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  1. Lucene - Core
  2. LUCENE-3412

SloppyPhraseScorer returns non-deterministic results for queries with many repeats

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 3.1, 3.2, 3.3, 4.0-ALPHA
    • Fix Version/s: 3.5, 4.0-ALPHA
    • Component/s: core/search
    • Labels:
      None

      Description

      Proximity queries with many repeats (four or more, based on my testing) return non-deterministic results. I run the same query multiple times with the same data set and get different results.

      So far I've reproduced this with Solr 1.4.1, 3.1, 3.2, 3.3, and latest 4.0 trunk.

      Steps to reproduce (using the Solr example):
      1) In solrconfig.xml, set queryResultCache size to 0.
      2) Add some documents with text "dog dog dog" and "dog dog dog dog". http://localhost:8983/solr/update?stream.body=%3Cadd%3E%3Cdoc%3E%3Cfield%20name=%22id%22%3E1%3C/field%3E%3Cfield%20name=%22text%22%3Edog%20dog%20dog%3C/field%3E%3C/doc%3E%3Cdoc%3E%3Cfield%20name=%22id%22%3E2%3C/field%3E%3Cfield%20name=%22text%22%3Edog%20dog%20dog%20dog%3C/field%3E%3C/doc%3E%3C/add%3E&commit=true
      3) Do a "dog dog dog dog"~1 query. http://localhost:8983/solr/select?q=%22dog%20dog%20dog%20dog%22~1
      4) Repeat step 3 many times.

      Expected results: The document with id 2 should be returned.

      Actual results: The document with id 2 is always returned. The document with id 1 is sometimes returned.

      Different proximity values show the same bug - "dog dog dog dog"~5, "dog dog dog dog"~100, etc show the same behavior.

      So far I've traced it down to the "repeats" array in SloppyPhraseScorer.initPhrasePositions() - depending on the order of the elements in this array, the document may or may not match. I think the HashSet may be to blame, but I'm not sure - that at least seems to be where the non-determinism is coming from.

        Attachments

        1. LUCENE-3412.patch
          7 kB
          Doron Cohen
        2. LUCENE-3412.patch
          2 kB
          Doron Cohen

          Activity

            People

            • Assignee:
              doronc Doron Cohen
              Reporter:
              michaelryan Michael Ryan
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              Dates

              • Created:
                Updated:
                Resolved: