Event Store VS mentat

I've been doing some research and found this: https://github.com/EventStore/EventStore

C#: In Europe, Java is still strong but many trading firms use C# because of the strong Microsoft culture in Europe, as well as because of strongly supported C# libraries like say EventStore, which tends to be used for the matchmaking engines for stock exchanges (especially that exchange matchmaking problem is basically SMR). And skimming over the code, it has Paxos implemented too, making it good for dealing with partial failures (failover), essential for any HFT/trading firm. C#'s also the biggest ecosystem that many of the breakthrough java tech mentioned earlier was first ported to.

Support for eventstore.com eventstore. esdb

Where's the catch, then? Well, there's a couple of catches, in fact. First of all, in a distributed setting, appending data to a log isn't that easy. First, you need to make your log distributed. Again, Kafka/Cassandra/EventStore make this possible, however, whenever you start dealing with distributed data, you‘re introducing new operational and implementation complexity.

Why did Mozilla abandon the Mentat database?

There is (now unmaintained) project called Mentat [0] from Mozilla.

[0] https://github.com/mozilla/mentat

Mozilla was working on the opposite, a Datalog of SQLite, with Mentat, now abandoned: https://github.com/mozilla/mentat

Strikes me as a basically sound idea and it would be lovely if someone picked up the ball.

mentat was archived by mozilla back in 2017, but there are a bunch of forks. Because github is dumb and has a terrible interface for exploring forks [0], I used the Active GitHub Forks tool [1] that helped to find:

qpdb/mentat [2] seems to be the largest (+131 commits) and most recently modified (May this year) fork of mozilla/mentat.

[0]: https://github.com/mozilla/mentat/network/members - Seriously, how am I supposed to use this? Hundreds of entries, but no counts for stars, contributors, or commits, no details about recent commits. Just click every one?

[1]: https://techgaun.github.io/active-forks/index.html

[2]: https://github.com/qpdb/mentat

There are plenty of open source Datomic Inspired databases. Check out https://github.com/juji-io/datalevin and scroll down all the way down to “Alternatives”. There was even the beginning of a rust one by Mozilla: https://github.com/mozilla/mentat

I think you might be slightly misreading things, from what you quoted it’s about the query language (sql vs Datalog) not the database engine, that would likely be SQLite in any case. Now whether grafting a Datalog query engine onto SQLite is a good idea is a different question (though it’s been done, eg https://github.com/mozilla/mentat), but we should all at least talk about the same thing :)

You might be interested in the now defunct Mentat project from Mozilla. They made an EAV store with syncing on top of sqlite. It ran datalog queries by translating them into sql.

https://github.com/mozilla/mentat