Performance problems on OpenVMS : Was Re : Performance Tolls

Lalith, thanks for responding to my post. We haven't been able to get anybody
to respond to our repeated requests for help.
>
>In article <3pgci0$aao_at_gatekeeper.cognos.com> you write:
>>I'd be very interested in hearing about any performance tools available
>>for Open VMS systems.
>>
>>Currently we are wrestling with a performance problem that just doesn't
>>seem to make sense. Our connect times through DECNET is over a minute.
>>Through TCP/iP it's over 40 seconds. We have not been able to figure
 out
>>what is going on. When we monitor the network they are only running at
>>about 10% so there is no excuse there for connect times.
>
>I haven't worked with VMS Oracle in a while, but I've seen just
>such problems due to the time it takes VMS to spawn processes. The
>overhead of spawning processes is quite large on VMS, unlike on Unix.
>You can see evidence of this in the way FAL processes are reused, etc.
>So, if the performance of is OK _once_ the connection is made, then
>the problem is your system's inability to spawn a process fast
>enough, perhaps due to the load on it or whatever. You may also have
>to tune the WSxxxx parameters, etc. so the OS doesn't have to initially
>allocate a huge working set to your process. This affects paging...

Can you suggest any particular Oracle process that we should be looking at.
Should we look at the listener or should we be looking at the user process
working sets ?

To be a little more detailed than I was above. We are trying to get the metadata on tables in an Oracle database. The initial startup is not the only
place where we have a problem. We have been getting even worse times for 3rd
file access. ie. We request the metadata for the first file. Time to connect and
receive back the information is anywhere from 40 seconds to five minutes. The
second file's metadata is returned almost immediately (less than 3 seconds).
The third file has a wide range, typically it is approximately 1 minute but we
have seen it take 20-30 minutes.

We have checked system resources on both machines. The parent process which is
asking fro the metadata takes up less than 1% of the CPU and typically this
system is running at less than 50%CPU usage. The network is running around 10%
as mentioned above. The system where Oracle is running is running at 95-100%
where Oracle is taking up approximately 90-95% of the CPU. When there isn't a
request to Oracle going on the system is running at 5-10% usage.

If you can give me any suggestions it would be appreciated.
>
>Let me know what you find out!
>
>Lalith
>--
>--------------------------------------------------------------------
>Lalith Subramanian Internet: lalith_at_documentum.com
>Documentum, Inc.
>Pleasanton, CA Work : (510)-463-6830
>

Peter Farrell
peterf_at_Cognos.com Received on Thu May 25 1995 - 00:00:00 CEST