US Patent 7308541 Optimistic reads in a multi-node environment

A method, system, computer system, and computer program produce to support a distributed environment in which changes to data shared by multiple nodes are logged using private logs and managed by a coordinator. The coordinator recognizes invalidating operations and informs a reader when data need to be read again after an invalidating operation corrupted and/or caused the copy of the data read by the reader to be out-of-date. The coordinator can provide a location from which current valid data can be read. The coordinator can use an operations history to detect invalidating operations and operations trackers to determine when a node is not synchronized with the coordinator.