Tatva-Artha

There was an interesting thread on ruby-passenger application server newsgroup recently: http://groups.google.com/group/phusion-passenger/browse_thread/thread/f48ad0eb018a2482

Here is my take away:

  # returns [class, count] tuples for all active records in the heap 
  def ar_space 
    GC.start 
    h = Hash.new(0) 
    ObjectSpace.each_object do |o| 
      next if o.__id__ == self.__id__ 
      next unless ActiveRecord::Base === o 
      h[o.class.to_s] += 1 
    end 
    return h.sort{|a,b| -(a[1]<=>b[1])} 
  end

Nifty little snippet to fetch number of active record objects on heap. I am guessing, incorporating this as Controller after_filter can help with cost of each request..

Installing passenger to work with apache for rails application is especially pleasant since it gives you direction to setup apache passenger module properly. I have done it several times and it has always worked. Recently I had to change the version of ruby that passenger uses and all I had to do is change the PassengerRuby directive in httpd.conf (or apache.conf) as follows:

#LoadModule passenger_module /opt/ruby-enterprise-1.8.6-20090421/lib/ruby/gems/1.8/gems/passenger-2.2.2/ext/apache2/mod_passenger.so
#PassengerRoot /opt/ruby-enterprise-1.8.6-20090421/lib/ruby/gems/1.8/gems/passenger-2.2.2
#PassengerRuby /opt/ruby-enterprise-1.8.6-20090421/bin/ruby
LoadModule passenger_module /opt/ruby/lib/ruby/gems/1.8/gems/passenger-2.1.2/ext/apache2/mod_passenger.so
PassengerRoot /opt/ruby/lib/ruby/gems/1.8/gems/passenger-2.1.2
PassengerRuby /opt/ruby/bin/ruby

I am not sure if this is the recommended way but it worked for me.

Enjoy!