Lucene is an open-source embedded search engine software library.
Document / XML
K-D Tree Inverted Index (Full Text)
Custom API
Decomposition Storage Model (Columnar)
Embedded
https://lucene.apache.org/
https://github.com/apache/lucene
https://lucene.apache.org/core/documentation.html
Apache Software Foundation
US
1999
Open Source
Java
Java, Python
All OS with Java VM
Apache v2
https://en.wikipedia.org/wiki/Apache_Lucene