@Override
  public void assignRowColumn(VectorizedRowBatch batch, int batchIndex, int columnNum,
      AggregationBuffer agg) throws HiveException {

    LongColumnVector outputColVector = (LongColumnVector) batch.cols[columnNum];
    Aggregation myagg = (Aggregation) agg;
    outputColVector.isNull[batchIndex] = false;
    outputColVector.vector[batchIndex] = myagg.value;
  }
class for storing the current aggregate value.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/aggregates/VectorUDAFCountMerge.java