Book Image

ElasticSearch Cookbook

By : Alberto Paro
Book Image

ElasticSearch Cookbook

By: Alberto Paro

Overview of this book

Table of Contents (20 chapters)
ElasticSearch Cookbook Second Edition
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Using a function score query


This kind of query is one of the most powerful queries available, because it allows extensive customization. The function score query allows you to define a function that controls the score of the documents that are returned by a query.

Generally, these functions are CPU-intensive and executing them on a large dataset requires a lot of memory, but computing them in a small subset can significantly improve the search quality.

These are the common scenarios used for this query:

  • Creating a custom score function (for example with the decay function)

  • Creating a custom boost factor, for example, based on another field (such as boosting a document by its distance from a point)

  • Creating a custom filter score function, for example based on scripting ElasticSearch capabilities

  • Ordering the documents randomly

Getting ready

You need a working ElasticSearch cluster and an index populated with the script (chapter_05/populate_query.sh) available in the code bundle for this book.

How...