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https://issues.apache.org/jira/browse/HADOOP-13826?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15744762#comment-15744762
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Steve Loughran commented on HADOOP-13826:
-----------------------------------------
Ok, I've sat down for a review. Like I said before, the test needs some work.
BTW, {{S3AFastOutputStream}} is gone. Are you referring to
{{S3ABlockOutputStream}}?
h2. {[S3AFileSystem]}
Aren't there limits on the size of the AWS httpclient pool, or is there
something I'm missing?
h2. {[ITestConcurrentOps]}
This must be a subclass of {{AbstractS3ATestBase}}, so only run when
{{-Dscale}} is set. This will automatically give it extended test timeout, and
allow that timeout to be overridden in the config or on the maven command line.
* Must use {{path(subpath)}} to get a unique path which works in parallel
execution, rather than {{new Path("/ITestS3AManyFiles");}}
* {[getRestrictedFileSystem]} can just go "5M" and "10M" when setting sizes
* {{teardown()}} must check auxFS for being null, just in case something went
wrong in setup.
* Note you can use {{ContractTestUtils.dataset()}} to create a 1MB file; it
writes in a range of values so it's easier to detect problems on reads. Not
really needed here, but you should get into the habit of using those methods
where possible.
* {{testParallelRename}} must give the threads useful names.
* {{testParallelRename}} should use Callables, so any exceptions raised in
threads can be raised by test runner. We don't want tests to go wrong and us
not to notice.
* If {{testParallelRename}} logs exceptions, it must use {{LOG.error()}}
* {{testParallelRename}} must check that the dest files exist, and that the
source ones don't. Otherwise, it's not actually verifying that the rename
worked,
only that a parallel series of operations completed.
> S3A Deadlock in multipart copy due to thread pool limits.
> ---------------------------------------------------------
>
> Key: HADOOP-13826
> URL: https://issues.apache.org/jira/browse/HADOOP-13826
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs/s3
> Affects Versions: 2.7.3
> Reporter: Sean Mackrory
> Assignee: Sean Mackrory
> Priority: Critical
> Attachments: HADOOP-13826.001.patch, HADOOP-13826.002.patch,
> HADOOP-13826.003.patch
>
>
> In testing HIVE-15093 we have encountered deadlocks in the s3a connector. The
> TransferManager javadocs
> (http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/s3/transfer/TransferManager.html)
> explain how this is possible:
> {quote}It is not recommended to use a single threaded executor or a thread
> pool with a bounded work queue as control tasks may submit subtasks that
> can't complete until all sub tasks complete. Using an incorrectly configured
> thread pool may cause a deadlock (I.E. the work queue is filled with control
> tasks that can't finish until subtasks complete but subtasks can't execute
> because the queue is filled).{quote}
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