How does Microservices Architecture handle distributed transactions?

Microservices Architecture handles distributed transactions by adopting various strategies and patterns to ensure consistency and reliability across multiple services. Here are some approaches commonly used:

1. Choreography-based Saga Pattern: In this pattern, each microservice involved in a transaction emits events to notify other services about its state changes. These events trigger corresponding actions in other services, forming a sequence of compensating actions to maintain consistency. If any service fails, compensating actions are executed to rollback or compensate for the changes made by the failed service.

2. Orchestration-based Saga Pattern: In this pattern, a central orchestrator service coordinates the transaction by sending commands to individual microservices. The orchestrator maintains the transaction state and ensures that all services perform their actions in a coordinated manner. If any service fails, the orchestrator can initiate compensating actions to undo the changes made by the failed service.

3. Two-Phase Commit (2PC): 2PC is a traditional distributed transaction protocol that can be used in microservices architecture as well. It involves a coordinator and multiple participants. The coordinator sends a prepare message to all participants, and if all participants agree to commit, the coordinator sends a commit message. If any participant disagrees or fails to respond, the coordinator sends an abort message to all participants to rollback the transaction. However, 2PC has some limitations, such as blocking behavior and vulnerability to network failures.

4. Compensation-based approach: This approach involves designing compensating actions for each microservice to undo the changes made during a transaction. If any service fails, the compensating actions are executed to revert the changes made by the failed service. This approach requires careful design and implementation of compensating actions to ensure consistency.

5. Eventual consistency: Microservices architecture often embraces eventual consistency, where services may temporarily be in an inconsistent state during a transaction. Instead of enforcing immediate consistency, services eventually converge to a consistent state over time. This approach allows for better scalability and fault tolerance but requires careful handling of potential inconsistencies.

It is important to note that there is no one-size-fits-all solution for handling distributed transactions in microservices architecture. The choice of approach depends on factors such as the nature of the business domain, performance requirements, fault tolerance, and complexity trade-offs. Each approach has its own advantages and challenges, and it is crucial to carefully evaluate and select the most suitable approach for a specific scenario.