Does the size of the AWS Lambda Layer affect my Lambda machine's uptime or Cold Start?

Question

AWS Lambda Runtime: Python 3.7

The Lambda Layer attached to my Lambda has a capacity of nearly 200MB when decompressed.

I would like to know if this large capacity Lambda Layer will affect the uptime or cold start of Lambda machine.

Answer 1

Yes! The package size (including the layer) does affect the Init Duration "cold-start" time

This is some benchmarking test on nodejs function with our without webpack (its a tool that helps to reduce the package size for nodejs). And we can see clearly how its effect the cold start init time:

The picture was taken from our blog in lumigo: https://lumigo.io/blog/this-is-all-you-need-to-know-about-lambda-cold-starts/ we have a detailed blog post about that issue, with solutions suggestion