cqrs-implementation

CQRS is an architectural pattern that separates command and query responsibilities to improve system scalability, performance, and maintainability. You should use it when building systems requiring distinct write and read models, event-driven updates, and optimized complex queries across large data sets.

To implement a basic CQRS setup, create a minimal structure with a simple write path for commands, a distinct read path for queries, and a basic projector to keep the read model in sync with the write model.

CQRS does not strictly require event sourcing, but this implementation pattern uses event-driven updates and projection-based read models to ensure fast queries and maintain auditability across the system.

The best way to scale complex queries across large data sets is using CQRS with projection-based read models, which optimizes persistence and querying by maintaining separate paths for reads and writes.

A full CQRS stack requires infrastructure for commands, queries, events, projectors, read models, and buses, plus templates for a practical application to support end-to-end event-driven updates.

You should not use CQRS when your system does not require distinct write and read models or when the overhead of maintaining separate event-driven updates and projection-based read models outweighs the scalability and performance benefits for your data sets.