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  1. #1
    Join Date
    Jan 2009
    Location
    Zoetermeer, Holland
    Posts
    746

    Unanswered: STMM A-typical behaviour: should I worry?

    A few months ago I converted my client's database to win2003/64 with 32Gb RAM and db2 v9.5.2a. When the system is booted and db2 starts, it occupies a humble part of the available memory. That's the way I configured it using the DB2_OVERRIDE_BPF parameter. In the days that follow I notice the database grow (STMM) to occupy around 16 Gb (according to db2top M) and the windows task manager reports around 20 Gb used. That's the way this server runs for a few months now and a situations wich I consider to be "normal".

    Yesterday afternoon I saw this
    Code:
    2009-02-23-14.49.36.835000+000 E23381596F659      LEVEL: Warning
    PID     : 696                  TID  : 2108        PROC : db2syscs.exe
    INSTANCE: xxx                  NODE : 000         DB   : xxxxx 
    APPHDL  : 0-12                 APPID: *LOCAL.DB2.090207101311
    AUTHID  : xxxxxx
    EDUID   : 2108                 EDUNAME: db2stmm (P00BANK)
    FUNCTION: DB2 UDB, Self tuning memory manager, stmmCheckIfFreeMemoryIsEnoughForSizeIncr, probe:555
    MESSAGE : ZRC=0xFFFFEC49=-5047
    DATA #1 : String, 145 bytes
    There is not enough free memory for size increase. Free memory in pages: Physical memory = 0, Instance memory = 2390839, Database memory = 793632
    
    2009-02-23-14.49.36.835000+000 I23382257F655      LEVEL: Error
    PID     : 696                  TID  : 2108        PROC : db2syscs.exe
    INSTANCE: xxx                  NODE : 000         DB   : xxxxxx
    APPHDL  : 0-12                 APPID: *LOCAL.DB2.090207101311
    AUTHID  : xxxxxxx
    EDUID   : 2108                 EDUNAME: db2stmm (P00BANK)
    FUNCTION: DB2 UDB, Self tuning memory manager, stmmUpdateDBConfig, probe:275
    MESSAGE : ZRC=0x82AE00A7=-2102525785=STMM_CONFIG_UPDATE_FAILED
              "An attempted configuration update failed"
    DATA #1 : String, 80 bytes
    Error updating parameter Database_memory, updateValue = 5752659, sqlcode = -5047
    I cannot understand this. The hosting OS has plenty memory to spare...
    This morning I notice that DB2 is returning memory to the O.S.!
    db2top is reporting less than 10 Gb and according to the windows task manager only 14Gb is used.

    Strange, as far as I can see the workload is normal and besides bufferpools reporting decreases in sizes no db2diag messages... Should I worry?

  2. #2
    Join Date
    Jan 2009
    Location
    Zoetermeer, Holland
    Posts
    746
    Its 2 days later now. The database re-claimed most of the storage and is still running without any problems.
    It has been a dip I cannot explain..... creepy.

  3. #3
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    My personal experience is that STMM does not work well for bufferpools, and for that reason (and some other reasons) I hard-code the bufferpools but use STMM for almost everything else.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

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