Explore events base queues as a strategy

[thoven87]

Currently, we poll by default every 100ms for jobs unless a user change this on the config.

I think it'll be beneficial to also support Postgres LISTEN / NOTIFY (yes, the payload limit is 8KB) it would help with #17
I see PostgresNIO has support for LISTEN / NOTIFY, but it's not well documented. Maybe @fabianfett can help point us in the right direction?

What do you think @adam-fowler @Joannis ?

[adam-fowler]

It is worth looking into for sure. We should setup a proper benchmark to verify performance changes.

[adam-fowler]

What happens if the a job is added to the queue, but no job handler is running ie the LISTEN/NOTIFY is not running

[thoven87]

What happens if the a job is added to the queue, but no job handler is running ie the LISTEN/NOTIFY is not running

These jobs won't be processed and marked as failed. The queue.cleanup func can be used to rerun these jobs should a job handler which can process these jobs become available.