Decentralised Commitment for Optimistic Semantic Replication

Pierre Sutra (1) , Joao Barreto (2) , Marc Shapiro (1)

1 Regal - Large-Scale Distributed Systems and Applications
2 INESC-ID - Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa

We study large-scale distributed cooperative systems that use optimistic replication. We represent a system as a graph of actions (operations) connected by edges that reify semantic constraints between actions. Constraint types include conflict, execution order, dependence, and atomicity. The local state is some schedule that conforms to the constraints; because of conflicts, client state is only tentative. For consistency, site schedules should converge; we designed a decentralised, asynchronous commitment protocol. Each client makes a proposal, reflecting its tentative and/or preferred schedules. Our protocol distributes the proposals, which it decomposes into semantically-meaningful units called candidates, and runs an election between comparable candidates. A candidate wins when it receives a majority or a plurality. The protocol is fully asynchronous: each site executes its tentative schedule independently, and determines locally when a candidate has won an election. The committed schedule is as close as possible to the preferences expressed by clients.

Mots clés: rep

Domaines: Calcul parallèle, distribué et partagé [cs.DC]

Pierre Sutra, Joao Barreto, Marc Shapiro. Decentralised Commitment for Optimistic Semantic Replication. International Conference on Cooperative Information Systems (CoopIS), Nov 2007, Vilamoura, Algarve, Portugal. pp.318-335, ⟨10.1007/978-3-540-76848-7_21⟩. ⟨inria-00444783⟩