Make the Leader Work: Executive Deferred Update Replication

In this paper we propose executive deferred update replication (EDUR), a novel algorithm for multi-primary replication of transactional memory and databases. EDUR streamlines transaction certification (i.e., checking for conflicts between concurrent transactions) with the broadcast protocol, which improves overall performance and scalability compared to deferred update replication based on total order broadcast (TOB). EDUR uses executive order broadcast (EOB), a novel protocol that can be seen as a generalization of TOB. Compared to TOB, EOB features new primitives and properties that enable the application to delegate some work to a leader -- a process inherently present in many TOB algorithms that is responsible for coordination of message dissemination. The results of experimental evaluation show significant performance gains when using our approach.