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Posted to dev@lucene.apache.org by "Dawid Weiss (JIRA)" <ji...@apache.org> on 2015/02/12 14:21:12 UTC
[jira] [Commented] (LUCENE-6242)
SparseFixedBitDocIdSet.ramBytesUsed() reports wrong size if alignment of
JVM is not 8
[ https://issues.apache.org/jira/browse/LUCENE-6242?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14318170#comment-14318170 ]
Dawid Weiss commented on LUCENE-6242:
-------------------------------------
Just a note -- I was toying with alignments a while ago and I had random JVM crashes.
> SparseFixedBitDocIdSet.ramBytesUsed() reports wrong size if alignment of JVM is not 8
> -------------------------------------------------------------------------------------
>
> Key: LUCENE-6242
> URL: https://issues.apache.org/jira/browse/LUCENE-6242
> Project: Lucene - Core
> Issue Type: Bug
> Reporter: Uwe Schindler
>
> There seems to be a bug in SparseFixedBitDocIdSet's ramBytesUsed. To me this is a bit crazy implemented, so I have not yet found the issue. To me it looks like some of the summing up breaks if the alignment of the JVM is not 8:
> {noformat}
> [junit4] Suite: org.apache.lucene.util.TestSparseFixedBitDocIdSet
> [junit4] 2> NOTE: reproduce with: ant test -Dtestcase=TestSparseFixedBitDocIdSet -Dtests.method=testRamBytesUsed -Dtests.seed=
> C1F3B881CB1C5E8A -Dtests.locale=es_BO -Dtests.timezone=America/Detroit -Dtests.asserts=true -Dtests.file.encoding=ISO-8859-1
> [junit4] FAILURE 0.06s J1 | TestSparseFixedBitDocIdSet.testRamBytesUsed <<<
> [junit4] > Throwable #1: java.lang.AssertionError: expected:<264> but was:<256>
> [junit4] > at __randomizedtesting.SeedInfo.seed([C1F3B881CB1C5E8A:3350AAC1016341DC]:0)
> [junit4] > at org.apache.lucene.util.BaseDocIdSetTestCase.testRamBytesUsed(BaseDocIdSetTestCase.java:104)
> [junit4] > at java.lang.Thread.run(Thread.java:745)
> {noformat}
> To reproduce this failure, run inside core (with 64 bits JVM):
> {noformat}
> ant test -Dtestcase=TestSparseFixedBitDocIdSet -Dtests.method=testRamBytesUsed -Dargs="-XX:ObjectAlignmentInBytes=16" -Dtests.seed=C1F3B881CB1C5E8A
> {noformat}
> The default works:
> {noformat}
> ant test -Dtestcase=TestSparseFixedBitDocIdSet -Dtests.method=testRamBytesUsed -Dargs="-XX:ObjectAlignmentInBytes=8" -Dtests.seed=C1F3B881CB1C5E8A
> {noformat}
> I think we should randomly also specify the ObjectAlignmentInBytes for test runs on Policeman Jenkins. Any Power of 2 is fine.
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