Re: Rethinking our fulltext phrase-search implementation

I wrote:
> It's worth noting that with these rules, phrase searches will act as
> though "!x" always matches somewhere; for instance "!a <-> !b" will match
> any tsvector. I argue that this is not wrong, not even if the tsvector is
> empty: there could have been adjacent stopwords matching !a and !b in the
> original text. Since we've adjusted the phrase matching rules to treat
> stopwords as unknown-but-present words in a phrase, I think this is
> consistent. It's also pretty hard to assert this is wrong and at the same
> time accept "!a <-> b" matching b at the start of the document.

To clarify this point, I'm imagining that the patch would include
documentation changes like the attached.

regards, tom lane