Which property of ACID is primarily responsible for ensuring that once a transaction has been committed, its effects persist after a crash?

• A. Atomicity
• B. Isolation
• C. Durability
• D. Consistency

Answer: (C)

Durability is the property that ensures committed changes survive crashes. Once a transaction is committed, the system must persist its effects to non-volatile storage (typically by writing to a log and syncing to disk) so that, even if the machine crashes or loses power, the changes can be recovered when the system restarts. This is what lets you trust that a successful commit remains durable over time. Atomicity is about all-or-nothing execution within the transaction, isolation prevents interference between concurrent transactions, and consistency ensures data adheres to rules and constraints during processing. None of these guarantees persistence after a crash in the same way durability does.