I think this is quite common. I get this in my RAC environment.

Look at this one -specifically Table 17.9 in the middle of the page):

http://otn.oracle.com/docs/products/...les.htm#444555

In terms of normal for your enviroment though...

Have you added anything new to the listener config within the last few months? Or maybe someone else has changed this?

Duration of the polling/service_update is similar to mine - @10 minutes per instance. This frequency is not tunable.

http://metalink.oracle.com/metalink/...1&p_showHelp=1

Question 2 of the FAQ touches on this.

In terms of rapid growth do you have an application that is constantly running (ie, 24x7) or that consistently times out? Check metalink as there a couple of queries on this specific topic - all of which point to an application trying to access the database and for various reasons creating multiple connections, closing them, then opening them again, or failing to connect properly, etc.

[Edited by ramaral on 08-02-2002 at 01:31 PM]