It's not an eternity in a task queue which supports DAG-style workflows with concurrency limits and fairness strategies. The reason for this is you need to check all of the subscribed workers and assign a task in a transactional way.
The limit on the Postgres level is probably on the order of 5-10ms on a managed PG provider. Have a look at: >>39593384 .
Also, these are not my benchmarks, but have a look at [1] for Temporal timings.
[1] https://www.windmill.dev/blog/launch-week-1/fastest-workflow...