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RE: dedicated server process memory usage ....

From: Mark W. Farnham <>
Date: Mon, 7 Jun 2004 10:33:50 -0400
Message-ID: <>

MessageUnfortunately it is non-trivial to figure out how much of the shared memory area of the running Oracle instance is reported as part of each server connection, and this varies by OS, release of OS, and tool used to report "sz" and "RSS."

I'm not sure what you meant about "no SQL fired" since I'm not aware of how to open a sqlplus connection without the query of username/password firing, along with whatever level of auditing you may have.

Possibly someone else can refer you to a good resource for evaluating MTS, but please be sure to avoid taking the .6G per server process allocation seriously. I doubt Solaris 8 has this problem, but some old Unix varieties had page/swap limits that did not take into account shared memory, so executing a table scan would drive "false paging" unless you configured
"RSSMAX" to the ceiling of your shared memory plus the program space. By
"false paging" I mean copying shared memory your process has mapped to page
or swap (from whence it will never be recalled, since the shared memory is still actually current.) Setting the RSSMAX high would in turn then allow applications to run rampant on your memory, so this tipped the balance of whether to allow a certain application on your database server far in favor of saying no if an application had big libraries.

Good luck!

  -----Original Message-----
[]On Behalf Of Pampati, Sree   Sent: Monday, June 07, 2004 9:42 AM
  Subject: dedicated server process memory usage ....


  How is memory allocated to a dedicated server process ? I just opened a sqlplus connection ( no SQL fired!), did ps -elf | grep <pid> on the server pid, which showed sz: 592M, RSS: 558. There are about 800 server processes running at that time ( the box has 10G physical mem, of which about 2GB was free at that time. Solaris 8 . Oracle version : ).

  *_area_size parameters in init.ora are : bitmap_merge_area_size = 1048576 (1MB)

create_bitmap_area_size= 8388608 (8MB)

= 4194304     (4MB)
= 2097152     (2MB)

  Oracle 10gAS and 9iAS too are running on the box in addition to the oracle instance.

  Is this a good candidate for MTS ? Do I get substantial benefit using pga_target_aggregate features of 9i ?

  I would very sincerely appreciate your valuable feed back ( any pointers to docs/info are highly appreciated).

  Sree Pampati

  -----Original Message-----
  From: Darrell Landrum []   Sent: Saturday, June 05, 2004 12:58 AM   To:
  Subject: Re: Hardware Question

    Hey Jay,

    I hate when management comes to me with questions like you mention about this new hardware handling the workload.

    But, I have a response now that I love because it can be confusing to them.

    I simply ask, "Why?".
    Why are they looking at new hardware? Does the current hardware not handle the workload? Is there a forthcoming app server/database upgrade that will require more resources? Are they scaling out their current utilization, perhaps to more users? Are they adding more databases? I know this may not seem like the best attitude and trust me, I love newer, faster hardware more than most, but really the justification for new hardware should come before the shopping for hardware. In my role as a DBA, I should be the one (or, of course, the sys admins) that recognizes the need for hardware upgrades and hopefully before management starts to feel the need. If I can't quantify the need for new servers or additional hardware (or software for that matter), I actually speak against it. This way, when I tell them we need something, they listen!

    Just one guy's 2 cents.
    However, you mention a bottleneck on the SAN controllers. That is a big red flag. There's always a chance (and some would argue a very good chance) that faster processors and more memory will make this SAN controller bottleneck worse or at least more noticeable. Hopefully, additional channels to the SAN are being considered with this new box as well.

    Good luck!

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Received on Mon Jun 07 2004 - 09:36:50 CDT

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