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From Yura Smolsky <i...@altervisionmedia.com>
Subject Re[4]: ParallelMultiSearcher
Date Fri, 22 Sep 2006 13:29:10 GMT
Hello, Yonik.

>> ok. I have big issue when I try to search ParallelMultiSearcher for
>> PrefixQuery. This query is being rewritten to BooleanQuery during
>> search. This causes Similarity to calculate docFreq for each Term in the
>> BooleanQuery. So if we have a lot of results for some PrefixQuery then
>> we have a lot of calls to docFreq method of Searchable object passed
>> to ParallelMultiSearcher.

YS> IDF often does not make sense for auto-expanding queries (range, prefix, etc).
YS> If you don't need the idf factor that makes rarer terms count more,
YS> then use a PrefixFilter wrapped in a ConstantScoreQuery.

YS> http://lucene.apache.org/java/docs/api/org/apache/lucene/search/ConstantScoreQuery.html
YS> http://incubator.apache.org/solr/docs/api/org/apache/solr/search/PrefixFilter.html

Thank you so much! PrefixFilter has eliminated counting idf's.. I
wonder why it is not inside of Lucene yet :)

--
Yura Smolsky,
http://altervisionmedia.com/



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