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https://issues.apache.org/jira/browse/LUCENE-4872?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13613035#comment-13613035
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Michael McCandless commented on LUCENE-4872:
--------------------------------------------
I really don't really know what the typical/common use cases are for
minShouldMatch.
I agree we should err towards BS2, since it can be insanely faster
while BS1 can only be ~3X faster (on super-slow queries to begin
with), in this test anyway.
A more accurate cost model for scorers would be awesome! This could
be a general framework that we'd be able to use for various forms for
query optimizing (which we don't do today or do with heuristics), eg
things like whether to apply a filter (AND) high vs low, whether to
use BS1 or BS2 for pure conjunctions, when to split a PhraseQuery into
conjunction + position checking, flattening of nested boolean
queries, MultiTermQuery rewrite method, etc. But probably we should
explore this on a new issue.
> 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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