Mapr (HP) Hadoop Developer Certification Questions and Answers (Dumps and Practice Questions)

Question : Which of the following are MapReduce processing phases ?

1. Map
2. Reduce
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4. Sort
5. 1 and 2 only

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Mapreduce Consists of two phases: Map, and then Reduce
- Between the two is a stage known as the shuffle and sort





Question : What is true about HDFS ?


1. HDFS is based of Google File System
2. HDFS is written in Java
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4. All above are correct

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HDFS is a filesystem written in Java
- Based on Google GFS
Sits on top of a native filesystem
ext3, xfs etc







Question : What are sequence files and why are they important?


1. Sequence files are a type of the file in the Hadoop framework that allow data to be sorted
2. Sequence files are binary format files that are compressed and are splitable.
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4. All of the above

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Hadoop is able to split data between different nodes gracefully while keeping data compressed. The sequence files have special markers that allow data to be split across entire
cluster
The sequence file format supported by Hadoop breaks a file into blocks and then optionally compresses the blocks in a splittable way
It is also worth noting that, internally, the temporary outputs of maps are stored using SequenceFile. The SequenceFile provides a Writer, Reader and Sorter classes for writing,
reading and sorting respectively.
SequenceFiles are flat files consisting of binary key value pairs. And that are compressed and are splitable.
Essentially there are 3 different formats for SequenceFiles depending on the CompressionType specified
It is extensively used in MapReduce as input/output formats. It is also worth noting that, internally; the temporary outputs of maps are stored using SequenceFile.
The SequenceFile provides a Writer, Reader and Sorter classes for writing, reading and sorting respectively.

SequenceFiles are flat files consisting of binary key value pairs. And that are compressed and are splitable.
Essentially there are 3 different formats for SequenceFiles depending on the CompressionType specified
It is extensively used in MapReduce as input/output formats. It is also worth noting that, internally, the temporary outputs of maps are stored using SequenceFile.
The SequenceFile provides a Writer, Reader and Sorter classes for writing, reading and sorting respectively.

Related Questions

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Question : Which of the following class is responsible for committing output of the Job


1. OutputFormat

2. Job

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4. Context


Question : You are running a word count MapReduce job. But somehow job is not successfully completed and fails after processing % of reducer class.
Which statement is correct in this case?



1. It will generate 90% output only

2. It will only generate _logs directory as output

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4. 1,2

5. 2,3



Question : Select correct statements


1. RecordWriter writes the key-value pairs to the output files

2. The TextOutputFormat.LineRecordWriter implementation requires a java.io.DataOutputStream
object to write the key-value pairs to the HDFS/MapR-FS file system

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4. 1,2
5. 1,2,3


Question : Default separator between key and value is tab

1. True
2. False


Question : Select correct statement regarding Reducer


1. Each reducer will take , partitioned generated and decided by Hadoop framework as an input. And processes one iterable list of key-value
pairs at a time.

2. Reducer generates output as a patitioned file in a format part-r-0000x

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4. 1,2
5. 1,2,3


Question : Select correct statement regarding input key-values of a Mapper class



1. Whatever you have configured as an input key and value type must match in the Mapper class

2. Input key and value type defined on the Mapper class level must match in map() method arguments

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4. 1,2
5. 1,2,3