[ 
https://issues.apache.org/jira/browse/LUCENE-3328?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13069061#comment-13069061
 ] 

Michael Busch commented on LUCENE-3328:
---------------------------------------

{quote}
The ConjunctionTermScorer sorts the DocsEnums by their frequency in the ctor. 
The leader will always be the lowest frequent term in the set. is this what you 
mean here?
{quote}

Cool, yeah that's roughly what I meant. In general, it's best to always pick 
the lowest-df enum as leader:
1) after initialization
2) after a hit was found
3) whenever a doc matched m out of n enums, 1 < m < n

I think what you described covers situation 1), does it also cover 2) and 3)?

> Specialize BooleanQuery if all clauses are TermQueries
> ------------------------------------------------------
>
>                 Key: LUCENE-3328
>                 URL: https://issues.apache.org/jira/browse/LUCENE-3328
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: core/search
>    Affects Versions: 3.4, 4.0
>            Reporter: Simon Willnauer
>             Fix For: 4.0
>
>         Attachments: LUCENE-3328.patch, LUCENE-3328.patch, LUCENE-3328.patch
>
>
> During work on LUCENE-3319 I ran into issues with BooleanQuery compared to 
> PhraseQuery in the exact case. If I disable scoring on PhraseQuery and bypass 
> the position matching, essentially doing a conjunction match, 
> ExactPhraseScorer beats plain boolean scorer by 40% which is a sizeable gain. 
> I converted a ConjunctionScorer to use DocsEnum directly but still didn't get 
> all the 40% from PhraseQuery. Yet, it turned out with further optimizations 
> this gets very close to PhraseQuery. The biggest gain here came from 
> converting the hand crafted loop in ConjunctionScorer#doNext to a for loop 
> which seems to be less confusing to hotspot. In this particular case I think 
> code specialization makes lots of sense since BQ with TQ is by far one of the 
> most common queries.
> I will upload a patch shortly

--
This message is automatically generated by JIRA.
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