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Re: tsearch2 poor performance

From: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
To: Kris Kiger <kris(at)musicrebellion(dot)com>
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: tsearch2 poor performance
Date: 2004-09-27 18:45:32
Message-ID: Pine.GSO.4.58.0409272243140.14980@ra.sai.msu.su (view raw or flat)
Thread:
Lists: pgsql-adminpgsql-hackers
On Mon, 27 Sep 2004, Kris Kiger wrote:

> Oleg,
>
>     Thanks for the help on this.
>
>     The query I used to return the 508 number is:
>          SELECT * FROM stat('SELECT vector FROM product') ORDER BY ndoc
> desc, word ;
>
>     Testing says, the more words I use, the faster the query is.  My
> original search word, 'oil', appears in 226,357 documents 233,266 times.
>  As far as distinct words go, 'oil' is middle of the road for
> occurences.  As it is set up now, the best search time I am getting on
> this single word is roughly 22 seconds.

Does this time (22 seconds) is still better than seq. scan (no index)
or standard 'LIKE' ?

>
> Kris
>
> Oleg Bartunov wrote:
>
> >Kris,
> >
> >do you actually have only 508 disctinct words ? Could you try
> >more complex queries, say 2-3 words. Does these queries run faster ?
> >
> >
> >	Oleg
> >On Mon, 27 Sep 2004, Kris Kiger wrote:
> >
> >
> >
> >>Regardless of caching, the queries are still taking 19~20 seconds to run
> >>on the 3,000,000 rows.  I've played with performance tuning and nothing
> >>seems to make much of a difference.  If I am reading that list from stat
> >>correctly, then I am operating on  508 distinct words.  Is this the
> >>performance I should expect from tsearch2?  Or is something still awry?
> >> I'm inclined to think  something else is wrong, after reading some
> >>other people's tsearch performance stats.  Thanks!
> >>
> >>Kris
> >>
> >>
> >>
> >	Regards,
> >		Oleg
> >
> >
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>

	Regards,
		Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83

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