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https://issues.apache.org/jira/browse/HADOOP-12412?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14986464#comment-14986464
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Michael Harris commented on HADOOP-12412:
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[~vinodkv] yep no problems here. This has shifted off of me on my side of the
world and has also reduced in priority as we've bandaided over it by using
coarser grained synchronization at a higher level of our stack. Still should
get fixed here, but it's not critical for us anymore. Thanks!
> Concurrency in FileSystem$Cache is very broken
> ----------------------------------------------
>
> Key: HADOOP-12412
> URL: https://issues.apache.org/jira/browse/HADOOP-12412
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs
> Affects Versions: 2.7.0
> Reporter: Michael Harris
> Assignee: Michael Harris
> Priority: Critical
> Attachments: HADOOP-12412.patch, HADOOP-12412.patch
>
>
> The FileSystem cache uses a mild amount of concurrency to protect the cache
> itself, but does nothing to prevent multiple of the same filesystem from
> being constructed and initialized simultaneously. At best, this leads to
> potentially expensive wasted work. At worst, as is the case for Spark, it
> can lead to deadlocks/livelocks, especially when the same configuration
> object is passed into both calls. This should be refactored to use a results
> cache approach (reference Java Concurrency in Practice chapter 5 section 6
> for an example of how to do this correctly), which will be both
> higher-performance and safer.
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