1. What does the “A” in ACID transactions stand for?
A. Atomicity
B. Automation
C. Authorization
D. Analytics
2. Which of the following isolation levels allows “read uncommitted” data?
A. Serializable
B. Snapshot isolation
C. Read uncommitted
D. Repeatable read
3. Why is two-phase commit (2PC) often considered expensive in distributed transactions?
A. It requires every node to run in memory only
B. It introduces additional network round trips and blocking during coordination
C. It fully replaces concurrency control
D. It only works with NoSQL data stores
4. In distributed transactions, how can a system remain robust if one participant in a two-phase commit protocol goes offline?
A. Immediately abort all transactions forever
B. Design a recovery protocol or use a transaction coordinator with timeouts and participant consensus logs
C. Only allow commits if all nodes are guaranteed to be online forever
D. Switch to single-phase commit automatically