Patent ID: 7886180
Filing Date: 2011-02-08
Classification: G06Q,H04L

Abstract:
1. A method for fault recovery in a stateful publish-subscribe system, the method comprising: providing the stateful publish-subscribe system, the system including an overlay network, wherein the overlay network comprises a publisher that first transmits a plurality of structured messages through the overlay network, an object downstream from the publisher that receives the plurality of structured messages as a plurality of input messages from the publisher and applies at least one transform to the plurality of input messages to form at least one output message that is transmitted to a subscriber downstream from the object, and the subscriber that receives the at least one output message from the object; storing a history of the plurality of structured messages in a stable storage at the publisher; detecting missing information with respect to a message transmitted downstream through the overlay network from the plurality of input messages to the at least one output message, wherein view objects using protocols detect the missing information, wherein the view objects are represented by a set of values in a monotonic domain, wherein the monotonic domain is the set of values in a partial order, wherein detecting the missing information with respect to a message includes detecting a gap in the set of values, and wherein the gap is an indication that the message is lost or not arrived at all; transmitting an inquiry message requesting the missing information upstream through the overlay network to the object; determining whether the missing information is stored in the object using the inquiry message; responsive to a determination that the missing information is stored in the object, responding to the inquiry message by reapplying the at least one transform to the missing information and transmitting the missing information downstream through the overlay network; responsive to a determination that the missing information is not stored in the object, transmitting the inquiry message from the object to the publisher; responding to the inquiry message by retrieving the missing information from the plurality of structured messages in the stable storage at the publisher and transmitting the missing information from the publisher downstream through the overlay network.