Re: 9.6 phrase search distance specification
| От | Ryan Pedela |
|---|---|
| Тема | Re: 9.6 phrase search distance specification |
| Дата | |
| Msg-id | CACu89FR-6HW+77v6kSAwhjkjDDiafDDw_h7JPFOU6sztcRLY3g@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: 9.6 phrase search distance specification (Tom Lane <tgl@sss.pgh.pa.us>) |
| Ответы |
Re: 9.6 phrase search distance specification
Re: 9.6 phrase search distance specification |
| Список | pgsql-hackers |
On Tue, Aug 9, 2016 at 11:58 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Bruce Momjian <bruce@momjian.us> writes:
> Does anyone know why the phrase distance "<3>" was changed from "at most
> three tokens away" to "exactly three tokens away"?
So that it would correctly support phraseto_tsquery's use of the operator
to represent omitted words (stopwords) in a phrase.
I think there's probably some use in also providing an operator that does
"at most this many tokens away", but Oleg/Teodor were evidently less
excited, because they didn't take the time to do it.
The thread where this change was discussed is
https://www.postgresql.org/message-id/flat/ c19fcfec308e6ccd952cdde9e648b5 05%40mail.gmail.com
see particularly
https://www.postgresql.org/message-id/11252.1465422251% 40sss.pgh.pa.us
I would say that it is worth it to have a "phrase slop" operator (Apache Lucene terminology). Proximity search is extremely useful for improving relevance and phrase slop is one of the tools to achieve that.
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