Queue expiration only apply for message on the head of queue

[Hieu-PT]

Hi team,
I'm facing the issue similar to this #2007.
We have push many messages to the queue, and each had a per-message TTL. The problem is message expired still in the queue and cannot be discard ontime. After reading RabbitMQ documents, I'm realised that "Only when expired messages reach the head of a queue will they actually be discarded (or dead-lettered)."
We are now finding a solution to solve this problem.
So I want to ask Support Team provide us some suggestion for this situation.
Btw, the TTL section on RabbitMQ web said that "When retroactively applying a per-message TTL policy, it is recommended to have consumers online to make sure the messages are discarded quicker.". Does it mean if we have the consumer, message expired will be discard ontime without reaching head of a queue?
Thank you so much. Hope to see response from Support Team

[michaelklishin]

From the docs:

Only when expired messages reach the head of a queue will they actually be discarded (or dead-lettered

Consumers won't get them as deliveries but if a queue never has any activity, those messages will not be marked for deletion from disk. This design assumes that queues have consumers at least "most of the time", that is, that there aren't many situation of queues with messages but without consumers for, say, hours and hours.

Queue TTL will delete the entire queue and all of its messages very shortly after expiration. This can be used as an extra layer protection against such "orphan queues":

Queues will expire after a period of time only when they are not used (a queue is used if it has online consumers).