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From "Robert Muir (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-4100) Maxscore - Efficient Scoring
Date Tue, 24 Oct 2017 13:40:00 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-4100?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16216916#comment-16216916
] 

Robert Muir commented on LUCENE-4100:
-------------------------------------

Well that's why i wrote the "note: " :)

Technically the better code would be:
{code}
if (indexOptions = DOCS_ONLY) {
  return 1; // tf values are omitted
}
...
{code}

And yes when frequencies are present, according to the docs its allowed to return -1 here,
but that was solely motivated by PreFlexCodec: (Lucene 3.x indexes). What actually returns
-1 here for this case? 

We will never have maxScore working as long as we have such complexity: lets remove the problem.
I faced this same issue in LUCENE-7997 and i think its easier to just enforce that docCount
and sumDocFreq are always present, and that sumTotalTermFreq, and totalTermFreq are always
present when term freqs are stored.


> Maxscore - Efficient Scoring
> ----------------------------
>
>                 Key: LUCENE-4100
>                 URL: https://issues.apache.org/jira/browse/LUCENE-4100
>             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, 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
used.



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