Hadoop Interview Questions and Answers
Question - 11 : - Name some of the major organizations globally that use Hadoop?
Answer - 11 : -
Some of the major organizations globally that are using Hadoop as a Big Data tool are as follows:
- Netflix
- Uber
- The National Security Agency (NSA) of the United States
- The Bank of Scotland
- Twitter
Question - 12 : - What are the real-time industry applications of Hadoop?
Answer - 12 : -
Hadoop, well known as Apache Hadoop, is an open-source software platform for scalable and distributed computing of large volumes of data. It provides rapid, high-performance, and cost-effective analysis of structured and unstructured data generated on digital platforms and within the organizations. It is used across all departments and sectors today.
Here are some of the instances where Hadoop is used:
- Managing traffic on streets
- Streaming processing
- Content management and archiving emails
- Processing rat brain neuronal signals using a Hadoop computing cluster
- Fraud detection and prevention
- Advertisements targeting platforms are using Hadoop to capture and analyze clickstream, transaction, video, and social media data
- Managing content, posts, images, and videos on social media platforms
- Analyzing customer data in real-time for improving business performance
- Public sector fields such as intelligence, defense, cyber security, and scientific research
- Getting access to unstructured data such as output from medical devices, doctor’s notes, lab results, imaging reports, medical correspondence, clinical data, and financial data
Question - 13 : - What is HBase?
Answer - 13 : -
Apache HBase is a distributed, open-source, scalable, and multidimensional database of NoSQL. HBase is based on Java; it runs on HDFS and offers Google-Bigtable-like abilities and functionalities to Hadoop. Moreover, HBase’s fault-tolerant nature helps in storing large volumes of sparse datasets. HBase gets low latency and high throughput by offering faster access to large datasets for read or write functions.
Question - 14 : - What is a Combiner?
Answer - 14 : -
A combiner is a mini version of a reducer that is used to perform local reduction processes. The mapper sends the input to a specific node of the combiner, which later sends the respective output to the reducer. It also reduces the quantum of the data that needs to be sent to the reducers for improving the efficiency of MapReduce.
Question - 15 : - Is it okay to optimize algorithms or codes to make them run faster? If yes, why?
Answer - 15 : -
Yes, it is always suggested and recommended to optimize algorithms or codes to make them run faster. The reason for this is that optimized algorithms are pretrained and have an idea about the business problem. The higher the optimization, the higher the speed.
Question - 16 : - What is Apache Spark?
Answer - 16 : -
Apache Spark is an open-source framework engine known for its speed and ease of use in Big Data processing and analysis. It also provides built-in modules for graph processing, machine learning, streaming, SQL, etc. The execution engine of Apache Spark supports in-memory computation and cyclic data flow. It can also access diverse data sources such as HBase, HDFS, Cassandra, etc.
Question - 17 : - Can you list the components of Apache Spark?
Answer - 17 : -
The components of the Apache Spark framework are as follows:
- Spark Core Engine
- Spark Streaming
- Mllib
- GraphX
- Spark SQL
- Spark R
One thing that needs to be noted here is that it is not necessary to use all Spark components together. But yes, the Spark Core Engine can be used with any of the other components listed above.
Question - 18 : - What are the differences between Hadoop and Spark?
Answer - 18 : -
| Criteria | Hadoop | Spark |
| Dedicated storage | HDFS | None |
| Speed of processing | Average | Excellent |
| Libraries | Separate tools available | Spark Core, SQL, Streaming, MLlib, and GraphX |
Question - 19 : - What is Apache Hive?
Answer - 19 : -
Apache Hive is an open-source tool or system in Hadoop; it is used for processing structured data stored in Hadoop. Apache Hive is the system responsible for facilitating analysis and queries in Hadoop. One of the benefits of using Apache Hive is that it helps SQL developers to write Hive queries almost similar to the SQL statements that are given for analysis and querying data.
Question - 20 : - Does Hive support multiline comments?
Answer - 20 : -
No. Hive does not support multiline comments. It only supports single-line comments as of now.