A messaging system implements messaging among application servers and databases, utilizing other servers that implement messaging brokers. A large flood of incoming messages can bring down messaging brokers by overflowing the message queues, negatively impacting performance of the overall system. This disclosure in some embodiments detects and identifies “flooders” in a timely manner and isolates their message traffic to dedicated queues to avoid impacting other system users. Subsequently, a preferred system de-allocates the queues and returns the messaging system to normal operation when flooding conditions subside, and “sweeps” up any remaining orphan messages.