I am new to AWS and having some difficulty tracking down and resolving some latency we are seeing on our API. Looking for some help diagnosing and resolving the issue.

Here is what we are seeing: If an endpoint hasn't been hit recently, then on the first request we see a 1.5-2s delay marked as "Initialization" in the CloudWatch Trace. I do not believe this is a cold start, because each endpoint is configured to have 1 provisioned concurrency, so we should not get a cold start unless there are 2 simultaneous requests. Also, the billed duration includes this initialization period.

CodePudding user response：

Cold start means when your first request hit to aws lambda it will be prepared container to run your scripts,this will take some time and your request will delay.

When second request hit lambda and lambda and container is already up and runing will be process quickly

• https://aws.amazon.com/blogs/compute/operating-lambda-performance-optimization-part-1/

CodePudding user response：

This is the default behavior of cold start, but since you said that you were using provisioned concurrency, that shouldn't happen.

Provisioned concurrency has a delay to activate in the account, you can follow this steps to verify if this lambda used on demand or provisioned concurrency.

AWS Lambda sets an ENV called AWS_LAMBDA_INITIALIZATION_TYPE that contain the values on_demand or provisioned_concurrency.