MicroStream documentation says that MicroStream is an embedded database so multiple processes may not access the same database files concurrently:
At any given time, only one JVM process may directly access the files representing a unique set of data.
However, the blog post on the MicroStream website suggests that MicroStream on S3 is a good option for AWS Lambda:
https://microstream.one/blog/article/the-future-is-serverless-with-microstream/
MicroStream basically enables you to store any Java object as a blob in a very simple and object-oriented, convenient way somewhere, for instance in a plain file or in AWS S3. So, MicroStream and S3 are a great fit. Now, with MicroStream you can read the state of a Lamda from S3, work with it, and finally write it back to S3.
This statement sounds contradictory to the first link. Is it still possible to use MicroStream at S3 from an AWS Lambda function?