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Thread: how to find Maximum users

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  1. #1
    Join Date
    Dec 2001
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    2
    How to find the maximum client connections that can b made to a database.I have specified a number at the time of installation of the oracle8i database.

  2. #2
    Join Date
    Oct 2000
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    467
    i think this depends on the processes parameter given in y our init.ora . Of these, some are already taken by Oracle background processes.
    Vinit

  3. #3
    Join Date
    Dec 2001
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    2
    i guess i have given the number as 150 but the processes parameters give me as 165!!!!why so?

  4. #4
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
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    Originally posted by vijithv
    How to find the maximum client connections that can b made to a database.I have specified a number at the time of installation of the oracle8i database.
    Sessions are limited on users level, not on database level. This is done via profiles. The default is UNLIMITTED. In order to set max number of sessions per user, say 130, you first run:

    ALTER SYSTEM SET RESOURCE_LIMIT = TRUE;

    Then you create a profile, say PROFILE_1:

    CREATE PROFILE PROFILE_1 LIMIT
    SESSIONS_PER_USER 130
    IDLE_TIME X
    CONNECT_TIME X...

    Run this:

    select
    profile prof,
    resource_name res,
    limit lim
    from
    dba_profiles
    order by
    1,2
    /

  5. #5
    Join Date
    Oct 2000
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    467
    Julian - are you talking about MTS ? Coz what i know is that each session takes up a process.
    Vinit

  6. #6
    Join Date
    Feb 2001
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    119
    The other 15 is for the backgroung process (like dbwr,lgwr,arch,smon,pmon latch etc ....)

  7. #7
    Join Date
    Jul 2000
    Posts
    521
    According to ORACLE docs :

    'processes' is init.ora parameter.
    sessions=processes*1.1+5
    transactions=sessions*1.1
    svk

  8. #8
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
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    Originally posted by vinit
    Julian - are you talking about MTS ? Coz what i know is that each session takes up a process.
    No, I am not talking about MTS. I explained how you can control the maximum number of sessions per user in the database.

    Of course, processes in the init.ora is sort of a hard limit but if we go in further detail you will see that SEMMNS, that is, the semaphores are also a hard limit.

    Here is an intersting formula for setting the number of semaphores (semmns):

    "Set to the sum of the PROCESSES parameter for each Oracle database, adding the largest one twice, then add an additional 10 for each database. For example, consider a system that has three Oracle instances with the PROCESSES parameter in their init sid.ora files set to the following values:
    ORACLE_SID=A, PROCESSES=100
    ORACLE_SID=B, PROCESSES=100
    ORACLE_SID=C, PROCESSES=200
    The value of SEMMNS is calculated as follows:
    SEMMNS = [(A=100) + (B=100)] + [(C=200) * 2] + [(# of instances=3) * 10] = 630

    DBAs: be careful! Do not set a large value for SEMMNS, because you then run into the risk of some other user creating so many processes that the kernel process table is totally filled.



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