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  1. #1
    Join Date
    Jan 2011

    Unanswered: db2fmp processes


    We see several db2fmp processes on our system. The UID is not the same, some match our instances, others have db2fenc1, db2fenc2. But there are some that belong to nobody:

    nobody 1801990 974930 0 15:42:54 - 0:00 db2fmp (C)
    nobody 1809996 1020136 0 11:21:57 - 0:00 db2fmp (idle)

    What is the difference please?


  2. #2
    Join Date
    May 2003
    db2fmp processes are fenced mode processes that run outside (fenced) from the DB2 address space. These are typically things like C or java Stored Procedures or UDF's. SQL procedures always run as unfenced inside the DB2 address space. Java processes are always fenced, and C can be fenced or unfenced at your option.

    The reason for running fenced is that if the process has a bug that results in an address violation or other severe error, then it could potentially cause DB2 to crash. Fenced mode processes typically run a little slower than unfenced mode.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

  3. #3
    Join Date
    Jan 2007
    Jena, Germany
    The reason why you see different users as the owners of those processes is that each DB2 instance can be configured to use a different fenced user. So one instance is using "nobody", another uses user "db2fenc1" and yet another "db2fenc2". You may want to have a look at the file ownership of sqllib/adm/.fenced in each instance to determine which instance is using which fenced user - the owner of that file will be used as process owner.

    p.s: The overhead of a fenced process is only in the communication with DB2 (passing parameters to/from UDFs, executing queries from withing the fenced code). The actual process is not slower, of course - unless you used WLM or some other mechanisms to throttle it.
    Knut Stolze
    IBM DB2 Analytics Accelerator
    IBM Germany Research & Development

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