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  1. Lucene - Core
  2. LUCENE-3097

Post grouping faceting


    • New Feature
    • Status: Closed
    • Minor
    • Resolution: Fixed
    • None
    • 3.4, 4.0-ALPHA
    • modules/grouping
    • None
    • Patch Available


      This issues focuses on implementing post grouping faceting.

      • How to handle multivalued fields. What field value to show with the facet.
      • Where the facet counts should be based on
        • Facet counts can be based on the normal documents. Ungrouped counts.
        • Facet counts can be based on the groups. Grouped counts.
        • Facet counts can be based on the combination of group value and facet value. Matrix counts.

      And properly more implementation options.

      The first two methods are implemented in the SOLR-236 patch. For the first option it calculates a DocSet based on the individual documents from the query result. For the second option it calculates a DocSet for all the most relevant documents of a group. Once the DocSet is computed the FacetComponent and StatsComponent use one the DocSet to create facets and statistics.

      This last one is a bit more complex. I think it is best explained with an example. Lets say we search on travel offers:

      hotel departure_airport duration
      Hotel a AMS 5
      Hotel a DUS 10
      Hotel b AMS 5
      Hotel b AMS 10

      If we group by hotel and have a facet for airport. Most end users expect (according to my experience off course) the following airport facet:
      AMS: 2
      DUS: 1

      The above result can't be achieved by the first two methods. You either get counts AMS:3 and DUS:1 or 1 for both airports.


        1. LUCENE-3097.patch
          50 kB
          Martijn van Groningen
        2. LUCENE-3097.patch
          49 kB
          Martijn van Groningen
        3. LUCENE-30971.patch
          44 kB
          Martijn van Groningen
        4. LUCENE-3097.patch
          33 kB
          Martijn van Groningen
        5. LUCENE-3097.patch
          26 kB
          Martijn van Groningen
        6. LUCENE-3097.patch
          25 kB
          Martijn van Groningen

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              martijn.v.groningen Martijn van Groningen
              martijn.v.groningen Martijn van Groningen
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