Why We Deleted the Distributed Lock We Designed — When Your Own Data Refutes Your Own Design
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In the final installment of a refactoring series on a reservation system, the engineering team reflects on abandoning a carefully designed per-slot distributed lock after operational data refuted their initial architectural assumptions. While distributed locking is often treated as a standard pattern for concurrency control, real-world execution metrics revealed that the added complexity and network overhead outweighed its practical benefits. For backend developers evolving toward systems design roles, this post offers a valuable lesson in architectural humility: data-driven refactoring requires being willing to delete sophisticated distributed primitives when empirical metrics prove simpler consistency guarantees or database constraints suffice.