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  1. Lucene - Core
  2. LUCENE-9071

Speed up computation of BM25 scores

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 8.4
    • Component/s: None
    • Labels:
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    • Lucene Fields:
      New

      Description

      We changed the way BM25 scores are computed in LUCENE-7997 in order to guarantee monotonicity of scores, but this translated to a small decrease of throughput, see annotation CC (October 2017) on Mike's nightly benchmarks. Even though the total number of score computations has decreased since we introduced block-max WAND, its relative cost is not negligible since we not only compute scores on collected documents, but also when decoding skip lists in order to compute the maximum score per block, or group of blocks.

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              • Assignee:
                Unassigned
                Reporter:
                jpountz Adrien Grand
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