LogicBlox is a commercial deductive DBMS with a datalog query interface.
LogicBlox was acquired by Predictix in 2014.
Worst-Case Optimal Join
LogicBlox supports a worst-case optimal join algorithm called the Leapfrog Trie Join.
Datalog
http://www.logicblox.com/
@logicblox
US
Predictix
Commercial
Proprietary
