[ 
https://issues.apache.org/jira/browse/HDFS-7597?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14369384#comment-14369384
 ] 

Kihwal Lee commented on HDFS-7597:
----------------------------------

precommit should work now. Kicked the build.

> Clients seeking over webhdfs may crash the NN
> ---------------------------------------------
>
>                 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
>         Attachments: 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)

Reply via email to