Hi, are there any open source databases on the level of postgres that use a prolog or datalog esque logic programming language for querying?

datomic or https://opencrux.com/ ?

Will look into them. Thanks.

Datomic isn't open source, is it?

Datomic is not open source. OTOH, pretty much every triple store uses SPARQL, which is a dialect of Datalog.

opencrux is open source and I think it covers most of the features

Yep! Here's a Nextjournal notebook that gives a good introduction to Crux: https://nextjournal.com/a/UjQcdHg2KcbVaHXTSdcC5d/

https://en.wikipedia.org/wiki/Datalog has a fairly good list of various Datalog systems floating around.

I don't think there's anything nearly as as popular as postgres but a few ideas: • SWI Prolog rdf package implements an efficient RDF database as a C extension • Prolog bindings to terminusDB data store library

Asami is opensource