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From Arjen van der Meijden <acmmail...@tweakers.net>
Subject Re: Performance measurements
Date Thu, 25 Jul 2013 07:14:48 GMT
On 24-7-2013 21:58 Sriram Sankar wrote:
> On Wed, Jul 24, 2013 at 10:24 AM, Jack Krupansky <jack@basetechnology.com>wrote:
>> Scoring has been a major focus of Lucene. Non-scored filters are also
>> available, but the query parsers are focused (exclusively) on scored-search.
>>
>
> When you say "filter" do you mean a step performed after retrieval?  Or is
> it yet another retrieval operation?

He is really referring to the Filters available as an addition to 
retrieval. The ones you supply with the search-method:
http://lucene.apache.org/core/4_4_0/core/org/apache/lucene/search/IndexSearcher.html#search%28org.apache.lucene.search.Query,%20org.apache.lucene.search.Filter,%20int%29

Unfortunately the documentation of Lucene is a bit fragmented, but 
basically they limit the scope of your search domain (i.e. reduce the 
available set of documents) during the processing of a query. So it 
basically becomes (query) AND (filters).

There are several useful implementations available for the filters. But 
in your case you can just create a single TermsFilter (its in the 
queries module/package) which is simply a OR-list like the one in your 
example (similar to a basic IN in sql):

http://lucene.apache.org/core/4_4_0/queries/org/apache/lucene/queries/TermsFilter.html

So searching would become:
- Create a Query with only your termA
- Create a TermsFilter with all your termB's
- execute your preferred search-method with both the query and the filter

If you where interested in the scores of each result, this would not 
work too well since all scores will only be based on the query that only 
contains termA... But since you don't care about that, this should be 
get you a big performance gain.

Best regards,

Arjen

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