> monolithic databases like CockroachDB (SQL) or FaunaDB (NoSQL) trade off extensibility The CockroachDB documentation says their SQL implementation is layered

> monolithic databases like CockroachDB (SQL) or FaunaDB (NoSQL) trade off extensibility The CockroachDB documentation says their SQL implementation is layered on top of their K/V interface: https://www.cockroachlabs.com/docs/stable/architecture/overview.html#layers https://www.cockroachlabs.com/docs/stable/architecture/overv... This would make it similar to TiDB/TiKV and FoundationDB. Here's and old article from VoltDB insisting that layering SQL on pure K/V forfeits too much performance: https://www.voltdb.com/blog/2015/04/01/foundationdbs-lesson-fast-key-value-store-not-enough/ https://www.voltdb.com/blog/2015/04/01/foundationdbs-lesson-... Edit: And a response: https://news.ycombinator.com/item?id=15505194 https://news.ycombinator.com/item?id=15505194