[jira] [Commented] (CASSANDRA-4480) Binary protocol: adds events push

["Sylvain Lebresne (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-4480?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13431652#comment-13431652 ] 

Sylvain Lebresne commented on CASSANDRA-4480:
---------------------------------------------

Btw, for each event, the intend is to send the ip and port on which the node can be contacted by the client. However, to do that properly we would need to start gossiping the ip and port each node use for the binary protocol (like we currently gossip the rpc address) so for now the patch assume all node use the same port and reuse the endpoint ip, but that may not be correct. Opened CASSANDRA-4501 for that.
                
> 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
>
>         Attachments: 4480.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.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira