[jayd16]

It's a bit of trick that the outbox to queue part of it likely needs to support "at least once but duplicates possible" into the queue.

[mrkeen]

"Send multiple times from D to Q and deduplicate with a UUID" (idempotency) is well short of "insert into both D and Q or neither" (atomicity)

[jayd16]

What are you saying here? I'm pointing out that you need to be ok with the lack of exactly once transaction between O and Q. Maybe you're agreeing and simply saying that's a fine?

[KraftyOne]

Every item will be written to the queue exactly once (as the update is transactional). Queue processing may need at-least-once semantics, yes, depending on what exactly you're doing.

[jayd16]

The queue write is not in the transaction. The proposed trick is that that is ok because an outbox is able to be transacted on. It kicks the can some what...