public boolean batchNeedsClone() {
    return false;
  }
This method should return true, when the particular VectorAggregateExpression must use a cloned batch
while processing one, see Operator.batchNeedsClone() for further details.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/aggregates/VectorAggregateExpression.java