public static KllHistogramEstimator getEmptyHistogramEstimator() {
    return new KllHistogramEstimator();
  }
This method creates an empty histogram estimator with a KLL sketch with k=200.
@return an empty histogram estimator with a KLL sketch with k=200
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/common/histogram/KllHistogramEstimatorFactory.java