We're using twisted, but I believe Python 3's asyncio has a similar feature with use of non-blocking sockets, which is that you can add a hook to be triggered w

We're using twisted, but I believe Python 3's asyncio has a similar feature with use of non-blocking sockets, which is that you can add a hook to be triggered when too much data accumulates in user-space (can't be flushed to the kernel's tcp buffer). In our case, when notifications buffer for a slow client, this API gets triggered and we mark the client connection as 'paused'. Until that state is cleared by more data getting to the client, notifications go to the database instead with just a flag on the client connection to check the db when the pending data was retrieved. We do a similar thing on the receiving end to pause reading off the socket if we're already doing more work on behalf of the client at once than desired. twisted documents this as producer/consumer: http://twisted.readthedocs.org/en/twisted-15.4.0/core/howto/producers.html http://twisted.readthedocs.org/en/twisted-15.4.0/core/howto/...