[andrewstuart]

Postgres is not the only database that does queues.

Any database that supports SKIP LOCKED is fine including MySQL, MSSQL, Oracle etc.

Even SQLite makes a fine queue not via skip locked but because writes are atomic.

[mike_hearn]

SKIP LOCKED isn't quite enough to get a real MQ product. Oracle has a full blown MQ product inside it transactional with other data.

In particular you need the ability to wait for messages to appear in a queue without polling, and for a proper MQ you need things like message priority, exception queues, multi-queue listening, good scalability etc.