ASF subversion and git services commented on LUCENE-9418:

Commit 3ff331072a7435e971e35c2e28c38a90ca70802b in lucene-solr's branch 
refs/heads/master from Alan Woodward
[ https://gitbox.apache.org/repos/asf?p=lucene-solr.git;h=3ff3310 ]

LUCENE-9418: Fix ordered intervals over interleaved terms (#1618)

Given the input text 'A B A C', an ordered interval 'A B C' will currently 
return an incorrect
internal [2, 3] in addition to the correct [0, 3] interval. This is due to a 
bug in the ORDERED
algorithm, where we assume that after the first interval is returned, the 
sub-intervals are
always in-order. This assumption only holds during minimization, as minimizing 
an interval
may move the earlier terms beyond the trailing terms.

For example, after the initial [0, 3] interval is found above, the algorithm 
will attempt to
minimize it by advancing A to [2,2]. Because this is still before C at [3,3], 
but after B at
[1,1], we then try advancing B, leaving it at [Inf,Inf]. Minimization has 
failed, so we return
the original interval of [0,3]. However, when we come to retrieve the next 
interval, our
subintervals look like this: A[2,2], B[Inf,Inf], C[3,3] - the assumption that 
they are in order
is broken. The algorithm sees that A is before B, assumes that therefore all 
subintervals are in order, and returns the new interval.

This commit fixes things by changing the assumption of ordering to only hold 
minimization. When first finding a candidate interval, the algorithm now checks 
all sub-intervals appear in order.

> Ordered intervals can give inaccurate hits on interleaved terms
> ---------------------------------------------------------------
>                 Key: LUCENE-9418
>                 URL: https://issues.apache.org/jira/browse/LUCENE-9418
>             Project: Lucene - Core
>          Issue Type: Bug
>            Reporter: Alan Woodward
>            Assignee: Alan Woodward
>            Priority: Major
>          Time Spent: 20m
>  Remaining Estimate: 0h
> Given the text 'A B A C', an ordered interval over 'A B C' will return the 
> inaccurate interval [2, 3], due to the way minimization is handled after 
> matches are found.

This message was sent by Atlassian Jira

To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org
For additional commands, e-mail: issues-h...@lucene.apache.org

Reply via email to