@Explain(vectorization = Vectorization.EXPRESSION, displayName = "aggregators", explainLevels = { Level.DEFAULT, Level.EXTENDED })
    public List<String> getAggregators() {
      VectorAggregationDesc[] vecAggrDescs = vectorGroupByDesc.getVecAggrDescs();
      List<String> vecAggrList = new ArrayList<String>(vecAggrDescs.length);
      for (VectorAggregationDesc vecAggrDesc : vecAggrDescs) {
        vecAggrList.add(vecAggrDesc.toString());
      }
      return vecAggrList;
    }
Checks if this grouping is like distinct, which means that all non-distinct grouping
columns behave like they were distinct - for example min and max operators.
ql/src/java/org/apache/hadoop/hive/ql/plan/GroupByDesc.java