Outgoing publish message was dropped. Receiving client: asyncMqtt90iu2z, topic: ad/c/r, qos: 1, reason: The client message queue is full.
this log message is an indication that the client with id asyncMqtt90iu2z is not consuming its MQTT PUBLISHEs.
This can basically have two reasons:
The client has a persistent session but is currently not connected to the broker.
The client is connected but is consuming messages (sending the corresponding PUBACK, etc.) not fast enough. This could be due to a bug in the client implementation or its just too much load for one client. If the later is the case, shared subscriptions can help alleviate the problem.
I wish you a great 2021
Thank you very much for your answers,
Corresponding to the 1 answer persistent conversation, is it because the message does not have a corresponding topic consumer consumer message?
Corresponding to 2 is because the client cannot consume the accumulated data normally?
Can I delete the data/persistence/client_queue file to alleviate the problem of queue congestion? Will deleting the file affect the normal operation of the system?..