Postgres was first written in Lisp and had to be re-written in C because of slow performance [1]. YugaByte DB reuses the same C-based Postgres query layer but runs it on a Google Spanner-inspired distributed document store written in C++. The goal of this new “rewrite” is to add horizontal write scaling, native failover/repair and geo-distribution. As long as users love the language they interact with, the underlying software will continue to see such re-writes in order to meet the needs of the current times.
[1] https://thenewstack.io/the-slow-climb-of-postgres-and-the-va...