ActiveRecord establish_connection

gistfile1.rb

#from module ConnectionHandling   

 def establish_connection(spec = ENV["DATABASE_URL"])
      resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new spec, configurations
      spec = resolver.spec

      unless respond_to?(spec.adapter_method)
        raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
      end

      remove_connection
      connection_handler.establish_connection name, spec
    end

#which calls....
   def remove_connection(klass = self)
      connection_handler.remove_connection(klass)
    end


#connection handler is a ConnectionPool fron connection_pool.rb
      def remove_connection(klass)
        pool = class_to_pool.delete(klass.name)
        return nil unless pool

        connection_pools.delete pool.spec
        pool.automatic_reconnect = false
        pool.disconnect!
        pool.spec.config
      end