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Manish Thakurani for CodeGreen

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CQRS Design Pattern in Spring Boot? Explain with Example

CQRS Design Pattern in Spring Boot

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What is CQRS Design Pattern?

The CQRS (Command Query Responsibility Segregation) design pattern separates the responsibility of handling commands (write operations) from queries (read operations) into separate components.

Example: Online Shopping Platform

Problem Statement:

An Online shopping platform where users can browse products, add them to cart, place orders, and sellers can manage product listings and process orders. All read and write operations are currently handled within a single monolithic microservice.

Suggested Approach using CQRS:

  • Write Microservice: Handles commands such as creating orders, updating order status, managing product listings, etc. Utilizes Kafka for publishing events related to write operations.
  • Read Microservice: Handles queries such as fetching product details, order history, etc. Subscribes to events published by the Write Microservice using Kafka for eventual consistency.

Benefits of Using CQRS:

  • Scalability: Each microservice can be scaled independently based on the workload.
  • Performance: Optimizes read and write operations separately, leading to improved performance.
  • Maintainability: Clear separation of concerns simplifies the system architecture and enhances maintainability.

Conclusion:

Implementing CQRS with Kafka in the online shopping platform improves scalability, performance, and maintainability by segregating read and write operations into separate microservices, ensuring a more efficient and scalable system architecture.

Top comments (1)

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Ted M. Young

I'm not sure this really explains anything about CQRS? What are the compelling reasons to move to CQRS vs. a non-CQRS architecture? Why the specific mention of Kafka, which might be inappropriate, depending on how the system is designed? Why start with microservices, which are more difficult to work with (scalability is not necessarily solved with microservices). CQRS is more complex and may be harder to maintain.