[zeromq-dev] PUB/SUB guarantee on message order

[Pieter Hintjens]

Messages carried over TCP or IPC will be delivered in order if they
pass through the same network paths. This is guaranteed and it's a TCP
guarantee, nothing to do with ZeroMQ. ZeroMQ does not reorder
messages, ever. However if you pass messages through two or more
paths, and then merge those flows again, you will in effect shuffle
the messages.

On Thu, Jan 22, 2015 at 11:51 AM, Auer, Jens <jens.auer at cgi.com> wrote:
> Hi,
>
> I am trying to find some reference to the guarantees zeroMQ gives when receiving data via PUB/SUB. The guide says that basically zeroMQ tries hard to deliver messages, but they may get lost. If a message is received, it is complete. Now, I am interested in guarantees on the order of messages. When I send messages from PUB to SUB, is it guaranteed that if they arrive, that will be in sending order? I have not found any official statement in the protocols or in the guide, and searching the internet has not shown a real consensus.
>
> It would be nice if somebody could point to a document or other source.
>
> Thanks,
>   Jens
>
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