presto-main/src/main/java/io/prestosql/operator/scalar/RowDistinctFromOperator.java/RowDistinctFromOperator/isDistinctFrom
class RowDistinctFromOperator:    public static boolean isDistinctFrom(Type rowType, List<MethodHandle> argumentMethods, Block leftRow, boolean leftNull, Block rightRow, boolean rightNull)
    {
        if (leftNull != rightNull) {
            return true;
        }
        if (leftNull) {
            return false;
        }
        List<Type> fieldTypes = rowType.getTypeParameters();
        for (int i = 0; i < leftRow.getPositionCount(); i++) {
            Type type = fieldTypes.get(i);
            Object leftValue = readNativeValue(type, leftRow, i);
            boolean leftValueNull = leftValue == null;
            if (leftValueNull) {
                leftValue = defaultValue(type.getJavaType());
            }
            Object rightValue = readNativeValue(type, rightRow, i);
            boolean rightValueNull = rightValue == null;
            if (rightValueNull) {
                rightValue = defaultValue(type.getJavaType());
            }
            try {
                if ((boolean) argumentMethods.get(i).invoke(
                        leftValue,
                        leftValueNull,
                        rightValue,
                        rightValueNull)) {
                    return true;
                }
            }
            catch (Throwable t) {
                throw internalError(t);
            }
        }
        return false;
    }