Hadoop MCQ Questions Answers

1. To copy a file into the Hadoop file system, what command should you use?

2. What kind of storage and processing does Hadoop support?

3. Which file system does Hadoop use for storage?

4. Hadoop Common is written in which language?

5. Which feature is used to roll back a corrupted HDFS instance to a previously known good point in time?

6. To view the execution details of an Impala query plan, which function would you use ?

7. Which object can be used to distribute jars or libraries for use in MapReduce tasks?

8. Hadoop systems are _ RDBMS systems.

9. Where would you configure the size of a block in a Hadoop environment?

10. In a MapReduce job, which phase runs after the Map phase completes?

11. Suppose you are trying to finish a Pig script that converts text in the input string to uppercase. What code is needed on line 2 below? 1 data = LOAD '/user/hue/pig/examples/data/midsummer.txt'... 2

12. Which type of Hadoop node executes file system namespace operations like opening, closing, and renaming files and directories?

13. MapReduce 1.0 _ YARN

14. _ is the query language, and _ is storage for NoSQL on Hadoop

15. MapReduce applications use which of these classes to report their statistics?

16. If no reduction is desired, you should set the numbers of _ tasks to zero

17. What type of software is Hadoop Common?

18. In MapReduce, _ have _

19. Hadoop 2.x and later implement which service as the resource coordinator?

20. To implement high availability, how many instances of the master node should you configure?

21. Which Hive query returns the first 1,000 values?

22. To what does the Mapper map input key/value pairs?

23. In what format does RecordWriter write an output file?

24. In the Hadoop system, what administrative mode is used for maintenance?

25. When implemented on a public cloud, with what does Hadoop processing interact?

26. What is the output of the Reducer?

27. Which library should you use to perform ETL-type MapReduce jobs?

28. A distributed cache file path can originate from what location?

29. HDFS file are of what type?

30. HBase works with which type of schema enforcement?

31. To connect Hadoop to AWS S3, which client should you use?

32. To create a MapReduce job, what should be coded first?

33. State _ between the JVMs in a MapReduce job

34. If you started the NameNode, then which kind of user must you be?

35. Which library should be used to unit test MapReduce code?

36. In what form is Reducer output presented?

37. Which command imports data to Hadoop from a MySQL database?

38. Skip bad records provides an option where a certain set of bad input records can be skipped when processing what type of data?

39. To reference a master file for lookups during Mapping, what type of cache should be used?

40. In a MapReduce job, where does the map() function run?

41. Which method is used to implement Spark jobs?

42. DataNode supports which type of drives?

43. For high availability, use multiple nodes of which type?

44. To set up Hadoop workflow with synchronization of data between jobs that process tasks both on disk and in memory, use the ___ service, which is ___.

45. What are the primary phases of a Reducer?

46. Hadoop Core supports which CAP capabilities?

47. To get the total number of mapped input records in a map job task, you should review the value of which counter?

48. Which line of code implements a Reducer method in MapReduce 2.0?

49. To verify job status, look for the value ___ in the ___.

50. To perform local aggregation of the intermediate outputs, MapReduce users can optionally specify which object?

51. MapReduce jobs can be written in which language?

52. Hadoop Auth enforces authentication on protected resources. Once authentication has been established, it sets what type of authenticating cookie?

53. Rather than adding a Secondary Sort to a slow Reduce job, it is Hadoop best practice to perform which optimization?

54. SQL Windowing functions are implemented in Hive using which keywords?

55. Partitioner controls the partitioning of what data?

56. The hadoop framework consists of the ________ algorithm to solve large scale problems.

57. Which statements are false?

58. A production house needs a sale report where total sale of the day is more than $20,000. Which of the following query should be used?

59. Which field is the ideal candidate for the primary key in a student record base?

60. Examine the query:- select (2/2/4) from tab1; where tab1 is a table with one row. This would give a result of:

61. The AND operator displays a row if ANY conditions listed are true. The OR operator displays a row if ALL of the conditions listed are true

62. You are maintaining data for its products in the Products table, and want to see the products that are 50 or more in number, far from the minimum stock limit. The structure of the Products table is:

63. Examine the code given below: SELECT employee_id FROM employees WHERE commission_pct=.5 OR salary > 23000 Which of the following statements is correct with regard to this code?

