CQRS Pattern in Microservices

In traditional applications, we use a single database for both reading and writing data. However, as applications scale, this approach can lead to performance bottlenecks. The CQRS Pattern (Command Query Responsibility Segregation) solves this by separating read and write operations into different models.

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This guide is beginner-friendly and explains:

• What is CQRS?
• Why do we need it?
• How does it work?
• A step-by-step example with Spring Boot
• Real-world applications of CQRS
• Using Kafka as a message broker for event-driven CQRS

1️⃣ What is CQRS?

CQRS (Command Query Responsibility Segregation) is a design pattern that separates reading and writing operations into different models. Instead of using a single database for both tasks, it introduces two separate models:

• Command Model → Handles write operations (Insert, Update, Delete).
• Query Model → Handles read operations (Select, Fetch, View).

This means that instead of having one service do both reads and writes, we split it into two services: