The problem I started experienceing is that a few messages got stuck in a queue for about 30 minutes. It looks like a message got delivered to a queue (I can see it via camel). I can see the timestamp of the message: 9:52:21. It stays in the queue even there are 200 consumers connected to a queue. But suddenly, after 30 minutes, it got delivered to a consumer! I can see it is processed in a one's consumer log. And everything seems just perfect, but I can't undertand what causes this 30 minutes delay.
I use AMQ scheduler heavily. But afaik messages with a scheduler delivery delay don't appear in a queue. And if they appear, Redelivered flag should be set to true and my custom header should also be changed, but it is not. So I am almost sure that it is not a scheduled message. But what is that? Why it stays in a queue for so long? Can it be connected with my recent changes in broker configuration?