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https://issues.apache.org/jira/browse/HDFS-4486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14107714#comment-14107714
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Colin Patrick McCabe commented on HDFS-4486:
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Weird that the "NoClassDefFound" exceptions are now gone in the latest Jenkins
run. Like you, I could not reproduce them locally, either.
Given that the test runs with NoClassDefFound had some other environment
problems (like many "too many open file descriptors" messages), this seems
likely to be a Jenkins environment issue.
The test failures here aren't related (this is a trivial logging change)
+1.
> Add log category for long-running DFSClient notices
> ---------------------------------------------------
>
> Key: HDFS-4486
> URL: https://issues.apache.org/jira/browse/HDFS-4486
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Todd Lipcon
> Assignee: Zhe Zhang
> Priority: Minor
> Attachments: HDFS-4486-20140820.patch, HDFS-4486-20140821.patch,
> HDFS-4486-20140822-2.patch, HDFS-4486-20140822.patch,
> hdfs-4486-20140821-2.patch
>
>
> There are a number of features in the DFS client which are transparent but
> can make a fairly big difference for performance -- two in particular are
> short circuit reads and native checksumming. Because we don't want log spew
> for clients like "hadoop fs -cat" we currently log only at DEBUG level when
> these features are disabled. This makes it difficult to troubleshoot/verify
> for long-running perf-sensitive clients like HBase.
> One simple solution is to add a new log category - eg
> o.a.h.h.DFSClient.PerformanceAdvisory - which long-running clients could
> enable at DEBUG level without getting the full debug spew.
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