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https://issues.apache.org/jira/browse/LUCENE-3390?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13109332#comment-13109332
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Uwe Schindler commented on LUCENE-3390:
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Doron: That's exactly the problem. This easy use case is problematic:
You allow sorting by Price. The user can switch between forward and backward
sorting. In all cases, you want all articles without a price at the beginning.
To achieve this, you have to set the price value e.g. to negative_infinity for
the forward sorting, but positive_infinity for backwards sorting. If now two
users are using your user interface in parallel, they collide.
The fix used here is identical to Lucene trunk and we should keep the code
similar. FieldComparator is now almost identical between trunk and 3.x (except
the new BytesRef/Docvalues stuff in trunk).
Thinking more about it: Another apporoach (also possible for trunk) is to
supply the missing value to FieldCache.getXxx(). The FieldCache would the first
use Arrays.fill() to populate the FieldCache array with the default value and
after that populate the index values. The drawback is that you get a separate
FieldCache entry for each distinct missing value. For the above se case, you
would have two float/double price caches.
> Incorrect sort by Numeric values for documents missing the sorting field
> ------------------------------------------------------------------------
>
> Key: LUCENE-3390
> URL: https://issues.apache.org/jira/browse/LUCENE-3390
> Project: Lucene - Java
> Issue Type: Bug
> Components: core/search
> Affects Versions: 3.3
> Reporter: Gilad Barkai
> Assignee: Doron Cohen
> Priority: Minor
> Labels: double, float, int, long, numeric, sort
> Fix For: 3.4
>
> Attachments: LUCENE-3390-fix-like-trunk.patch,
> LUCENE-3390-fix-like-trunk.patch, LUCENE-3390-fix-like-trunk.patch,
> LUCENE-3390.patch, SortByDouble.java
>
>
> While sorting results over a numeric field, documents which do not contain a
> value for the sorting field seem to get 0 (ZERO) value in the sort. (Tested
> against Double, Float, Int & Long numeric fields ascending and descending
> order).
> This behavior is unexpected, as zero is "comparable" to the rest of the
> values. A better solution would either be allowing the user to define such a
> "non-value" default, or always bring those document results as the last ones.
> Example scenario:
> Adding 3 documents, 1st with value 3.5d, 2nd with -10d, and 3rd without any
> value.
> Searching with MatchAllDocsQuery, with sort over that field in descending
> order yields the docid results of 0, 2, 1.
> Asking for the top 2 documents brings the document without any value as the
> 2nd result - which seems as a bug?
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