Basically I'm looking for an Open-Source (or free) RDBMS with a SQL-like interface that is highly concurrent.
Some features I'm looking for:
- A rigid schema defined at "compile-time"
- A production-ready database that I can run on my laptop (No Bigtable, Aurora, etc; no trial versions)
- Highly concurrent reads and writes.
- A JDBC-compatible interface.
- BASE semantics, including eventual consistency.
- (optional) Support for constraints, including foreign keys
- (optional) Explicit indexes (simple or compound)
I'm also open to a plain-old RDBMS that can be configured to achieve BASE semantics.