Lambda SnapStart is a performance optimization that helps your Java functions to achieve up to 10x faster start-up times by reducing the variable latency incurred during execution of one-time initialization code. Lambda SnapStart works broadly across all functions in your application or account at no additional cost. When a customer publishes a function version with Lambda SnapStart, the function’s code is initialized ahead of time, instead of being initialized on the first invoke. Lambda then takes a snapshot of the initialized execution environment and persists it in a tiered cache for low-latency access. When the function is first invoked and then scaled, Lambda resumes the function from the cached snapshot instead of initializing from scratch, driving a lower startup latency.
While Lambda SnapStart reduces startup latency, it works as a best-effort optimization, and does not guarantee elimination of cold starts. If your application has strict latency requirements and requires double-digit millisecond startup times, we recommend you use PC.