An apparatus is provided to manage memory utilization by a topic in a publish-subscribe environment, wherein the topic is a logical container for the messages. The apparatus includes a primary memory device configured to store messages published to a topic, and a secondary storage device. A processor operationally coupled to the primary and secondary memory devices is configured to monitor utilization of a portion of the primary memory device assigned to the topic. In response to detecting that the utilization of the portion of the primary memory device has equaled or exceeded a threshold for memory utilization, the processor performs at least one of throttling the rate of publishing to the topic and transferring a portion of the messages from the topic to the secondary memory device. Each of the throttling and the transferring keeps the portion of the primary memory device assigned to the topic from overloading.