I've got an application that I'd written using gmq that consistently failed to connect to my MQTT server. I had been subscribed to a couple of topics (wildcarded) at QoS2 and was not using clean sessions. Apparently I lost a connection with some messages in flight and on reconnect, the broker was attempting to redeliver lost messages, confusing the client.
I was able to make my application work again by dropping to QoS0 and getting a clean session (probably only the latter mattered), but I didn't notice the loss for several hours, so I can't make a reliable app currently with QoS > 0 and reusing sessions.
I've got an application that I'd written using gmq that consistently failed to connect to my MQTT server. I had been subscribed to a couple of topics (wildcarded) at
QoS2and was not using clean sessions. Apparently I lost a connection with some messages in flight and on reconnect, the broker was attempting to redeliver lost messages, confusing the client.I was able to make my application work again by dropping to
QoS0and getting a clean session (probably only the latter mattered), but I didn't notice the loss for several hours, so I can't make a reliable app currently withQoS> 0 and reusing sessions.