Re: Should phraseto_tsquery('simple', 'blue blue') @@ to_tsvector('simple', 'blue') be true ?

On Thu, Jun 9, 2016 at 12:47 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Oleg Bartunov <obartunov(at)gmail(dot)com> writes:
>> On Wed, Jun 8, 2016 at 8:12 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Another thing I noticed: if you test with tsvectors that don't contain
>>> position info, <-> seems to reduce to &, that is it doesn't enforce
>>> relative position:
>
>> yes, that's documented behaviour.
>
> Oh? Where? I've been going through the phrase-search documentation and
> copy-editing it today, and I have not found this stated anywhere.

Hmm, looks like it is missing. We have told about this since 2008. Just found
http://www.sai.msu.su/~megera/postgres/talks/2009.pdf (slide 5) and
http://www.sai.msu.su/~megera/postgres/talks/pgcon-2016-fts.pdf (slide 27)

We need to reach a consensus here, since there is no way to say "I don't know".
I inclined to agree with you, that returning false is better in such a
case.That will
indicate user to the source of problem.

>
> regards, tom lane