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From "Stefan Pohl (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (LUCENE-4571) speedup disjunction with minShouldMatch
Date Wed, 20 Mar 2013 17:55:19 GMT

     [ https://issues.apache.org/jira/browse/LUCENE-4571?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Stefan Pohl updated LUCENE-4571:
--------------------------------

    Attachment: LUCENE-4571.patch

During working on a new cost-API based implementation, I stumbled upon a bug in the previous
implementation that affected the scores returned by the advance()-method of this Scorer. I
assume that it has not been called for the measurements in the previous comments (and obviously
current tests), so all above should be valid.
For reference, I however attach a fixed (soon to be obsolete) patch.
                
> 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
>         Attachments: LUCENE-4571.patch, LUCENE-4571.patch, LUCENE-4571.patch, LUCENE-4571.patch
>
>
> 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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