// expected type for the row-mode aggregation
// For decimal, the type is "same number of integer digits and 4 more decimal digits"
DecimalTypeInfo dtiSum = GenericUDAFAverage.deriveSumFieldTypeInfo(inputPrecision, inputScale);
this.sumScale = (short) dtiSum.scale();
this.sumPrecision = (short) dtiSum.precision();
List<ObjectInspector> foi = new ArrayList<ObjectInspector>();
foi.add(PrimitiveObjectInspectorFactory.writableLongObjectInspector);
foi.add(PrimitiveObjectInspectorFactory.getPrimitiveWritableObjectInspector(dtiSum));
List<String> fname = new ArrayList<String>();