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DBMS Checkpoint MCQs: This section contains multiple-choice questions and answers on Checkpoint in DBMS.
Submitted by Anushree Goswami, on April 19, 2022
1. Checkpoints are types of mechanisms that ___ all previous logs from the system and permanently store them in the storage disk.
- Partially Remove
- Remove
- Partially Add
- Add
Answer: B) Remove
Explanation:
Checkpoints are types of mechanisms that remove all previous logs from the system and permanently store them in the storage disk.
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2. Checkpoints serve as ___.
- Books
- Covers
- Pages
- Bookmarks
Answer: D) Bookmarks
Explanation:
Checkpoints serve as bookmarks.
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3. The log files will be created based on the checkpoints ___ the execution of the transaction and the steps of the transaction.
- At the beginning of the
- At the end of the
- In the middle of the
- During
Answer: D) During
Explanation:
The log files will be created based on the checkpoints during the execution of the transaction and the steps of the transaction.
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4. The transaction will be updated in the database at the ___, and the log file will be deleted until it reaches that point.
- Point
- Check
- Checkpoint
- None
Answer: C) Checkpoint
Explanation:
The transaction will be updated in the database at the checkpoint, and the log file will be deleted until it reaches that point.
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5. Once the transaction has reached the ___ checkpoint, the log file is updated with the new step.
- Previous
- New
- Next
- Middle
Answer: C) Next
Explanation:
Once the transaction has reached the next checkpoint, the log file is updated with the new step.
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6. In DBMSes, a checkpoint marks when the DBMS was consistently configured and all transactions had been ___.
- Rollbacked
- Aborted
- Begin
- Committed
Answer: D) Committed
Explanation:
In DBMSes, a checkpoint marks when the DBMS was consistently configured and all transactions had been committed.
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7. Log files are read from end to end by the ___ system.
- Recovery
- Storage
- DBMS
- Data
Answer: A) Recovery
Explanation:
Log files are read from end to end by the recovery system.
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8. What are the two lists maintained by the recovery system?
- Redo-list
- Undo-list
- Both A and B
- None of the above
Answer: C) Both A and B
Explanation:
The two lists maintained by the recovery system are redo-list and undo-list.
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9. When the recovery system sees a transaction log containing <__, Start> and <__, Commit> or just <__, Commit>, the transaction is put into a redo state.
- Start
- Commit
- Tn
- None
Answer: C) Tn
Explanation:
When the recovery system sees a transaction log containing <Tn, Start> and <Tn, Commit> or just <Tn, Commit>, the transaction is put into a redo state.
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10. After all transactions are removed and redone in the ___ list and the previous list, the log is saved.
- Undo
- Redo
- Undo & Redo
- None
Answer: B) Redo
Explanation:
After all transactions are removed and redone in the redo list and the previous list, the log is saved.
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11. What will the transaction T2 and T3 have in the log file?
- <Tn, Start>
- <Tn, Commit>
- Both A and B
- None of the above
Answer: C) Both A and B
Explanation:
T2 and T3 will have <Tn, Start> and <Tn, Commit> in the log file.
Case: T1 at the Checkpoint, T2 and T3 in the middle of Checkpoint and Failure, T4 at the Failure respective to time.
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12. During the T1 transaction, there will be only one entry in the log file: ___.
- <Tn, Start>
- <Tn, Commit>
- <Tn, Tn>
- <Start, Start>
Answer: B) <Tn, Commit>
Explanation:
During the T1 transaction, there will be only one entry in the log file: <Tn, commit>.
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13. After the checkpoint is crossed, the transaction is ___.
- Rollbacked
- Committed
- Aborted
- Ended
Answer: B) Committed
Explanation:
After the checkpoint is crossed, the transaction is committed.
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14. If the recovery system finds a log with <Tn, Start> but not a ___ log, the transaction goes into undo state.
- Commit
- Abort
- Both A and B
- None of the above
Answer: C) Both A and B
Explanation:
If the recovery system finds a log with <Tn, Start> but not a commit or abort log, the transaction goes into undo state.
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15. All transactions are undone in the undo list, which also removes their ___ files.
- Data
- Log
- Table
- Rows
Answer: B) Log
Explanation:
All transactions are undone in the undo list, which also removes their log files.
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16. <Tn, ___> indicates that transaction T4 is still incomplete and has failed amid because it is not yet complete.
- Start
- Commit
- Rollback
- Abort
Answer: A) Start
Explanation:
<Tn, Start> indicates that transaction T4 is still incomplete and has failed amid because it is not yet complete.
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