Abstract: Improved access control techniques for distributed messaging systems such as content-based publish/subscribe systems are disclosed. For example, a method for providing access control in a content-based publish/subscribe system, wherein messages are delivered from publishing clients to subscribing clients via a plurality of brokers, includes the following steps/operations. One or more changes to an access control policy are specified. An access control version identifier is associated to the one or more changes. The one or more changes are sent to one or more brokers of the plurality of brokers that have a publishing client or a subscribing client associated therewith that is affected by the one or more changes. The access control version identifier associated with the one or more changes is sent to each of the plurality of brokers.

Abstract: Improved access control techniques for distributed messaging systems such as content-based publish/subscribe systems are disclosed. For example, a method for providing access control in a content-based publish/subscribe system, wherein messages are delivered from publishing clients to subscribing clients via a plurality of brokers, includes the following steps/operations. One or more changes to an access control policy are specified. An access control version identifier is associated to the one or more changes. The one or more changes are sent to one or more brokers of the plurality of brokers that have a publishing client or a subscribing client associated therewith that is affected by the one or more changes. The access control version identifier associated with the one or more changes is sent to each of the plurality of brokers.

Abstract: A publish/subscribe system is non-disruptively reconfigured, such that messages are not lost during the reconfiguration. After reconfiguration is initiated, messages that are to be delivered within the publish/subscribe system are forwarded using either an old path or a new path. That is, until the reconfigured system is stabilized, some messages may be delivered using the old path, while other messages are delivered using a new path. After the system is stabilized, the new path is used for delivery of all the messages, until another reconfiguration is initiated.

Abstract: Techniques for arranging operations performable on information in an information processing system are provided. In a system having a plurality of information producers and a plurality of information subscribers, paths are identified over which information traverses, and within which the information is subject to select and/or transform operations. The present invention optimizes the system by reorganizing the sequence of select and transform operations so that transforms follow select operations; and by combining multiple select and transform operations into single select and transform operations, respectively. Using these optimizations, the processing resources of the system can be reorganized, and/or information flow graphs describing the system can be designed, so that the select operations are “pushed” toward the producers, and transform operations are “pushed” toward the subscribers. Efficient content-based routing systems can then be used to implement the select operations.

Abstract: A group-based multicast messaging system implementing dedicated logger member for logging all multicast messages sent in the system, and a reliable recovery method for missing messages. The reliable recovery method includes soliciting retransmissions of fresh missing messages to other group members and soliciting of retransmissions of stale missing messages to logger members of the group. One of the loggers or other group members repairs the missing message to thereby ensure reliable delivery of messages in the multicast messaging system. The soliciting of retransmissions makes use of negative gossips for fresh missing messages in the system, with the system implementing a mechanism for propagating the latest state information of members to enable garbage collection of archived messages at logging servers in the system. Further, employed is a selective hashing technique to further reduce control traffic and a relaxed group membership protocol for tracking multicast group membership.

Abstract: Techniques for arranging operations performable on information in an information processing system are provided. In a system having a plurality of information producers and a plurality of information subscribers, paths are identified over which information traverses, and within which the information is subject to select and/or transform operations. The present invention optimizes the system by reorganizing the sequence of select and transform operations so that transforms follow select operations; and by combining multiple select and transform operations into single select and transform operations, respectively. Using these optimizations, the processing resources of the system can be reorganized, and/or information flow graphs describing the system can be designed, so that the select operations are “pushed” toward the producers, and transform operations are “pushed” toward the subscribers. Efficient content-based routing systems can then be used to implement the select operations.

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.

Abstract: Techniques for arranging operations performable on information in an information processing system are provided. In a system having a plurality of information producers and a plurality of information subscribers, paths are identified over which information traverses, and within which the information is subject to select and/or transform operations. The present invention optimizes the system by reorganizing the sequence of select and transform operations so that transforms follow select operations; and by combining multiple select and transform operations into single select and transform operations, respectively. Using these optimizations, the processing resources of the system can be reorganized, and/or information flow graphs describing the system can be designed, so that the select operations are “pushed” toward the producers, and transform operations are “pushed” toward the subscribers. Efficient content-based routing systems can then be used to implement the select operations.

Abstract: A technique for optimizing published event message sequences destined for information subscribers in an information processing system. Subscribers specify event interpretation rules which map event message streams into states. The event interpretation rules are maintained elsewhere in the system in preparation for providing optimized, possibly shorter, event message streams to subscribers, sufficient to correctly update the states. If a subscriber temporarily loses access to its event message stream, the optimized event message stream is determined using a shortest path graph search technique between the states defined by the start and end of the missing portion of the stream. Optimizations to the shortest path graph search technique are disclosed for use when the event interpretation rule is in replacement form, in which estimator functions based on extended rules are employed.

Abstract: An electronic exchange implemented over a network that processes a series of call auctions, wherein each call auction occurs at an end of a trading interval, thus allowing customers at disparate network locations to participate in a fair manner. The system comprises: a plurality of network nodes that communicate market information, wherein the market information includes orders submitted from market participants; a plurality of gateway agents that timestamp orders after they are submitted by the market participants to the network; and a market maker system that receives and executes orders over the network, wherein the market maker system determines if each order qualifies for the call auction at the end of a current trading interval by examining the timestamp for the order.