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From Otis Gospodnetic <otis_gospodne...@yahoo.com>
Subject Re: TermsFilter instead of "should" TermQueries
Date Sun, 09 May 2010 16:07:18 GMT
I think what Tomislav was trying to ask is:

Can filters replace only strictly boolean clauses (i.e. only MUST and MUST_NOT), such as:
+gender:F, -rating:xxx)?
Or can filters also replace SHOULD clauses, such as: food:banana (which is neither absolutely
required or strictly prohibited)?

 Otis
----
Sematext :: http://sematext.com/ :: Solr - Lucene - Nutch
Lucene ecosystem search :: http://search-lucene.com/



----- Original Message ----
> From: Erick Erickson <erickerickson@gmail.com>
> To: java-user@lucene.apache.org
> Sent: Fri, May 7, 2010 8:30:18 PM
> Subject: Re: TermsFilter instead of "should" TermQueries
> 
> Well, you construct the filter by enumerating the terms you're
interested in 
> and pass it along to the relevant search.

But it looks like you've 
> figured that part out. If you're asking
how can you use a Filter and still 
> have the terms replaced
by the filter contribute to scoring, you can't. But 
> it's a reasonable
question to ask whether it changes the score enough 
> to
matter given that this is only a problem when there are 
> many
terms.

If this doesn't speak to your question, can you ask for 
> more
detail?

HTH
Erick

On Fri, May 7, 2010 at 1:19 PM, 
> Tomislav Poljak <
> href="mailto:tpoljak@gmail.com">tpoljak@gmail.com> wrote:

> 
> Hi,
> in API documentation for TermsFilter:
>
>
> 
> href="http://search-lucene.com/jd/lucene/org/apache/lucene/search/TermsFilter.html" 
> target=_blank 
> >http://search-lucene.com/jd/lucene/org/apache/lucene/search/TermsFilter.html
>
> 
> it states:
>
> 'As a filter, this is much faster than the equivalent 
> query (a
> BooleanQuery with many "should" TermQueries)'
>
> I 
> would like to replace "should" TermQueries with TermsFilter to benefit
> 
> in performance, but I'm trying to understand how this change/switch can
> 
> work.
>
> I was under the impression that the BooleanQuery with many 
> "should"
> TermQueries affects scoring like: each "should" term present in 
> result,
> increases the result's score.
>
> If someone could 
> explain how can a TermsFilter (which is like any filter
> a binary thing - 
> result document is matched or not) be used to replace
> should clauses, I 
> would really appreciate it.
>
> Tomislav
>
>
> 
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