message: Update has null statistics.
diff: @@ -12,6 +12,9 @@ void Statistics::Verify(Vector &vector) {
  if (!has_stats || vector.count == 0)
  return;
  + if (!can_have_null) {
  + assert(!VectorOperations::HasNull(vector));
  + }
  if (!min.is_null) {
  Value actual_min = VectorOperations::Min(vector);
  assert(Value::LessThanEquals(min, actual_min));
  @@ -33,6 +36,9 @@ void Statistics::Update(Vector &new_vector) {
  if (type != new_vector.type) {
  throw Exception("Appended vector does not match statistics type!");
  }
  + if (!can_have_null) {
  + can_have_null = VectorOperations::HasNull(new_vector);
  + }
  if (TypeIsNumeric(type)) {
  Value new_min = VectorOperations::Min(new_vector);
  Value new_max = VectorOperations::Max(new_vector);
  