Book Image

Learning Neo4j 3.x - Second Edition

By : Jerome Baton
Book Image

Learning Neo4j 3.x - Second Edition

By: Jerome Baton

Overview of this book

Neo4j is a graph database that allows traversing huge amounts of data with ease. This book aims at quickly getting you started with the popular graph database Neo4j. Starting with a brief introduction to graph theory, this book will show you the advantages of using graph databases along with data modeling techniques for graph databases. You'll gain practical hands-on experience with commonly used and lesser known features for updating graph store with Neo4j's Cypher query language. Furthermore, you'll also learn to create awesome procedures using APOC and extend Neo4j's functionality, enabling integration, algorithmic analysis, and other advanced spatial operation capabilities on data. Through the course of the book you will come across implementation examples on the latest updates in Neo4j, such as in-graph indexes, scaling, performance improvements, visualization, data refactoring techniques, security enhancements, and much more. By the end of the book, you'll have gained the skills to design and implement modern spatial applications, from graphing data to unraveling business capabilities with the help of real-world use cases.
Table of Contents (24 chapters)
Title Page
Credits
About the Authors
Acknowledgement
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Concepts


In a causal cluster, there can be two categories of servers. Core servers are the most important over read replica servers, as replicas are disposable and can be either added or removed during the scaling of the cluster. Let's go through their roles.

Core servers

Core servers are the most important servers of a cluster. The minimum number of core servers in a cluster is three for a transaction is reported as successful to the user who started it when the update generated is propagated to half the size of the cluster plus 1.

The roles of core servers are as follows:

  • They are the targets of all the updating queries; they uphold data consistency via the consensus commit
  • They are responsible for data safety
  • They do the query routing, along with the bolt protocol drivers
  • They copy data to read replicas (when polled)

Although this is transparent for the users, the admins know that, in a cluster, one server is the leader and is elected by the other core servers.

Read replica servers

Read replica...