[zeromq-dev] Fwd: Exact matching on subscription topics

Martin Sustrik sustrik at 250bpm.com
Thu Jan 19 23:17:58 CET 2012

Hi Staffan,

> For example, it'd be nice to have the ability to drop a subscription
> request if you're running low on resources. As it is now, you can force
> a PUB node into swapping just by making a ton of subscription requests,
> and the node can't really do anything about it.

This is an interesting problem.

I guess the solution would have to take advantage of the fact that 
PUB/SUB is intrinsically unreliable, i.e.when low on resources the 
messages may be dropped even though they match the filter.

Similarly, when low on resources, application of subscriptions may be 
delayed until the point when there are more resources available.

There are different possibilities further on the way: Applying 
backpressure if the publisher is not able accept the subscription at the 
moment, periodic re-trying to send the subscription and similar.


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