Hadoop HBase Quiz - MCQ Questions and Answers

Introduction

Welcome to this beginner-level quiz on Hadoop HBase, a distributed, scalable, big data store. HBase is a NoSQL database that runs on top of the Hadoop Distributed File System (HDFS) and provides real-time read/write access to large datasets.

This quiz contains 20 multiple-choice questions designed to test your understanding of HBase’s key concepts, architecture, and commands. Each question is followed by an explanation to help you learn more effectively.

Take your time with each question; don’t worry if you get some wrong. The goal is to learn and improve your understanding of HBase. Good luck!

1. What type of database is HBase?

a) Relational Database

b) NoSQL Database

c) Graph Database

d) Document Store

Answer:

b) NoSQL Database

Explanation:

HBase is a NoSQL database that provides a distributed, scalable big data store. It is designed to handle large amounts of unstructured data across many servers.

2. Which of the following is the primary data model of HBase?

a) Column Family

b) Key-Value Pair

c) Document

d) Graph

Answer:

a) Column Family

Explanation:

HBase is built on the concept of a column family data model, where data is stored in tables that consist of rows and column families.

3. HBase is built on top of which file system?

a) NTFS

b) HDFS

c) FAT32

d) ext4

Answer:

b) HDFS

Explanation:

HBase runs on top of the Hadoop Distributed File System (HDFS), which provides the necessary scalability and fault tolerance for storing large datasets.

4. What is the primary use case of HBase?

a) Online Transaction Processing (OLTP)

b) Real-time analytics on large datasets

c) Storing multimedia files

d) Document management

Answer:

b) Real-time analytics on large datasets

Explanation:

HBase is primarily used for real-time analytics on large datasets. It provides fast read and write access, making it suitable for applications that require quick access to vast amounts of data.

5. What is the default programming language used for interacting with HBase?

a) SQL

b) Java

c) Python

d) C++

Answer:

b) Java

Explanation:

HBase is primarily written in Java, and most of its APIs and client interactions are also Java-based.

6. Which command is used to create a table in HBase?

a) CREATE

b) ADD TABLE

c) CREATE TABLE

d) NEW TABLE

Answer:

c) CREATE TABLE

Explanation:

The CREATE TABLE command is used in HBase to create a new table with specified column families.

7. What is a “region” in HBase?

a) A part of a column family

b) A subset of rows in a table

c) A cluster of HBase nodes

d) A section of HDFS

Answer:

b) A subset of rows in a table

Explanation:

A region in HBase is a subset of rows in a table. Each region is served by one region server, and the table’s data is automatically split into regions as it grows.

8. What is the role of a RegionServer in HBase?

a) To manage and store data for a region

b) To load balance requests across the cluster

c) To serve as the master node

d) To manage HDFS storage

Answer:

a) To manage and store data for a region

Explanation:

In HBase, a RegionServer is responsible for managing and serving the data for one or more regions. It handles read and write requests for these regions and communicates with HDFS to store the data.

9. Which component in HBase assigns regions to RegionServers?

a) RegionManager

b) Master Server

c) Zookeeper

d) HDFS

Answer:

b) Master Server

Explanation:

The HBase Master Server is responsible for assigning regions to RegionServers, ensuring load balancing and the proper functioning of the HBase cluster.

10. What is the purpose of Zookeeper in an HBase cluster?

a) To manage HDFS storage

b) To manage the configuration of HBase tables

c) To coordinate and manage the distributed environment

d) To store backup data

Answer:

c) To coordinate and manage the distributed environment

Explanation:

Zookeeper is used in an HBase cluster to coordinate and manage the distributed environment, including maintaining configuration information, providing distributed synchronization, and ensuring that the system remains consistent.

11. What is the default block size in HBase?

a) 32 KB

b) 64 KB

c) 128 MB

d) 64 MB

Answer:

d) 64 MB

Explanation:

The default block size in HBase is 64 MB, which determines how much data is stored in a single block in HDFS.

12. Which command is used to delete a table in HBase?

a) REMOVE TABLE

b) DELETE TABLE

c) DROP TABLE

d) ERASE TABLE

Answer:

c) DROP TABLE

Explanation:

The DROP TABLE command is used to delete a table in HBase. However, the table must be disabled before it can be dropped.

13. What is an HBase “row key”?

a) A unique identifier for a row in a table

b) A key that maps to multiple rows

c) A unique identifier for a column family

d) A key that maps to multiple columns

Answer:

a) A unique identifier for a row in a table

Explanation:

A row key in HBase is a unique identifier for a row in a table. It allows quick access to the row’s data and is used for efficient data retrieval.

14. What is an HBase “snapshot”?

a) A backup of a region

b) A point-in-time copy of a table

c) A log of all operations performed on a table

d) A copy of the HDFS configuration

Answer:

b) A point-in-time copy of a table

Explanation:

A snapshot in HBase is a point-in-time copy of a table. It allows you to create backups and restore tables to a specific state without downtime.

15. Which of the following is true about HBase tables?

a) They have a fixed schema

b) They are schema-less

c) They have a partially defined schema

d) They require an external schema file

Answer:

c) They have a partially defined schema

Explanation:

HBase tables have a partially defined schema, where the column families are predefined, but the columns themselves are dynamic and can vary between rows.

16. How do you disable a table in HBase before deletion?

a) DISABLE TABLE

b) DROP TABLE

c) DELETE TABLE

d) REMOVE TABLE

Answer:

a) DISABLE TABLE

Explanation:

The DISABLE TABLE command is used to disable a table in HBase before it can be dropped or deleted.

17. What does the SCAN command do in HBase?

a) Retrieves a specific row

b) Lists all tables

c) Iterates over rows in a table

d) Deletes rows from a table

Answer:

c) Iterates over rows in a table

Explanation:

The SCAN command in HBase is used to iterate over rows in a table, allowing you to retrieve and filter data across multiple rows.

18. How is data in an HBase table organized?

a) By columns

b) By rows and column families

c) By files

d) By blocks

Answer:

b) By rows and column families

Explanation:

Data in an HBase table is organized by rows and column families, where each row contains data in multiple columns grouped into families.

19. What is a “timestamp” in HBase used for?

a) Identifying a row uniquely

b) Versioning data

c) Sorting rows

d) Managing regions

Answer:

b) Versioning data

Explanation:

A timestamp in HBase is used to version data. Each cell in HBase can store multiple versions of data, with the timestamp identifying each version.

20. How can you add data to an HBase table?

a) INSERT

b) ADD

c) PUT

d) SAVE

Answer:

c) PUT

Explanation:

The PUT command in HBase is used to add data to a table. It allows you to insert or update a specific row with new values.

Conclusion

We hope this quiz has helped you better understand Hadoop HBase and its key concepts. Whether you're working with large datasets, managing real-time data access, or exploring HBase's advanced features, understanding these basics is essential for effective use. Keep practicing and deepening your knowledge of HBase to master this powerful NoSQL database. Good luck with your continued learning journey!