[jira] Commented: (LUCENE-1470) Add TrieRangeQuery to contrib

["Earwin Burrfoot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LUCENE-1470?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12651014#action_12651014 ] 

Earwin Burrfoot commented on LUCENE-1470:
-----------------------------------------

Lucene (at least 2.3.2 version) cannot index Strings containing 0xFFFF characters, as it is used internally as EOS marker.
I've implemented binary encoding similar to yours, but after hitting this issue with come converted Date, switched to base-2^15^ encoding, leaving high bit always zero.

{code}
  public String toLucene(Long n) {
    if (n == null) {
      return null;
    }

    long u = n + Long.MAX_VALUE + 1;

    return new String(new char[]{
        (char) ((u & 0xFFFE000000000000L) >> 49),
        (char) ((u & 0x0001FFFC00000000L) >> 34),
        (char) ((u & 0x00000003FFF80000L) >> 19),
        (char) ((u & 0x000000000007FFF0L) >> 4),
        (char) ((u & 0x000000000000000FL) << 11),
    });
  }

  public Long fromLucene(String string) {
    if (string == null) {
      return null;
    }

    return (((long) string.charAt(0)) << 49 |
            ((long) string.charAt(1)) << 34 |
            ((long) string.charAt(2)) << 19 |
            ((long) string.charAt(3)) << 4 |
            ((long) string.charAt(4)) >> 11
    ) - Long.MAX_VALUE - 1;
  }
{code}

> Add TrieRangeQuery to contrib
> -----------------------------
>
>                 Key: LUCENE-1470
>                 URL: https://issues.apache.org/jira/browse/LUCENE-1470
>             Project: Lucene - Java
>          Issue Type: New Feature
>          Components: contrib/*
>    Affects Versions: 2.4
>            Reporter: Uwe Schindler
>         Attachments: LUCENE-1470.patch
>
>
> According to the thread in java-dev (http://www.gossamer-threads.com/lists/lucene/java-dev/67807 and http://www.gossamer-threads.com/lists/lucene/java-dev/67839), I want to include my fast numerical range query implementation into lucene contrib-queries.
> I implemented (based on RangeFilter) another approach for faster
> RangeQueries, based on longs stored in index in a special format.
> The idea behind this is to store the longs in different precision in index
> and partition the query range in such a way, that the outer boundaries are
> search using terms from the highest precision, but the center of the search
> Range with lower precision. The implementation stores the longs in 8
> different precisions (using a class called TrieUtils). It also has support
> for Doubles, using the IEEE 754 floating-point "double format" bit layout
> with some bit mappings to make them binary sortable. The approach is used in
> rather big indexes, query times are even on low performance desktop
> computers <<100 ms (!) for very big ranges on indexes with 500000 docs.
> I called this RangeQuery variant and format "TrieRangeRange" query because
> the idea looks like the well-known Trie structures (but it is not identical
> to real tries, but algorithms are related to it).

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