# File lib/thinking_sphinx/deltas/default_delta.rb, line 11
      def index(model, instance = nil)
        return true unless ThinkingSphinx.updates_enabled? &&
          ThinkingSphinx.deltas_enabled?
        return true if instance && !toggled(instance)
        
        update_delta_indexes model
        delete_from_core     model, instance if instance
        
        true
      end