When will people stop trying to build queuing systems on top of a database and use a queuing service. Amazon's SQS or RabbitMQ or one of dozens of other tools that are specialized for message queuing. A job queue is just a message queue in which the messages hold a job.

ZeroMQ is the thing to use to roll your own queuing service, not a database server whether SQL or NoSQL. Databases are not queueus and database servers are not designed with queues as any kind of important priority when features are implemented.