Strange Loop

Geo-Replicated Transactions in 1.5RTT

Transactions make building modern applications much easier, but are often seen as too expensive for use in distributed systems or large scale applications. Almost a decade ago, common distributed systems in widespread use abandoned the idea of transactions for more simple interfaces that were both faster and easier to implement correctly. More recently, systems such as Google's Spanner and CockroachDB have brought transactions back to the mainstream for geo-replicated databases spanning data centers. There's a fundamental bottleneck in these systems in that the latency between data centers directly affects the latency of a transaction's execution and commit.

This talk presents work on a new geo-replicated, transactional key-value store called Consus. The key insight in Consus is a new commit protocol that commits a fully general transaction in three wide area message delays---just 1.5RTT---in the common case. Compared to traditional two-phase commit, this protocol completes with one less message delay and without a central transaction coordinator. Further, transactions are "masterless" or "active-active" and can begin executing in any data center. This talk presents the high level motivation and design for Consus and then do a deep dive into its commit protocol. The talk will be mostly self contained, providing the background necessary to understand both the primitives on which builds and the contributions of the protocol.

Robert Escriva

Robert Escriva


Robert Escriva received his PhD in Computer Science from Cornell University for his work on distributed systems. His research focuses on the intersection of distributed systems and large scale infrastructure. He currently works as a Software Engineer at Dropbox.

Outside of his professional life, Robert takes care of a wonderful black lab mix named Hennessey and enjoys the little things in life, like coffee and breakfast burritos.