RE: Why is Oracle process using 25 MB of RAM when idle?

Hi Stephane,

thanks for your reply.

We are measuring the values by getting the OS process ID of a specific Oracle connection and then trach that process ID using glance (on HP-UX).

Since the SGA is ab 1.5 GB, it is definitely not attached to the memory consumed by each process. I know that this is an issue on Solaris.

We tried and used a whole bunch of different processes and they were all using 20-25 MB of RAM (doing nothing). This number seems just a little bit high to me...

Example: If I have an SGA with 1 GB, 200 MB of pga-aggregate-target and 200 users connecting to the datbase (although only about 10% of them are active at the same point in time).
This would mean that my memory consumption is: 1 GB + 200 MB + 200*25 MB = 6.2 GB...

Regards,
Helmut

-----Original Message-----
Sent: Monday, November 17, 2003 10:30 AM To: Multiple recipients of list ORACLE-L

Helmut,

   I don't know how you are measuring your numbers, but beware that what the operating system reports is often somewhat misleading. Typically, shared memory is often 'attributed' to each and every process linked to it. When you think about it it makes sense, but at the same time it does mean that n processes will really use much less than n * the amount of memory reported as used by one process. This is true both of the 'program' part of user memory (shared libraries) and of the 'data' part of it (SGA). When your process connects, it attaches the SGA and some shared libraries, and more shared libraries come into play as it starts doing something. You may have a better view of what is really used by your process by checking into V$SESSTAT, which holds a number of values about it.

HTH, SF

>----- ------- Original Message ------- -----
>From: "Daiminger, Helmut" <HELMUT.DAIMINGER_at_wwk.de>
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Sent: Sun, 16 Nov 2003 23:09:26
>
>Hi,
>
>we are running 9.2 on HP-UX here.
>
>We have pg_aggregate_target configured, but I
>realized (in my opinion) very
>high memory consumption of Oracle Unix processes.
>
>a) How come that one Oracle Connection (i.e.
>dedicated Unix process on HP)
>is using up at least 22 MB of RAM? It is using 22
>MB if the user is just
>connected, not doing anything.
>
>Any way I can modify this?
>
>b) If the user is querying data and the like, the
>memory consumption goes up
>to 60 MB. How come?
>
>Thanks!
>
>Regards,
>Helmut
>

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