Rails - Aug 2005 - How to catch exceptions in prefilter action?

How to catch globally any errors even those in prefilter action?

application.rb:

class ApplicationController < ActionController::Base
  before_filter :set_globals

  def set_globals
    # getting some data from mysql
    # but mysql is down


  def rescue_action_in_public(exception)
    # this does not work: :(
    render_text "db is down" 
  end
  
  def local_request?
    false
  end

--
JZ