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From "Paul Elschot (JIRA)" <>
Subject [jira] Commented: (LUCENE-1470) Add TrieRangeQuery to contrib
Date Thu, 27 Nov 2008 08:59:44 GMT


Paul Elschot commented on LUCENE-1470:

I simply used the maximum number of terms at each level times the number of levels.
For a trie factor of 2**b (using b bits), and a long of 64 bits, that is:
(2**b - 1) * (64/b)
The actual values for b = 8, b = 4 and b = 2 are shown above.

> Add TrieRangeQuery to contrib
> -----------------------------
>                 Key: LUCENE-1470
>                 URL:
>             Project: Lucene - Java
>          Issue Type: New Feature
>          Components: contrib/*
>    Affects Versions: 2.4
>            Reporter: Uwe Schindler
>            Assignee: Michael McCandless
>         Attachments: LUCENE-1470.patch, LUCENE-1470.patch
> According to the thread in java-dev (
and, 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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