How do you explain MapReduce?

What is MapReduce? MapReduce is a software framework for processing (large1) data sets in a distributed fashion over a several machines. The core idea behind MapReduce is mapping your data set into a collection of pairs, and then reducing over all pairs with the same key.

What do you always have to specify for a MapReduce job?

The main configuration parameters which users need to specify in “MapReduce” framework are: Job’s input locations in the distributed file system. Job’s output location in the distributed file system. JAR file containing the mapper, reducer and driver classes.

What are the basic parameters of a reducer?

The four basic parameters of a reducer are Text, IntWritable, Text, IntWritable. The first two represent intermediate output parameters and the second two represent final output parameters.

What is the use of MapReduce?

MapReduce is an emerging programming framework for data-intensive applications proposed by Google. MapReduce borrows ideas from functional programming [12], where the programmer defines Map and Reduce tasks to process large sets of distributed data.

Is MapReduce still used?

Why MapReduce Is Still A Dominant Approach For Large-Scale Machine Learning. Google stopped using MapReduce as their primary big data processing model in 2014. Meanwhile, development on Apache Mahout had moved on to more capable and less disk-oriented mechanisms that incorporated the full map and reduce capabilities.

What are the phases of MapReduce?

MapReduce program executes in three stages, namely map stage, shuffle stage, and reduce stage. Map stage − The map or mapper’s job is to process the input data.

What are the four basic parameters of a mapper?

The basic parameters of a mapper function are LongWritable, text, text and IntWritable.

What are the core methods of a reducer?

1)setup () – This method of the reducer is used for configuring various parameters like the input data size, distributed cache, heap size, etc. 2)reduce () it is heart of the reducer which is called once per key with the associated reduce task.

What is MapReduce and how it works?

A MapReduce job usually splits the input data-set into independent chunks which are processed by the map tasks in a completely parallel manner. Minimally, applications specify the input/output locations and supply map and reduce functions via implementations of appropriate interfaces and/or abstract-classes.

What is difference between yarn and MapReduce?

YARN is a generic platform to run any distributed application, Map Reduce version 2 is the distributed application which runs on top of YARN, Whereas map reduce is processing unit of Hadoop component, it process data in parallel in the distributed environment.

How many interview questions are there for MapReduce?

As it deals with processing of data it is likely to be asked in Hadoop MapReduce Interview Questions and Answers. So in this section, we covered 60 MapReduce interview questions and answers framed by our company expert.

How does the map function work in an interview?

The map function takes up the dataset, further converting it by breaking individual elements into tuples. This MapReduce Interview Questions blog consists of some of the sample interview questions that are asked by professionals.

What are the best interview questions for Hadoop?

These Hadoop MapReduce Interview Questions and Answers are as per the latest trend followed in an interview. A Proper care has been taken while answering these Hadoop MapReduce Interview Questions. So we can provide you with the best question and their answer.

Which is an example of the working of MapReduce?

Illustrate a simple example of the working of MapReduce. Let’s take a simple example to understand the functioning of MapReduce. However, in real-time projects and applications, this is going to be elaborate and complex as the data we deal with Hadoop and MapReduce is extensive and massive.