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GATE CSE 2021 Set 1 Q23: Recovering again after a crash during recovery

Question

Suppose a database system crashes again while recovering from a previous crash. Assume checkpointing is not done by the database either during the transactions or during recovery.

Which of the following statements is/are correct?

Try it: multiple select: one or more correct options

Select one or more options
Select all correct options. No negative marking, no partial marks.
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Answer: A (official GATE 2021 final answer key)

Concept used: Undo and redo are idempotent, so log-based recovery can simply be restarted from the same log.

First step: Without a checkpoint, recovery rebuilds its undo and redo lists from the same log: does anything change after a second crash?

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Source: official GATE 2021 Set 1 CS question paper and final answer key, organised by IIT Bombay. Question paper · Answer key

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