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https://issues.apache.org/jira/browse/HDFS-14084?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16713168#comment-16713168
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Erik Krogen commented on HDFS-14084:
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Nice, v002 became surprisingly easy :) A few comments:
* Can we create a separate log for this e.g. {code}private static final Logger
PERF_LOG = LoggerFactory.getLogger(DFSClient.getClass().getCanonicalName() +
"_Performance");{code} or something like that? Then you can more easily
enable/disable this logging without having to affect the log level of the rest
of DFSClient.
* Can you please post an example of what the log output looks like?
* You took a few things that were guarded by {{isDebugEnabled()}} and now have
them execute regardless of log level. I would prefer to see all of this code
guarded by {{isDebugEnabled()}} so that none of it is evaluated unless output
will be produced.
As a more general comment, I would still love to see this integrated with
{{StorageStatistics}}, but I think the logging approach makes sense as a
complement. It might not be a bad idea to leave this JIRA as the v002 patch and
do a follow-on to integrate with {{StorageStatistics}}.
> Need for more stats in DFSClient
> --------------------------------
>
> Key: HDFS-14084
> URL: https://issues.apache.org/jira/browse/HDFS-14084
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 3.0.0
> Reporter: Pranay Singh
> Assignee: Pranay Singh
> Priority: Minor
> Attachments: HDFS-14084.001.patch, HDFS-14084.002.patch
>
>
> The usage of HDFS has changed from being used as a map-reduce filesystem, now
> it's becoming more of like a general purpose filesystem. In most of the cases
> there are issues with the Namenode so we have metrics to know the workload or
> stress on Namenode.
> However, there is a need to have more statistics collected for different
> operations/RPCs in DFSClient to know which RPC operations are taking longer
> time or to know what is the frequency of the operation.These statistics can
> be exposed to the users of DFS Client and they can periodically log or do
> some sort of flow control if the response is slow. This will also help to
> isolate HDFS issue in a mixed environment where on a node say we have Spark,
> HBase and Impala running together. We can check the throughput of different
> operation across client and isolate the problem caused because of noisy
> neighbor or network congestion or shared JVM.
> We have dealt with several problems from the field for which there is no
> conclusive evidence as to what caused the problem. If we had metrics or stats
> in DFSClient we would be better equipped to solve such complex problems.
> List of jiras for reference:
> -------------------------
> HADOOP-15538 HADOOP-15530 ( client side deadlock)
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