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From "Yonik Seeley (JIRA)" <j...@apache.org>
Subject [jira] Commented: (LUCENE-1470) Add TrieRangeQuery to contrib
Date Sat, 07 Feb 2009 18:44:59 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-1470?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12671504#action_12671504
] 

Yonik Seeley commented on LUCENE-1470:
--------------------------------------

bq. for the beginners API there is missing the possibility to store the full-precision value

They could simply store it in a different field, in whatever format they desire, right?  It
seems like TrieRange should be about range matching, not the format of stored fields.

bq. NumberUtils tries to get the most out of each char vs. this tries to not affect UTF-8
encoding and use ASCII only?

NumberUtils in Solr was developed a *long* time ago, before Parser support in the FieldCache,
etc (Lucene 1.4).  I chose 14 bit numbers to minimize size in FieldCache using a StringIndex,
and because I didn't understand Lucene prefix compression at the time :-)

If there are to be many in-memory representations, then using 14 bit chars might be better.
 Otherwise it seems like 7 bit might be preferable (better prefix compression, more predictable
branches in the UTF8 encoder/decoder).  Of course it's a trivial switch, so perhaps we should
just try and benchmark it when everything else is done.

As for TrieRangeFilter, I guess the most generic constructor would look like:
{code}
TrieRangeFilter(int precisionStep, String[] fields, long lowerSortableBits, long upperSortableBits,
boolean includeLower, boolean includeUpper)
{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
>            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, 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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