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https://issues.apache.org/jira/browse/LUCENE-5460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13906956#comment-13906956
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Shai Erera commented on LUCENE-5460:
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You mean that if the filter is wrapped as ConstantScoreQuery and AND'd w/ the
rest of the query, then ConjunctionScorer will probably pick it as the lead
(assuming its cost is implemented properly) and therefore will execute a
cheaper leapfrog? I can test it.
Do you think there's any reason to e.g. fold such logic into
IndexSearcher.search, so it's done automatically by wrapping the Filter and
using ConjunctionScorer?
> Allow driving a query by sparse filters
> ---------------------------------------
>
> Key: LUCENE-5460
> URL: https://issues.apache.org/jira/browse/LUCENE-5460
> Project: Lucene - Core
> Issue Type: Improvement
> Components: core/search
> Reporter: Shai Erera
>
> Today if a filter is very sparse we execute the query in sort of a leap-frog
> manner between the query and filter. If the query is very expensive to
> compute, and/or matching few docs only too, calling scorer.advance(doc) just
> to discover the doc it landed on isn't accepted by the filter, is a waste of
> time. Since Filter is always the "final ruler", I wonder if we had something
> like {{boolean DISI.advanceExact(doc)}} we could use it instead, in some
> cases.
> There are many combinations in which I think we'd want to use/not-use this
> API, and they depend on: Filter's complexity, Filter.cost(), Scorer.cost(),
> query complexity (span-near, many clauses) etc.
> I open an issue so we can discuss. DISI.advanceExact(doc) is just a
> preliminary proposal, to get an API we could experiment with. The default
> implementation should be fairly easy and straightforward, and we could
> override where we can offer a more optimized imp.
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