Performance OptimisationScaling (1/3)
What is concurrency in AWS Lambda?
Concurrency in AWS Lambda refers to the number of instances of a function that can run simultaneously. When multiple events invoke a Lambda function at the same time, AWS Lambda launches multiple instances (up to a limit) to handle the load in parallel. This helps in handling scale and latency effectively for event-driven workloads.
Types of Concurrency in Lambda
- Unreserved Concurrency: The default concurrency pool shared by all functions in an account.
- Reserved Concurrency: Dedicates a fixed number of concurrent executions to a specific function.
- Provisioned Concurrency: Pre-initializes Lambda instances so they’re ready to respond instantly, ideal for low-latency needs.
Important Notes About Lambda Concurrency
- Each function can scale up to the regional concurrency limit by default (e.g., 1,000 concurrent executions).
- Setting reserved concurrency for a function prevents other functions from affecting its concurrency.
- Provisioned concurrency helps eliminate cold starts for high-performance applications.
CLI Command to Set Reserved Concurrency