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

[timfox]

"clebert.suconic at jboss.com" wrote : I already have consumers seamlessly reconnecting to a new server during a HA event.
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  | Basically what I do on failover is to create a new consumer on the new server, replace IDs and re-register the Callback handler.
  | 

Sounds about right. But what do you mean by "replace ids"?

anonymous wrote : 
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  | There are some issues that I would like to discuss now:
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  | If the consumer receives a message from CallBack but if it didn't send an ACK yet, after the failover, the server not knowing the message might throw an exception (messageId not known). 
  | 
  | There are a couple of use cases we have to consider.
  | -   Persistent Messages. (how to treat a redelivery). 
  | -   Should we send the list of previously ACKs to the server?
  | 
  | 

Yes - we should send the ids of every persistent message as part of the failover protocol - the server then repopulates the delivery list in the server consumer endpoint

anonymous wrote : 
  | -   Should we ignore ACKs for non existent messages on the server?
  | 

Non existent messages on the server will be non persistent messages that didn't survive the failover.

They should be removed from the client side list on failover so the acks will never get sent.



anonymous wrote : 
  | Second point also:
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  | What to do when a durable subscriber gets the queue refilled?
  | -   The client will probably receive the message again. I would just ignore redeliveries.
  | 
  | 

I don't understand the issue here. Can you explain more?

anonymous wrote : 
  | I'm considering having a conference call with developers about these possibilities.
  | 
  | Clebert Suconic

Yes, let's do that

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