Cassandra Interview Questions & Answers

Q.1 Define replication factor.

Ans: 

The data in a node undergoes replication. The data is copied from one node to another to ensure fault tolerance. The replication factor is the number of copies of the data that are sent to different nodes.

Q.2 Define replication strategy.

Ans: 

These strategies define the technique how the replicas are placed in a cluster. There are mainly two types of Replication Strategy:
Simple strategy
Network Topology Strategy

Q.3 Name some features of Apache Cassandra.

Ans: 

Cassandra has following features:
High Scalability
High fault tolerant
Flexible Data storage
Easy data distribution
Tunable Consistency
Efficient Wires
Cassandra Query Language

Q.4 Name different types of NoSQL database.

Ans: 

There are four types of NoSQL Database:
Key Value Store type database
Document Store type database
Column STore type database
Graph Database

Q.5 Define NoSQL Database.

Ans: 

It is a database that deals with the non-relational database. It is referred to as a Not only SQL database. It provides a mechanism to store and retrieve the different type of data that includes images, sounds etc.

Q.6 Give key features of any NoSQL database.

Ans: 

The features of NoSQL Database are:

Schema Agnostic
AutoSharding and Elasticity
Highly Distributable
Easily Scalable
Integrated Caching

Q.7 Define a column family.

Ans: 

A keyspace contains many column families. They basically represent the table. Furthermore, it basically defines titles or application specific tables.

Q.8 Define Node.

Ans: 

A node represents a system that is a part of a cluster. It is the main area in which data is stored.

Q.9 Define data centre.

Ans: 

Data centre consists of the all the data that is contained in Cluster.

Q. 10 What is a Keyspace?

Ans: 

Keyspace is the outermost storage unit in a node. It contains many column families.

Q.11 Give the data storage units in Cassandra.

Ans: 

The storage units are:

Cluster
Node
Keyspace
Column Family
Row
Column

Q.12 Give the name of some components of Cassandra.

Ans: 

Some components of Cassandra are:

Table
Node
Cluster
Data Centre
Memtable
SSTable
Commit log
Bloom Filter

Q.13 Tell something about the query language used in Cassandra Database.

Ans: 

Cassandra query language is used for Cassandra Database. It is an interface that a user uses to access the database. It basically is a communication medium. All the operations are carried out from this panel.

Q.14 Give some advantages of Cassandra.

Ans: 

These are the advantages if Cassandra:

Since data can be replicated to several nodes, Cassandra is fault tolerant.

Cassandra can handle a large set of data.

Cassandra provides high scalability.

Q.15 Define Cassandra.

Ans: 

Cassandra is a free and open source distributed database management system. It is used to handle a large amount of data with a high fault tolerance and high scalability.

Q. 16 Who developed Cassandra and in which language?

Ans: 

Avinash Lakshman and Prashant Malik developed Cassandra using Java. Later Apache took it under it for further development.

Q.17 What is the main objective of creating Cassandra?

Ans: 

The main objective of Cassandra is to handle a large amount of data. Furthermore, the objective also ensures fault tolerance with the swift transfer of data.

Q.18 Define data replication.

Ans: 

Data replication is an operation in which data from one node is copied to different nodes in the cluster. This operation ensures redundancy and fault tolerance in the database. The replication factor decides the number of copies and the replication strategy decides the nodes in which the data is copied.

Q.19 Define commit log.

Ans: 

It is a mechanism that is used to recover data in case the database crashes. Every operation that is carried out is saved in the commit log. Using this the data can be recovered.

Q.20 Define composite key.

Ans: 

Composite keys include row key and column name. They are used to define column family with a concatenation of data of different type.

Q.21 Define consistency.

Ans: 

This is a technique to synchronize and update rows of Cassandra data and it replica.

Q.22 Name the types of tunable consistency.

Ans: 

Cassandra support two types of consistencies:

Eventual Consistency

Strong Consistency

Q.23 Describe Memtable.

Ans: 

Memtables are basically a cache space containing content in key and column format.

Q.24 Define SSTable.

Ans: 

SSTable is Sorted String Table. It is a data file that accepts regular Mem Tables.

Q.25 Name the management tools in Cassandra.

Ans: 

These are the management tools used in Cassandra.

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