anchor.diff:        end, ListOfLists),
       [hd(ets:lookup(ETS, T)) || #stat_entry{timestamp = T} <- MainSamples].
   
  -bucket_nodes("@system") ->
  +section_nodes("@system") ->
       ns_cluster_membership:actual_active_nodes();
  -bucket_nodes("@query") ->
  +section_nodes("@query") ->
       ns_cluster_membership:n1ql_active_nodes(ns_config:latest_config_marker());
  -bucket_nodes("@index-"++_) ->
  +section_nodes("@index-"++_) ->
       ns_cluster_membership:index_active_nodes(ns_config:latest_config_marker());
  -bucket_nodes("@goxdcr-"++Bucket) ->
  +section_nodes("@goxdcr-"++Bucket) ->
       ns_bucket:live_bucket_nodes(Bucket);
  -bucket_nodes(Bucket) ->
  +section_nodes(Bucket) ->
       ns_bucket:live_bucket_nodes(Bucket).
   
   is_persistent("@query") ->
  
positive.code:     ns_bucket:is_persistent(BucketName).
  
  grab_system_aggregate_op_stats(all, ClientTStamp, Window) ->
      grab_aggregate_op_stats("@system", bucket_nodes("@system"), ClientTStamp, Window);
  grab_system_aggregate_op_stats([Node], ClientTStamp, Window) ->
      grab_aggregate_op_stats("@system", [Node], ClientTStamp, Window).
  
  grab_aggregate_op_stats(Bucket, all, ClientTStamp, Window) ->
      grab_aggregate_op_stats(Bucket, bucket_nodes(Bucket), ClientTStamp, Window);
  grab_aggregate_op_stats(Bucket, Nodes, ClientTStamp, Window) ->
      {_MainNode, MainSamples, Replies} =
          menelaus_stats_gatherer:gather_stats(Bucket, Nodes, ClientTStamp, Window),
  
negative.code: do_couchbase_index_stats_descriptions(BucketId, AddIndex) ->
      Nodes = case AddIndex of
                  all ->
                      section_nodes("@index-" ++ BucketId);
                  XNodes ->
                      XNodes
              end,
  