public static boolean isHistogramAvailable(ColStatistics colStats) {
    return colStats != null && colStats.getHistogram() != null && colStats.getHistogram().length > 0;
  }
Returns true if histogram statistics are available in the column statistics information, false otherwise.
@param colStats the input column statistics information
@return true if histogram statistics are available in the column statistics information, false otherwise.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/stats/FilterSelectivityEstimator.java