public String extendedToString() {
    StringBuilder sb = new StringBuilder();
    if (runtimeStats) {
      sb.append(" (runtime) ");
    }
    sb.append(" numRows: ");
    sb.append(numRows);
    sb.append(" dataSize: ");
    sb.append(dataSize);
    sb.append(" basicStatsState: ");
    sb.append(basicStatsState);
    sb.append(" colStatsState: ");
    sb.append(columnStatsState);
    sb.append(" colStats: ");
    sb.append(columnStats);
    return sb.toString();
  }
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