Re: BUG #17125: Operator precedence bug in websearch_to_tsquery function

"David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
> On Tuesday, July 27, 2021, PG Bug reporting form <noreply(at)postgresql(dot)org>
> wrote:
>> postgres=# select websearch_to_tsquery('english', 'foo bar or baz');
>> websearch_to_tsquery
>> -----------------------
>> 'foo' & 'bar' | 'baz'
>> (1 row)
>>
>> Expected: 'foo' & ('bar' | 'baz')

> The documentation describes the operator precedence and it isn’t what you
> expect.

It does appear from what I could find on the web that Google does it
the other way. Whether that's enough reason to change a behavior
that's stood since v11 is hard to say. We're not trying to be
entirely bug-compatible with Google here ... and even if we were,
who's to say whether they might not change this tomorrow?

Perhaps a more useful way to think about it is whether it's possible
to get the behavior opposite to the default. AFAICS there isn't any
way to get 'a & (b | c)' out of websearch_to_tsquery. However, if
we changed the default precedence, then there'd be no way to get the
old behavior, which is not nice at all. I first thought that maybe
you could write '"a b" or c', but that produces 'a <-> b | c' which
isn't the same.

Anyway, given that most people probably have no idea about this fine
point, I doubt that the benefits of changing it would outweigh the
costs.

regards, tom lane