Elasticsearchs

Elasticsearchs, commonly referred to as Elasticsearch, is a distributed search and analytics engine built on top of Apache Lucene. It is developed by Elastic N.V. and forms a central part of the Elastic Stack, together with Logstash, Kibana, and Beats. Elasticsearch stores data as JSON documents and provides near real-time search, retrieval, and analysis over large datasets.

In terms of architecture, Elasticsearch runs as a cluster of nodes. Data is organized into indices, which are subdivided into shards that are distributed across nodes; shards can have replicas for fault tolerance. Documents are indexed with mappings that describe fields and data types; mapping types have been deprecated in favor of a single document type per index. The query language is a RESTful JSON-based DSL that supports full-text search, structured queries, and aggregations. Ingest pipelines and analyzers process and index data, including language-specific tokenization and stemming.

Elasticsearch emphasizes scalability and resilience, with horizontal scaling by adding nodes, automatic shard allocation, and snapshot-based backups. Security features vary by edition but commonly include access control, encryption in transit, and audit logging.

As part of the Elastic Stack, Elasticsearch integrates with Kibana for visualization, Logstash for data processing, and Beats for lightweight data shippers. It is widely used for log and event analytics, site and product search, and operational intelligence. Licensing has evolved since 2021, with Elastic’s proprietary Elastic License and Server Side Public License, and community forks like OpenSearch continuing in parallel.