Does EventBridge maintain FIFO order during replay of an SQS FIFO source?

Question

I am looking into using EventBridge as our platform for events/messaging. One concern is the lack of support for FIFO within EventBridge. This can be resolved by using an SQS FIFO source combined with an EventBridge pipe.

I would like to know if messages are archived and then replayed, will the replay maintain the original FIFO ordering of the messages or will the replay simply blast out events in "random" order.

Any real life experience would be appreciated.

Answer 1

EventBridge doesn't replay the events in random order however it doesn't guarantee that it will replay them in strict order either. It is based somewhat on the "time" field on the event.

This snippet from AWS docs can confirm.

"Note that EventBridge does not provide ordering guarantees, and replays are performed in a multi-threaded manner that might result in events being delivered in an order different from that of their original ordering."

https://aws.amazon.com/blogs/aws/new-archive-and-replay-events-with-amazon-eventbridge/