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From "Robert Muir (JIRA)" <>
Subject [jira] [Commented] (LUCENE-4100) Maxscore - Efficient Scoring
Date Fri, 13 Oct 2017 20:25:00 GMT


Robert Muir commented on LUCENE-4100:

Thanks for the benchmarking! It is unfortunate we have to make the api more complicated /
specialize disjunctions even more, but seems like the right tradeoff i suppose.

Can you elaborate on what you find confusing? This looks similar to how you should not call
Score.score() if you passed needsScores=false to me?

That's exactly it, i think we should try to avoid situations like that. its basically the
opposite of type-safety, and the more of these conditionals / "methods you should not call"
that we add, the more confusing it should get. That's why i'm still mulling what we can do
to keep scorers simpler...

but for now, to move along, I think we have some basic idea of what to do to fix indexsearcher
(a boolean about whether exact total hits are needed, for various purposes), but yeah lets
keep it separate from what we do about createWeight. For the latter maybe an explicit boolean
for maxScore is the simplest for now, and we can see where it goes.

> Maxscore - Efficient Scoring
> ----------------------------
>                 Key: LUCENE-4100
>                 URL:
>             Project: Lucene - Core
>          Issue Type: Improvement
>          Components: core/codecs, core/query/scoring, core/search
>    Affects Versions: 4.0-ALPHA
>            Reporter: Stefan Pohl
>              Labels: api-change, gsoc2014, patch, performance
>             Fix For: 4.9, 6.0
>         Attachments: LUCENE-4100.patch, LUCENE-4100.patch, contrib_maxscore.tgz, maxscore.patch
> At Berlin Buzzwords 2012, I will be presenting 'maxscore', an efficient algorithm first
published in the IR domain in 1995 by H. Turtle & J. Flood, that I find deserves more
attention among Lucene users (and developers).
> I implemented a proof of concept and did some performance measurements with example queries
and lucenebench, the package of Mike McCandless, resulting in very significant speedups.
> This ticket is to get started the discussion on including the implementation into Lucene's
codebase. Because the technique requires awareness about it from the Lucene user/developer,
it seems best to become a contrib/module package so that it consciously can be chosen to be

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