Combining Generality and Practicality in a Conit-Based Continuous Consistency Model for Wide-Area Replication

Replication is a key approach to scaling wide-area applications. However, the overhead associated with largescale replication quickly becomes prohibitive across widearea networks. One effective approach to addressing this limitation is to allow applications to dynamically trade reduced consistency for increased performance and availability. Although extensive study has been performed on relaxed consistency models in traditional replicated databases, none of the models can simultaneously achieve the following two typically conflicting requirements imposed by wide-area applications: generality (capturing applicationspecific consistency semantics) and practicality (enabling efficient application-independent consistency protocols to be designed and providing natural ways to express appli-