Skip to main content

Big Data: Top Hadoop Interview Questions (4 of 5)

Hadoop,Jobs,Career
1) What is MAP Reduce program?
- You need to give actual steps in this program
- You have to write scripts and codes

2) What is MAPReduce?
-Mapreduce is a data processing model
-It is combination of 2 parts. One is Mappers and the other one is Reducers

3)What will happen in Mapping phase?
It takes the input data, and feeds each data element into the mapper

4)What is the function of Reducer?
The reducer process all outputs from mapper and arrives at a final result

5)What kind of input required for Mapreduce?
It should be structured in the form of (Key,Value) pairs

6)What is HDFS?
HDFS is a file system designed for large-scale data processing under frameworks such as MapReduce.

7) Is HDFS like UNIX?
No, but commands in HDFS works similarly to UNIX

8) What is Simple file command?
hadoop fs -ls

9) How to copy data into HDFS file system?

Copy a file into HDFS from local system

10) What is default working directory in HDFS?
/user/$USER
$USER ==> Your login user name

Comments

Popular posts from this blog

Four Tableau products a quick review and explanation

I want to share you what are the Products most popular.

Total four products. Read the details below.

Tableau desktop-(Business analytics anyone can use) - Tableau  Desktop  is  based  on  breakthrough technology  from  Stanford  University  that  lets  you drag & drop to analyze data. You can connect to  data in a few clicks, then visualize and create interactive dashboards with a few more.

We’ve done years of research to build a system that supports people’s natural  ability  to  think visually. Shift fluidly between views, following your natural train of thought. You’re not stuck in wizards or bogged down writing scripts. You just create beautiful, rich data visualizations.  It's so easy to use that any Excel user can learn it. Get more results for less effort. And it’s 10 –100x faster than existing solutions.

Tableau server
Tableau  Server  is  a  business  intelligence  application  that  provides  browser-based  analytics anyone can use. It’s a rapid-fire alternative to th…

The Sqoop in Hadoop story to process structural data

Why Sqoop you need while working on Hadoop-The Sqoop and its primary reason is to import data from structural data sources such as Oracle/DB2 into HDFS(also called Hadoop file system).
To our readers, I have collected a good video from Edureka which helps you to understand the functionality of Sqoop.

The comparison between Sqoop and Flume

The Sqoop the word came from SQL+Hadoop Sqoop word came from SQL+HADOOP=SQOOP. And Sqoop is a data transfer tool. The main use of Sqoop is to import and export the large amount of data from RDBMS to HDFS and vice versa. List of basic Sqoop commands Codegen- It helps to generate code to interact with database records.Create-hive-table- It helps to Import a table definition into a hiveEval- It helps to evaluateSQL statement and display the resultsExport-It helps to export an HDFS directory into a database tableHelp- It helps to list the available commandsImport- It helps to import a table from a database to HDFSImport-all-tables- It helps to import tables …

Different Types Of Payment Cards

The Credit Card (Shopping): The purpose o this card is to buy any item withing the limit prescribed by banks to cardholder. These cards can have both Magnetic stripe and Chip cards. 
Now a days all banks are issuing credit cards with CHIP and PIN. After entering the PIN by cardholder, then transaction starts for further processing.

The debit (ATM, Cash) card is a relatively new method of payment. It is different from a credit card because the debit cardholder pays with the money available in their bank account, which is debited immediately in real time. A debit card seems to be more dangerous compared to a credit card because the debit card is directly linked to the bank checking account and usually allows ATM cash withdrawals.

On the other hand, it is more protected by the required two-factor authentication (PIN number plus card itself). The real dangerous element of many branded debit cards is that they can be processed as credit cards, without entering the PIN.

The Gift card
is simila…