Book Image

Elasticsearch Server - Third Edition

By : Rafal Kuc
Book Image

Elasticsearch Server - Third Edition

By: Rafal Kuc

Overview of this book

ElasticSearch is a very fast and scalable open source search engine, designed with distribution and cloud in mind, complete with all the goodies that Apache Lucene has to offer. ElasticSearch’s schema-free architecture allows developers to index and search unstructured content, making it perfectly suited for both small projects and large big data warehouses, even those with petabytes of unstructured data. This book will guide you through the world of the most commonly used ElasticSearch server functionalities. You’ll start off by getting an understanding of the basics of ElasticSearch and its data indexing functionality. Next, you will see the querying capabilities of ElasticSearch, followed by a through explanation of scoring and search relevance. After this, you will explore the aggregation and data analysis capabilities of ElasticSearch and will learn how cluster administration and scaling can be used to boost your application performance. You’ll find out how to use the friendly REST APIs and how to tune ElasticSearch to make the most of it. By the end of this book, you will have be able to create amazing search solutions as per your project’s specifications.
Table of Contents (18 chapters)
Elasticsearch Server Third Edition
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Querying Elasticsearch


So far, when we havesearched our data, we used the REST API and a simple query or the GET request. Similarly, when we were changing the index, we also used the REST API and sent the JSON-structured data to Elasticsearch. Regardless of the type of operation we wanted to perform, whether it was a mapping change or document indexation, we used JSON structured request body to inform Elasticsearch about the operation details.

A similar situation happens when we want to send more than a simple query to Elasticsearch, we structure it using the JSON objects and send it to Elasticsearch in the request body. This is called the query DSL. In a broader view, Elasticsearch supports two kinds of queries: basic ones and compound ones. Basic queries, such as the term query, are used for querying the actual data. We will cover these in the Basic queries section of this chapter. The second type of query is the compound query, such as the bool query, which can combine multiple queries...