There's a brief comparison with RocksDB and LevelDB in the README file, which concludes: "If you require a high random write throughput or you need to use spinning disks then LevelDB could be a good choice unless there are requirements of versioning, authenticated proofs or other features of Graviton database."
This was a reply to another comment in the thread that suggested a user use sqlite. I commented using the Octal ios app. Not sure why it didn’t post it correctly....