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https://issues.apache.org/jira/browse/CASSANDRA-4480?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13450480#comment-13450480
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Sylvain Lebresne commented on CASSANDRA-4480:
---------------------------------------------
bq. when I stop an existing node and start it again, I still receive a
TOPOLOGY_CHANGE - NEW_NODE event after the two STATUS_CHANGE - UP events, even
though the up'd node was previously known
That's weird, but I'll blame gossip. I've doubled-checked and the patch don't
send a NEW_NODE expect on gossiper.onJoin() calls. I don't know, maybe it's a
know behavior of gossip though. Anyway, I've committed (since I'm pretty sure
this has nothing to do with patch) this but I'll check why gossip do that.
Regardless, clients will probably have to be resilient to that kind of things.
> Binary protocol: adds events push
> ----------------------------------
>
> Key: CASSANDRA-4480
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4480
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Sylvain Lebresne
> Assignee: Sylvain Lebresne
> Priority: Minor
> Fix For: 1.2.0 beta 1
>
> Attachments: 4480.txt, 4480-v2.txt
>
>
> Clients needs to know about a number of cluster changes (new/removed nodes
> typically) to function properly. With the binary protocol we could start
> pushing such events to the clients directly.
> The basic idea would be that a client would register to a number of events
> and would then receive notifications when those happened. I could at least
> the following events be useful to clients:
> * Addition and removal of nodes
> * Schema changes (otherwise clients would have to pull schema all the time to
> know that say a new column has been added)
> * node up/dow events (down events might not be too useful, but up events
> could be helpful).
> The main problem I can see with that is that we want to make it clear that
> clients are supposed to register for events on only one or two of their
> connections (total, not per-host), otherwise it'll be just flooding. One
> solution to make it much more unlikely that this happen could be to
> distinguish two kinds of connections: Data and Control (could just a simple
> flag with the startup message for instance). Data connections would not allow
> registering to events and Control ones would allow it but wouldn't allow
> queries. I.e. clients would have to dedicate a connection to those events,
> but that's likely the only sane way to do it anyway.
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