protected AggregationBuffer[] newAggregations() throws HiveException {
    AggregationBuffer[] aggs = new AggregationBuffer[aggregationEvaluators.length];
    for (int i = 0; i < aggregationEvaluators.length; i++) {
      aggs[i] = aggregationEvaluators[i].getNewAggregationBuffer();
      // aggregationClasses[i].reset(aggs[i]);
    }
    return aggs;
  }
@return the size of each row
ql/src/java/org/apache/hadoop/hive/ql/exec/GroupByOperator.java