A Replica Consistency Protocol For GlobData
João Martins · Portuguese National Funding Agency for Science, Research and Technology (RCAAP Project by FCT) · 2003
This thesis addresses the problem of replica management in a distributed object-oriented database system. It presents a protocol to ensure data consistency across the different nodes of the system. This protocol relies on recent advances in group communication techniques, and on the use of atomic broadcast as a building block to help serialize conflicting transactions. The protocol was implemented in the context of the GlobData project. GlobData was an European IST project designed and implemented a data management middleware tool, named COPLA. The tool offers the abstraction of a global object database repository, supporting transactional access to geographically distributed persistent objects independent of their location. COPLA supports the replication of data according to different consistency criteria. Each consistency criteria is implemented by one or more consistency protocols, that offer different trade-offs between performance and fault-tolerance. A general description of the algorithm is given, followed by a thorough description of its implementation within the COPLA tool. This implementation is then evaluated against other COPLA consistency protocols