Re: Memory usage for Oracle User Process

From: Anil Sikri <anil_sikri_at_hotmail.com>
Date: Thu, 24 Aug 2000 13:06:43 CDT
Message-Id: <10599.115497@fatcity.com>

Original Message ************************* Hi, I found that some of the Oracle user process consumes memory as high as 300M. (For a single process only!) Is there any tuning that I can do to control the memory usage on each user process ?

Database is version 8.1.6 on Solaris 2.6

TIA,
Michael

Michael,

        I believe that  you must be monitoring your Oracle processes
        using top or some other Unix monitoring tool. If you look into
        the virtual memory model of a Unix process , the shared memory
        is a part of it ( A Unix process has 3 main segments - text
        segment, data segment and stack segment and the shared memory
        fits between the text and the stack segment ).
        My point is that the shared memory ( or the SGA ) is also
        reported as a part of the memory being consumed by the process.
        You might want to look into a Unix internals book ( I like
        Maurice Bach even though it is slightly outdated ).

        For finding the exact amount of memory being used by the Oracle
        process, you can use the following :

           On Solaris ( this won't work on HP ), find the PID of the
           process using ps and use the pmap utility to generate a
           process map as follows :
              /usr/proc/bin/pmap /proc/<PID>
           The pmap output will include a line of the type :

          <address> <memory> read/write/exec/shared  [ shmid=<address> ]

           The <memory> is the memory used by the shared memory segment
           Subtract it from the total to get the memory used by the
           Oracle process.

           Note : On HP-Unix, top reports the actual memory being
                  used by the process unlike Sun Solaris.

Regards,
Anil Sikri

Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com Received on Thu Aug 24 2000 - 13:06:43 CDT