Command Query Responsibility Segregation (CQRS) is a design pattern that divides read and write operations in a database environment. This separation helps manage distinct performance characteristics for reads and writes, tackling issues like lock contention and security risks. In microservice architectures, where workflows often require data from multiple services, CQRS can improve efficiency by allowing an aggregating database to handle complex queries without being hindered by slow individual services. The article outlines the benefits of CQRS, such as improved security through read-only databases and the ability for different microservices to evolve independently. However, it also highlights challenges, primarily around increased complexity and managing data consistency between the write and read databases. The pattern can lead to eventual consistency, which is generally acceptable in many applications but requires careful planning. Implementing CQRS typically involves one of three scenarios for data replication. The simplest is using the same database for both models, though this approach sacrifices many CQRS benefits. A more common method involves using built-in replication features of the database, like PostgreSQL’s streaming replication. The third scenario requires third-party tools like Debezium for Change Data Capture, allowing real-time data propagation across different databases. The article emphasizes using Debezium to set up replication effectively while demonstrating these concepts through a voting application built with Quarkus, showcasing how to manage REST APIs and UI integration in a microservices setup.