Re: tsearch2 anomoly?

From: Teodor Sigaev <teodor(at)sigaev(dot)ru>
To: RC Gobeille <bob(dot)gobeille(at)hp(dot)com>
Cc: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: tsearch2 anomoly?
Date: 2007-09-07 14:07:17
Message-ID: 46E15B15.2090703@sigaev.ru
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Usual text hasn't strict syntax rules, so parser tries to recognize most
probable token. Something with '.', '-' and alnum characters is often a
filename, but filename is very rare finished or started by dot.

RC Gobeille wrote:
> Thanks and I didn't know about ts_debug, so thanks for that also.
>
> For the record, I see how to use my own processing function (e.g.
> dropatsymbol) to get what I need:
> http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/docs/tsearch-V2-intro
> .html
>
> However, can you explain the logic behind the parsing difference if I just
> add a ".s" to a string:
>
>
> ossdb=# select ts_debug('gallery2-httpd-2.1-conf.');
> ts_debug
> -----------------------------------------------------------------------
> (default,hword,"Hyphenated word",gallery2-httpd-2,{simple},"'2' 'httpd'
> 'gallery2' 'gallery2-httpd-2'")
> (default,part_hword,"Part of hyphenated word",gallery2,{simple},'gallery2')
> (default,lpart_hword,"Latin part of hyphenated
> word",httpd,{en_stem},'httpd')
> (default,float,"Decimal notation",2.1,{simple},'2.1')
> (default,lpart_hword,"Latin part of hyphenated word",conf,{en_stem},'conf')
> (5 rows)
>
> ossdb=# select ts_debug('gallery2-httpd-2.1-conf.s');
> ts_debug
> ---------------------------------------------------------------------
> (default,host,Host,gallery2-httpd-2.1-conf.s,{simple},'gallery2-httpd-2.1-c
> onf.s')
> (1 row)
>
> Thanks again,
> Bob
>
>
> On 9/6/07 11:19 AM, "Oleg Bartunov" <oleg(at)sai(dot)msu(dot)su> wrote:
>
>> This is how default parser works. See output from
>> select * from ts_debug('gallery2-httpd-conf');
>> and
>> select * from ts_debug('httpd-2.2.3-5.src.rpm');
>>
>> All token type:
>>
>> select * from token_type();
>>
>>
>> On Thu, 6 Sep 2007, RC Gobeille wrote:
>>
>>> I'm having trouble understanding to_tsvector. (PostreSQL 8.1.9 contrib)
>>>
>>> In this first case converting 'gallery2-httpd-conf' makes sense to me and is
>>> exactly what I want. It looks like the entire string is indexed plus the
>>> substrings broken by '-' are indexed.
>>>
>>>
>>> ossdb=# select to_tsvector('gallery2-httpd-conf');
>>> to_tsvector
>>> ---------------------------------------------------------
>>> 'conf':4 'httpd':3 'gallery2':2 'gallery2-httpd-conf':1
>>>
>>>
>>> However, I'd expect the same to happen in the httpd example - but it does not
>>> appear to.
>>>
>>> ossdb=# select to_tsvector('httpd-2.2.3-5.src.rpm');
>>> to_tsvector
>>> ---------------------------
>>> 'httpd-2.2.3-5.src.rpm':1
>>>
>>> Why don't I get: 'httpd', 'src', 'rpm', 'httpd-2.2.3-5.src.rpm' ?
>>>
>>> Is this a bug or design?
>>>
>>>
>>> Thank you!
>>> Bob
>> 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
>
>

--
Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
WWW: http://www.sigaev.ru/

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