[zeromq-dev] Important: backward incompatible changes for 0MQ/3.0!

Martin Sustrik sustrik at 250bpm.com
Wed Mar 23 07:43:22 CET 2011

Hi Min,

>> 10. I would like to remove ZMQ_PAIR pattern altogether, however, Pieter
>> uses it in the guide, so he proposes to instead limit it to inproc
>> transport which is the only use case there. Please, if you are using
>> PAIR, whether over inproc or tcp or whatever, scream now!
> I use PAIR quite a bit, because many of my small cases really are
> symmetric a<=>b connections (not REQ/REP pattern).

Ok. The pair will remain.

> What would be the recommended
> socket type(s) for a symmetric pair of sockets with flexible send/recv
> pattern if PAIR is removed?

I know nothing about your app, but I assume the traffic on the socket is 
a mix of different feeds, some of them req/rep some of them pub/sub etc.

If you plan never to scale beyond 2 nodes, using pair is very convenient 
-- you don't have to decompose the business logic into distinct feeds, 
which is often a complex task.

 From a global point of view however, limiting the scalability to 2 
nodes is not a good thing. It should be always assumed that the 
application will have to scale later on, if for no other reason, then it 
at least means being nice towards future maintainers of the app.


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