Programming FlashCards - Learn Coding Concepts

Hadoop Reducer

In Hadoop, the Reducer processes grouped data after the Map phase. It takes the output of the Mapper, groups it by key, and performs aggregation functions like sum or average to produce a final output.

Hadoop

Hadoop Group By

In Hadoop, 'group by' is used to aggregate data based on a specific key. It allows you to perform operations like counting, summing, or averaging on grouped data, making it essential for data analysis tasks.

Hadoop

Hadoop Formats

Understand how to define custom input and output formats in Hadoop for processing different data types. This allows for efficient data handling and processing in MapReduce jobs.

Hadoop

Output Formats

In Hadoop, output formats determine how the output data is written. Common formats include TextOutputFormat, SequenceFileOutputFormat, and AvroOutputFormat. Choosing the right format can optimize storage and processing efficiency.

Hadoop

Mappers & Reducers

In Hadoop, Mappers process input data into key-value pairs, while Reducers aggregate those pairs to produce final output. This paradigm is essential for handling large datasets efficiently. Each Mapper reads input splits and emits intermediate key-value pairs, which Reducers consume to perform aggregation.

Hadoop

Mappers and Reducers

In Hadoop, Mappers process input data and produce intermediate key-value pairs, while Reducers aggregate these pairs to produce final output. This example illustrates a word count application where Mappers count occurrences of words and Reducers sum these counts.

Hadoop

HDFS Architecture

Hadoop Distributed File System (HDFS) is designed to store large files across multiple machines. It uses a master/slave architecture where the NameNode manages metadata and DataNodes store the actual data blocks.

Hadoop

Hadoop MapReduce

MapReduce is a programming model for processing large data sets with a distributed algorithm on a cluster. It allows for parallel processing of data across many nodes, optimizing performance and scalability.

Hadoop

Quota Monitoring Tools

Utilize Hadoop's built-in tools to track and monitor directory quotas, helping administrators identify and manage resource allocation in distributed file systems.

Hadoop

HDFS Quota Management

Configure and enforce storage space and namespace quotas for HDFS directories to control resource usage and prevent single directories from consuming excessive cluster resources.