Re: full text search to_tsquery performance with ispell dictionary - Mailing list pgsql-general

From Pavel Stehule
Subject Re: full text search to_tsquery performance with ispell dictionary
Date
Msg-id BANLkTikXvVz=h9z1FaQMJVQL4gGwvEDg=Q@mail.gmail.com
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In response to Re: full text search to_tsquery performance with ispell dictionary  (Pavel Stehule <pavel.stehule@gmail.com>)
Responses Re: full text search to_tsquery performance with ispell dictionary  (Stanislav Raskin <raskin@livn.de>)
List pgsql-general
Hello

2011/5/11 Stanislav Raskin <raskin@livn.de>:
>
> On 11.05.11 15:45, "Pavel Stehule" <pavel.stehule@gmail.com> wrote:
>
>>it is expected behave :( . A loading of ispell dictionary is very slow.
>>
>>Use a german snowball instead.
>>
>>You can you a some pooling connection software too.
>
>
> Thank you for the response.
> Is the dictionary german_stem supplied with postgresql a snowball stemmer?
> If yes, it sure is incredibly fast, but yields much worse results and thus
> fewer and worse matches for search queries.
>
> To use connections pooling is...difficult in my situation, to say the
> least. We currently use quite a complex pgcluster/corosync setup for
> multi-master replication, load balancing and high availability. To
> introduce connection pooling to this setup could turn out to be quite a
> big project.
>

German_stem is part of distribution. I am thinking so result of stems
are usable because the reports about slow speed are not often.

There are not exists Czech stem, so we have to use a ispell. I wrote a
patch that stores loaded dictionary in shared memory. You can find
source code in archive pg_hacker mailing list. But it isn't well
tested and it is just prototype - not accepted to pg. You can test it.
Sometimes people use a >>simple<< configuration here. It isn't best
but it is fast.

Regards

Pavel Stehule

> --
>
> Stanislav Raskin
>
>
>
>

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