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https://issues.apache.org/jira/browse/HADOOP-9150?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Todd Lipcon updated HADOOP-9150:
--------------------------------
Attachment: hadoop-9150.txt
Attached patch implements something like what's described above.
Note that this changes behavior for those who are extending the FileSystem
interface. It's marked as Public and Stable, so we should probably add a
release note for this. I think we should allow it nonetheless -- it's not clear
that the {{Stable}} marking there refers to "stable for FileSystem developers
to inherit from" vs "stable for developers to code against". Since the changes
are only to protected methods, we've only changed something for the former and
not the latter.
> Unnecessary DNS resolution attempts for logical URIs
> ----------------------------------------------------
>
> Key: HADOOP-9150
> URL: https://issues.apache.org/jira/browse/HADOOP-9150
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs/s3, ha, performance, viewfs
> Affects Versions: 3.0.0, 2.0.2-alpha
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Priority: Critical
> Attachments: hadoop-9150.txt, hadoop-9150.txt, hadoop-9150.txt,
> hadoop-9150.txt, hadoop-9150.txt, log.txt, tracing-resolver.tgz
>
>
> In the FileSystem code, we accidentally try to DNS-resolve the logical name
> before it is converted to an actual domain name. In some DNS setups, this can
> cause a big slowdown - eg in one misconfigured cluster we saw a 2-3x drop in
> terasort throughput, since every task wasted a lot of time waiting for slow
> "not found" responses from DNS.
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