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  1. Lucene - Core
  2. LUCENE-5159

compressed diskdv sorted/sortedset termdictionaries

Details

    • Improvement
    • Status: Closed
    • Major
    • Resolution: Fixed
    • None
    • 4.5, 6.0
    • core/index
    • None
    • New

    Description

      Sorted/SortedSet give you ordinal(s) per document, but them separately have a "term dictionary" of all the values.

      You can do a few operations on these:

      • ord -> term lookup (e.g. retrieving facet labels)
      • term -> ord lookup (reverse lookup: e.g. fieldcacherangefilter)
      • get a term enumerator (e.g. merging, ordinalmap construction)

      The current implementation for diskdv was the simplest thing that can possibly work: under the hood it just makes a binary DV for these (treating ordinals as document ids). When the terms are fixed length, you can address a term directly with multiplication. When they are variable length though, we have to store a packed ints structure in RAM.

      This variable length case is overkill and chews up a lot of RAM if you have many unique values. It also chews up a lot of disk since all the values are just concatenated (no sharing).

      Attachments

        1. LUCENE-5159.patch
          24 kB
          Robert Muir
        2. LUCENE-5159.patch
          24 kB
          Robert Muir
        3. LUCENE-5159.patch
          31 kB
          Robert Muir

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            Unassigned Unassigned
            rcmuir Robert Muir
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              Updated:
              Resolved:

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