Thanks Simon, I'll fix the nocommit and add some comments.. the
ord/BytesRef comparators are tricky...
this seems to be very specific to in-memory docvalues while we don't support direct source here.
Hmm, true; though I suspect sorting by a direct source will be rather
slow. Still I agree we should support it for completeness.
Can we maybe extract an interface from PackedInts.Reader & RandomAccessReaderIterator (those are already very similar) so we can simply use the reader interface for both on-disk and in-memory variants.
OK I like your idea of using PackedInts.Reader for on-disk and
in-memory variants; you shouldn't have to pull an enum from PackedInts
if you just need the disk-based get.
I'll open a new issue to do that refactoring first; I think we can
remove the PackedInts.RandomAccessReaderIterator if we just let the
Reader.get throw IOE? Lemme try to work up a patch.