That was a fantastic read. I can't count the number of hours I have wasted trying to figure out a bug (or trace a problem) in the system because someone decided to update the data silently. I think this is the kind of database which should be standard in finance industry. I have been working for financial companies in NYC for last 8 years and I have yet to see anyone use this product. Does anyone on HN have used this on a live system?

I really like the fact that facts are immutable in the Datomic model. It actually makes it easier to reason about eventually consistent, because you can rely on causal consistency between facts. Eventually consistent systems can give you durability, isolation, and atomicity, but it's typically hard to reason about, because the interface that's given to the user is some sort of multi-value, vector-clock tracked thing, and it's hard to reason about.

Datomic can manage a commit protocol under the hood, and deal with causality tracking without requiring the developer to "get dirty." It's query language is declarative, and doesn't provide the same implicit guarantees that SQL queries need.

Are there any promising open source alternatives with similar philosophies to datomic?