Amazon suggests to not include big libraries/dependencies in lambda functions.
As far as I know, SQLAlchemy is quite a big python library. Do you think it is a good idea to use it in lambda functions? An option would be to include it as a Lambda Layer and use it across all related Lambda functions.
Anyways, what is the best practise?
From what I read, SQLAlchemy performs in memory caching of data it has read and uses that for future calls.  Based on what you are doing, it would be good to check out the SQLAlchemy caching strategy so another Lambda does not change the data from under the first lambda with SQLAlchemy.
Is it a good idea to use Python SQLAlchemy in AWS Lambda?