1. A computer-implemented method for managing message queues in a database system having a message queue system that includes queues shared by multiple message types and tenants, the method comprising: estimating an enqueue rate of new messages coming from a sender in the message queue system; based on the estimated enqueue rate exceeding a predetermined enqueue rate threshold value— identifying the sender as a flooder; allocating a dedicated message queue to the flooder; diverting the flooder's message traffic to the dedicated message queue; and responsive to the flooding condition subsiding, de-allocating the dedicated message queue and discontinue said diverting the flooder's message traffic.