We are using HiveMQ to send message from a few publishers (something like 10), to a few applications. For each topic, the consummer need the last message so all our published messaged are retained.
When we are starting the publishers, we first need to clean the topics so to be sure that the information in the broker is uptodate comparing to the one in the publisher. To do that, we send a payload of 0 bytes in each topic (not that much, around 6000 topics).
In hive Mq, I got these funny warning line
No payload was found for the retained message on topic XXXX after a few days running. The message is a bit weird for me as normally either there is a payload, either, the 0 byte payload means the broker needs to delete the retained topic.
I had a look in HiveMQCE code but could really find a concrete explanation on these logs.