Elasticsearch is a distributed, open-source search and analytics engine built on Apache Lucene and developed in Java. It started as a scalable version of the Lucene open-source search framework then added the ability to horizontally scale Lucene indices. Elasticsearch allows you to store, search, and analyze huge volumes of data quickly and in near real-time and give back answers in milliseconds. It’s able to achieve fast search responses because instead of searching the text directly, it searches an index. It uses a structure based on documents instead of tables and schemas and comes with extensive REST APIs for storing and searching the data. At its core, you can think of Elasticsearch as a server that can process JSON requests and give you back JSON data.
How does Elasticsearch work?
Fundamentally, Elasticsearch organizes data into documents, which are JSON-based units of information representing entities. Documents are grouped into indices, similar to databases, based on their characteristics. Elasticsearch uses inverted indices, a data structure that maps words to their document locations, for an efficient search. Elasticsearch’s distributed architecture enables the rapid search and analysis of massive amounts of data with almost real-time performance.