Optimistic Voting for Managing Replicated Data

An epidemic model gives an efficient approach for transaction processing of replication systems in weakly connected environments. The approach has the advantages of high adaptation, support for low-bandwidth network, and committing updates in an entirely decentralized control fashion. But the previous implementing protocols, like ROWA protocol, quorum protocol, and voting protocol, have a common shortcoming that they are pessimistic in conflict reconciliation, therefore bring high transaction abort rate and reduce system performance dramatically when the workload scales up. In this paper, an optimistic voting protocol, which introduces condition vote and order vote in the voting process of transactions, is proposed. The condition vote and order vote postpone the final decision on conflicting transactions and avoid transaction aborts that are incurred by read-write and write-write conflicts. Experimental results indicate that the optimistic voting protocol decreases abort rate and improves average response time of transactions markedly when compared to other protocols.