Distributed Locking & Concurrency

This skill prevents data corruption and race conditions when multiple server instances try to modify the same resource simultaneously.

Instructions

1. Use distributed lock managers like Redis (Redlock) or ZooKeeper.
2. Implement 'Leasing' to ensure locks are released if a process crashes.
3. Use Optimistic Concurrency Control (OCC) with version numbers or timestamps.
4. Design 'Idempotent' operations to safely retry failed requests.
5. Audit code for shared-state bottlenecks that limit horizontal scaling.

Examples

• "Prevent two users from booking the same seat using a Redis distributed lock."
• "Make this 'Increment Balance' function idempotent for safe retries."