Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 4.0-ALPHA
    • Component/s: core/index
    • Labels:
      None
    • Lucene Fields:
      New

      Description

      PrefixCodedTermsReader/Writer (used by all "real" core codecs) already
      supports pluggable terms index impls.

      The only impl we have now is FixedGapTermsIndexReader/Writer, which
      picks every Nth (default 32) term and holds it in efficient packed
      int/byte arrays in RAM. This is already an enormous improvement (RAM
      reduction, init time) over 3.x.

      This patch adds another impl, VariableGapTermsIndexReader/Writer,
      which lets you specify an arbitrary IndexTermSelector to pick which
      terms are indexed, and then uses an FST to hold the indexed terms.
      This is typically even more memory efficient than packed int/byte
      arrays, though, it does not support ord() so it's not quite a fair
      comparison.

      I had to relax the terms index plugin api for
      PrefixCodedTermsReader/Writer to not assume that the terms index impl
      supports ord.

      I also did some cleanup of the FST/FSTEnum APIs and impls, and broke
      out separate seekCeil and seekFloor in FSTEnum. Eg we need seekFloor
      when the FST is used as a terms index but seekCeil when it's holding
      all terms in the index (ie which SimpleText uses FSTs for).

        Attachments

        1. LUCENE-2843.patch
          193 kB
          Michael McCandless
        2. LUCENE-2843.patch
          205 kB
          Michael McCandless

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            People

            • Assignee:
              mikemccand Michael McCandless
              Reporter:
              mikemccand Michael McCandless
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              Dates

              • Created:
                Updated:
                Resolved: