[jira] Commented: (LUCENE-1183) TRStringDistance uses way too much memory (with patch)

["Grant Ingersoll (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LUCENE-1183?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12571040#action_12571040 ] 

Grant Ingersoll commented on LUCENE-1183:
-----------------------------------------

It occurs to me that we apparently have two different implementations of Levenshtein, one in spellchecker and one for FuzzyQuery.  I haven't analyzed them individually to know for sure, but if this is a much better implementation, then we should think about using it for FuzzyQuery, too.  

The FuzzyQuery (FuzzyTermEnum) version claims to have a fast-fail mechanism, too:
{quote}
<p>Embedded within this algorithm is a fail-fast Levenshtein distance
   * algorithm.  The fail-fast algorithm differs from the standard Levenshtein
   * distance algorithm in that it is aborted if it is discovered that the
   * mimimum distance between the words is greater than some threshold.
   *
   * <p>
{quote}

Cedrik, since you seem to know about these things, would you have time to look at FuzzyTermEnum?  A 3x speedup there would be great for users, too.

> TRStringDistance uses way too much memory (with patch)
> ------------------------------------------------------
>
>                 Key: LUCENE-1183
>                 URL: https://issues.apache.org/jira/browse/LUCENE-1183
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: contrib/*
>    Affects Versions: 1.9, 2.0.0, 2.1, 2.2, 2.3
>            Reporter: Cédrik LIME
>         Attachments: TRStringDistance.java, TRStringDistance.patch
>
>   Original Estimate: 0.17h
>  Remaining Estimate: 0.17h
>
> The implementation of TRStringDistance is based on version 2.1 of org.apache.commons.lang.StringUtils#getLevenshteinDistance(String, String), which uses an un-optimized implementation of the Levenshtein Distance algorithm (it uses way too much memory). Please see Bug 38911 (http://issues.apache.org/bugzilla/show_bug.cgi?id=38911) for more information.
> The commons-lang implementation has been heavily optimized as of version 2.2 (3x speed-up). I have reported the new implementation to TRStringDistance.

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