code: public long readExecutionCount (Path dir) throws IOException {
      State state = loadState(fs, dir);
      return Long.parseLong(state.getProp(CompactionSlaEventHelper.EXEC_COUNT_TOTAL, "0"));
    }
docs: Read execution count from a specific directory.
  File name is {@link InputRecordCountHelper#STATE_FILE}
  @param dir directory where a state file is located
  @return record count