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

Basic queries


Elasticsearch has extensive search and data analysis capabilities that are exposed in forms of different queries, filters, aggregates, and so on. In this section, we will concentrate on the basic queries provided by Elasticsearch. By basic queries we mean the ones that don't combine the other queries together but run on their own.

The term query

The term query is one of the simplest queries in Elasticsearch. It just matches the document that has a term in a given field - the exact, not analyzed term. The simplest term query is as follows:

{
  "query" : {
  "term" : {
    "title" : "crime"
  }
  }
}

It will match the documents that have the term crime in the title field. Remember that the term query is not analyzed, so you need to provide the exact term that will match the term in the indexed document. Note that in our input data, we have the title field with the value of Crime and Punishment (upper cased), but we are searching for crime, because the Crime terms becomes crime after...