Hi,

at first I have to say this bug might only appear when you have many environments and hostgroups. What we have, is around 1400 Classes, 70 Environments and 600 Hostgroups.

In our installation it is not possible to open the Classes view, because the ruby process will eat all the memory and then crash the server. We were able to track this down to the controller, which eager loads all the depending elements. In our case this results in a 800k rows resultset. When this is converted to ActiveRecord objects it takes a long time and uses a lot (>16GB) of memory.

In app/controllers/puppetclasses_controller.rb:

  def index
    eager_load_tables = [:config_group_classes, :class_params, :environments,
                         :hostgroups]
    @puppetclasses = resource_base_search_and_page(eager_load_tables)
    @hostgroups_authorizer = Authorizer.new(User.current, :collection => HostgroupClass.where(:puppetclass_id => @puppetclasses.map(&:id)).uniq.pluck(:hostgroup_id))
  end

Removing the eager loading solves all of our problems and makes the view work again (and really fast too).