A company is hosting a MySQL database in AWS using the AWS RDS service. A Read Replica has been created, and reports are run off the Read Replica database to offload the reads. But at certain times, the reports show stale data. What could be the possible reason behind this?

Answer options:

A.The Read Replica has not been created properly.
B.The backup of the original database has not been set properly.
C.This is due to the replication lag.
D.The Multi-AZ feature is not enabled.

Correct Answer – C
An AWS Whitepaper on the caveat for reading Replicas is given below which must be considered by architects.
Read Replicas are separate database instances that are replicated asynchronously. As a result, they are subject to replication lag and might be missing some of the latest transactions. Application architects need to consider which queries have the tolerance to slightly stale data. Those queries can be executed on a Read Replica, while the rest should run on the primary node. Read Replicas may also not accept any write queries.
For more information on AWS Cloud best practices, please visit the following URL-
https://d1.awsstatic.com/whitepapers/AWS_Cloud_Best_Practices.pdf