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From Apache Wiki <wikidi...@apache.org>
Subject [Lucene-java Wiki] Update of "SearchNumericalFields" by UweSchindler
Date Wed, 07 Oct 2009 06:03:25 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Lucene-java Wiki" for change notification.

The "SearchNumericalFields" page has been changed by UweSchindler:
http://wiki.apache.org/lucene-java/SearchNumericalFields?action=diff&rev1=16&rev2=17

  = Searching Numerical Fields =
  
- == NumericRangeQuery (in Lucene Core since version 2.9-dev, which is not yet released) ==
+ == NumericRangeQuery (in Lucene Core since version 2.9) ==
  
  Because Apache Lucene is a full-text search engine and not a conventional database, it cannot
handle numerical ranges (e.g., field value is inside user defined bounds, even dates are numerical
values). We have developed an extension to Apache Lucene that stores the numerical values
in a special string-encoded format with variable precision (called trie, all numerical values
like doubles, longs, Dates, floats, and ints are converted to lexicographic sortable string
representations and indexed with different precisions). A range is then divided recursively
into multiple intervals for searching: The center of the range is searched only with the lowest
possible precision in the trie, while the boundaries are matched more exactly. This reduces
the number of terms dramatically. See: http://hudson.zones.apache.org/hudson/job/Lucene-trunk/javadoc/core/org/apache/lucene/search/NumericRangeQuery.html
  

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