anchor.diff:                                 fun () ->
                                          Tab = table_name(Node, Bucket, Period),
                                          Key = mnesia:last(Tab),
  -                                       mnesia:read(Tab, Key)
  +                                       hd(mnesia:read(Tab, Key))
                                  end)}
                 end, Nodes, length(Nodes)).
   
  
positive.code:     Tab = table_name(node(), Bucket, minute),
      {atomic, ok} = mnesia:transaction(fun () -> mnesia:write(Tab, Sample, write) end),
      gen_event:notify(ns_stats_event, {sample_archived, Bucket, Sample}),
      {noreply, maybe_truncate(State)};
  handle_info({sample_archived, _, _}, State) ->
      {noreply, State}.
  
  
  
negative.code: 
  %% @doc Get the latest samples for a given interval from the archive
  latest(Period, Node, Bucket) when is_atom(Node) ->
      [{Node, Result}] = latest(Period, [Node], Bucket),
      Result;
  latest(Period, Nodes, Bucket) when is_list(Nodes), is_list(Bucket) ->
      misc:pmap(fun (Node) ->
  