Read replicas
Read replicas are copies of a database that are used to offload read traffic from the primary database instance.
Description
In the context of AWS, read replicas are a feature of Amazon RDS (Relational Database Service) that allows users to create one or more replicas of a primary database instance. These replicas can be used to handle read queries, thereby reducing the load on the primary instance and improving overall performance. Read replicas are asynchronously updated, meaning that changes made to the primary database are propagated to the replicas, but there may be a slight delay. This feature is particularly useful in applications with high read-to-write ratios, as it allows for better scalability and improved response times. Organizations can deploy read replicas in different AWS regions to enhance availability and reduce latency for geographically distributed users. Additionally, read replicas can serve as a failover solution in case the primary instance fails, ensuring continuous availability of data.
Examples
- An e-commerce website that uses read replicas to handle product catalog queries while keeping the primary database focused on order processing.
- A mobile application that leverages read replicas to serve user profile data to multiple users simultaneously, reducing response times.
Additional Information
- Read replicas can be created in the same AWS region or in different regions to optimize read performance for global applications.
- AWS allows up to five read replicas per primary database instance, enabling significant scaling capabilities without affecting write operations.