What is the best approach to monitor site performance in rails

Question

I'd like to have a special part of administrate area which shows a list of pages/queries that was slow for the past week.

Is there a gem / plugin or other easy way to implement/automate such functionality for the Rails framework?

Answer 1

http://www.newrelic.com/features.html

And a short screencast for RPM:

http://railslab.newrelic.com/2009/01/22/new-relic-rpm

P.S. I don't work for New Relic:)

Answer 2

Here's one example, and another and yet another. See google for even more.