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https://issues.apache.org/jira/browse/LUCENE-5460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13926048#comment-13926048
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Mikhail Khludnev edited comment on LUCENE-5460 at 3/10/14 7:00 PM:
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LUCENE-5495
bq. Really, this is all one giant hack/workaround, because Lucene is unable to
properly/generally handle the "post filter" use case (something Solr has had
for some time). I think we should fix that; i.e., we need some way for a Filter
to express that 1) it's random-access (supports Bits), and 2) it's very costly.
[~mikemccand] let me disturb you with SampleSlowQuery attached, which :
* implements post-filtering by SlowQueryScorer.confirm(int)
* can be random-access, however, it's not my favor case, I'd like to
post-filter observing state of underlying leap-frogging scorers
* allows to handle custom ranking case as well.
I your feedback is much appreciated! Thanks
was (Author: mkhludnev):
bq. LUCENE-5495 Really, this is all one giant hack/workaround, because Lucene is
unable to properly/generally handle the "post filter" use case
(something Solr has had for some time). I think we should fix that;
i.e., we need some way for a Filter to express that 1) it's random-access
(supports Bits), and 2) it's very costly.
[~mikemccand] let me disturb you with SampleSlowQuery attached, which :
* implements post-filtering by SlowQueryScorer.confirm(int)
* can be random-access, however, it's not my favor case, I'd like to
post-filter observing state of underlying leap-frogging scorers
* allows to handle custom ranking case as well.
I your feedback is much appreciated! Thanks
> 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
> Attachments: TestSlowQuery.java
>
>
> 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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