[Spread-users] Unique message id

Jonathan Stanton jonathan at cnds.jhu.edu
Fri Aug 9 23:04:07 EDT 2002


The sequence numbers generated by Spread to order messages are not
accessible to applications, so I'm not sure how you were going to use
them. In actuality the internal sequence numbers are unique within each
'view' of the membership, but as soon as a daemon crashes or restarts or
a network partition occurs or recoveres, the sequence numbers will start
over at 1, so I don't think they will work for you.

The best way is to just tag your application level messages with a unique
message id such as a tuple of local application sequence number and
spread connection private name (which is guaranteed to be unique until
your application disconnects) or some other 'name' attached to each
instance of your application.


On Fri, Aug 09, 2002 at 02:50:23PM -0400, Sam Liu wrote:
> Hi,
> I would need to attach a message id to each message
> delivered to the applications. I am considering to use
> the seq no of the last packet of the message as the
> message id. Is the seq no of the packet grobally
> unique in a specific configuration? Thanks.
> yisheng
> McGill U
> Canada

Jonathan R. Stanton         jonathan at cs.jhu.edu
Dept. of Computer Science   
Johns Hopkins University    

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