[
https://issues.apache.org/jira/browse/HDFS-12103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16078771#comment-16078771
]
Xiaowei Zhu commented on HDFS-12103:
------------------------------------
+1. The workaround looks reasonable to me.
> libhdfs++: Provide workaround to support cancel on filesystem connect until
> HDFS-11437 is resolved
> --------------------------------------------------------------------------------------------------
>
> Key: HDFS-12103
> URL: https://issues.apache.org/jira/browse/HDFS-12103
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: James Clampffer
> Assignee: James Clampffer
> Attachments: HDFS-12103.HDFS-8707.000.patch
>
>
> HDFS-11437 is going to take a non-trivial amount of work to do right. In the
> meantime it'd be nice to have a way to cancel pending connections (even when
> the FS claimed they are finished).
> Proposed workaround is to relax the rules about when
> FileSystem::CancelPending connect can be called since it isn't able to
> properly determine when it's connected anyway. In order to determine when
> the FS has connected you can do some simple RPC call since that will wait on
> failover. If CancelPending can be called during that first RPC call then it
> will effectively be canceling FileSystem::Connect
> Current cancel rules - asterisk on steps where CancelPending is allowed
> FileSystem::Connect called
> FileSystem communicates with first NN *
> FileSystem::Connect returns - even if it hasn't communicated with the active
> NN
> Proposed relaxation
> FileSystem::Connect called
> FileSystem communicates with first NN*
> FileSystem::Connect returns *
> FileSystem::GetFileInfo called * -any namenode RPC call will do, ignore perm
> errors
> RPC engine blocks until it hits the active or runs out of retries *
> FileSystem::GetFileInfo returns
> It'd be up to the user to add in the dummy NN RPC call. Once HDFS-11437 is
> fixed this workaround can be removed.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
