814        PROC : db2sysc
    0
    INSTANCE: mcornish             NODE : 000         DB   : TEST
    APPHDL  : 0-42                 APPID:
    *LOCAL.mcornish.121030140331
    AUTHID  : MCORNISH
    EDUID   : 1814                 EDUNAME: db2agent (TEST) 0
    FUNCTION: DB2 UDB, buffer pool services,
    sqlbScaleAutoBPsByFactor, probe:35
    MESSAGE : Altering bufferpool "BP1" From: "20000"<automatic> To:
              "1000"<automatic>
    
    2012-10-30-10.03.31.351426-240 E32445A837         LEVEL: Warning
    PID     : 8585406              TID  : 1814        PROC : db2sysc
    0
    INSTANCE: mcornish             NODE : 000         DB   : TEST
    APPHDL  : 0-42                 APPID:
    *LOCAL.mcornish.121030140331
    AUTHID  : MCORNISH
    EDUID   : 1814                 EDUNAME: db2agent (TEST) 0
    FUNCTION: DB2 UDB, buffer pool services,
    sqlbSetNumSlotsAndNBPForNewRTBPDef, probe:20
    MESSAGE : ADM6069W  Buffer pool "BP1" (ID "2") has a
    NUMBLOCKPAGES value of
              "10000" which exceeds the maximum supported value for
    a buffer pool
              of this size.  The NUMBLOCKPAGES value for this buffer
    pool has been
              reduced to "980" for its current activation.  The
    value of
              NUMBLOCKPAGES can be permanently changed by using the
    ALTER
              BUFFERPOOL SQL statement.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Systems using automatic (STMM) tuning for a bufferpool with  *
    * a block-based area configured                                *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 9.7 Fix pack 9                        *
    ****************************************************************
    

Problem conclusion

  • Problem first fixed in DB2 Version 9.7 Fix Pack 9
    

Temporary fix

  • See Local Fix
    

Comments

APAR Information

  • APAR number

    IC90556

  • 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

    2013-02-28

  • Closed date

    2013-12-16

  • Last modified date

    2013-12-16

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

    IC87650

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

Modules/Macros

  • sqb
    

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:
16 December 2013