AWS Lambda and Python's .pyc files

Question

I'm trying to understand the exact effect of including .pyc files with a Python package to AWS Lambda.

The very few references I was able to find on this say there is no need to include .pyc files with the package. However, I'm seeing huge performance hit with my Lambda function when I don't include these files.

Trying to include a library with my package (Jinja2, for example), when omitting its .pyc files, the time it takes for the import jinja2 is always over 3 seconds.

When I do provide .pyc files, the first execution still takes 3 seconds but after that, it goes down to 100-200ms (I guess until the function gets eventually unloaded?).

I found this SO question which may suggest that AWS Lambda is unable to save its own compiled files, does this make sense?

My questions are - is there any definite source of information regarding the usage .pyc files with Python on AWS Lambda? Is there any way to make AWS Lambda save its own .pyc files? Or should I just continue to include them with my package?

Answer 1

I don't think so, the .pyc files is a Byte code which Python interpreter compiles the source to and then this code is executed. With this in mind, we can control what files should the "python virtual machine runs".

I Think the best solution is like you said:

just continue to include them with my package.

Once you do that, the code executor already have your bytecode files.