Database Multiple Choice Questions on “ARIES”.
1. ARIES uses a ___________ to identify log records, and stores it in database pages.
a) Log sequence number
b) Log number
c) Lock number
d) Sequence
Answer: b
Clarification: LSN is used to identify which operations have been applied to a database page.
2. ARIES supports ___________ operations, which are physical in that the affected page is physically identified, but can be logical within the page.
a) Physiological redo
b) Physiological undo
c) Logical redo
d) Logical undo
Answer: a
Clarification: The deletion of a record from a page may result in many other records in the page being shifted, if a slotted page structure is used.
3. ______________ is used to minimize unnecessary redos during recovery.
a) Dirty page table
b) Page table
c) Dirty redo
d) All of the mentioned
Answer: a
Clarification: Dirty pages are those that have been updated in memory, and the disk version is not up-to-date.
4. __________ scheme that records only information about dirty pages and associated information and does not even require of writing dirty pages to disk.
a) Fuzzy logic
b) Checkpoints
c) Fuzzy-checkpoint
d) Logical checkpoint
Answer: c
Clarification: It flushes dirty pages in the background, continuously, instead of writing them during checkpoints.
5. Whenever an update operation occurs on a page, the operation stores the LSN of its log record in the _______ field of the page.
a) LSN
b) ReadLSN
c) PageLSN
d) RedoLSN
Answer: c
Clarification: Each page maintains an identifier called the PageLSN.
6. There are special redo-only log records generated during transaction rollback, called _________ in ARIES.
a) Compensation log records
b) Read log records
c) Page log records
d) Redo log records
Answer: a
Clarification: These serve the same purpose as the redo-only log records in our earlier recovery scheme.
7. The __________________ contains a list of pages that have been updated in the database buffer.
a) Dirty page table
b) Page table
c) Dirty redo
d) All of the mentioned
Answer: a
Clarification: Dirty pages are those that have been updated in memory, and the disk version is not up-to-date.
8. ___________ determines which transactions to undo, which pages were dirty at the time of the crash, and the LSN from which the redo pass should start.
a) Analysis pass
b) Redo pass
c) Undo pass
d) None of the mentioned
Answer: a
Clarification: The analysis pass finds the last complete checkpoint log record, and reads in the DirtyPageTable from this record.
9. __________ starts from a position determined during analysis, and performs a redo, repeating history, to bring the database to a state it was in before the crash.
a) Analysis pass
b) Redo pass
c) Undo pass
d) None of the mentioned
Answer: b
Clarification: The redo pass repeats history by replaying every action that is not already reflected in the page on disk.
10. ______________ rolls back all transactions that were incomplete at the time of crash.
a) Analysis pass
b) Redo pass
c) Undo pass
d) None of the mentioned
Answer: c
Clarification: It performs a single backward scan of the log, undoing all transactions in undo-list.