CockroachDB - the open source, cloud-native distributed SQL database.
CockroachDB is a distributed SQL database built on a transactional and strongly-consistent key-value store. It scales horizontally; survives disk, machine, rack, and even datacenter failures with minimal latency disruption and no manual intervention; supports strongly-consistent ACID transactions; and provides a familiar SQL API for structuring, manipulating, and querying data.
has a confusing license situation:
CockroachDB core is free to use. Most core features are licensed under the BSL, but some core features are subject to the CCL or third-party licenses.
Non-CCL core features from version 19.1 and earlier are licensed under Apache 2.0; however, some features remain under third-party licenses. Beginning in version 19.2, these non-CCL features are licensed under the BSL for three years before converting to the Apache 2.0 license.
CockroachDB Enterprise features require a paid license from Cockroach and are licensed under the Cockroach Community License.