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From "Uwe Schindler (JIRA)" <j...@apache.org>
Subject [jira] Commented: (LUCENE-1470) Add TrieRangeQuery to contrib
Date Sun, 08 Feb 2009 16:28:59 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-1470?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12671639#action_12671639
] 

Uwe Schindler commented on LUCENE-1470:
---------------------------------------

There may be one issue with signedness in your's and mine code for the special case of a precisionStep
of 1. In this case the outermost/innermost calculation of the range bounds can fail, but I
am not sure. I wanted to write a test for it.

I am currently testing only 8, 4, 2 - as the results for that *must* be identical to my old
code (I also printed a lot of System.outs in my old code to generate a exact match of everything).
There are some special cases in range splitting that are very sensitive. It took me also very
long time to reimplement it. But the usage of longs/ints is really nicer and cleaner than
incrementing/decrementing string values, as I did before.

It is now also possible to use a completely other encoding, without changing the range splitting
(e.g. to compare 7bit chars to 13/14 bit chars from NumberUtils).

> 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
>            Assignee: Uwe Schindler
>             Fix For: 2.9
>
>         Attachments: fixbuild-LUCENE-1470.patch, fixbuild-LUCENE-1470.patch, LUCENE-1470-readme.patch,
LUCENE-1470.patch, LUCENE-1470.patch, LUCENE-1470.patch, LUCENE-1470.patch, LUCENE-1470.patch,
LUCENE-1470.patch, LUCENE-1470.patch, TrieRangeFilter.java, TrieUtils.java, TrieUtils.java,
TrieUtils.java, TrieUtils.java, TrieUtils.java
>
>
> 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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