CHAPTER 11: DATABASE PERFORMANCE TUNING AND QUERY OPTIMIZATION

Question 1

Question

1. One of the main functions of a database system is to provide timely answers to end users.

Answer

True
False

Question 2

Question

2. Good database performance is easy to evaluate

Answer

True
False

Question 3

Question

3. All factors must be checked to ensure that each system component operates at its optimum level and has sufficient resources to minimize the occurrence of bottlenecks.

Answer

True
False

Question 4

Question

4. Good database performance starts with good database design.

Answer

True
False

Question 5

Question

5. DBMS implementations are typically similar in complexity to two-tier client/server configurations.

Answer

True
False

Question 6

Question

6. A data file can contain rows from a single table alone.

Answer

True
False

Question 7

Question

7. The data cache caches system catalog data and the contents of the indexes.

Answer

True
False

Question 8

Question

8. The SQL cache stores the end-user written SQL.

Answer

True
False

Question 9

Question

9. To work with data, the DBMS must retrieve the data from permanent storage and place it in RAM.

Answer

True
False

Question 10

Question

10. The purpose of an I/O operation is to move data to and from different computer components or devices.

Answer

True
False

Question 11

Question

11. Working with data in the data cache is many times faster than working with data in the data files.

Answer

True
False

Question 12

Question

12. Fully equivalent means that the optimized query results are always the same as the original query.

Answer

True
False

Question 13

Question

13. The SQL execution activities are performed by the query optimizer.

Answer

True
False

Question 14

Question

14. All transaction management commands are processed during the parsing and execution phases of query processing.

Answer

True
False

Question 15

Question

15. An index scan is less efficient than a full table scan.

Answer

True
False

Question 16

Question

16. Indexes do not facilitate join operations.

Answer

True
False

Question 17

Question

17. Using index characteristics, a database designer can determine the best type of index to use.

Answer

True
False

Question 18

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18. A cost-based optimizer uses a set of preset rules and points to determine the best approach to execute a query.

Answer

True
False

Question 19

Question

19. The primary factor in determining the most efficient access plan is the I/O cost.

Answer

True
False

Question 20

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20. Most current-generation relational DBMSs perform automatic query optimization at the client end.

Answer

True
False

Question 21

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21. Indexes are very useful in small tables or tables with low sparsity.

Answer

True
False

Question 22

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22. Character field comparisons are faster than numeric, date, and NULL comparisons

Answer

True
False

Question 23

Question

23. In-memory database systems are optimized to store small portions of the database in disk storage alone

Answer

True
False

Question 24

Question

24. DBMS performance tuning includes global tasks such as managing the DBMS processes in primary memory and managing the structures in physical storage.

Answer

True
False

Question 25

Question

25. Maximizing disk contention is one of the general recommendations for the physical storage of databases.

Answer

True
False

Question 26

Question

26. RAID systems use a single disk to create storage volumes.

Answer

True
False

Question 27

Question

27. On the client side, the objective is to generate an SQL query that returns a correct answer in the least amount of time, using a minimum amount of resources at the server end. The activities required to achieve this goal are commonly referred to as tuning.

Answer

a. client SQL
b. database SQL
c. SQL performance
d. DBMS performance

Question 28

Question

28. On the server side, the database environment must be properly configured to respond to clients' requests in the fastest way possible, while making optimum use of existing resources. The activities required to achieve this goal are commonly referred to as tuning.

Answer

a. client and server
b. database SQL
c. SQL performance
d. DBMS performance

Question 29

Question

29. When moving data from permanent storage to RAM, an I/O disk operation retrieves:

Answer

a. an entire table.
b. an entire physical disk block.
c. only the row containing the attribute requested.
d. only the attribute which was requested.

Question 30

Question

30. A DBA determines the initial size of the data files that make up the database; however, as required, the data files can automatically expand in predefined increments known as .

Answer

a. procedure cache
b. buffer cache
c. supplements
d. extends

Question 31

Question

31. A(n) is a logical grouping of several data files that store data with similar characteristics.

Answer

a. procedure cache
b. table space
c. data cache
d. listener

Question 32

Question

32. A system table space, a user data table space, an index table space, and a temporary table space are examples of _____.

Answer

a. procedure caches
b. file groups
c. data caches
d. operation modes

Question 33

Question

33. The data cache is where the data read from the database data files are stored the data have been read or the data are written to the database data files.

Answer

a. after; before
b. after; after
c. before; before
d. before; after

Question 34

Question

34. To work with data, a DBMS must retrieve the data from and place them in .

Answer

a. data files; procedure cache
b. RAM; data cache
c. permanent storage; RAM
d. temporary files; procedure cache

Question 35

Question

35. The data cache or is a shared, reserved memory area that stores the most recently accessed data blocks in RAM.

Answer

a. buffer cache
b. procedure cache
c. SQL cache
d. permanent storage

Question 36

Question

36. The is a shared, reserved memory area that stores the most recently executed SQL statements or PL/SQL procedures, including triggers and functions.

