Hi there, in our hivemq-ce-2019.1 installation we observe different log entries and are quite unsure about their meaning. Could you give some information about the following log entries and the consequence of their occurrance:
"Tried to decrement a payload reference counter (123443870) that was already zero." (WARN)
This seems to be connected to message drops (reported in hivemq.messages.dropped.count), which I find a little surprising, because generally, decrementing a reference counter should happen after processing is complete.
Basically, decreasing such a counter more than it had been increased doesn’t sound like a situation that can happen due to the usual exceptional circumstances, like crashed/cancelled tasks. Can this be a bug?
"No message id available for client xyz" (ERROR)
After all I could find out, the messageIDs seem to be held per client and their number seems limited to 64k.
Now, if this ID pool is exhausted (and client xyz is a subscriber), does it mean that there are more than 64k messages not dispatched (=queued) to that client xyz?
We are using QoS=0, so I wonder why MessageIDs are generated at all, since afaik they are normally required only for QoS>0.
What happens in the case of this message? Will the message be dropped or does processing wait until a messageID gets available?
Any help and information is appreciated.
Greetings & thanks!