how to setup and test if a location is using the closest rds read replica? aws

Question

I am currently learning how rds replica works in aws. I got everything setup and now I have a postgres rds instance in the origin of oregon which is the original rds instance. Then I created one cross origin read replica which is in the origin of tokyo. How do I setup and test if people nearby tokyo is actually access the read replica from tokyo instead of accessing the original rds instance in oregon?

Answer 1

Each RDS Read Replica has a DNS endpoint. You could combine DNS Server Geolocation, such as provided by Route 53, to provide the endpoint closest to the customer's location.

To test and verify this, you would need to enable logging for your RDS instance and then manually map the customer's IP address -> region -> read replica to verify.