Re: Range phrase operator in tsquery

From: Dmitry Dolgov <9erthalion6(at)gmail(dot)com>
To: a(dot)parfenov(at)postgrespro(dot)ru
Cc: PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Range phrase operator in tsquery
Date: 2018-11-30 20:08:14
Message-ID: CA+q6zcX2oiF5tGHAvbpn0_PcOC1d3iyb3MpveNqj3QqoBPYJ6A@mail.gmail.com
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> On Thu, Nov 15, 2018 at 11:15 PM Dmitry Dolgov <9erthalion6(at)gmail(dot)com> wrote:
>
> > On Fri, 27 Apr 2018 at 13:03, Aleksandr Parfenov <a(dot)parfenov(at)postgrespro(dot)ru> wrote:
> >
> > Nowadays, phrase operator in Postgres FTS supports only exact match of
> > the distance between two words. It is sufficient for a search of
> > simple/exact phrases, but in some cases exact distance is unknown and we
> > want to words be close enough. E.g. it may help to search phrases with
> > additional words in the middle of the phrase
>
> Hi,
>
> Thank you for the patch, it looks like a nice feature. Few questions:
>
> + if (!distance_from_set)
> + {
> + distance_from = distance_to < 0 ? MINENTRYPOS : 0;
> + }
> + if (!distance_to_set)
> + {
> + distance_to = distance_from < 0 ? 0 : MAXENTRYPOS;
> + }
>
> Why use 0 here instead of MAXENTRYPOS/MINENTRYPOS ? It looks a bit strange:
>
> SELECT 'a <,-1000> b'::tsquery;
> tsquery
> ------------------------
> 'a' <-16384,-1000> 'b'
> (1 row)
>
> SELECT 'a <,1000> b'::tsquery;
> tsquery
> ------------------
> 'a' <0,1000> 'b'
> (1 row)
>
> Also I wonder why after introducing MINENTRYPOS the LIMITPOS wasn't changed?
>
> #define LIMITPOS(x) ( ( (x) >= MAXENTRYPOS ) ? (MAXENTRYPOS-1) : (x) )

Due to lack of response I'm marking this as returned with feedback.

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