RE: dedicated server process memory usage ....

  • From: "Mark W. Farnham" <mwf@xxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 7 Jun 2004 10:33:50 -0400

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-----
  From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Pampati, Sree
  Sent: Monday, June 07, 2004 9:42 AM
  To: oracle-l@xxxxxxxxxxxxx
  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

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

  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 [mailto:darrell@xxxxxxxxxxx]
  Sent: Saturday, June 05, 2004 12:58 AM
  To: oracle-l@xxxxxxxxxxxxx
  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
    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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