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Idempotency
In simple terms, idempotency is the property where an operation can be applied multiple times without changing the result beyond the initial application.
Think of an elevator button: whether you press it once or mash it ten times, the elevator is still only called once to your floor. The first press changed the state; the subsequent ones are “no-ops.”
In technology, this is the “secret sauce” for reliability. If a network glitch occurs and a request is retried, idempotency ensures you don’t end up with duplicate orders, double payments, or corrupted data.
Popular Examples
- The MERGE (Upsert) Operation
- ABS(-5)
- Using Terraform to deploy server