what is the lifetime of ActionController, etc?

I realize that I don't know what causes an ActionController to be
created and destroyed. As a specific example, consider:

  class UsersController < ApplicationController

    def myState
      @myState ||= Object.new
    end

    def show
      ...
    end
end

Is there one ActionController created per user session? Will myState
persist across GET and POST calls? Is the lifetime different in
developer mode versus production mode?

To generalize the question: Are there any good references on the
lifetime of various RoR objects in a running server?

I realize that I don't know what causes an ActionController to be
created and destroyed. As a specific example, consider:

class UsersController < ApplicationController

def myState
  @myState ||= Object\.new
end

def show
  \.\.\.
end

end

Is there one ActionController created per user session? Will myState
persist across GET and POST calls? Is the lifetime different in
developer mode versus production mode?

No - one per request.

Fred