Henry - One idea for you to try is to "nice" the import job when you start
it. Check your O.S. documentation for available values. This has helped me
on some jobs that have tended to overwhelm the online users. Just a thought.
Good luck, sounds as if you may have other system problems.


Dennis Williams
DBA
Lifetouch, Inc.
[EMAIL PROTECTED] 

-----Original Message-----
Sent: Wednesday, October 09, 2002 6:35 PM
To: Multiple recipients of list ORACLE-L


Dennis,
Users are complaining, and at least this time the guilty process seems to be
an import from a database out of my control. What I am trying to do is
control how often this happens. It seems a bit strange that one moderate,
single threaded import should drain both CPUs on the server, so I was trying
to see how much could be pinned on those processes (imp and associated
oracle shadow process)and how much was due to other use and poor
configuration.

As I mentioned, both %wio (wa on vmstat AIX) and %idle were ~0. Everything
was split (kind of evenly 50-50 to 40-60) between %usr and %sys. Using ps -o
pcpu I could pin about 30% of %CPU on the import. I am not sure if this
includes the associated system calls (io) from this process. I don't think
so. (I wasn't seeing my %CPU adding up to 100% earlier because I was leaving
out the kernal processes. I needed a ps -k flag).

Now I am seeing some other funky stuff (maybe related, maybe not. I haven't
looked carefully for this before so I don't know) on the same machine. The
import ended and the %usr %sys breakdown was still 40-60. There are two
kproc processes (async IO???) each using 44.4%CPU. That's been unchanged for
hours and the machine is not being heavily used. Also, some other processes
are using 10-20%CPU which puts me up over 100% (I guess it really can give
120%).

I'll let you know what I find.

Henry

-----Original Message-----
WILLIAMS
Sent: Wednesday, October 09, 2002 3:50 PM
To: Multiple recipients of list ORACLE-L


Henry - Here are my reactions, and hopefully someone that knows how to track
system CPU usage back to an application will reply. One thought I have is to
run each application on a test server and observe the system I/O there. I
haven't tried this. Other thoughts:
 1) Are interactive users complaining? If they are, then you have a definite
problem.
 2) In terms of maxing out the CPU, does this situation continue for long
periods of time? For example, I have a financial system that is overloaded
at the first of the month, but underutilized the rest of the month. But
another system simply couldn't process everything they needed each day, so
we had to do something. In that case the users ceased running some reports.
 3) I looked in Oracle Performance Tuning 101 to see what Gaja has to say.
He points out that the Solaris sar -q command has a "%wio" column, a measure
of processes that are currently using the CPU, but are waiting for I/O
requests to be serviced and hence are not making prudent use of the CPU. He
further says that %sys and %wio should be less than 10-15% and if it is
consistently higher you need to get to the bottom of it, and usually it is a
application causing the problem. No details on how to get to the bottom.
 4) Maybe you can get some type of O.S. audit that can report what system
calls are being made, and that will give you a clue.

Dennis Williams
DBA
Lifetouch, Inc.
[EMAIL PROTECTED]

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