Empress Embedded Database vs eXtremeDB

Empress Embedded Database has no write-up on Specifiction yet; its figures are above.

eXtremeDB is an in-memory database system designed for embedded devices and applications. It can combine in-memory and persistent storage within one database system. Interfaces include native APIs, REST, SQL, ODBC, and JDBC, with language APIs for C/C++, Java, Python, C#, Go, and Rust. For time-series data, a sequence type provides columnar storage. Distributed options include High Availability, Cluster, and Active Replication Fabric for replication across IoT tiers. Network communications can use TLS/SSL with OpenSSL or wolfSSL. Technical specifications list maximum database sizes of 4 GB on 32-bit architectures and 18.4 exabytes on 64-bit architectures. eXtremeDB supports Android, iOS, Linux, macOS, and Windows, and can be self-hosted. Evaluation downloads are listed for Linux, macOS, and Windows; custom trial packages can be requested for other platforms. McObject offers annual engineering support contracts that include software updates and a 50 percent discount on major upgrades. Commercial licensing is paid, with pricing available on request, and a 60-day trial is listed.