I wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
>> and then gives a query which calculates normalization in an incorrect
>> manner,
> On what basis do you claim that's an incorrect manner? It's exactly
> what is described in the paragraph just before the examples.
... although on reflection, it seems pretty stupid to be recommending
a method that requires two evaluations at each row of an admittedly
expensive function.
Seems like we should add one more normalization flag bit:
32 --- replace computed rank by rank / (rank + 1)
and then the second example would be
SELECT title, ts_rank_cd(textsearch, query, 32 /* rank/(rank+1) */) AS rank
FROM apod, to_tsquery('neutrino|(dark & matter)') query
WHERE query @@ textsearch
ORDER BY rank DESC LIMIT 10;
with no change in the example output.
regards, tom lane