Sundial: Harmonizing Concurrency Control and Caching in a Distributed OLTP Database Management System

This post introduces Sundial, an in-memory distributed optimistic concurrency control protocol for OLTP databases. Sundial addresses high latency and contention by dynamically determining transaction order at runtime using logical leases on data elements and by caching remote data locally to reduce access overhead. The unified protocol integrates concurrency control and cache coherence, outperforming existing protocols under high contention by up to 57% and improving performance by up to 4.6x in workloads with high access skew.