Abstract: A method for tracking a sent message in a distributed messaging system is presented. The method includes providing a sequence of data structures that when queried have a known probability of returning a false positive result and creating a message history by associating a range map with each of the sequence of data structures, where the range map includes a range of time stamps. The method further includes providing a message tracking ID corresponding to the sent messages, where the message tracking ID includes a client ID, a message time stamp that includes a bounded skew, and a server ID. The method further includes storing the message tracking ID in one of the sequence of data structures.

Abstract: A content-based publish/subscribe system for providing gapless message delivery from a publishing client to a subscribing client, the system includes a plurality of brokers operatively coupled to one another via a network. Each of the brokers include at least one processor and are configured as a publisher-hosting broker, a subscriber-hosting broker or an intermediate broker. The subscriber-hosting broker is operatively coupled to the publisher-hosting broker via the network through the intermediate broker. At least a portion of the plurality of brokers are configured so as to eliminate a need for persistent storage of messages at the intermediate broker and to substantially guarantee a gapless delivery of one or more messages transmitted by the publishing client to the subscribing client, even in the presence of a failure in the publish/subscribe system.

Abstract: A method, system, and computer program for delivering messages and data to competing consumers. One aspect of the invention includes a message delivery system including a destination messaging engine, one or more receiver messaging engines, and a message pool. The destination messaging engine is configured to distribute data from one or more producers. The receiver messaging engines are configured to request data from the destination messaging engine and transmit the data to one or more consumers. The message pool is configured to store data from the producers, with the destination messaging engine arbitrating data in the message pool among the receiver messaging engines.

Abstract: A facility is provided for distributing events to consumers in a content-based publish-subscribe system, wherein the consumers each have at least one subscription. The facility includes deriving a set of g approximate multicast groups from a larger set of G possible multicast groups in the publish-subscribe system. The deriving includes exploiting knowledge of subscription predicates of the consumers of the publish-subscribe system. The set of G possible multicast groups is collapsed to the smaller set of g approximate multicast groups, while minimizing the expected performance penalty in using the approximate multicast groups. The set of g approximate multicast groups is then used to forward events to consumers within the publish-subscribe system.