Web applications have been shifting their storage systems from SQL to NOSQL systems. NOSQL systems scale well but drop many convenient SQL features, such as joins, secondary indexes, and/or transactions. We design, develop, and evaluate Yesquel, a system that provides performance and scalability comparable to NOSQL with all the features of a SQL relational system. Yesquel has a new architecture and a new distributed data structure, called YDBT, which Yesquel uses for storage, and which performs

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... well under contention by many concurrent clients. We evaluate Yesquel and find that Yesquel performs almost as well as Redis-a popular NOSQL system-and much better than MYSQL Cluster, while handling SQL queries at scale.