| 摘要 |
Provided are methods, apparatus and computer programs for managing updates to replicated data, which enable one or many replicas of a data resource to be updated independently of a master copy of the data resource, and then each replica to be separately consolidated with the master copy. If data updates applied "optimistically' to a local replica conflict with updates applied to the master copy (since the last consolidation with that replica), then the local updates will not be applied to the master copy. Instead, the conflicting local updates are replaced using the current version of the master copy-preferably by backing out the conflicting update transactions and then applying the latest updates from the master copy. If there are no data conflicts when consolidation is performed, then both the master copy and the replica are successfully updated. This provides the high data availability and scalability of concurrently updatable replicas, while avoiding the complexity of conventional solutions to conflict resolution between replicas. The invention is applicable to on-line goods or services ordering applications, especially where replicas of a data resource are updated on a mobile device.
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