Re: n-gram search function

From: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
To: Guillaume Smet <guillaume(dot)smet(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: n-gram search function
Date: 2007-02-19 15:05:25
Message-ID: Pine.LNX.4.64.0702191805000.400@sn.sai.msu.ru
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On Mon, 19 Feb 2007, Guillaume Smet wrote:

> On 2/19/07, Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> wrote:
>> pg_trgm was developed for spelling corrrection and there is a threshold of
>> similarity, which is 0.3 by default. Readme explains what does it means.
>
> Yes, I read it.
>
>> Similarity could be very low, since you didn't make separate column and
>> length
>> of the full string is used to normalize similarity.
>
> Yep, that's probably my problem. Ignored records are a bit longer than
> the others.
>
> I tried the tip in README.pg_trgm to generate a table with all the words.
>
> It can do the work in conjunction of tsearch2 and a bit of AJAX to
> suggest the full words to the users. The reason why I was not using
> tsearch2 is that it's sometimes hard to spell location names
> correctly.
>
> The only problem is that it is still quite slow on a 50k rows words
> table but I'll make further tests on a decent server this afternoon.

You need to wait GiN support.

Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru)
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83

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