message_queue_size increasing

[Frank Wettstein]

Hello

There's something I do not understand in regards of the message_queue. Maybe somebody can give me a clue :-)

I've a vernemq-installation with version 1.12.4 running on a single VM'.

 vmq-admin metrics show says

counter.queue_message_in = 520951

counter.queue_message_expired = 0
counter.queue_message_drop = 0
counter.queue_message_out = 121261

This gives us a queue_size of 399690 messages, this is also shown on the /status page. 

However

 cat /etc/vernemq/vernemq.conf | grep messages

max_inflight_messages = 20
max_online_messages = 1000
max_offline_messages = 1000

How can I have a queue_size > 2000 given the above configuration? I expect having messages beeing dropped, but this is not the case. What's wrong here? Or is there a piece missing I do not understand?

Thanks for your help!

Frank

[André Fatton]

Hello Frank,

It is a known open issue where the broker gives you wrong stats for messages queued. As you can see (with vmq-admin session command, for example), you have no offline messages queued.

The counters are valid for the lifecycle of a VerneMQ boot to boot. What we count here is every message that enters a queue, and every message that leaves a queue. Now, quite obviously, in some specific situations, we either count too many in's, or too few out's.

So the most likely reason is that we missed an edge case scenario (re-send, inter-node delivery...) that makes the counters go off.

We will eventually fix this, as just has been done for the connection counters. I'm aware it is annoying.

Best regards,

André