Re: GIN improvements part2: fast scan

I plan to do more thorough testing over the weekend, but I'd like to

make sure I understand what to expect. My understanding is that this
patch should:

- give the same results as the current code (e.g. the fulltext should
  not return different rows / change the ts_rank etc.)

- improve the performance of fulltext queries

Are there any obvious rules what queries will benefit most from this?
The queries generated by the tool I'm using for testing are mostly of
this form:

  SELECT id FROM messages
   WHERE body_tsvector @ plainto_tsquery('english', 'word1 word2 ...')
   ORDER BY ts_rank(...) DESC LIMIT :n;

with varying number of words and LIMIT values. During the testing today
I haven't noticed any obvious performance difference, but I haven't
spent much time on that.