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

Pipeline aggregations


The last type of aggregation we will discuss is pipeline aggregations. Till now we've learned about metrics aggregations and bucket aggregations. The first one returned metrics while the second type returned buckets. And both metrics and buckets aggregations worked on the basis of returned documents. Pipeline aggregations are different. They work on the output of the other aggregations and their metrics, allowing functionalities such as moving-average calculations (https://en.wikipedia.org/wiki/Moving_average).

Note

Remember that pipeline aggregations were introduced in Elasticsearch 2.0 and are considered experimental. This means that the API can change in the future, breaking backwards-compatibility.

Available types

There are two types of pipeline aggregation. The so called parent aggregations family works on the output of other aggregations. They are able to produce new buckets or new aggregations to add to existing buckets. The second type is called sibling aggregations...