[zeromq-dev] Getting information about connected hosts, hitting high water mark, etc.

[Pieter Hintjens]

On Tue, May 14, 2013 at 2:54 PM, Randall Nortman <rnzmq at wonderclown.net> wrote:

> While I'm complaining about stuff missing from the current API, let me
> mention this: It would be nice to be able to get at some information
> about what peers are currently connected to a socket, and how close
> each peer is to hitting its high water mark (i.e., how many queued
> messages).  It would also be nice to get connect/disconnect and
> muted/unmuted notifications somehow.

Connected peers and connect/disconnect events would be nice. They
really need to come through the same socket, and even then you can't
really use the information reliably ("Ah, a peer has connected, I'll
start to send data... oops, they've just disappeared again...").

HWM data is really quite useless. In a low-volume scenario you should
never be queuing messages. On a high volume scenario the information
will almost always be out of date before you get it. These aren't
queues that build up slowly. They're buffers that dampen peaks.

This is why the (IMO successful) strategy is a mix of things like
suicidal snail and credit-based flow control.

-Pieter