What's the difference between Oban and RabbitMQ

They don’t really compete in the same space…

Oban is kinda job scheduler, backed by database.
RabbitMQ is kinda Enterprise Bus, where You submit and listen to events.

But could Oban be used for submitting and listening for events like RabbitMQ? and conversely can RabbitMQ be used as job scheduler?

It seems RabbitMQ will be well suited when integrating 2 or more applications through a common bus using events, right?

Not really, You need a rabbitmq client. You use Oban to start a job each night for example.

Right

In terms of performance at what point in time does Oban/Postgres show its limitations to warrant using RabbitMQ?

Oban is not RabbitMQ, I don’t see one replacing the other.

RabbitMQ is purely a message broker, which is suitable for sending persistent messages between nodes. It doesn’t handle scheduling, retries, concurrency, testing concerns, or any of the other features Oban provides. To get some of those features you’ll need to use a library like Broadway, but it still won’t handle errors/retries/schedules/discards or provide the ability to query your data.

Regarding the performance, Oban can easily process 1-10k jobs per-queue per-node, depending on your concurrency levels.

in what unit of time?

That is per second, as measured on my local machine.

@sorentwo Since you are the author of Oban, is it possible for you to share benchmarks since 1-10 is pretty wide range and I need to justify to my superiors in a Forture 200 company the choice of using Oban vs RabbitMQ, which I understand is not the right choice for job scheduling and requires jumping hoops and managing retries etc.

Some benchmarks are included in the Oban repo. The variance is down to two factors:

1. The concurrency limit
2. The cool down period

With a cool down of 1ms and a concurrency of 1, you can run at most 1k in a second. With a more realistic concurrency of 10 you can run 10k in a minute.

Most of my benchmarking focuses on throughput, or how many jobs can be processed with sustained inserts and execution simultaneously.