• Default Queue - Contains any query that cannot be placed into an existing active queue. Every user in the system will use the default queue if necessary. The database administrator can create a queue and set it as the default queue, with the restriction that the queue must be a read-write queue (since the queue must be allowed to run any query). Only one default queue can exist. The default queue has no restrictions out of the box.

• Superuser Queue - Contains any queries run by superusers. This queue has no restrictions and allows superusers to run queries unhindered. To use this queue, a user, group, or role must be assigned to the ‘$superuser’ queue.

• Express Queue - Contains queries that are estimated to run extremely fast. The Express queue has no concurrency limit.  A query in the Express queue is moved back to an appropriate non-express queue if it exceeds three seconds of runtime.

• System Queue - Contains any query running against internal system tables and procedures.