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https://issues.apache.org/jira/browse/HBASE-2269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12841938#action_12841938
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stack commented on HBASE-2269:
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@Tatsuya For sure super.hashCode() gives a different answer per instance of
Test? Thanks.
> PerformanceEvaluation "--nomapred" may assign duplicate random seed over
> multiple testing threads
> -------------------------------------------------------------------------------------------------
>
> Key: HBASE-2269
> URL: https://issues.apache.org/jira/browse/HBASE-2269
> Project: Hadoop HBase
> Issue Type: Bug
> Components: test
> Affects Versions: 0.20.3
> Environment: Any operating system
> Reporter: Tatsuya Kawano
> Priority: Minor
>
> When you use PerformanceEvaluation with "--nomapred" option, you will end up
> having the same random seeds assigned over multiple testing threads. So
> you'll get inaccurate results from "random~~" tests.
> {code:title=PerformanceEvaluation.java}
> 542: abstract class Test {
> 543: protected final Random rand = new Random(System.currentTimeMillis());
> {code}
> Milliseconds won't be sufficient; today's JVM is much faster to create
> multiple Test objects in one millisecond. You might want to use something
> like "{{super.hashCode()}}" instead.
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