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From "Robert Muir (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-4872) BooleanWeight should decide how to execute minNrShouldMatch
Date Thu, 28 Mar 2013 01:21:16 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-4872?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13615951#comment-13615951
] 

Robert Muir commented on LUCENE-4872:
-------------------------------------

{quote}
I really don't really know what the typical/common use cases are for
minShouldMatch.
{quote}

One very practical thing is that solr queryparsers (probably elasticsearch has similar ones
too?) such as dismax/edismax actually seem to be fully defined in terms of minShouldMatch
(with the extremes being handled as OR and AND). 

I know Tom Burton-West has experimented with this some on chinese TREC data (he has some comments
on SOLR-3589), etc.

                
> BooleanWeight should decide how to execute minNrShouldMatch
> -----------------------------------------------------------
>
>                 Key: LUCENE-4872
>                 URL: https://issues.apache.org/jira/browse/LUCENE-4872
>             Project: Lucene - Core
>          Issue Type: Sub-task
>          Components: core/search
>            Reporter: Robert Muir
>             Fix For: 5.0, 4.3
>
>         Attachments: crazyMinShouldMatch.tasks
>
>
> LUCENE-4571 adds a dedicated document-at-time scorer for minNrShouldMatch which can use
advance() behind the scenes. 
> In cases where you have some really common terms and some rare ones this can be a huge
performance improvement.
> On the other hand BooleanScorer might still be faster in some cases.
> We should think about what the logic should be here: one simple thing to do is to always
use the new scorer when minShouldMatch is set: thats where i'm leaning. 
> But maybe we could have a smarter heuristic too, perhaps based on cost()

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