Halfmoon: Log-Optimal Fault-Tolerant Stateful Serverless Computing

Serverless computing separates function execution from state management. Simple retry-based fault tolerance might corrupt the shared state with duplicate updates. Existing solutions employ log-based fault tolerance to achieve exactlyonce semantics, where every single read or write to the external state is associated with a log for deterministic replay. However, logging is not a free lunch, which introduces considerable overhead to stateful serverless applications.