Cloudera Hadoop Developer Certification Questions and Answer (Dumps and Practice Questions)

Question :

Is there anyway in the MapReduce model that reducers communicate with each other in Hadoo framework ?


1. Yes, using JobConf confguration object it is possible
2. Using distributed cache it is possible
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4. No, each reducers runs independently and in isolation.




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Question :

What is true about combiner ?


1. Combiner does the local aggregation of data, thereby allowing the number of mappers to process input data faster.
2. Combiner does the local aggregation of data, thereby reducing the number of mappers that need to run.
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Question :

in 3 mappers and 2 reducers how many distinct copy operations will be there in the sort or shuffle phase


1. 3
2. 2
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4. 5



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Explanation: Since each mappers intermediate output will go to every reducers

Related Questions

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Question :We have extracted the data from
MySQL backend database of QuickTechie.com
website and stored in the
Hive table called MAINPROFILE as shown in image
with the sample data and also shown column datatype.

As this table is created from the data
which is already stored in a
warehouse directory of Hive.

As this table is created from the data
which is already stored in a
warehouse directory of Hive.
Select the correct MapReduce
code which simulate
the following Query in a single file.

SELECT FIRST_NAME,CITY,LAST_NAME
FROM MAINPROFILE
ORDER BY CITY;

1. 1
2. 2
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4. 4


Question : We have extracted the data from
MySQL backend database of QuickTechie.com
website and stored in the
Hive table called MAINPROFILE as shown in image
with the sample data and also shown column datatype.

As this table is created from the data
which is already stored in a
warehouse directory of Hive.

As this table is created from the data
which is already stored in a
warehouse directory of Hive.
Select the correct MapReduce
code which simulate
the following Query in a single file.

SELECT DISTINCT FIRST_NAME
FROM MAINPROFILE
WHERE CITY != "MUMBAI"


1. 1
2. 2
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4. 4


Question : Given this data file: MAIN.PROFILE.log
1 Feeroz Fremon
2 Jay Jaipur
3 Amit Alwar
10 Banjara Banglore
11 Jayanti Jaipur
101 Sehwag Shimla

You write the following Pig script:
users = LOAD 'MAIN.PROFILE.log' AS (userid, username, city);
sortedusers = ORDER users BY id DESC;
DUMP sortedusers;

The output looks like this:
(3,Amit , Alwar)
(2,Jayanti, Jaipur)
(11,Jane, Jaipur)
(101,Sehwag, Shimla)
(10,Banjara, Banglore)
(1,Feeroz, Fremon)


Choose one line which, when modified as shown, would result in the output being displayed in descending ID order


1. DUMP sortedusers;
2. users = LOAD 'MAIN.PROFILE.log' AS (userid:int, usernamename,city);
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Question : QuickTechie Inc has a log file which is tab-delimited text file. File contains two columns username and loginid
You want use an InputFormat that returns the username as the key and the loginid as the value. Which of the following
is the most appropriate InputFormat should you use?


1. KeyValueTextInputFormat
2. MultiFileInputFormat
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4. SequenceFileInputFormat
5. TextInputFormat



Question : Apache Sqoop(TM) is a tool designed for efficiently transferring bulk data between Apache Hadoop and structured datastores such as relational
databases. You use Sqoop to import a table from your RDBMS into HDFS. You have configured to use 3 mappers in Sqoop, to controll the number of
parallelism and memory in use. Once the table import is finished, you notice that total 7 Mappers have run, there are 7 output files in HDFS,
and 4 of the output files is empty. Why?


1. The table does not have a numeric primary key
2. The table does not have a primary key
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4. The table does not have a unique key




Question : In the QuickTechie Inc Hadoop cluster you have defined block size as MB. The input file contains MB of valid input data
and is loaded into HDFS. How many map tasks should run without considering any failure of MapTask during the execution of this job?



1. 1
2. 2
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4. 4