MQTT subscriber missed messages

0
votes

I have a basic MQTT question. If I am publishing on a topic lets say myTopic/1 and I am publishing messages faster than the broker is delivering them to the subscriber will some messages get overwritten and not delivered? This seems to be my experience when testing using AWS IOT broker service. Also messages seem to be delivered to the subscriber on a random order.

Im using the M2MQtt c# library for my publisher and subscriber tests.

Many Thanks

1
mqttiot

1 Answers

0
votes

It depends of used QoS. Only QoS1 and QoS2 guarantee message to be delivered. For low throughput problem you can search for non-standard implementation like shared-subsciption: https://www.hivemq.com/blog/mqtt-client-load-balancing-with-shared-subscriptions/