@Override
  public long getAggregationBufferFixedSize() {
    JavaDataModel model = JavaDataModel.get();
    return JavaDataModel.alignUp(
        model.object() +
        model.primitive2() +
        model.primitive1(),
        model.memoryAlign());
  }
class for storing the current aggregate value.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/aggregates/VectorUDAFCountMerge.java