anchor.diff:              _ ->
                   Acc
           end
  -    end,
  -    _List = leo_backend_db_api:fetch(State, TargetPrefix, Fun),
  -%%%    io:format(user, "[debug]prefix 1: list:~p~n", [List]),
  -    {ok, State}.
  +    end.
   
  -%% ${integer}_
   gen_prefix() ->
       NumOfPrefix = basho_bench_config:get(num_of_prefix, 1000),
       IntPrefix = random:uniform(NumOfPrefix),
  
positive.code: 
  run(prefix_get, _KeyGen, _ValueGen, State) ->
      TargetPrefix = gen_prefix(),
      Fun = fun(K, _V, Acc) ->
          [PrefixBin|_]= binary:split(K, <<$:>>),
          case PrefixBin of
              TargetPrefix ->
  
negative.code: 
  % print status when finished benchmark
  terminate(Reason, State) ->
      case erlang:get(worker_id) of
          1 -> finalize(Reason, State);
          _ -> void
      end.
  
  finalize(Reason, State) ->
      % debug output for prefix data
      BackendDB    = basho_bench_config:get(backend_db,    'bitcask'),
      TargetPrefix = <<"123">>,
      Fun = case BackendDB of
          'bitcask' -> gen_prefix_fun(TargetPrefix);
          'leveldb' -> gen_prefix_fun(TargetPrefix)
      end,
      List = leo_backend_db_api:fetch(State, TargetPrefix, Fun),
      io:format(user, "[debug]prefix 123: list:~p~n", [List]),
      Ret = leo_backend_db_api:status(State),
      io:format(user, "[terminate]reason:~p status:~p~n", [Reason, Ret]),
      ok.
  