Minor Description
NumericLeafComparator must have a method getPointValues similar how it has getNumericDocValues.
Numeric Sort optimization with points relies on the assumption that points and doc values record the same information, as we substitute iterator over doc_values with one over points.
If we extend getNumericDocValues it almost certainly means that whatever PointValues NumericComparator is going to look at shouldn't be used to skip non-competitive documents. Returning null for pointValues in this case will force comparator NOT to use sort optimization with points, and continue with a traditional way of iterating over doc values.
