[zeromq-dev] PUB doesn't discard msg when no SUB

[Martin Sustrik]

On 05/26/2011 09:49 PM, Li, Jia wrote:

> OR: with HWM in effect, do FIFO to kick out the oldest message in the
> waiting buffer.

The problem with that is that Internet, as is widely known, is a series 
of tubes, meaning that there's a lot of tubes between the sender and the 
receiver, the 0MQ tx queue being just first of them. Thus if we start 
dropping oldest messages from the tx queue, we won't be actually 
dropping oldest queued messages but rather middle-aged messages. (The 
other tubes are TCP buffers, any intermediary devices, 0MQ queue on the 
receiver etc.)

The only coherent solution for getting rid of outdated messages IMO are 
the rate-controlled rolling buffers, similar to those used by PGM.

Martin