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Thread: High Memory Usage

  1. #1
    Join Date
    Jan 2003
    Location
    Bahrain
    Posts
    109

    High Memory Usage

    Hi,

    $ top

    load averages: 0.39, 0.38, 0.36 02:11:59
    308 processes: 297 sleeping, 10 zombie, 1 on cpu
    CPU states: 95.1% idle, 2.7% user, 2.2% kernel, 0.0% iowait, 0.0% swap
    Memory: 2048M real, 179M free, 1956M swap in use, 3687M swap free

    Though CPU is 95%idle and load averages are less than one, always it is showing high physcical memory usage.

    My performance is very bad.

    Is that High memory usage affect the performance problem?

    If yes, how can I reduce that?

    Seelan

  2. #2
    Join Date
    May 2001
    Posts
    736
    What is the type of ur application? Iam suspecting that ur application is using lot of memory.Even a badly tuned application will eat up all ur memory and consequently u will have the performance problem.

  3. #3
    Join Date
    Jan 2003
    Location
    Bahrain
    Posts
    109
    Hi,

    I newly joined in this company as a DBA.

    Anyway this is a Multi tier web based application.

    How can I start tuning my application?


    Seelan

  4. #4
    Join Date
    May 2001
    Posts
    736
    Go through some of the utilities like,TKPROF,EXPLAIN PLAN,AUTOTRACE to find out which SQL statement require tuning.

  5. #5
    Join Date
    Jan 2003
    Location
    Bahrain
    Posts
    109
    Hi,

    From my statspack report I found the following.(Duration -1 hour)

    Top 5 Wait Events
    ~~~~~~~~~~~~~~~~~ Wait % Total
    Event Waits Time (cs) Wt Time
    -------------------------------------------- ------------ ------------ -------
    queue messages 24,853 22,094,928 72.91
    PL/SQL lock timer 7,653 7,753,002 25.58
    library cache load lock 1,698 216,981 .72
    db file sequential read 1,725,741 127,314 .42
    library cache lock 623 41,864 .14


    My queue message wait event is pretty high.


    Shared Pool Statistics
    **********************

    Memory Usage : 23%

    This percetage is very low. That means we are wasting memory. Am I correct?

    Load Profile
    ~~~~~~~~~~~~ Per Second Per Transaction


    Logical reads: 669.70 1,369.20
    Physical reads: 166.51 340.42

    My physical reads ratios are pretyy high? Am I correct?


    Executions Rows Processed Rows per Exec Hash Value
    ------------ ---------------- ---------------- ------------
    29,217 4 0.0 1623015130

    Select R.Rowid From Fnd_Concurrent_Requests R Where R.Hold_Flag
    = 'N' And R.Status_Code = 'I' And R.Requested_Start_Date <= S
    ysdate AND EXISTS ( Select Null From Fnd_Concurrent_Programs
    P Where P.Enabled_Flag = 'Y' And R.Program_Application_Id = P.
    Application_Id And R.Concurrent_Program_Id = P.Concurrent_Prog

    To processed only 4 rows , the above query executed in 29217 times. I think it is pretty high. Am I correct?

    Physical Reads Executions Reads per Exec % Total Hash Value
    --------------- ------------ -------------- ------- ------------
    1,677,931 453 3,704.0 70.1 238087931
    select t.schema, t.name, t.flags, q.name from system.aq$_queue_t
    ables t, sys.aq$_queue_table_affinities aft, system.aq$_que
    ues q where aft.table_objno = t.objno and aft.owner_instance = :
    1 and q.table_objno = t.objno and q.usage = 0 and b
    itand(t.flags, 4+16+32+64+128+256) = 0 for update of t.name, aft


    In case of above query, only for 453 executions, it made 1677931 executions.

    I think it is pretty high? Am I correct?

    Can you pleae comment about this?

    Seelan

  6. #6
    Join Date
    May 2000
    Location
    ATLANTA, GA, USA
    Posts
    3,135
    I believe you are using either Oracle Apps 11i or Oracle CRM.

    You can hardly tune these applications. Both are junk.

    Tamil

  7. #7
    Join Date
    Jan 2003
    Location
    Bahrain
    Posts
    109
    Hi,

    yes, you are correct. I am using Oracle APPS 11i

    Seelan

  8. #8
    Join Date
    Jun 2000
    Posts
    295
    Do you experience paging and swapping?
    What is vmstat output?

  9. #9
    Join Date
    Dec 2002
    Location
    Bangalore ( India )
    Posts
    2,434
    Originally posted by tamilselvan
    I believe you are using either Oracle Apps 11i or Oracle CRM.

    You can hardly tune these applications. Both are junk.

    Tamil
    Have never used these appl.. but jus curious to know why are they junk?

    Abhay.
    funky...

    "I Dont Want To Follow A Path, I would Rather Go Where There Is No Path And Leave A Trail."

    "Ego is the worst thing many have, try to overcome it & you will be the best, if not good, person on this earth"

  10. #10
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,447
    All erp are junk. Oracle is worse because they develop using their own database and is still junk. Others have some excuses, they have to develop for several RDBMS vendor.

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