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  1. Lucene - Core
  2. LUCENE-8197

Make top-k queries fast when static scoring signals are incorporated into the score

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Details

    • Improvement
    • Status: Closed
    • Minor
    • Resolution: Fixed
    • None
    • 7.4, 8.0
    • None
    • None
    • New

    Description

      Block-max WAND (LUCENE-8135) and some earlier issues made Lucene faster at computing the top-k matches of boolean queries.

      It is quite frequent that users want to improve ranking and end up scoring with a formula that could look like bm25_score + w * log(alpha + pagerank) (w and alpha being constants, and pagerank being a per-document field value). You could do this with doc values and FunctionScoreQuery but unfortunately this will remove the ability to optimize top-k queries since the scoring formula becomes opaque to Lucene.

      I'd like to add a new field that allows to store such scoring signals as term frequencies, and new queries that could produce log(alpha + pagerank) as a score. Then implementing the above formula can be done by boosting this query with a boost equal to w and adding this boosted query as a SHOULD clause of a BooleanQuery. This would give Lucene the ability to compute top-k hits faster, especially but not only if the index is sorted by decreasing pagerank.

      Attachments

        1. LUCENE-8197.patch
          38 kB
          Adrien Grand
        2. LUCENE-8197.patch
          43 kB
          Adrien Grand
        3. LUCENE-8197.patch
          29 kB
          Adrien Grand
        4. LUCENE-8197.patch
          26 kB
          Adrien Grand

        Activity

          People

            Unassigned Unassigned
            jpountz Adrien Grand
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            Dates

              Created:
              Updated:
              Resolved: