Database Read Replica

Problem

Your primary database handles writes correctly. But millions of reporting and read requests consume its resources. Most of those requests don't need to execute on the writer.

Solution — Read Replica

Replicate data to additional database nodes and direct suitable reads there.

           Primary
          ↙      ↘
Replica A        Replica B
   ↑                ↑
 reads            reads

Core idea: read replicas scale suitable read workloads by using replicated copies.