Re: Very bad FTS performance with the Polish config - Mailing list pgsql-hackers

From Oleg Bartunov
Subject Re: Very bad FTS performance with the Polish config
Date
Msg-id Pine.LNX.4.64.0911181738440.6801@sn.sai.msu.ru
Whole thread Raw
In response to Re: Very bad FTS performance with the Polish config  (Wojciech Knapik <webmaster@wolniartysci.pl>)
Responses Re: Very bad FTS performance with the Polish config  (Wojciech Knapik <webmaster@wolniartysci.pl>)
Re: Very bad FTS performance with the Polish config  (Pavel Stehule <pavel.stehule@gmail.com>)
List pgsql-hackers
On Wed, 18 Nov 2009, Wojciech Knapik wrote:

>
>> your polish_english, polish configurations uses ispell language and slow,
>> while english configuration doesn't contains ispell. So, what's your
>> complains ? Try add ispell dictionary to english configuration and see
>> timings.
>
> Oh, so this is not anomalous ? These are the expected speeds for an ispell 
> dictionary ? I didn't realize that. Sorry for the bother then. It just seemed 
> way too slow to be practical.

You can see real timings using ts_lexize() function for different dictionaries
(try several time to avoid cold-start problem) instead of ts_headline(), 
which involves other factors.

On my test machine I see no real difference between very simple dictionary
and french ispell, snowball dictionaries:

dev-oleg=# select ts_lexize('simple','voila'); ts_lexize
----------- {voila}
(1 row)

Time: 0.282 ms
dev-oleg=# select ts_lexize('simple','voila'); ts_lexize
----------- {voila}
(1 row)

Time: 0.269 ms

dev-oleg=# select ts_lexize('french_stem','voila'); ts_lexize
----------- {voil}
(1 row)

Time: 0.187 ms

I see no big difference in ts_headline as well:

dev-oleg=# select ts_headline('english','I can do voila', 'voila'::tsquery);      ts_headline
----------------------- I can do <b>voila</b>
(1 row)

Time: 0.265 ms
dev-oleg=# select ts_headline('nomaofr','I can do voila', 'voila'::tsquery);      ts_headline
----------------------- I can do <b>voila</b>
(1 row)

Time: 0.299 ms

This is 8.4.1 version of PostgreSQL.
    Regards,        Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83


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