Re: [tsvector] to_tsvector called multiple times

Thanks, Oleg. Unfortunately, that does not work quite well as German is
comprised of many compound nouns.

In fact, I discovered that anomaly by searching through a
domain-specific word table. For example: Waferhandlingsystem. There are
many '*system' but the PostgreSQL does not allow me to have a suffix;
only a prefix and only for to_tsquery
(http://www.postgresql.org/docs/9.3/static/textsearch-dictionaries.html#TEXTSEARCH-SYNONYM-DICTIONARY)

Is there another possibility?

On 26.05.2015 11:05, Oleg Bartunov wrote:
> You can ask http://snowball.tartarus.org/ for stemmer. Meanwhile,
> you can have small personal dictionary (before stemmer) with such
> exceptions, for example, use synonym template
>
> system system
>
> Oleg
>
>
> On Tue, May 26, 2015 at 11:18 AM, Sven R. Kunze <srkunze(at)tbz-pariv(dot)de
> <mailto:srkunze(at)tbz-pariv(dot)de>> wrote:
>
> Hi everybody,
>
> the following stemming results made me curious:
>
> select to_tsvector('german', 'systeme'); > 'system':1
> select to_tsvector('german', 'systemes'); > 'system':1
> select to_tsvector('german', 'systems'); > 'system':1
> select to_tsvector('german', 'systemen'); > 'system':1
> select to_tsvector('german', 'system'); > 'syst':1
>
>
> First of all, this seems to be a bug in the German stemmer. Where
> can I fix it?
>
> Second, and more importantly, as I understand it, the stemmed
> version of a word should be considered normalized. That is, all
> other versions of that stem should be mapped to it as well. The
> interesting problem here is that PostgreSQL maps the stem itself
> ('system') to a completely different stem ('syst').
>
> Should a stem not remain stable even when to_tsvector is called on
> it multiple times?
>
> --
> Sven R. Kunze
> TBZ-PARIV GmbH, Bernsdorfer Str. 210-212, 09126 Chemnitz
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> e-mail: srkunze(at)tbz-pariv(dot)de <mailto:srkunze(at)tbz-pariv(dot)de>
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>
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--
Sven R. Kunze
TBZ-PARIV GmbH, Bernsdorfer Str. 210-212, 09126 Chemnitz
Tel: +49 (0)371 33714721, Fax: +49 (0)371 5347920
e-mail: srkunze(at)tbz-pariv(dot)de
web: www.tbz-pariv.de

Geschäftsführer: Dr. Reiner Wohlgemuth
Sitz der Gesellschaft: Chemnitz
Registergericht: Chemnitz HRB 8543