International Business Machines Corporation

Roman Vitenberg

Alan Jay Wecker

Dean Har'el Lorenz

James William Stopyro

Alexander Krits

A rollback support method for transactions a node among nodes in a distributed system, including modifying a disposable cache copy of data as part of transaction, propagating a version state and/or a data state of the modified cache to any of the nodes, verifying non-violation of a transaction semantic and/or a replication policy relating to the transaction, committing the transaction to any nodes if successful, revising a version state of other reliable replicas and disposable cache copies in the system based on the version state of the modified disposable cache copy, the disposable cache copies being members of a membership-based view, and updating a data state of other reliable replicas in the system based on the data state of the modified copy, and aborting the transaction if it fails, including restoring the disposable cache copy based on any reliable replicas and/or disposable cache copies in the system.

Rollback support in distributed data management systems

Methods and systems are provided in a group communication system for dynamically changing a version of a group communication protocol from a first version to a second version transparently to external sources and destinations. The system accommodates newly joining members that can only support versions of the protocol other than the version currently in use without interruption in service. Similarly, the system can upgrade its operating version of the group communication protocol to improve performance when a member having relatively low capabilities exits the group.

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Oslo, Norway

Roman Vitenberg