[ http://issues.apache.org/jira/browse/HADOOP-252?page=comments#action_12418394 ]
Yoram Arnon commented on HADOOP-252: ------------------------------------ having a handshake when setting up a connection is fairly standard. Both sides may either agree on the lowest common denominator, and send messages in a previously supported format, or decide to throw. It's better than a version in each message for two reasons: 1(minor) a few bytes less per message 2(major) allows a new component to avoid sending new messages to an old component, that doesn't support it. > add versioning to RPC > --------------------- > > Key: HADOOP-252 > URL: http://issues.apache.org/jira/browse/HADOOP-252 > Project: Hadoop > Type: Improvement > Components: ipc > Versions: 0.3.0 > Reporter: Yoram Arnon > Fix For: 0.5.0 > > currently, any change to any rpc message breaks the protocol, with mysterious > exceptions occurring at run time. > a versioning sceme would have two benefits: > - intelligent error messages, indicating that an upgrade is required > - backwards compatibility could be supported. > the proposal is to add a "const version" for each protocol, and a method: int > getVersion(int version) that sends the client's version and receives the > server's version. This would be the first method invoked on connection. Both > sides then either agree on the lowest version number, providing backwards > compatibility support, or abort the connection as "unsupported version". -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
