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https://issues.apache.org/jira/browse/HBASE-13382?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14395482#comment-14395482
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Hudson commented on HBASE-13382:
--------------------------------
SUCCESS: Integrated in HBase-TRUNK #6343 (See
[https://builds.apache.org/job/HBase-TRUNK/6343/])
HBASE-13382 IntegrationTestBigLinkedList should use SecureRandom (Dima Spivak)
(stack: rev f561ef71a505d9e3d63a9ac4c1a950d7c066dc78)
*
hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestBigLinkedList.java
> IntegrationTestBigLinkedList should use SecureRandom
> ----------------------------------------------------
>
> Key: HBASE-13382
> URL: https://issues.apache.org/jira/browse/HBASE-13382
> Project: HBase
> Issue Type: Bug
> Components: integration tests
> Reporter: Todd Lipcon
> Assignee: Dima Spivak
> Fix For: 2.0.0, 1.0.1, 1.1.0
>
> Attachments: HBASE-13382_master_v1.patch
>
>
> IntegrationTestBigLinkedList currently uses java.util.Random to generate its
> random keys. The keys are 128 bits long, but we generate them using
> Random.nextBytes(). The Random implementation itself only has a 48-bit seed,
> so even though we have a very long key string, it doesn't have anywhere near
> that amount of entropy.
> This means that after a few billion rows, it's quite likely to run into a
> collision: filling in a 16-byte key is equivalent to four calls to
> rand.nextInt(). So, for 10B rows, we are cycling through 40B different 'seed'
> values. With a 48-bit seed, it's quite likely we'll end up using the same
> seed twice, after which point any future rows generated by the colliding
> mappers are going to be equal. This results in broken chains and a failed
> verification job.
> The fix is simple -- we should use SecureRandom to generate the random keys,
> instead.
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