[fernandotakai]

at least for me, every system has its place.

i love posgresql, but i would not use it to replace a rabbitmq instance -- one is an RDBMS, the other is a queue/event system.

"oh but psql can pretend to be kafka/rabbitmq!" -- sure, but then you need to add tooling to it, create libraries to handle it, and handle all the edge cases.

with rmq/kafka, there already a bunch of tools to handle the exact case of a queue/event system.

[zbentley]

I think having ad hoc query capabilities on your job queue/log (not possible with rabbit and only possible by running extra software like KQL with Kafka, and even then at a full-table-scan cost equivalent) is a benefit to using postgres that should not be overlooked. For monitoring and debugging message broker behavior SQL is a very powerful tool.

I say this as someone squarely in the "bigger than can work with an RDBMS" message processing space, too: until you are at that level, you need less tooling (e.g. read replicas, backups, very powerful why-is-it-on-fire diagnostics informed by decades of experience), and get generally higher reliability, with postgres as a broker.