anchor.diff:  %% @hidden
   -spec init(non_neg_integer()) -> {ok, state()} | {stop, any()}.
   init(Index) ->
  -  {ok, _Ref} = timer:send_interval(?ACCESS_DUMP_INTERVAL, access_dump),
     case eleveldb:open("db/edis-" ++ integer_to_list(Index), [{create_if_missing, true}]) of
       {ok, Ref} ->
  -      {ok, #state{index = Index, db = Ref, last_save = edis_util:timestamp()}};
  +      {ok, #state{index = Index, db = Ref, last_save = edis_util:timestamp(),
  +                  start_time = edis_util:now(), accesses = dict:new()}};
       {error, Reason} ->
         ?THROW("Couldn't start level db #~p:~b\t~p~n", [Index, Reason]),
         {stop, Reason}
  
positive.code:                        Pad = Offset - erlang:size(Prefix),
                         NewV = <<Prefix/binary, 0:Pad/unit:8, Value/binary>>,
                         {erlang:size(NewV), Item#edis_item{value = NewV}}
                 end, <<>>),
        {reply, Reply, State}
    end;
  handle_call({str_len, Key}, _From, State) ->
    case get_item(State#state.db, string, Key) of
      #edis_item{value = Value} ->
        {reply, {ok, erlang:size(Value)}, State};
      not_found ->
        {reply, {ok, 0}, State};
      {error, Reason} ->
        {reply, {error, Reason}, State}
    end;
  handle_call({del, Keys}, _From, State) ->
    DeleteActions =
        [{delete, Key} || Key <- Keys, exists_item(State#state.db, Key)],
    case eleveldb:write(State#state.db, DeleteActions, []) of
      ok ->
        {reply, {ok, length(DeleteActions)}, State};
      {error, Reason} ->
        {reply, {error, Reason}, State}
    end;
  handle_call({exists, Key}, _From, State) ->
    Reply =
        case exists_item(State#state.db, Key) of
  
negative.code: %% =================================================================================================
  %% Private functions
  %% =================================================================================================
  %% @private
  stamp([], State) -> State;
  stamp([Key|Keys], State) ->
    stamp(Keys, stamp(Key, State));
  stamp(Key, State) ->
    State#state{accesses =
                  dict:store(Key, edis_util:now() -
                               State#state.start_time, State#state.accesses)}.
  
  %% @private
  exists_item(Db, Key) ->
    case eleveldb:get(Db, Key, []) of
  