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Comment by jeremyjh | Hacker News Reader

Datomic is intriguing and powerful but I'd be reluctant to use a proprietary database developed by such a small company. I think Riak has a better model for free/paid usage. There is nothing like Datomic but there are so many excellent open-source databases these days.

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I'm the dev for an open source event-based database called Sky (http://skydb.io). Similar data model but it's aimed at a different use case than Datomic -- it's primarily used for analytics. The event data model is nice for avoiding conflicts but it's an up road battle to try and replace traditional relational databases. I find that storing historical events is primarily useful for either analytics or auditing. It makes more sense to move that off your primary data store if possible.

I do find that making databases smarter about the data they hold can really provide some great optimizations. Sky can crunch through about 60MM events per second on a single core because it is built for event data models. I'm sure Datomic can probably get some good optimizations too. I'll be curious to see some benchmarks.

Here's a demo app of Sky crunching all the events in the GitHub Archive (starts around 3m:20s):

http://skydb.io/blog/github-archive-visualizer.html

I'm working on multi-core distribution right now and I'll be doing multi-node after that. Check out the web site or GitHub (https://github.com/skydb/sky) for more information. It's MIT licensed so feel free to hack away.

You really need a "how it works" section. Few people are willing to read the source code to see if you have interesting or useful ideas.

That's a good point. I'm cleaning up and stabilizing the code right now and part of my v0.2.0 release is going to be documentation.

I did a presentation recently about some of the ideas behind the database:

https://speakerdeck.com/benbjohnson/behavioral-databases

The intro on the GitHub Archive Visualizer video explains some more of it too:

https://vimeo.com/51629936

I'll add that stuff to the README though.

I agree completely; we are looking at tech choices for a new project and Datomic is an excellent fit for the way we want our systems to work, but we're just not comfortable with the closed/paid model, especially for such a young product. For now we are looking at ways to use an accumulation based system (vs update-in-place) in PostgreSQL. If anyone has any experience with this I'd love to hear about it!

Take a look at event sourcing. This is a good introduction. http://martinfowler.com/eaaDev/EventSourcing.html

There is another database which can be used in the 'accumulation-based' space: http://geteventstore.com

It has the same main drawbacks as Datomic - it's young and multi-node deployment comes with commercial plan only, however it's really fast and easy to work with once you embrace the event-sourcing programming model.

How long do they plan on keeping it proprietary? Is there a timeline?

I doubt very much that there is a timeline. It's a product and the last I heard was staying close sourced. Having said that, I would not be surprised if some of its libraries are open sourced. I know of at least one that is in the pipeline.

If you say the datalog query aspect of Datomic, I would be tremendously (maybe embarrassingly) happy.

Datalog for clojure's data structures would take Clojure to a new productivity level. It would also greatly simplify a lot of the code out there today, further driving software to be more data-oriented. Data is the ultimate API. Please make it be Datalog.

The datomic-free jar provides Datalog. I use it myself https://clojars.org/com.datomic/datomic-free.

Datomic Free gives you that capability right now, for free, no strings attached, and no need to use a Datomic db. Not open source, but free as in gratis, a la Creative Commons.

We may trim down the deps a bit for that use case.

A trimmed down version is great news. Datalog makes Clojure so much better! Ideally it would be part of Clojure itself, but I'll take what I can get :)

I would also love to see a trimmed down version just to use datalog.

I'm working on a port of BloomL for clojure which will include a semi-naive datalog interpreter (it will already support naive, monotonic datalog by tonight). It will likely never be as well optimised as the Datomic libs but it is LGPL.

Source:

https://github.com/jamii/droplet

Background:

http://www.bloom-lang.net/

http://boom.cs.berkeley.edu/

http://db.cs.berkeley.edu/papers/UCB-lattice-tr.pdf

In related news Riak was in fact added as supported storage today: http://blog.datomic.com/2012/11/riak-and-couchbase-support.h...

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