anchor.diff:      SD#state{replies = Replies};
   save_reply(IdxNode, Obj, SD = #state{system = metric, replies = Replies0}) ->
       {Res, Metrics} = Obj,
  -    Replies = [{IdxNode, {Res, decompress(Metrics)}} | Replies0],
  +    Replies = [{IdxNode, {Res, decompress(Metrics, SD)}} | Replies0],
       SD#state{replies = Replies}.
   
   -spec merge(state(), [E]) -> E.
  
positive.code: init([ReqId, {VNode, System}, Op, From, Entity, Val]) ->
      {ok, N} = application:get_env(dalmatiner_db, n),
      {ok, R} = application:get_env(dalmatiner_db, r),
      SD = #state{req_id=ReqId,
                  r=R,
                  n=N,
                  from=From,
                  op=Op,
                  val=Val,
                  vnode=VNode,
                  system=System,
                  entity=Entity},
      {ok, prepare, SD, 0}.
  
  %% @doc Calculate the Preflist.
  
negative.code: %%-type metric_reply() :: {partition(), metric_element()}.
  
  -record(state, {req_id,
                  compression :: snappy | none,
                  from,
                  entity,
                  op,
  