[
https://issues.apache.org/jira/browse/HDFS-7597?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15297236#comment-15297236
]
Yongjun Zhang commented on HDFS-7597:
-------------------------------------
HI [~daryn], [~cnauroth] and [~xiaobingo],
Thanks a lot for your work here.
Per my read of earlier discussion, it makes sense to me to replace the secure
part fix of HDFS-8855 with the patch here (which is more general). However, I
agree with Chris that we can commit the patch here and defer any further
clean-up to a separate issue. I just kicked off a jenkins build to see if tests
are clean.
Thanks.
> DNs should not open new NN connections when webhdfs clients seek
> ----------------------------------------------------------------
>
> Key: HDFS-7597
> URL: https://issues.apache.org/jira/browse/HDFS-7597
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: webhdfs
> Affects Versions: 2.0.0-alpha
> Reporter: Daryn Sharp
> Assignee: Daryn Sharp
> Priority: Critical
> Labels: BB2015-05-TBR
> Attachments: HDFS-7597.patch, HDFS-7597.patch, HDFS-7597.patch
>
>
> Webhdfs seeks involve closing the current connection, and reissuing a new
> open request with the new offset. The RPC layer caches connections so the DN
> keeps a lingering connection open to the NN. Connection caching is in part
> based on UGI. Although the client used the same token for the new offset
> request, the UGI is different which forces the DN to open another unnecessary
> connection to the NN.
> A job that performs many seeks will easily crash the NN due to fd exhaustion.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
