lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Doron Cohen (JIRA)" <j...@apache.org>
Subject [jira] Updated: (LUCENE-736) Sloppy Phrase Scoring Misbehavior
Date Fri, 01 Dec 2006 10:26:22 GMT
     [ http://issues.apache.org/jira/browse/LUCENE-736?page=all ]

Doron Cohen updated LUCENE-736:
-------------------------------

    Attachment: sloppy_phrase_java.patch.txt
                perf-search-new.log
                perf-search-orig.log

Attached sloppy_phrase_java.patch.txt is fixing the failing new tests. 
This also includes the skipTo() bug from issue 697.

The fix does not guarantee that document A B C B A would score "A B C"~4 and "C B A"~4 the
same. 
It does that for "B C"~2 and "C B"~2.
This is because a general fix for that (at least the one that I devised) would be too expensive.
Although this is an interesting case, I'd like to think it is not an important one.

This fix comes with a performance cost:  about 15% degradation in CPU activity of sloppy phrase
scoring, as the attcahed perf logs show.
Here is the summary of these tests:

.......Operation..........runCnt...recsPerRun.....rec/s..elapsedSec
Orig:..SearchSameRdr_3000......4.........3000.....216.1.......55.52
New:...SearchSameRdr_3000......4.........3000.....187.8.......63.91

I think that in a real life scenario - real index, real documents, real queries - this extra
CPU will be shaded by IO, but I also belive we should refrain from slowing down search, so,
unhappy with this degradation (anyone would:-), I would look for a other ways to fix this
- ideas are welcome.

Perf test was done using the task benchmark framework (see issue 675), The logs show also
the queries that were searched.

All tests pass with new code.

> Sloppy Phrase Scoring Misbehavior
> ---------------------------------
>
>                 Key: LUCENE-736
>                 URL: http://issues.apache.org/jira/browse/LUCENE-736
>             Project: Lucene - Java
>          Issue Type: Bug
>          Components: Search
>            Reporter: Doron Cohen
>         Assigned To: Doron Cohen
>            Priority: Minor
>         Attachments: perf-search-new.log, perf-search-orig.log, sloppy_phrase_java.patch.txt,
sloppy_phrase_tests.patch.txt
>
>
> This is an extension of https://issues.apache.org/jira/browse/LUCENE-697
> In addition to abnormalities Yonik pointed out in 697, there seem to be other issues
with slopy phrase search and scoring.
> 1) A phrase with a repeated word would be detected in a document although it is not there.
> I.e. document = A B D C E , query = "B C B" would not find this document (as expected),
but query "B C B"~2 would find it. 
> I think that no matter how large the slop is, this document should not be a match.
> 2) A document containing both orders of a query, symmetrically, would score differently
for the queru and for its reveresed form.
> I.e. document = A B C B A would score differently for queries "B C"~2 and "C B"~2, although
it is symmetric to both.
> I will attach test cases that show both these problems and the one reported by Yonik
in 697. 

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

---------------------------------------------------------------------
To unsubscribe, e-mail: java-dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: java-dev-help@lucene.apache.org


Mime
View raw message