Clarification Needed: Where Are RabbitMQ Delayed Messages Stored Before Delivery?

[Baskar santhanam]

Hi Team,

We're using the x-delayed-message plugin in RabbitMQ and publishing messages with a delay using the x-delay header. I want to understand the internals — where are these delayed messages held before they are routed to the queues?

Thanks in advance !!!

Regards,

Baskar

[Michal Kuratczyk]

It's covered in the Limitations section of the README:

https://github.com/rabbitmq/rabbitmq-delayed-message-exchange?tab=readme-ov-file#limitations

The TL;DR is: delayed messages are stored in Mnesia, a database built-in into Erlang/OTP (same database

that's used for RabbitMQ metadata, until Khepri is enabled, see https://www.rabbitmq.com/docs/metadata-store for more details).

The fact that Mnesia is used for storage is at the source of many of the plugin's limitations, which is why we are

working on a completely new implementation, that will use a different storage backend and will be free of those limitations.

It'll be a commercial extension however.

Best,

--
You received this message because you are subscribed to the Google Groups "rabbitmq-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rabbitmq-user...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/rabbitmq-users/22972501-3442-429f-ab5e-77463200c581n%40googlegroups.com.

--

Michal

RabbitMQ Team

This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it.