Tell me about distributed transactions. What is the difference between orchestration and choreography?

Distributed transactions are transactions that span multiple independent services or databases, ensuring data consistency across them.

Orchestration and choreography are two approaches to managing such transactions:

• Orchestration — a centralized controller (orchestrator) manages the sequence of actions across all services. It sends commands and waits for responses, controlling the entire process.

• Choreography — each service independently reacts to events and performs its actions without a central controller. Services exchange events and respond to them, ensuring consistency through interaction.

Example: when ordering a product, the orchestrator may sequentially call payment, warehouse, and delivery services. In choreography, each service reacts to the "order created" event and performs its part, publishing events for subsequent steps.

The choice of approach depends on system complexity, control requirements, and scalability.