Server is started with queue deployed. Attribute statistics-enabled is then set to true in messaging server. This operation doesn't require reload. Start sending messages and look at outputs of operation list-message-counter-as-json or list-message-counter-as-html at queue you are using to send messages. (message-counter-sample-period is set to 10s by default, so give it some time).
Only attributes messageCount, messageCountDelta contain updated values . Other attributes are either null, 0 or default timestamp.
Output of list-message-counter-history-as-json is also not correctly updated
After server reload, output of operations updates and starts working as expected.
Values are also correctly updated when new messages are sent now.
As administrator, I would like to be able to turn on/off statistics also without server reload. Although it is possible with messaging subsystem, it is not working correctly until reload.