[
https://issues.apache.org/jira/browse/HADOOP-9150?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13555198#comment-13555198
]
Daryn Sharp commented on HADOOP-9150:
-------------------------------------
Skimming the patch, to reduce adding more methods and complexity, maybe we
should consider either of the following:
# Default impl of {{getCanonicalUri()}} just returns {{getUri()}}. Filesystem
like DFS can specifically override {{getCanonicalUri}} to call
{{NetUtils.getCanonicalUri}}. The advantage is that it won't preclude
other/future logical filesystems from utilizing a port.
# {{getCanonicalUri()}} continues to call {{NetUtils.getCanonicalUri}}.
Logical filesystems should have a default port of -1 (ie. URI considers this as
no port), so perhaps {{NetUtils.getCanonicalUri}} can just return the given uri
if there's no default port.
I lean towards #1.
> 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, 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.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
