Re: Why not keeping positions in GIN?

On 5/25/07, Hitoshi Harada <hitoshi_harada@forcia.com> wrote:
> It's not only about Japanese. When you search "phrase" for text in English,
> the same logic above will be needed. I don't research about tsearch2 but is
> there any problem?? Also, in some case int-array inverted index needs the
> entry positions as well, I guess. Obtaining positions with posting lists is
> "general" enough for GIN, isn't it?
>
> Is there any future plan around it?

We talked of this with Oleg and Teodor when I worked on GIN for
pg_trgm. I know there is a long term plan to solve this issue (and
especially improve ranking in full text search).

I'm not sure the position is general enough.  What I'd like to have is
the ability to add metadata. For example, in the case of pg_trgm, I'd
like to have the length of the original string as it's a strong factor
in similarity calculation. Currently, we get a lot of results which
are rechecked after the first index pass: it's not very efficient.

--
Guillaume