Re: [htdig] Prefix search


Subject: Re: [htdig] Prefix search
From: Geoff Hutchison (ghutchis@wso.williams.edu)
Date: Tue Aug 22 2000 - 10:07:46 PDT


On Tue, 22 Aug 2000, Reich, Stefan wrote:

> Is htdig building this list before searching or during search? Whats about
> the performance of this approach. (doesn't look to bad!)

Prefix searches are done on-the-fly during search.

> The reason I'm asking is: I want to do a "range search". Is it a good idea
> to do it the same way, by pre-building such a list using the db.wordlist.
> I thought this may be a performance problem but if htdig is using this kind
> of monster search string anyway, it can't get worse.

I'm not quite sure what you mean by "range search," but some fuzzy
algorithms are done on-the-fly and some build databases after digging. The
prefix and substring searches are done on-the-fly because it would be
impossible to generate databases for all possible queries beforehand.

(Actually the way the word DB is stored, the prefix search uses the DB as
an optimized prebuilt list anyway.)

For fuzzy algorithms, the question comes down to:
(a) Can I actually build an auxilliary database for the method that is a
reasonable size?
(b) Can I quickly generate the list of alternatives on-the-fly w/o needing
a separate database.

For example, the speling (sic) fuzzy algorithm in the 3.2 code can do (b),
even though (a) could work.

--
-Geoff Hutchison
Williams Students Online
http://wso.williams.edu/

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