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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: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org