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  1. #1
    Join Date
    Jun 2008
    Posts
    7

    Unanswered: UDF performance issues with WLM.

    Hi All,

    I am trying to implement an external(C++) UDF in a WLM environment on DB2 UDB for z/OS.

    While doing some performance testing on the same I am getting very slow response. I am not doing anything in the UDF just assigning a value returning which should be very fast when it runs in a stand alone. When I define the same as a UDF in a WLM the performance is very slow.

    I dont have any sql statements in the UDF so I dont think it can be something with the way UDF is created but the way how WLM is invoking the UDF etc.. does anyone has any idea of how any of how the WLM can be configured to get maximum performance. Any tips etc..

    WLM is defined as

    //DB8GWLM PROC DB2SSN=DB8G,NUMTCB=10,APPLENV=DB8GENV
    //*
    //NUMTCB@1 SET NUMTCB=
    //*
    //DSNTPSMP EXEC PGM=DSNX9WLM,TIME=1440,
    // PARM='&DB2SSN,10,&APPLENV',
    // REGION=0M,DYNAMNBR=5
    //STEPLIB DD DISP=SHR,DSN=DSN810.RUNLIB.LOAD

    and my create fucntions just accepts one numeric paramter and returns the same.

    Any help on this is highly appreciated.

    Thanks
    Ramesh.

  2. #2
    Join Date
    Dec 2007
    Location
    Richmond, VA
    Posts
    1,328
    Provided Answers: 5
    Ramesh,
    You should probably be speaking with someone in your systems group about how the WLM application environment is set up, service classes, etc... Have you tried making a call to the C++ module from another to see what the performance is like when used outside of DB2? There are quite a few places you could be having issues that really aren't part of DB2.

  3. #3
    Join Date
    Jun 2008
    Posts
    7
    Thanks for the thoughts Dav, I tried calling the C++ routine from outside and I am getting like 2000 transactions per second and if I call the same as a UDF with the WLM my performance is like 15 transactions per second which is very bad. I am not getting much support from system people over here because they are not clear of where they need to look at. Can you please list the few places you were mentioning so that I can point them to a direction..?

    Thanks again
    Ramesh.

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