Both Cockroach and CedarDB didn't rewrite anything, they built stuff from scratch. Just used the same client protocol. There are a bunch of other unrelated databases using Postgres protocol btw.
I'm not talking about speaking the protocol. I'm talking about trying as hard as they can to be as indistinguishable from Postgres (to a non-operations user) as they can. And that list is very small.
Comments
Who isn't? Cockroach rewrote Postgres in Go. CedarDB rewrote Postgres in C++.
And then to lesser degrees you've got Yugabyte, AlloyDB, and Aurora DSQL (and certainly more I'm forgetting) that only replace parts of Postgres.
Both Cockroach and CedarDB didn't rewrite anything, they built stuff from scratch. Just used the same client protocol. There are a bunch of other unrelated databases using Postgres protocol btw.
I'm not talking about speaking the protocol. I'm talking about trying as hard as they can to be as indistinguishable from Postgres (to a non-operations user) as they can. And that list is very small.