Hortonworks HDPCD Exam Practice Test Instant Access

Question 1

You want to understand more about how users browse your public website, such as which pages they visit prior to placing an order. You have a farm of 200 web servers hosting your website. How will you gather this data for your analysis?

AIngest the server web logs into HDFS using Flume.

BWrite a MapReduce job, with the web servers for mappers, and the Hadoop cluster nodes for reduces.

CImport all users' clicks from your OLTP databases into Hadoop, using Sqoop.

DChannel these clickstreams inot Hadoop using Hadoop Streaming.

ESample the weblogs from the web servers, copying them into Hadoop using curl.

Answer : A

Question 2

Which one of the following statements is FALSE regarding the communication between DataNodes and a federation of NameNodes in Hadoop 2.2?

AEach DataNode receives commands from one designated master NameNode.

BDataNodes send periodic heartbeats to all the NameNodes.

CEach DataNode registers with all the NameNodes.

DDataNodes send periodic block reports to all the NameNodes.

Answer : A

Question 3

You are developing a MapReduce job for sales reporting. The mapper will process input keys representing the year (IntWritable) and input values representing product indentifies (Text).

Indentify what determines the data types used by the Mapper for a given job.

AThe key and value types specified in the JobConf.setMapInputKeyClass and JobConf.setMapInputValuesClass methods

BThe data types specified in HADOOP_MAP_DATATYPES environment variable

CThe mapper-specification.xml file submitted with the job determine the mapper's input key and value types.

DThe InputFormat used by the job determines the mapper's input key and value types.

Answer : D

The input types fed to the mapper are controlled by the InputFormat used. The default input format, 'TextInputFormat,' will load data in as (LongWritable, Text) pairs. The long value is the byte offset of the line in the file. The Text object holds the string contents of the line of the file.

Note: The data types emitted by the reducer are identified by setOutputKeyClass() andsetOutputValueClass(). The data types emitted by the reducer are identified by setOutputKeyClass() and setOutputValueClass().

By default, it is assumed that these are the output types of the mapper as well. If this is not the case, the methods setMapOutputKeyClass() and setMapOutputValueClass() methods of the JobConf class will override these.

Question 4

What does the following WebHDFS command do?

Curl -1 -L ''http://host:port/webhdfs/v1/foo/bar?op=OPEN''

AMake a directory /foo/bar

BRead a file /foo/bar

CList a directory /foo

DDelete a directory /foo/bar

Answer : B

Question 5

Indentify which best defines a SequenceFile?

AA SequenceFile contains a binary encoding of an arbitrary number of homogeneous Writable objects

BA SequenceFile contains a binary encoding of an arbitrary number of heterogeneous Writable objects

CA SequenceFile contains a binary encoding of an arbitrary number of WritableComparable objects, in sorted order.

DA SequenceFile contains a binary encoding of an arbitrary number key-value pairs. Each key must be the same type. Each value must be the same type.

Answer : D

SequenceFile is a flat file consisting of binary key/value pairs.

There are 3 different SequenceFile formats:

Uncompressed key/value records.

Record compressed key/value records - only 'values' are compressed here.

Block compressed key/value records - both keys and values are collected in 'blocks' separately and compressed. The size of the 'block' is configurable.

Question 6

You have the following key-value pairs as output from your Map task:

(the, 1)

(fox, 1)

(faster, 1)

(than, 1)

(the, 1)

(dog, 1)

How many keys will be passed to the Reducer's reduce method?

ASix

BFive

CFour

DTwo

EOne

FThree

Answer : B

Only one key value pair will be passed from the two (the, 1) key value pairs.

Question 7

Examine the following Pig commands:

Which one of the following statements is true?

AThe SAMPLE command generates an 'unexpected symbol' error

BEach MapReduce task will terminate after executing for 0.2 minutes

CThe reducers will only output the first 20% of the data passed from the mappers

DA random sample of approximately 20% of the data will be output

Answer : D

Hortonworks Data Platform Certified Developer HDPCD Exam Practice Test