Book Image

Mastering Elasticsearch 5.x - Third Edition

By : Bharvi Dixit
Book Image

Mastering Elasticsearch 5.x - Third Edition

By: Bharvi Dixit

Overview of this book

Elasticsearch is a modern, fast, distributed, scalable, fault tolerant, and open source search and analytics engine. Elasticsearch leverages the capabilities of Apache Lucene, and provides a new level of control over how you can index and search even huge sets of data. This book will give you a brief recap of the basics and also introduce you to the new features of Elasticsearch 5. We will guide you through the intermediate and advanced functionalities of Elasticsearch, such as querying, indexing, searching, and modifying data. We’ll also explore advanced concepts, including aggregation, index control, sharding, replication, and clustering. We’ll show you the modules of monitoring and administration available in Elasticsearch, and will also cover backup and recovery. You will get an understanding of how you can scale your Elasticsearch cluster to contextualize it and improve its performance. We’ll also show you how you can create your own analysis plugin in Elasticsearch. By the end of the book, you will have all the knowledge necessary to master Elasticsearch and put it to efficient use.
Table of Contents (20 chapters)
Mastering Elasticsearch 5.x - Third Edition
About the Author
About the Reviewer
Customer Feedback

Choosing the default similarity model

In order to change the similarity model used by default, we need to provide a configuration of a similarity model that will be called by default. For example, if we would like to use our mastering_similarity name as the default one, we would have to change the preceding configuration to the following one (the whole example is stored in the posts_default_similarity.json file):

  "settings" : { 
  "index" : { 
    "similarity" : { 
      "default" : { 
        "type" : "classic", 
        "discount_overlaps" : false 

Because of the fact that the query norm and coordination factors (which were explained in The changed default text scoring in Lucene section, in Chapter 2, The Improved Query DSL) are used by all similarity models globally and are taken from the default similarity, Elasticsearch allows us to change them when needed. To do this, we need to define...