[infinispan-dev] Put issues with newly joining node

[Galder Zamarreño]

On Dec 4, 2012, at 11:52 AM, Bela Ban <bban at redhat.com> wrote:

> 
> 
> On 12/4/12 11:30 AM, Dan Berindei wrote:
>> BTW, I also got an exception yesterday in MarshallExternalPojosTest and
>> I investigated it, but in my case the error was much weirder: two nodes
>> both opened a TCP connection to each other, yet none of them received
>> the forwarded command. I've asked Bela to investigate as well, but he
>> didn't find anything suspicious in JGroups.
> 
> If a node A connects to B and B connects to A at the exact same time 
> (and there wasn't any existing connection between the 2 nodes, then one 
> of the 2 will 'win' and the other one will close its connection. The 
> message to be sent is then lost.
> 
> This is corrected by one of the upper layers, e.g. UNICAST retransmits 
> the message until it gets an ack. Re-sending a message will then create 
> a new connection, if the existing one was closed / removed.
> 
> However, with UNICAST2, if a given message was the last message and no 
> further messages are sent, then only UNICAST2's stability messages will 
> detect that the other node is missing the last message sent. Stability 
> is triggered every 60 seconds by default, so unless that property was 
> changed, or stability was triggered programmatically, that last (lost) 
> message won't get retransmitted for 60 seconds.

^ Isn't that a default too high?

Seems to me the scenario explained could happen relatively easily if two nodes are started simultaneously.

We no longer ask users to stagger their startups?

> 
> -- 
> Bela Ban, JGroups lead (http://www.jgroups.org)
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--
Galder Zamarreño
galder at redhat.com
twitter.com/galderz

Project Lead, Escalante
http://escalante.io

Engineer, Infinispan
http://infinispan.org