Google PubSub ordered Messages to Dead Letter Queue process

Question

I have a scenario of Pub/Sub with ordered messages and a Dead Letter queue. Do all the ordered messages land on a Dead Letter queue or just the one of the Ordered messages, that is not able to be processed, lands individually on the DL Queue.

Answer 1

Right now, it should not be possible to set up a dead letter queue on a subscription that has message ordering enabled. The reason is that dead letter queues are best effort and so it's possible that the redelivery of a message would not be consistent if it was going to be moved to the dead letter topic, which could violate the ordering guarantees.