Create database in Cassandra

Data Distribution in Cassandra

Last Updated : 18 Nov, 2019

In this article we will discussed Data distribution in Cassandra and how data distributes over cluster. So, let's have a look. In Cassandra data distribution and replication go together. In Cassandra distribution and replication depending on the three thing such that partition key, key value and Token range. Cassandra Table: In this table there are two rows in which one row contains four columns and its values. 2nd row contains two columns (column 1 and column 3) and its values. In this table column 1 having the primary key.

Figure - Cassandra Table Now, let's take an example of how user data distributes over cluster.

E_id	E_name	E_sal
101	Ashish	90000
102	Aayush	95000
103	Rahul	70000
104	Abi	60000

Below given ring architecture of given four nodes has token range and each row has its own token id so, with the help of partitioner we will generate token values and assigned them and distribute over cluster accordingly.

Figure - Data Center with Random token range Token: Tokens are hash values and Murmur3 Hash Algorithm is use for hashing in Cassandra that partitioners use to determine where to store rows on each node in the ring. for Example: let's take random hash value for each row for given data in above table.

Partition key	Murmur3 Hash value
Ashish	1500
Aayush	-800
Rahul	-1500
Abi	700

Let's have a look for better understanding.

Figure - Example of Data Distribution in Cassandra Replication Factor: In Cassandra replication factor is very important which indicates the total number of replicas across the cluster. Let's take RF = 2 which simply means that there are two copies of each rows. There is no primary or master replica in Cassandra.

Figure - Example of data distribution when RF = 2

Create database in Cassandra

A

Ashish_rana

Improve

Article Tags :

DBMS
Apache

Similar Reads

CAST function in Cassandra

CAST function helps in Converts data from one data type to another data type in Cassandra. In Cassandra CAST function Supported in SELECT statements. lets have a look how we can used CAST function in select statement. SELECT CAST([fieldname] AS [data type]) FROM [table name] Basic function of CAST:

Data Manipulation in Cassandra

In this article, we will describe the following DML commands in Cassandra which help us to insert, update, delete, query data, etc. In CQL there are following data manipulation command. Letâ€™s discuss one by one. 1. Insert 2. Update 3. Delete 4. Batch Letâ€™s take an example: Table Name: Employee_info

Export and Import data in Cassandra

Prerequisite - Cassandra In this article, we are going to discuss how we can export and import data through cqlsh query. Let's discuss one by one. First, we are going to create table namely as Data in which id, firstname, lastname are the fields for sample exercise. Let's have a look. Table name: Da

Schema descriptions in Cassandra

In this article, we will discuss where we can use describe commands, how it will help to describe schema, also discuss how describe command is useful. Let's discuss one by one. Describe command is very helpful in CQL just because it gives the description of the newly created database, newly created

Create database in Cassandra

In this article, we are going to discuss how to create the database in Cassandra. so, for better understanding you can read "Introduction to Cassandra" article before creating a database in Cassandra. Step-1: login into cqlsh you can log in into the cqlsh using Cassandra default credential. Now, her

Data Backup and Restoration in Cassandra

In this article, we will discuss how we can Backup and Restore our data and also discuss how many ways we can restore our data in Cassandra. We can restore our data by using a snapshot and by using sstableloader utility and by using a nodetool refresh. Let's discuss one by one. First, we are going t

Inserting data using a CSV file in Cassandra

In this article, we will discuss how you can insert data into the table using a CSV file. And we will also cover the implementation with the help of examples. Let's discuss it one by one. Pre-requisite - Introduction to Cassandra Introduction :If you want to store data in bulk then inserting data fr

Inserting JSON data into a table in Cassandra

In this article, you will be able to understand how you can insert JSON data into a table in Cassandra and will discuss with the help of an example and then finally conclude the importance of JSON insertion. Let's discuss it one by one. Overview :It is a practical way than cqlsh to insert column and

Cassandra (NoSQL) Database

Recent Topics on Cassandra: Introduction Cassandra Architecture Cassandra Query Language Data Types Collection Data Types Functions in Cassandra Data Modelling and Designing Security Performance Monitoring Backup and Restore Data Misc Introduction Apache Cassandra (NoSQL) database Introduction to Ap

Configuring Clusters in Cassandra

Prerequisite - Monitoring cluster in Cassandra In this article, we will discuss how we can configure clusters setting in cassandra.yaml file. Also, we will cover some basic parts of cassandra.yaml file in which we can change the by default setting as per our requirements. Cluster : In Cassandra, a c