Unit
IV
1.) 2 Marks
1. What is transaction?1.) 2 Marks
2. What are the two statements regarding transaction?
3. What are the properties of transaction?
4. What is recovery management component?
5. When is a transaction rolled back?
6. What are the states of transaction?
7. What is a shadow copy scheme?
8. Give the reasons for allowing concurrency?
9. What is average response time?
10. What are the two types of serializability?
11. Define lock?
12. What are the different modes of lock?
13. Define deadlock?
14. Define the phases of two phase locking protocol
15. Define upgrade and downgrade?
16. What is a database graph?
17. What are the two methods for dealing deadlock problem?
18. What is a recovery scheme?
19. What are the two types of errors?
20. What are the storage types?
21. Define blocks?
The database system resides permanently on nonvolatile storage, and is
partitioned into fixed-length storage units called blocks.
22. What is meant by Physical blocks?
The input and output operations are done in block units. The blocks residing on
the disk are referred to as physical blocks.
23. What is meant by buffer blocks?
The blocks residing temporarily in main memory are referred to as buffer blocks.
24. What is meant by disk buffer?
The area of memory where blocks reside temporarily is called the disk buffer.
25. What is meant by log-based recovery?
The most widely used structures for recording database modifications is the log.
The log is a sequence of log records, recording all the update activities in the database.
There are several types of log records.
26. What are uncommitted modifications?
The immediate-modification technique allows database modifications to be output
to the database while the transaction is still in the active state. Data modifications written
by active transactions are called uncommitted modifications.
27. Define shadow paging.
An alternative to log-based crash recovery technique is shadow paging. This
technique needs fewer disk accesses than do the log-based methods.
28. Define page.
The database is partitioned into some number of fixed-length blocks, which are
referred to as pages.
29. Explain current page table and shadow page table.
The key idea behind the shadow paging technique is to maintain two page tables
during the life of the transaction: the current page table and the shadow page table. Both
the page tables are identical when the transaction starts. The current page table may be
changed when a transaction performs a write operation.
30. What are the drawbacks of shadow-paging technique?
• Commit Overhead
• Data fragmentation
• Garbage collection
30. Define garbage collection.
Garbage may be created also as a side effect of crashes. Periodically, it is
necessary to find all the garbage pages and to add them to the list of free pages. This
process is called garbage collection.
32. Differentiate strict two phase locking protocol and rigorous two phase locking protocol.
33. How the time stamps are implemented
34. What are the time stamps associated with each data item?
2.) 16 Marks
• Atomicity
• Consistency
• Isolation
• Durability
2. Explain serializability
• Conflict serializability
• View serializability
3. Explain lock based protocols
• Shared
• Exclusive
4. Explain two phase locking in detail.
• Strict two phase locking
• Rigorous two phase locking
5. Explain log based recovery in detail.
• Immediate database modifications
• Deferred modification