Hortonworks HDPCD Exam Questions Instant Access

Question 1

For each input key-value pair, mappers can emit:

AAs many intermediate key-value pairs as designed. There are no restrictions on the types of those key-value pairs (i.e., they can be heterogeneous).

BAs many intermediate key-value pairs as designed, but they cannot be of the same type as the input key-value pair.

COne intermediate key-value pair, of a different type.

DOne intermediate key-value pair, but of the same type.

EAs many intermediate key-value pairs as designed, as long as all the keys have the same types and all the values have the same type.

Answer : E

Mapper maps input key/value pairs to a set of intermediate key/value pairs.

Maps are the individual tasks that transform input records into intermediate records. The transformed intermediate records do not need to be of the same type as the input records. A given input pair may map to zero or many output pairs.

Question 2

Identify the MapReduce v2 (MRv2 / YARN) daemon responsible for launching application containers and monitoring application resource usage?

AResourceManager

BNodeManager

CApplicationMaster

DApplicationMasterService

ETaskTracker

FJobTracker

Answer : B

Question 3

How are keys and values presented and passed to the reducers during a standard sort and shuffle phase of MapReduce?

AKeys are presented to reducer in sorted order; values for a given key are not sorted.

BKeys are presented to reducer in sorted order; values for a given key are sorted in ascending order.

CKeys are presented to a reducer in random order; values for a given key are not sorted.

DKeys are presented to a reducer in random order; values for a given key are sorted in ascending order.

Answer : A

Reducer has 3 primary phases:

1. Shuffle

The Reducer copies the sorted output from each Mapper using HTTP across the network.

2. Sort

The framework merge sorts Reducer inputs by keys (since different Mappers may have output the same key).

The shuffle and sort phases occur simultaneously i.e. while outputs are being fetched they are merged.

SecondarySort

To achieve a secondary sort on the values returned by the value iterator, the application should extend the key with the secondary key and define a grouping comparator. The keys will be sorted using the entire key, but will be grouped using the grouping comparator to decide which keys and values are sent in the same call to reduce.

3. Reduce

In this phase the reduce(Object, Iterable, Context) method is called for each <key, (collection of values)> in the sorted inputs.

The output of the reduce task is typically written to a RecordWriter via TaskInputOutputContext.write(Object, Object).

The output of the Reducer is not re-sorted.

Question 4

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 5

Which best describes how TextInputFormat processes input files and line breaks?

AInput file splits may cross line breaks. A line that crosses file splits is read by the RecordReader of the split that contains the beginning of the broken line.

BInput file splits may cross line breaks. A line that crosses file splits is read by the RecordReaders of both splits containing the broken line.

CThe input file is split exactly at the line breaks, so each RecordReader will read a series of complete lines.

DInput file splits may cross line breaks. A line that crosses file splits is ignored.

EInput file splits may cross line breaks. A line that crosses file splits is read by the RecordReader of the split that contains the end of the broken line.

Answer : A

Question 6

Review the following data and Pig code:

What command to define B would produce the output (M,62,95l02) when invoking the DUMP operator on B?

AB = FILTER A BY (zip = = '95102' AND gender = = M');

BB= FOREACH A BY (gender = = 'M' AND zip = = '95102');

CB = JOIN A BY (gender = = 'M' AND zip = = '95102');

DB= GROUP A BY (zip = = '95102' AND gender = = 'M');

Answer : A

Question 7

Which HDFS command uploads a local file X into an existing HDFS directory Y?

Ahadoop scp X Y

Bhadoop fs -localPut X Y

Chadoop fs-put X Y

Dhadoop fs -get X Y

Answer : C

Hortonworks Data Platform Certified Developer HDPCD Exam Questions