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Date: Fri, 23 Nov 2012 21:24:58 +0000 (UTC)
From: "Mikhail Khludnev (JIRA)" <jira@apache.org>
To: dev@lucene.apache.org
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Subject: [jira] [Commented] (LUCENE-4571) speedup disjunction with
 minShouldMatch
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    [ https://issues.apache.org/jira/browse/LUCENE-4571?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13503285#comment-13503285 ] 

Mikhail Khludnev commented on LUCENE-4571:
------------------------------------------

Robert, 
I've got your points. I need some time to familiarize with luceneutil. btw, why it's not in the main Lucene codebase (I assume it's a frequent question)? 

About BS1 (despite it's an offtop formally), I'm not really understand how you want to score via [term-at-time|http://nlp.stanford.edu/IR-book/html/htmledition/computing-vector-scores-1.html#fig:cosinealg] for minShouldMatch, will you allocate more than single bit (or even byte) per document in a buffer?  
                
> speedup disjunction with minShouldMatch 
> ----------------------------------------
>
>                 Key: LUCENE-4571
>                 URL: https://issues.apache.org/jira/browse/LUCENE-4571
>             Project: Lucene - Core
>          Issue Type: Improvement
>          Components: core/search
>    Affects Versions: 4.1
>            Reporter: Mikhail Khludnev
>
> even minShouldMatch is supplied to DisjunctionSumScorer it enumerates whole disjunction, and verifies minShouldMatch condition [on every doc|https://github.com/apache/lucene-solr/blob/trunk/lucene/core/src/java/org/apache/lucene/search/DisjunctionSumScorer.java#L70]:
> {code}
>   public int nextDoc() throws IOException {
>     assert doc != NO_MORE_DOCS;
>     while(true) {
>       while (subScorers[0].docID() == doc) {
>         if (subScorers[0].nextDoc() != NO_MORE_DOCS) {
>           heapAdjust(0);
>         } else {
>           heapRemoveRoot();
>           if (numScorers < minimumNrMatchers) {
>             return doc = NO_MORE_DOCS;
>           }
>         }
>       }
>       afterNext();
>       if (nrMatchers >= minimumNrMatchers) {
>         break;
>       }
>     }
>     
>     return doc;
>   }
> {code}
> [~spo] proposes (as well as I get it) to pop nrMatchers-1 scorers from the heap first, and then push them back advancing behind that top doc. For me the question no.1 is there a performance test for minShouldMatch constrained disjunction. 

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