RE: OS Paging/performance question

  • From: "Justin Cave" <justin@xxxxxxxxxxx>
  • To: <esimmonds@xxxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 21 Sep 2004 09:04:34 -0600

Are you measuring "memory allocated" based on the SGA alone?  Or are you
adding in all the PGA's as well?  Batch processing implies DSS, which means
that your SGA's may end up being larger than your PGA's.  Do you have a

Justin Cave  <jcave@xxxxxxxxxxx>
Distributed Database Consulting, Inc.

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Ed
Sent: Tuesday, September 21, 2004 11:01 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: OS Paging/performance question

Looking for some advice here.

Windows 2000

We are running several instances on the machine, but the memory
allocated to them is far under the RAM available.  ie. I shouldn't be OS
paging as far as I can tell.  I have even shut down instances to reduce
the Oracle memory demands to much less than half the machine's RAM (4
gig total RAM), but I'm still paging like crazy.

Nonetheless, Windows Performance Monitor shows "pages/sec" going as high
as 1500 sometimes when large batch jobs are running against the
database.  Jobs that used to run in 4 hours now run over 24 and
sometimes fail.

In addition, I have massive "db file sequential read" wait events in the
database doing the large batch jobs, but my DB Cache Hit Ratios are over
90%.  I don't think Oracle's tuning utilities are going to help me
figure this one out.  Any ideas?  Hopefully I'm just missing something
very obvious.

The OS paging in particular is really bothering me!

Thanks in advance for your time.

Edward Simmonds



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