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  1. Lucene - Core
  2. LUCENE-2286

enable DefaultSimilarity.setDiscountOverlaps by default

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 3.1, 4.0-ALPHA
    • Component/s: core/query/scoring
    • Labels:
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    • Lucene Fields:
      New

      Description

      I think we should enable setDiscountOverlaps in DefaultSimilarity by default.

      If you are using synonyms or commongrams or a number of other 0-posInc-term-injecting methods, these currently screw up your length normalization.
      These terms have a position increment of zero, so they shouldnt count towards the length of the document.

      I've done relevance tests with persian showing the difference is significant, and i think its a big trap to anyone using synonyms, etc: your relevance can actually get worse if you don't flip this boolean flag.

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            • Assignee:
              rcmuir Robert Muir
              Reporter:
              rcmuir Robert Muir
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                Updated:
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