AWS Lambda cold start performance implementing Python 3.9 and Boto3 integration
I've been struggling with this for a few days now and could really use some help. I've been working on this all day and I'm stuck on something that should probably be simple. I'm sure I'm missing something obvious here, but After trying multiple solutions online, I still can't figure this out. I'm experiencing important cold start latencies with my AWS Lambda functions that use Python 3.9 and the Boto3 library for AWS SDK interactions. My functions are designed to retrieve data from S3 and then process it before returning a response. In particular, on the first invocation after a period of inactivity, the execution time can exceed 5 seconds, which is unacceptable for my use case. For example, here’s a simplified version of my Lambda handler: ```python import boto3 s3_client = boto3.client('s3') def lambda_handler(event, context): response = s3_client.get_object(Bucket='my-bucket', Key='my-object') data = response['Body'].read() return data.decode('utf-8') ``` I’ve tried several optimizations, including: - Packaging my dependencies in a lambda layer to reduce the size of the deployment package. - Using the `AWS_LAMBDA_EXEC_WRAPPER` environment variable to enable a custom wrapper script to try and keep the execution environment warm. - Adjusting the memory allocation from the default 128MB up to 512MB to see if it would help with the initialization time, but it didn’t make a noticeable difference. I also used AWS CloudWatch to monitor the invocation metrics and noticed that after the initial cold start, subsequent requests are significantly faster, with latencies under 200ms. However, the inconsistency in response times is causing issues in my application. Has anyone else faced this scenario with AWS Lambda and found effective strategies to mitigate the cold start question? Are there specific configurations or architectural changes I should consider using for a more performant solution? Has anyone else encountered this? This is part of a larger service I'm building. Any help would be greatly appreciated! My development environment is Linux. What am I doing wrong? I'm working on a application that needs to handle this. Any examples would be super helpful. This issue appeared after updating to Python LTS.