Why the caches_page can not work?

Fred wrote:

Hi,I want the page to be cached and be accessed by all users.And in my

class MyController < ApplicationController
caches_page :show
   def show
      render :layout => false

When I use link_to_remote to use My/show to update some div, i can not
see the template has been cached. However,If I use
<%= render_component :controller => 'My', :action => 'show'%>
in the default layout, I can see a cached file of 'index.html' is
generated under my RAILS_ROOT directory

POST requests are not cached by rails, and Prototype sends AJAX requests
via "POST" by default. If your are having performance problems you might
invest into action or fragment caching.