that is when the

def call(env)

method is invoked by hitting any url, can I inside that method make some ActiveRecord queries, use classes defined in lib, etc. etc.

Or is it more like an irb console without the rails env loaded? Another way to put it with a rake task example:

 task :foo => :environment do
    # with env
  end

 task :foo2 do
    # without env
  end

I would think rack classes would NOT get the environment so they are super fast and don't take all the overhead of a normal rails request.

But that doesn't seem to be the case. I CAN make ActiveRecord queries inside my rack class. So what is the advantage of rack then?