CQRS and Event Sourcing

Advanced patterns for command/query separation and event-based persistence.

When to Activate

• Separating read and write models for different scaling needs
• Implementing Event Sourcing (events as source of truth)
• Making DB writes and event publishing atomic (Outbox Pattern)
• Coordinating distributed transactions (Saga Pattern)
• Building temporal queries ("what was the state at time X?")
• Designing aggregate reconstruction with snapshots

CQRS — Command Query Responsibility Segregation