Recovery System
Subject: Database Systems
Sample Practice Questions
Question 1: The recovery scheme must also provide
- High availability
- Low availability
- High reliability
- High durability
Explanation: It must minimize the time for which the database is not usable after a failure.
Question 2: Which one of the following is a failure to a system
- Boot crash
- Read failure
- Transaction failure
- All of the mentioned
Explanation: Types of system failure are transaction failure, system crash and disk failure.
Question 3: Which of the following belongs to transaction failure
- Read error
- Boot error
- Logical error
- All of the mentioned
Explanation: Types of system transaction failure are logical and system error.
Question 4: The system has entered an undesirable state (for example, deadlock), as a result of which a transaction cannot continue with its normal execution. This is
- Read error
- Boot error
- Logical error
- System error
Explanation: The transaction, can be re-executed at a later time.
Question 5: The transaction can no longer continue with its normal execution because of some internal condition, such as bad input, data not found, overflow, or resource limit exceeded. This is
- Read error
- Boot error
- Logical error
- System error
Explanation: The transaction, can be re-executed at a later time.
Question 6: The assumption that hardware errors and bugs in the software bring the system to a halt, but do not corrupt the nonvolatile storage contents, is known as the
- Stop assumption
- Fail assumption
- Halt assumption
- Fail-stop assumption
Explanation: Well-designed systems have numerous internal checks, at the hardware and the software level, that bring the system to a halt when there is an error. Hence, the fail-stop assumption is a reasonable one.
Question 7: Which kind of failure loses its data in head crash or failure during a transfer operation.
- Transaction failure
- System crash
- Disk failure
- All of the mentioned
Explanation: Copies of the data on other disks, or archival backups on tertiary media, such as DVD or tapes, are used to recover from the failure.
Question 8: The failure occurred sufficiently early during the transfer that the destination block remains intact.
- Partial Failure
- Total failure
- Successful completion
- Data transfer failure
Explanation: Copies of the data on other disks, or archival backups on tertiary media, such as DVD or tapes, are used to recover from the failure.
Question 9: The database is partitioned into fixed-length storage units called
- Parts
- Blocks
- Reads
- Build
Explanation: Blocks are the units of data transfer to and from disk, and may contain several data items.
Question 10: Which of the following causes system to crash
- Bug in software
- Loss of volatile data
- Hardware malfunction
- All of the mentioned
Explanation: The content of non-volatile storage remains intact, and is not corrupted.