Apache Lucene/Solr
Apache Lucene is a full-text index.
Solr is a web app wrapper for Lucene.
Bibliography
Bibliography
https://lucene.apache.org/solr/http://www.lucenetutorial.com/http://www.lucenetutorial.com/lucene-vs-solr.htmlhttps://lucene.apache.org/https://www.lucenetutorial.com/basic-concepts.html https://dzone.com/articles/apache-lucene-a-high-performance-and-full-featured
https://confluence.atlassian.com/jirakb/understand-the-index-process-in-jira-server-776654790.html