Answer

a. buffer cache
b. procedure cache
c. data cache
d. permanent storage

Question 37

Question

37. The process analyzes SQL queries and finds the most efficient way to access data.

Answer

a. optimizer
b. scheduler
c. listener
d. user

Question 38

Question

38. To generate database object statistics manually, following syntax should be used in Oracle: .

Answer

a. ANALYZE <TABLE/INDEX> object_name;
b. CREATE <TABLE/INDEX> object_name;
c. ANALYZE <TABLE/INDEX> object_name COMPUTE STATISTICS;
d. CREATE <TABLE/INDEX> object_name COMPUTE STATISTICS;

Question 39

Question

39. Automatic query optimization means that the:

Answer

a. optimization takes place at compilation time by the programmer.
b. DBMS finds the most cost-effective access path without user intervention.
c. optimization process is scheduled and selected by the end user or programmer.
d. database access strategy is defined when the program is executed.

Question 40

Question

40. The DBMS the SQL query and chooses the most efficient access/execution plan.

Answer

a. parses
b. executes
c. fetches
d. processes

Question 41

Question

41. Which of the following is the first step of query processing at the DBMS server end?

Answer

a. Executing
b. Parsing
c. Fetching
d. Delivering

Question 42

Question

42. The DBMS the data and sends the result set back to the client.

Answer

a. parses
b. executes
c. fetches
d. processes

Question 43

Question

43. If there is no index, the DBMS will perform a scan.

Answer

a. loop
b. range
c. row ID table access
d. full table

Question 44

Question

44. refers to the number of different values a column could possibly have.

Answer

a. Database statistics
b. Data sparsity
c. A bitmap index
d. Clustering

Question 45

Question

45. Bitmap indexes tend to use less space than a because they use bits instead of bytes to store their data.

Answer

a. hash index
b. sparse index
c. B-tree index
d. reverse index

Question 46

Question

46. Knowing the sparsity of a column helps you decide whether the use of is appropriate.

Answer

a. query processing
b. query optimization
c. an index
d. a full table scan

Question 47

Question

47. is the central activity during the parsing phase in query processing.

Answer

a. Clustering
b. Partitioning
c. Query validation
d. Query optimization

Question 48

Question

48. When setting optimizer hints, instructs the optimizer to minimize the overall execution time, that is, to minimize the time it takes to return the total number of rows in the query result set. This hint is generally used for batch mode processes.

Answer

a. ALL_ROWS
b. FIRST_ROWS
c. INDEX(P_QOH_NDX)
d. OPTIMIZATION_ROWS

Question 49

Question

49. In standard SQL, the optimizer hint FIRST_ROWS is generally used for mode processes.

Answer

a. batch
b. interactive
c. transaction
d. real-time

Question 50

Question

50. In standard SQL, the optimizer hint ALL_ROWS is generally used for mode processes.

Answer

a. interactive
b. real-time
c. batch
d. transaction

Question 51

Question

51. The LIKE conditional operator is used by the OPERAND1.

Answer

a. P_PRICE
b. V_STATE
c. P_QOH
d. V_CONTACT

Question 52

Question

52. The must be set large enough to permit as many data requests to be serviced from cache as possible.

Answer

a. data cache
b. SQL cache
c. sort cache
d. optimizer mode

Question 53

Question

53. The majority of primary memory resources will be allocated to the cache.

Answer

a. data
b. SQL
c. sort
d. optimizer

Question 54

Question

54. The cache is used as a temporary storage area for ORDER BY or GROUP BY operations, as well as for index-creation functions.

Answer

a. data
b. SQL
c. sort
d. optimizer

Question 55

Question

55. From the performance point of view, databases eliminate disk access bottlenecks.

Answer

a. RAID
b. distributed
c. index-organized
d. in-memory

Question 56

Question

56. The table space is used for transaction-recovery purposes.

Answer

a. system
b. user data
c. temporary
d. rollback segment

Question 57

Question

57. In the context of RAID levels, refers to writing the same data blocks to separate drives.

Answer

a. striping
b. mirroring
c. partitioning
d. aggregating

Question 58

Question

58. The table space is used to store the data dictionary tables.

Answer

a. system
b. user data
c. temporary
d. rollback segment

Question 59

Question

59. In the context of RAID levels, striped arrays provide:

Answer

a. increased read performance and fault tolerance.
b. increased fault tolerance but decreased performance.
c. increased read performance but no fault tolerance
d. neither fault tolerance nor good performance.

Question 60

Question

60. In RAID level 5,:

Answer

a. the data and the parity data are striped across separate drives.
b. the data blocks are spread over separate drives and are duplicated.
c. the array requires a minimum of two drives and is known as a striped array.
d. the array requires a minimum of five drives and is known as duplexing.

	Created by Miguel Lucero about 7 years ago

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CHAPTER 11: DATABASE PERFORMANCE TUNING AND QUERY OPTIMIZATION

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