CHAPTER 11: DATABASE PERFORMANCE TUNING AND QUERY OPTIMIZATION

Beschreibung

CIS 3365 Quiz am CHAPTER 11: DATABASE PERFORMANCE TUNING AND QUERY OPTIMIZATION, erstellt von Miguel Lucero am 06/04/2017.
Miguel Lucero
Quiz von Miguel Lucero, aktualisiert more than 1 year ago
Miguel Lucero
Erstellt von Miguel Lucero vor etwa 7 Jahre
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Zusammenfassung der Ressource

Frage 1

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

Frage 2

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2. Good database performance is easy to evaluate
Antworten
  • True
  • False

Frage 3

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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.
Antworten
  • True
  • False

Frage 4

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4. Good database performance starts with good database design.
Antworten
  • True
  • False

Frage 5

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

Frage 6

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6. A data file can contain rows from a single table alone.
Antworten
  • True
  • False

Frage 7

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7. The data cache caches system catalog data and the contents of the indexes.
Antworten
  • True
  • False

Frage 8

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8. The SQL cache stores the end-user written SQL.
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  • True
  • False

Frage 9

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

Frage 10

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

Frage 11

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

Frage 12

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

Frage 13

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13. The SQL execution activities are performed by the query optimizer.
Antworten
  • True
  • False

Frage 14

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

Frage 15

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15. An index scan is less efficient than a full table scan.
Antworten
  • True
  • False

Frage 16

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16. Indexes do not facilitate join operations.
Antworten
  • True
  • False

Frage 17

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

Frage 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.
Antworten
  • True
  • False

Frage 19

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

Frage 20

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

Frage 21

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21. Indexes are very useful in small tables or tables with low sparsity.
Antworten
  • True
  • False

Frage 22

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22. Character field comparisons are faster than numeric, date, and NULL comparisons
Antworten
  • True
  • False

Frage 23

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

Frage 24

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

Frage 25

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

Frage 26

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26. RAID systems use a single disk to create storage volumes.
Antworten
  • True
  • False

Frage 27

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

Frage 28

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

Frage 29

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

Frage 30

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

Frage 31

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31. A(n) is a logical grouping of several data files that store data with similar characteristics.
Antworten
  • a. procedure cache
  • b. table space
  • c. data cache
  • d. listener

Frage 32

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32. A system table space, a user data table space, an index table space, and a temporary table space are examples of _____.
Antworten
  • a. procedure caches
  • b. file groups
  • c. data caches
  • d. operation modes

Frage 33

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

Frage 34

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34. To work with data, a DBMS must retrieve the data from and place them in .
Antworten
  • a. data files; procedure cache
  • b. RAM; data cache
  • c. permanent storage; RAM
  • d. temporary files; procedure cache

Frage 35

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35. The data cache or is a shared, reserved memory area that stores the most recently accessed data blocks in RAM.
Antworten
  • a. buffer cache
  • b. procedure cache
  • c. SQL cache
  • d. permanent storage

Frage 36

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36. The is a shared, reserved memory area that stores the most recently executed SQL statements or PL/SQL procedures, including triggers and functions.
Antworten
  • a. buffer cache
  • b. procedure cache
  • c. data cache
  • d. permanent storage

Frage 37

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37. The process analyzes SQL queries and finds the most efficient way to access data.
Antworten
  • a. optimizer
  • b. scheduler
  • c. listener
  • d. user

Frage 38

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

Frage 39

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39. Automatic query optimization means that the:
Antworten
  • 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.

Frage 40

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40. The DBMS the SQL query and chooses the most efficient access/execution plan.
Antworten
  • a. parses
  • b. executes
  • c. fetches
  • d. processes

Frage 41

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41. Which of the following is the first step of query processing at the DBMS server end?
Antworten
  • a. Executing
  • b. Parsing
  • c. Fetching
  • d. Delivering

Frage 42

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42. The DBMS the data and sends the result set back to the client.
Antworten
  • a. parses
  • b. executes
  • c. fetches
  • d. processes

Frage 43

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43. If there is no index, the DBMS will perform a scan.
Antworten
  • a. loop
  • b. range
  • c. row ID table access
  • d. full table

Frage 44

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44. refers to the number of different values a column could possibly have.
Antworten
  • a. Database statistics
  • b. Data sparsity
  • c. A bitmap index
  • d. Clustering

Frage 45

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45. Bitmap indexes tend to use less space than a because they use bits instead of bytes to store their data.
Antworten
  • a. hash index
  • b. sparse index
  • c. B-tree index
  • d. reverse index

Frage 46

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46. Knowing the sparsity of a column helps you decide whether the use of is appropriate.
Antworten
  • a. query processing
  • b. query optimization
  • c. an index
  • d. a full table scan

Frage 47

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47. is the central activity during the parsing phase in query processing.
Antworten
  • a. Clustering
  • b. Partitioning
  • c. Query validation
  • d. Query optimization

Frage 48

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

Frage 49

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49. In standard SQL, the optimizer hint FIRST_ROWS is generally used for mode processes.
Antworten
  • a. batch
  • b. interactive
  • c. transaction
  • d. real-time

Frage 50

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50. In standard SQL, the optimizer hint ALL_ROWS is generally used for mode processes.
Antworten
  • a. interactive
  • b. real-time
  • c. batch
  • d. transaction

Frage 51

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51. The LIKE conditional operator is used by the OPERAND1.
Antworten
  • a. P_PRICE
  • b. V_STATE
  • c. P_QOH
  • d. V_CONTACT

Frage 52

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52. The must be set large enough to permit as many data requests to be serviced from cache as possible.
Antworten
  • a. data cache
  • b. SQL cache
  • c. sort cache
  • d. optimizer mode

Frage 53

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53. The majority of primary memory resources will be allocated to the cache.
Antworten
  • a. data
  • b. SQL
  • c. sort
  • d. optimizer

Frage 54

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54. The cache is used as a temporary storage area for ORDER BY or GROUP BY operations, as well as for index-creation functions.
Antworten
  • a. data
  • b. SQL
  • c. sort
  • d. optimizer

Frage 55

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55. From the performance point of view, databases eliminate disk access bottlenecks.
Antworten
  • a. RAID
  • b. distributed
  • c. index-organized
  • d. in-memory

Frage 56

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56. The table space is used for transaction-recovery purposes.
Antworten
  • a. system
  • b. user data
  • c. temporary
  • d. rollback segment

Frage 57

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57. In the context of RAID levels, refers to writing the same data blocks to separate drives.
Antworten
  • a. striping
  • b. mirroring
  • c. partitioning
  • d. aggregating

Frage 58

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58. The table space is used to store the data dictionary tables.
Antworten
  • a. system
  • b. user data
  • c. temporary
  • d. rollback segment

Frage 59

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

Frage 60

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60. In RAID level 5,:
Antworten
  • 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.
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