Question : Why is view serializability harder to test than conflict serializability?
Solution :
Correct Answer : It involves checking multiple equivalence conditions and is computationally complex
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Question : Which of the following is NOT required for checking view serializability?
Solution :
Correct Answer : Precedence graph acyclicity
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Question : A schedule that is not conflict serializable but is view serializable must contain:
Solution :
Correct Answer : Blind writes
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Question : Which statement is TRUE regarding view serializability?
Solution :
Correct Answer : Every conflict serializable schedule is view serializable
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Question : Which of the following conditions must hold for two schedules to be view equivalent?
Solution :
Correct Answer : Same initial reads, same final writes, same read-from relations
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Question : Which statement is true regarding redo operations in deferred update?
Solution :
Correct Answer : Redo is idempotent (safe to repeat)
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Question : What is the role of a checkpoint in log-based recovery?
Solution :
Correct Answer : It reduces recovery time by limiting log scanning
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Question : In immediate update with undo/redo, which transactions are undone during recovery?
Solution :
Correct Answer : Transactions without a commit record
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Question : Which of the following correctly describes deferred database modification?
Solution :
Correct Answer : Updates are written only after transaction commits
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Question : In log-based recovery, why must log records be written to stable storage before the actual database modification?
Solution :
Correct Answer : To ensure atomicity and durability using Write-Ahead Logging
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Question : Which of the following correctly describes redo and undo lists in checkpoint-based recovery?
Solution :
Correct Answer : Redo list contains committed transactions, undo list contains incomplete ones
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Question : After a system crash, from where does recovery typically start when checkpoints are used?
Solution :
Correct Answer : Last checkpoint
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Question : Which type of checkpoint allows transactions to continue execution during checkpointing?
Solution :
Correct Answer : Fuzzy checkpoint
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Question : During checkpoint execution, which of the following operations is performed?
Solution :
Correct Answer : Dirty buffers are written to disk and checkpoint record is logged
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Question : Which of the following is the primary purpose of a checkpoint in DBMS?
Solution :
Correct Answer : To reduce recovery time after system failure
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Question : Which of the following is a key disadvantage of deadlock prevention techniques like Wait-Die and Wound-Wait?
Solution :
Correct Answer : They may unnecessarily abort transactions
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Question : Which statement is correct regarding Wound-Wait scheme?
Solution :
Correct Answer : Older transaction can force younger to abort
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Question : In the Wait-Die scheme, what happens when a younger transaction requests a resource held by an older transaction?
Solution :
Correct Answer : Younger transaction aborts
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Question : In a wait-for graph, deadlock exists if:
Solution :
Correct Answer : There is a cycle in the graph
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Question : Which of the following is NOT a necessary condition for deadlock in DBMS?
Solution :
Correct Answer : Preemption allowed
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