[
https://issues.apache.org/jira/browse/HADOOP-6904?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12965074#action_12965074
]
Sanjay Radia commented on HADOOP-6904:
--------------------------------------
@doug
> .. protocol introspection on the client and server. That would better
> integrate with Avro, should we ever decide to switch to that.
With Avro you get that for free.
Originally I was in favor of adding the method inspection to this jira; but if
you look at my comment above it does not make
much of a difference for the client - the client needs an if statement either
way. Most of the benefits come from the Major-minor number as
it eliminates all the if statements related to the minor change to the protocol.
I could live with doing method names later when we integrate with Avro (as Doug
suggests).
> A baby step towards inter-version communications between dfs client and
> NameNode
> --------------------------------------------------------------------------------
>
> Key: HADOOP-6904
> URL: https://issues.apache.org/jira/browse/HADOOP-6904
> Project: Hadoop Common
> Issue Type: New Feature
> Components: ipc
> Affects Versions: 0.22.0
> Reporter: Hairong Kuang
> Assignee: Hairong Kuang
> Fix For: 0.22.0
>
> Attachments: majorMinorVersion.patch, majorMinorVersion1.patch,
> rpcVersion.patch, rpcVersion1.patch
>
>
> Currently RPC communications in Hadoop is very strict. If a client has a
> different version from that of the server, a VersionMismatched exception is
> thrown and the client can not connect to the server. This force us to update
> both client and server all at once if a RPC protocol is changed. But sometime
> different versions do not mean the client & server are not compatible. It
> would be nice if we could relax this restriction and allows us to support
> inter-version communications.
> My idea is that DfsClient catches VersionMismatched exception when it
> connects to NameNode. It then checks if the client & the server is
> compatible. If yes, it sets the NameNode version in the dfs client and allows
> the client to continue talking to NameNode. Otherwise, rethrow the
> VersionMismatch exception.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
