# File lib/new_relic/agent/datastores/mongo/metric_translator.rb, line 152
          def self.collection_name_from_index(payload)
            if payload[:documents]
              if payload[:documents].is_a?(Array)
                # mongo gem versions pre 1.10.0
                document = payload[:documents].first
              else
                # mongo gem versions 1.10.0 and later
                document = payload[:documents]
              end

              if document && document[:ns]
                return document[:ns].split('.').last
              end
            end

            'system.indexes'
          end