Sundial: Distributed OLTP Database Concurrency Control and Caching

Two Sigma developed Sundial, an in-memory distributed optimistic concurrency control protocol for OLTP databases. Sundial addresses high latency and contention in distributed transactions by dynamically determining the logical order of transactions at runtime using logical leases on data elements, and by caching remote data locally to reduce access overhead. This unified protocol integrates concurrency control and cache coherence, outperforming existing protocols under high contention and significantly improving performance. This post details the research behind Sundial, including its design, implementation, and evaluation, and discusses its implications for future database systems.