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https://issues.apache.org/jira/browse/HDFS-9924?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15334770#comment-15334770
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Kai Zheng commented on HDFS-9924:
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Hi [~xiaobingo],
Thanks for the perf report! It looks great to me. I have some questions.
bq. In all cases, the larger number of calls tested, the less speedup. This
could be because larger number of calls saturated NameNode for longer time.
Could we verify this, maybe by trying different {{dfs.namenode.handler.count}}?
Looks like you also mentioned {{dfs.permissions}} and
{{dfs.datanode.handler.count}}, they're not relevant to the perf test logic
{{rename}} I guess, right?
How would you vision if we do the similar test for other operations like
read/write?
By the way, currently we're trying to hack the codes and do a workload test in
Hive, to see if any real benefit as mentioned. Hope we could have some output
sooner and provide some help here for you guys.
> [umbrella] Nonblocking HDFS Access
> ----------------------------------
>
> Key: HDFS-9924
> URL: https://issues.apache.org/jira/browse/HDFS-9924
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: fs
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Xiaobing Zhou
> Attachments: Async-HDFS-Performance-Report.pdf, AsyncHdfs20160510.pdf
>
>
> This is an umbrella JIRA for supporting Nonblocking HDFS Access.
> Currently, all the API methods are blocking calls -- the caller is blocked
> until the method returns. It is very slow if a client makes a large number
> of independent calls in a single thread since each call has to wait until the
> previous call is finished. It is inefficient if a client needs to create a
> large number of threads to invoke the calls.
> We propose adding a new API to support nonblocking calls, i.e. the caller is
> not blocked. The methods in the new API immediately return a Java Future
> object. The return value can be obtained by the usual Future.get() method.
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