| From: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
|---|---|
| To: | Jan Urbański <j(dot)urbanski(at)students(dot)mimuw(dot)edu(dot)pl> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Heikki Linnakangas <heikki(at)enterprisedb(dot)com>, Postgres - Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: gsoc, text search selectivity and dllist enhancments |
| Date: | 2008-07-10 20:27:31 |
| Message-ID: | 20080710202731.GH3757@alvh.no-ip.org |
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| Lists: | pgsql-hackers |
Jan Urbański wrote:
> Oh, one important thing. You need to choose a bucket width for the LC
> algorithm, that is decide after how many elements will you prune your
> data structure. I chose to prune after every twenty tsvectors.
Do you prune after X tsvectors regardless of the numbers of lexemes in
them? I don't think that preserves the algorithm properties; if there's
a bunch of very short tsvectors and then long tsvectors, the pruning
would take place too early for the initial lexemes. I think you should
count lexemes, not tsvectors.
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
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