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  1. Lucene - Core
  2. LUCENE-5316

Taxonomy tree traversing improvement

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Minor
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: modules/facet
    • Labels:
      None
    • Lucene Fields:
      New

      Description

      The taxonomy traversing is done today utilizing the ParallelTaxonomyArrays. In particular, two taxonomy-size int arrays which hold for each ordinal it's (array #1) youngest child and (array #2) older sibling.

      This is a compact way of holding the tree information in memory, but it's not perfect:

      • Large (8 bytes per ordinal in memory)
      • Exposes internal implementation
      • Utilizing these arrays for tree traversing is not straight forward
      • Lose reference locality while traversing (the array is accessed in increasing only entries, but they may be distant from one another)
      • In NRT, a reopen is always (not worst case) done at O(Taxonomy-size)

      This issue is about making the traversing more easy, the code more readable, and open it for future improvements (i.e memory footprint and NRT cost) - without changing any of the internals.
      A later issue(s?) could be opened to address the gaps once this one is done.

        Attachments

        1. LUCENE-5316.patch
          37 kB
          Gilad Barkai
        2. LUCENE-5316.patch
          40 kB
          Gilad Barkai
        3. LUCENE-5316.patch
          44 kB
          Gilad Barkai
        4. LUCENE-5316.patch
          44 kB
          Gilad Barkai
        5. LUCENE-5316.patch
          44 kB
          Gilad Barkai

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            People

            • Assignee:
              Unassigned
              Reporter:
              gilad Gilad Barkai
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              Dates

              • Created:
                Updated: