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

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:
>
> regression=# select 'cat bat fat rat'::tsvector @@ 'cat <-> rat'::tsquery;
> ?column?
> ----------
> t
> (1 row)
>
> regression=# select 'rat cat bat fat'::tsvector @@ 'cat <-> rat'::tsquery;
> ?column?
> ----------
> t
> (1 row)

yes, that's documented behaviour.

>
> I'm doubtful that this is a good behavior, because it seems like it can
> silently mask mistakes. That is, applying <-> to a stripped tsvector
> seems like user error to me. Actually throwing an error might be too
> much, but perhaps we should make such cases return false not true?

it's question of convention. Probably, returning false will quickly
indicate user
on his error, so such behaviour looks better.

>
> (This is against HEAD, without the patch I suggested yesterday.
> It strikes me that that patch might change this behavior, if the
> lexemes are all being treated as having position zero, but I have
> not checked.)

I didn't see the patch yet.

>
> regards, tom lane