[jboss-dev-forums] [Design of Messaging on JBoss (Messaging/JBoss)] - Re: Client failover redeliveries discussion

[clebert.suconic@jboss.com]

"ovidiu.feodorov at jboss.com" wrote : 
  | Clebert wrote : 
  |   | Basically what I do on failover is to create a new consumer on the new server, replace IDs and re-register the Callback handler. The server at this point will think it's a new client coming. In case of durable subscribers/queues and persistent messages you will have the queue refilled
  |   | 
  | 
  | Could you explain in a little bit more detail how this works? You detect the failure at remoting level, and then, what happens? Do you preserve the Connection/Session/Consumer hierarchy on the client? How do you create the corresponding endpoint hierarchy on the fail-over ServerPeer?
  | 

At this point I'm not detecting the failure at remoting level yet.
There is a method called failover on ClientConnectionDelegate:

class ClientConnectionDelegate:
  |     public void failOver(ConnectionDelegate newConnection)
  | 

That method is implemented as an aspect into ConnectionAspect::handleFailover.

handleFailover will navigate over the state hierarchy described at http://wiki.jboss.org/wiki/Wiki.jsp?page=NewMessagingHADesign, and it will create another ServerSide object for each instance found on the hierarchy.

Every time a new serverObject is created, the client object ID is swaped by the new created object, and the remotingConnection instance is swaped by the connection passed as a parameter. This way, all the failed delegates will take place on the new server.


"Ovidiu" wrote : Before having a conference call, I think a better idea is to summarize what you've implemented so far. Describe how the fail-over happens step by step.

I will work with some testcases today, and update the design document. After that we will be ready for a conference about this. This thread has provided the discussion I needed already.



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