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  1. #1
    Join Date
    Sep 2003
    Posts
    218

    Unanswered: db2syscs.exe process CPU utilization is 100%

    Hi,

    I am running db2 v8.1.4a on win2k.

    db2syscs.exe is at 95 to 100% CPU utilization frequently. Then it goes down very low. Goes up high again within an hour. There aren't much application work going on our system today.

    What could be the reason for this spike in CPU utilization?

    Any ideas?

    Thanks.

  2. #2
    Join Date
    Jan 2003
    Posts
    1,605
    Hi,

    Do you have enough memory? Is there some windows pageing?

    Grofaty

  3. #3
    Join Date
    Sep 2003
    Posts
    218
    thanks for your response..

    yes, its a 4GB RAM, P4 machine.. and I am running two instances (OLTP and Data warehouse)

    I don't understand your second question on the paging front.

    Thanks.

  4. #4
    Join Date
    Mar 2004
    Posts
    448
    when you have more processes then the real memory can accomodate.
    the processes are swapped out to paging space a type of physcial storage.
    page in and page out is common, but swapping is a problem.
    CPU is utilized heavily during that swapping.

    regards,

    mujeeb

  5. #5
    Join Date
    Sep 2003
    Posts
    218
    ....There are two physical drives designated by C: D: and E: and they have around 4092 MB set as the max paging size. Is this ok?

  6. #6
    Join Date
    Jan 2003
    Posts
    1,605
    Hi,

    Bmujeeb, that is correct!
    Dr_suresh20, the easyes way to find out if windows page-ing is present do the following:
    1. Start Task Manager
    2. Click on Performance tab
    3. In Physical Memory frame there is "Available" - that is the available real memory
    4. In Commit Charge frame there is "Total" - this is used memory
    5. If the "Available" > "Total" then you have a windows page-ing problem.

    If you have the windows pageing problem, then try to stop all the applications that are not needed. Also stop services that are not needed.

    On database there is the most common mistake to overlocate the bufferpools. So if the total amount of bufferpools are bigger then the real memory try to lower the bufferpools.

    Execute the db2 command:
    Code:
    select * from sysibm.sysbufferpools
    to see the amount of usage bufferpools.
    Then manualy calculate the BufferpoolUsageInBytes = NPAGES * PAGESIZE. If more then one bufferpool is defined then calculate the BufferpoolUsageInBytes and sum the results from each row.

    Hope this helps,
    Grofaty
    Last edited by grofaty; 07-27-04 at 02:46.

  7. #7
    Join Date
    Jan 2003
    Posts
    1,605
    Hi,

    Dr_suresh20, windows pageing in teory:
    Code:
    TotalPageSizeOnAllDrivesTogether = RealMemory * 1.5
    Sample:
    Real memory = 4 GB
    TotalPageSizeOnAllDrivesTogether = 4 GB * 1.5 = 6 GB.

    So the optimal page size is 6 GB. My favorite setting is to create a windows partition e.g. F: which is in your case 10 GB in size and then define windows page file 6 GB on this partition. You have 4 GB on "page partition" just in case if you would like to increase the size (e.g. if new real memory is bought)

    If page file is defined in seperate partition then no fragment of page file is present. So you do not need to defragment this partition on regular basis.

    Hope this helps,
    Grofaty
    Last edited by grofaty; 07-27-04 at 02:58.

  8. #8
    Join Date
    Mar 2004
    Posts
    448
    In window enviroment, my first step should be to stop the processes
    which I don't need.window has this problem of starting too many processes
    without needing them and most of these proceeses have multiple threads
    inside them.

    regards,

    mujeeb

  9. #9
    Join Date
    Sep 2003
    Posts
    218
    many thanks for your responses..

    Let me try this out and see if it reduces CPU utilization. I will share my findings shortly.

    Thanks once again.

  10. #10
    Join Date
    Jan 2003
    Posts
    1,605
    Hi dr_suresh20,

    Have you solved your problem?
    Please share with us your results!

    Thanks,
    Grofaty

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