[ 
https://issues.apache.org/jira/browse/LUCENE-5033?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13676919#comment-13676919
 ] 

Tim Allison commented on LUCENE-5033:
-------------------------------------

I agree that it appears to, but if you want a distance > 2, the current 
levenshtein automaton doesn't allow that 
(http://blog.mikemccandless.com/2011/03/lucenes-fuzzyquery-is-100-times-faster.html?showComment=1303598602291#c3051732466052117784).
  The classic QueryParser silently converts distances > 2 to 2.

If I understand SlowFuzzyQuery correctly, it uses the levenshtein automaton for 
distances <= 2, but it runs brute force if the distance is > 2.  

My personal preference would be to undeprecate SlowFuzzyQuery (certainly leave 
it in the sandbox) because it offers a capability that the current levenshtein 
automaton doesn't.  In cases where the indices are very large, it wouldn't make 
sense to expose distance > 2 capability; but on small to medium indices, there 
are use cases that require it.

                
> SlowFuzzyQuery appears to fail with edit distance >=3 in some cases
> -------------------------------------------------------------------
>
>                 Key: LUCENE-5033
>                 URL: https://issues.apache.org/jira/browse/LUCENE-5033
>             Project: Lucene - Core
>          Issue Type: Bug
>          Components: modules/other
>    Affects Versions: 4.3
>            Reporter: Tim Allison
>            Priority: Minor
>         Attachments: LUCENE-5033.patch
>
>
> Levenshtein edit btwn "monday" and "montugu" should be 4.  The following 
> shows a query with "sim" set to 3, and there is a hit.
>   public void testFuzzinessLong2() throws Exception {
>      Directory directory = newDirectory();
>      RandomIndexWriter writer = new RandomIndexWriter(random(), directory);
>      addDoc("monday", writer);
>      
>      IndexReader reader = writer.getReader();
>      IndexSearcher searcher = newSearcher(reader);
>      writer.close();
>      SlowFuzzyQuery query;
>      query = new SlowFuzzyQuery(new Term("field", "montugu"), 3, 0);   
>      ScoreDoc[] hits = searcher.search(query, null, 1000).scoreDocs;
>      assertEquals(0, hits.length);
>   }

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org
For additional commands, e-mail: dev-h...@lucene.apache.org

Reply via email to