[
https://issues.apache.org/jira/browse/LUCENENET-282?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14290943#comment-14290943
]
ASF GitHub Bot commented on LUCENENET-282:
------------------------------------------
GitHub user laimis opened a pull request:
https://github.com/apache/lucenenet/pull/58
Fix overflow resulting in negative values
Noticed while debugging failing Lucene42/45 codec tests that sometimes when
a test ran ForceMerge(1) on an index writer, the merge of segments did not
occur and the directory contained whatever the number of segments existed
before the merge. The tests then proceeded to fail as they expected only one
segment to be in the index.
The issue is LogByteSizeMergePolicy. It does not occur all the time in the
tests as its selection is random
(https://github.com/apache/lucenenet/blob/master/src/Lucene.Net.TestFramework/Util/LuceneTestCase.cs#L977).
LogByteSizeMergePolicy policy in constructor sets the max size of the segment
for forced merges. The value always ends up being too large for the long type
and gets overflown, ie set to a negative value. This then caused LogMergePolicy
to inappropriately mark small segments as too large at this logic branch:
https://github.com/apache/lucenenet/blob/master/src/Lucene.Net.Core/Index/LogMergePolicy.cs#L433
I double checked that Java does indeed behave by not setting the value to a
negative number and instead setting it to long.MaxValue. Looks like the
previous port developers dealt with this before as well :)
https://issues.apache.org/jira/browse/LUCENENET-282
Note that this does not fix all of the tests that use ForceMerges, most of
them continue to fail due to another bug, but the fix for that is coming up in
a separate PR.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/laimis/lucenenet LogByteSizeMergePolicy_fixes
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/lucenenet/pull/58.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #58
----
commit 593231b3b39cb81dfcd29ea81cf98dc1ba9a026a
Author: Laimonas Simutis <[email protected]>
Date: 2015-01-25T01:22:04Z
fix overflow resulting in negative values
----
> Handle potential overflow in LogByteSizeMergePolicy.SetMaxMergeMB
> -----------------------------------------------------------------
>
> Key: LUCENENET-282
> URL: https://issues.apache.org/jira/browse/LUCENENET-282
> Project: Lucene.Net
> Issue Type: Bug
> Reporter: Michael Garski
> Attachments: LUCENENET-282.patch
>
>
> Java gracefully overflows to long.maxValue, .NET to Int64.MinValue.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
