Apache Solr Search Platform

Apache Solr is an open source enterprise search platform written in Java and built on the Lucene search library, providing distributed indexing, replication, and load balanced querying with centralized configuration management. Originally developed at CNET Networks in 2004 by Yonik Seeley and donated to the Apache Software Foundation in 2006, the project graduated as a top level Apache project in 2019 and has powered search at organizations including Apple, Netflix, Instagram, eBay, Ticketmaster, Disney, Comcast, Sears, Bloomberg, and the Guardian. Key capabilities include full text search with complex Boolean queries, phrase matching, wildcards, fuzzy matching, proximity search, and field grouping. Faceted search and filtering enables drill down navigation through categorical aggregations, while spatial search supports geospatial queries with polygon filtering and distance sorting. SolrCloud provides horizontal scalability through automatic sharding, replication, and distributed query processing across clusters of nodes, managed by Apache ZooKeeper for cluster coordination. The analysis pipeline offers configurable tokenizers and filters for text processing including stemming, stopword removal, synonyms, phonetic matching, and multilingual support for over 30 languages. Additional features include near real time indexing with soft commit, highlighting of search terms in results, spell checking, auto suggestion, document clustering, and streaming expressions for real time analytics.