@Override
  public Statistics clone() {
    Statistics clone = new Statistics(numRows, dataSize, totalFileSize, numErasureCodedFiles);
    clone.setRunTimeNumRows(runTimeNumRows);
    clone.setBasicStatsState(basicStatsState);
    clone.setColumnStatsState(columnStatsState);
    if (columnStats != null) {
      Map<String, ColStatistics> cloneColStats = Maps.newHashMap();
      for (Map.Entry<String, ColStatistics> entry : columnStats.entrySet()) {
        cloneColStats.put(entry.getKey(), entry.getValue().clone());
      }
      clone.setColumnStats(cloneColStats);
    }
    // TODO: this boolean flag is set only by RS stats annotation at this point
    //clone.setRuntimeStats(runtimeStats);
    return clone;
  }
Statistics. Describes the output of an operator in terms of size, rows, etc
based on estimates.
ql/src/java/org/apache/hadoop/hive/ql/plan/Statistics.java