ElasticSearch

ElasticSearch is an open source, RESTful search engine built on top of Apache Lucene and released under an Apache license. It is Java-based and can search and index document files in diverse formats.

ElasticSearch has been compared to Apache Solr and offers several notable features:

• Provides a scalable search solution.
• Performs near-real-time searches.
• Provides support for Multi-tenancy.
• Streamlines backup processes and ensures data integrity.
• An index can be easily recovered in a case of a server crash.
• Uses Javascript Object Notation (JSON) and Java application program interfaces (APIs).
• Automatically indexes JSON documents.
• Indexing uses unique type-level identifiers.
• Each index can have its own settings.
• Searches can be done with Lucene-based querystrings.