anchor.diff:                               intervals:in(Key, intervals:new(LBr, LK, RK, RBr)) 
                        end, RingData),
       case N of
  -        [] -> 0;
           [{_Pid, _I, DB, _Pred, _Succ, ok}] -> length(DB);
           _ -> 0
       end.
  
positive.code:     is_subtype(Status,      db_generator:db_status()).
  start_sync(Config, NodeCount, DBSize, DBParams, Rounds, Fpr, RRConfig) ->
      NodeKeys = lists:sort(get_symmetric_keys(NodeCount)),
      %build and fill ring
      build_symmetric_ring(NodeCount, Config, RRConfig),
      config:write(rr_bloom_fpr, Fpr),
      %fill_symmetric_ring(DataCount, NodeCount, OutdatedProb),
      erlang:put(?DBSizeKey, ?REP_FACTOR * DBSize),
      db_generator:fill_ring(random, DBSize, DBParams),
      %measure initial sync degree
      InitDBStat = get_db_status(),
      print_status(0, InitDBStat),
      %run sync rounds
      util:for_to_ex(1, Rounds, 
                     fun(I) ->
                             startSyncRound(NodeKeys),
  
negative.code:                            print_status(I, get_db_status())
                     end),
      EndStat = get_db_status(),
      unittest_helper:stop_ring(),
      {InitDBStat, EndStat}.
  
  