I think the realtime requirement removes hadoop as an option. They might have considered using HDFS as the data store instead of S3, since putting lots of objects into s3 is expensive. Or just using a big EFS volume instead of S3.
It would be nice to know how much latency there was in the microservice version vs the monolithic version.
It would be nice to know how much latency there was in the microservice version vs the monolithic version.