That is bananas! The implementation details are worth a read. Plus, all the links to other bananas projects are great.

Eh ECS is basically all about making SELECT ... FROM bar, baz WHERE bar.id == baz.id, joins on primary keys, as fast as possible and use it as often as possible. Games are real-time databases with gaudy user interfaces so it stands to reason that posgresql is a game with a bland user interface.