Which term denotes a point in the log where pending changes are guaranteed to be written to disk?

Which term denotes a point in the log where pending changes are guaranteed to be written to disk?

• A. recovery log
• B. checkpoint
• C. rollback
• D. query cost

Answer: (B)

Checkpoint marks a durable point in the log where all changes up to that moment have been written to disk. It does this by flushing all dirty pages to storage and recording a checkpoint entry in the log, establishing a known safe state for recovery. When a crash happens, recovery starts from this checkpoint and uses the log to redo any committed work and undo uncommitted work, minimizing how much history must be processed. This concept sits at the core of durability in write-ahead logging, tying together in-memory changes, the log, and disk writes. The other terms don’t describe this specific guaranteed-persistence point: the recovery log is simply the log itself, rollback is the act of undoing uncommitted work during recovery, and query cost is unrelated to durability guarantees.

Checkpoint marks a durable point in the log where all changes up to that moment have been written to disk. It does this by flushing all dirty pages to storage and recording a checkpoint entry in the log, establishing a known safe state for recovery. When a crash happens, recovery starts from this checkpoint and uses the log to redo any committed work and undo uncommitted work, minimizing how much history must be processed. This concept sits at the core of durability in write-ahead logging, tying together in-memory changes, the log, and disk writes. The other terms don’t describe this specific guaranteed-persistence point: the recovery log is simply the log itself, rollback is the act of undoing uncommitted work during recovery, and query cost is unrelated to durability guarantees.