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  1. #1
    Join Date
    Aug 2003
    Posts
    33

    Unanswered: increasing MAXAGENTS

    Hi all

    What are the things we need to consider when increasing MAXAGENTS.

    Do we need to consider any memory constraints or any other issues that might come up.

    Would like to increase from 3000 to 5000. Ver is db2 7.2

    Thanks
    mc

  2. #2
    Join Date
    Sep 2002
    Posts
    456

    Re: increasing MAXAGENTS

    you also wanted to take a look at some of the following parameters (according to db2 manual):
    >> MAXAPPLS
    >> MAXCAGENTS
    >> MAX_COORDAGENTS
    >> MAXDARI
    >> MIN_PRIV_MEM
    >> NUM_POOLAGENTS

    You do have to consider allocating more memory as each connection require private memory.

    dollar

    Originally posted by mcdb2
    Hi all

    What are the things we need to consider when increasing MAXAGENTS.

    Do we need to consider any memory constraints or any other issues that might come up.

    Would like to increase from 3000 to 5000. Ver is db2 7.2

    Thanks
    mc

  3. #3
    Join Date
    Aug 2003
    Posts
    33

    Increasing MAXAGENTS

    Hi

    Thanks for giving me this info.


    Could someone give any idea how to find out the memory requirements for each connection.

    db2 VER is 7.2 on LINUX 7.2.0.


    Thanks in advance,
    mc

  4. #4
    Join Date
    Aug 2001
    Location
    UK
    Posts
    4,650

    Re: Increasing MAXAGENTS

    If you read DB2 Performance Guide (available online for free download - Link available in Useful DB2 Stuff thread), there is a topic 'How DB2 uses memory?' ... That should give you a fair idea ....

    Anyway, I don't think you can get a definitive figure ...

    This is something I remember vaguley ... Can anyone confirm :

    DB2 initially allocates the minimum amount of memory required for the process, but later on when running an application, it allocates more memory as required... On finishing its job, it never releases them back but retains assuming it will need again therby avoiding the cost of releasing and acquiring resources ... If you have a memory constrained system, you will see that db2 processes at somepoint grab 'all' available memory and restart will be the only option available ...

    There is a db2set variable to get around this, but don't have it on top of my head now

    Cheers
    Sathyaram


    Cheers
    Sathyaram

    Originally posted by mcdb2
    Hi

    Thanks for giving me this info.


    Could someone give any idea how to find out the memory requirements for each connection.

    db2 VER is 7.2 on LINUX 7.2.0.


    Thanks in advance,
    mc
    Last edited by sathyaram_s; 09-24-03 at 17:34.
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  5. #5
    Join Date
    Aug 2001
    Location
    UK
    Posts
    4,650

    Re: Increasing MAXAGENTS

    I referred back to my old emails and I can confirm that my description of how an agent uses memory is correct .

    Memory constrained systems can use the following parameter to 'alter' the behaviour:

    DB2MEMDISCLAIM
    DB2MEMMAXFREE

    These parameters seem to be only for AIX , though the original note I received from IBM doesn't seem to mention that the processes behave in this manner only in AIX ..


    Cheers
    Sathyaram
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