Elasticsearch is an open-source search engine built on top of Apache Lucene™, a full-text search-engine library. Lucene is arguably the most advanced, high-performance, and fully featured search engine library in existence today—both open source and proprietary.
But Lucene is just a library. To leverage its power, you need to work in Java and to integrate Lucene directly with your application. Worse, you will likely require a degree in information retrieval to understand how it works. Lucene is very complex.
Elasticsearch is also written in Java and uses Lucene internally for all of its indexing and searching, but it aims to make full-text search easy by hiding the complexities of Lucene behind a simple, coherent, RESTful API.
However, Elasticsearch is much more than just Lucene and much more than ``just'' full-text search. It can also be described as follows:
-
A distributed real-time document store where every field is indexed and searchable
-
A distributed search engine with real-time analytics
-
Capable of scaling to hundreds of servers and petabytes of structured and unstructured data
And it packages up all this functionality into a standalone server that your application can talk to via a simple RESTful API, using a web client from your favorite programming language, or even from the command line.
It is easy to get started with Elasticsearch. It ships with sensible defaults and hides complicated search theory away from beginners. It just works, right out of the box. With minimal understanding, you can soon become productive.
As your knowledge grows, you can leverage more of Elasticsearch’s advanced features. The entire engine is configurable and flexible. Pick and choose from the advanced features to tailor Elasticsearch to your problem domain.
You can download, use, and modify Elasticsearch free of charge. It is available under the Apache 2 license, one of the most flexible open source licenses available. The source is hosted on GitHub at github.com/elastic/elasticsearch. See Contributing to Elasticsearch if you would like to join our amazing community of contributors!
If you have any questions related to Elasticsearch, including specific features, language clients and plugins, join the conversation at discuss.elastic.co.
Many years ago, a newly married unemployed developer called Shay Banon followed his wife to London, where she was studying to be a chef. While looking for gainful employment, he started playing with an early version of Lucene, with the intent of building his wife a recipe search engine.
Working directly with Lucene can be tricky, so Shay started work on an abstraction layer to make it easier for Java programmers to add search to their applications. He released this as his first open source project, called Compass.
Later Shay took a job working in a high-performance, distributed environment with in-memory data grids. The need for a high-performance, real-time, distributed search engine was obvious, and he decided to rewrite the Compass libraries as a standalone server called Elasticsearch.
The first public release came out in February 2010. Since then, Elasticsearch has become one of the most popular projects on GitHub with commits from over 300 contributors. A company has formed around Elasticsearch to provide commercial support and to develop new features, but Elasticsearch is, and forever will be, open source and available to all.
Shay’s wife is still waiting for the recipe search…