Lambda cold starts occur when functions initialize from scratch. Container provisioning, runtime initialization, and code loading add latency. For latency-sensitive applications, cold start mitigation is essential.
Cold Start Causes
Cold starts happen after periods of inactivity, during scaling events, or after deployments. VPC configuration adds significant cold start time. Runtime choice impacts initialization duration.
- Minimize deployment package size reducing load time
- Use provisioned concurrency for consistent latency
- Keep functions warm with scheduled invocations
- Choose faster-initializing runtimes when possible
- Lazy-load dependencies reducing initialization overhead
Provisioned Concurrency
Provisioned concurrency keeps instances initialized and ready. Configure based on expected traffic patterns. Balance cost against latency requirements. Monitor actual cold start frequency to optimize spending.