Which solution meets these requirements?
Use an Amazon RDS DB instance deployed in the us-east-1 Region with a read replica instance in the ap-northeast-1 Region. Create an Amazon ElastiCache cluster in the ap-northeast-1 Region to cache application data from the replica to generate the dashboards.
Use an Amazon DynamoDB global table in the us-east-1 Region with replication into the ap-northeast-1 Region. Use Amazon QuickSight for displaying dashboard results.
Use an Amazon RDS for MySQL DB instance deployed in the us-east-1 Region with a read replica instance in the ap-northeast-1 Region. Have the dashboard application read from the read replica.
Use an Amazon Aurora global database. Deploy the writer instance in the us-east-1 Region and the replica in the ap-northeast-1 Region. Have the dashboard application read from the replica ap-northeast-1 Region.
Explanations:
Amazon RDS with read replicas in different regions can be used for read scalability, but latency between regions (us-east-1 to ap-northeast-1) will exceed 1 second. Using ElastiCache adds complexity, and the read replica may still not meet the 1-second requirement for the dashboard.
Amazon DynamoDB global tables offer low-latency replication across regions, but DynamoDB is not an ideal fit for the complex analytical queries required by the dashboards. QuickSight can visualize the data but may not meet the 1-second query requirement for complex queries.
Using Amazon RDS for MySQL with a read replica across regions can introduce latency that will exceed 1 second, making it unsuitable for the near-real-time dashboard requirement.
Amazon Aurora global databases are designed for cross-region replication with low-latency, meeting the requirement for fast access to application data (less than 1 second) for the dashboard in the Tokyo office.
I appraise that the answer is:
Use an Amazon Aurora global database. Deploy the writer instance in the us-east-1 Region and the replica in the ap-northeast-1 Region. Have the dashboard application read from the replica ap-northeast-1 Region.