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https://issues.apache.org/jira/browse/HDFS-12977?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16366464#comment-16366464
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Plamen Jeliazkov commented on HDFS-12977:
-----------------------------------------
Attaching a rough first patch.
All the necessary logic is there but I found myself having to inject
o.a.h.ipc.Call from Server and Client into the NameNodeRpcServer and DFSClient
respectively.
I'm not much of a fan of the approach and am struggling to find a better way to
do it so I can avoid having to put try/finally everywhere. Some guidance would
be useful. Perhaps this is the only way however.
The stateId is added into the RpcResponseHeader as a int64 field. The default
value, representing an invalid lastWrittenId, is represented as -1L. I believe
this part to be correct in the patch. We can strip the patch down to just this
one bit if we don't want to deal with the DFSClient and NNRPCServer just yet.
Looking forward to this line of work.
> Add stateId to RPC headers.
> ---------------------------
>
> Key: HDFS-12977
> URL: https://issues.apache.org/jira/browse/HDFS-12977
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: ipc, namenode
> Reporter: Konstantin Shvachko
> Assignee: Plamen Jeliazkov
> Priority: Major
> Attachments: HDFS_12977.trunk.001.patch
>
>
> stateId is a new field in the RPC headers of NameNode proto calls.
> stateId is the journal transaction Id, which represents LastSeenId for the
> clients and LastWrittenId for NameNodes. See more in [reads from Standby
> design
> doc|https://issues.apache.org/jira/secure/attachment/12902925/ConsistentReadsFromStandbyNode.pdf].
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