[pavlov]

As mentioned in the article, Datomic is a database that uses Datalog as its query language:

https://docs.datomic.com/on-prem/query/query.html#why-datalo...

(Some ten years ago worked at a startup that used Datomic. It seemed to work great, although the only queries I ever needed to add to the system were simple copy-paste hacks of existing ones, so I never got to dive into Datalog.)

[dmitriid]

Datascript is the open source analog for Clojure, ClojureScript and JS: https://github.com/tonsky/datascript

[simongray]

There are many open source alternatives in Clojure using this query language: https://github.com/simongray/clojure-graph-resources#datalog

[mpenet]

'ish.

datahike would be the closest to datomic in terms of features/implementation (support for as-of, transactor etc).

Then in terms of maturity I think the choice is between xtdb and datascript, both are very solid/maintained but they are also vastly different.