64. Which constraints can be used to enforce the uniqueness of rows in a table?

65. What is the numeric range that is supported by the datatype tinyint?

66. A cursor is a pointer that identifies a specific working row within a set

67. How can you change 'Hansen' into 'Nilsen' in the LastName column in the PersonsTable?

68. You should avoid the use of cursors because:

69. Consider the transaction: Begin Transaction Create table A ( x smallint , y smallint ) Create table B ( p smallint , q smallint ) Update A set x=600 where y > 700 Update B set p=78 where q=99 If @@ error != 0 Begin RollBack Transaction Return End Commit Transaction Select the correct option:

70. Which one is true with reference to Triggers?

71. What does referential integrity (also called relational integrity) prevent?

72. Which one must be specified in every DELETE statement?

73. ___________ is the highest level of a transaction isolation implemented by SQL Server.

74. A table has following values for its department field: marketing, production, production, sales, NULL, NULL, Marketing, Null What will the following query return: Select distinct(department) from employees

75. Which one is an invalid statement for manipulation of binary data?

76. Which of the following is not a control statement?

77. Which one is not a column property?

78. Does SQL Server support user-defined datatypes?

79. Which one is not a valid Arithmetic operator in SQL Server?

80. Consider the query: SELECT name FROM Student WHERE name LIKE '_a%'; Which names will be displayed?

81. State which of the following are true

82. Evaluate the following SQL statement: SELECT e.employee_id, (.15* e.salary) + (.5 * e.commission_pct) + (s.sales_amount * (.35 * e.bonus)) AS CALC_VALUE FROM employees e, sales s WHERE e.employee_id = s.emp_id; What will happen if all the parentheses are removed from the calculation?

83. What is the correct SQL syntax for selecting all the columns where the 'LastName' is alphabetically between (and including) 'Hansen' and 'Pettersen'?

84. Which is not (a) valid binary datatype in SQL Server?

85. Which ones are aggregate functions in SQL?

86. Which one is not a SQL operator?

87. Consider the following tables: Books ------ BookId BookName AuthorId SubjectId PopularityRating (the popularity of the book on a scale of 1 to 10) Language (such as French, English, German etc) Subjects --------- SubjectId Subject (such as History, Geography, Mathematics etc) Authors -------- AuthorId AuthorName Country What is the query to determine the names of the Authors who have written more than 1 book?

88. Consider the following tables: Books ------ BookId BookName AuthorId SubjectId PopularityRating (the popularity of the book on a scale of 1 to 10) Language (such as French, English, German etc) Subjects --------- SubjectId Subject (such as History, Geography, Mathematics etc) Authors -------- AuthorId AuthorName Country What is the query to determine how many books have been written on each subject. Displaying Name of Subject and count of the Books?

89. Consider the following table structure of students: rollno int name varchar(20) course varchar(20) What will be the query to display the courses in which the number of students enrolled is more than 5?

90. The IF UPDATE (column_name) parameter in a trigger definition will return TRUE in case of an INSERT statement being executed on the triggered table:

91. View the following Create statement: 1 Create table Pers 2(EmpNo Int not null, 3 EName Char not null, 4 Join Datetime not null, 5 Pay Smallmoney) Which line contains an error?

92. Which of the following are false for batches (batch commands)?

93. Examine the data in the EMPLOYEES table given below: LAST_NAME DEPARTMENT_ID SALARY ALLEN 10 3000 MILLER 20 1500 King 20 2200 Davis 30 5000 Which of the following Subqueries work?

94. Which query is valid?

95. Which operator is used for un-nesting the nested tuples and bags?

96. Which one is the correct syntax for resetting the space quota for directories in HDFS?

97. Which object is used by the RecordReader class for reading data from an InputSplit class?

98. Which one is the correct data type of the 'totalMB' element of the clusterMetrics object used in the YARN ResourceManager REST API?

99. Which are NOT the properties of the app (Application) object of NodeManager REST API?

100. Which Hadoop DFSAdmin command generates a list of DataNodes?