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Re: Excessive SQL*Net message from client waits

From: Jonathan Lewis <>
Date: Thu, 13 Mar 2003 09:19:22 -0800
Message-ID: <>

I'd start by being doubtful about anybody being able to work so fast that the can avoid a high percentage of time in 'sql*net from client' - in fact, it the percentage was low (when the client was a person at a terminal) I would write myself a memo to check whether the client code was executing an extreme number of very small statements behind the scenes (e.g. get all keys for a drop-down, then get each drop down by key one at a time every time the user hit the field).

It's always possible that the many layers of code at the client end are taking a surprising

However, assuming you have a truly
unreasonable loss of time on waiting for client - I would try and isolate the problem by using netstat and top. This can be hard in typical environments, though.

Start up the client session -

Start netstat running on the server with minimum snapshot time (usually one

Start top (or similar) running in real time or minimum snapshot time.

Start up event 10046 at the session.

Then get the client to do something,
and watch for:

  1. the peak in netstat as the request reaches the server.
  2. the burst from the server as the request is serviced
  3. the peak in netstat as the reply gets sent
  4. the delay before it appears on the client screen.

It's crude, but simple-minded, and if the client is causing the problem it may prove it quite convincingly.

Back it up with the trace file - which will record timestamps of a query coming in and results going out.

The biggest problem, usually, is that it simply isn't realistic to get a system so quiet that you can get just one client
running all by itself with nothing else going on.

In your particular case, I have to sya that I have noticed that Java can use a surprising amount of CPU sometimes.


Jonathan Lewis

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> Good point, but what if each user only has a single session?
> Not that I've noticed this exact same situation here on one of our
> Engineering support databases whose clients are Java, and I'm not
> if it has something to do with the application or if I can possibly
speed it
> up with tweaks to SDU/TDU. I'm just wondering... ;)

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Author: Jonathan Lewis

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Received on Thu Mar 13 2003 - 11:19:22 CST

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