Thread: tsearch dictionaries and stop words

tsearch dictionaries and stop words

From
"Robert John Shepherd"
Date:
Hi all,

The docs for tsearch don't seem to make it very clear about its use of
dictionaries. If anyone could answer the following questions I'd be very
grateful!

1) Do I need to specify a locale name? And if so what should I set it
to?

2) What exactly is mean't to be in the file that contain the endings of
words?

3) Is it better to have as big a dictionary as possible? Does this make
the text index more efficient?

TIA!


Yours Unwhettedly,
Robert John Shepherd.

Editor
DVD REVIEWER
The UK's BIGGEST Online DVD Magazine
http://www.dvd.reviewer.co.uk

For a copy of my Public PGP key, email: pgp@robertsworld.org.uk


Re: tsearch dictionaries and stop words

From
Oleg Bartunov
Date:
Robert,

I'm very busy right now, please search mailing list archives for
exactly the same question and several postings related to this topic.
I had hoped someone could write documentation :-(

current tsearch is not flexible as OpenFTS and we hope to return
to development in 1st quarter of 2003 year.

If you want to create your own dictionaries you could use
makedict.pl.

    Oleg
On Thu, 28 Nov 2002, Robert John Shepherd wrote:

> Hi all,
>
> The docs for tsearch don't seem to make it very clear about its use of
> dictionaries. If anyone could answer the following questions I'd be very
> grateful!
>
> 1) Do I need to specify a locale name? And if so what should I set it
> to?

Don't bother if you are from english world. Locale important for
several libc functions such as tolower.
Also, if locale name of dictionary differs from one
specified when starting postmaster, then this dictionary will not used.

>
> 2) What exactly is mean't to be in the file that contain the endings of
> words?
>

exactly what's written:

ing
s
isted
istic
....



> 3) Is it better to have as big a dictionary as possible? Does this make
> the text index more efficient?
>

index is more efficient if cardinality of unique words is kept small.
Dictionaries are your friend.


> TIA!
>
>
> Yours Unwhettedly,
> Robert John Shepherd.
>
> Editor
> DVD REVIEWER
> The UK's BIGGEST Online DVD Magazine
> http://www.dvd.reviewer.co.uk
>
> For a copy of my Public PGP key, email: pgp@robertsworld.org.uk
>
>
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    Regards,
        Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83