Vertica was written from scratch in C++. Maybe gram.y was used from Pg. But the client and SQL are strongly inspirited by Postgres. vsql is not psql probably, because psql is better. Last three years is not Vertica protocol compatible with Postgres. I don't know a reason why - I am expecting some strange marketing
According to some insider sources, they broke compatibility because it was "faster" (without any actual performance testing). In an update release, no less. I've been told that they lost a bunch of users over this because it broke their tools with no warning.
Interesting
Thank you for info
Pavel
-- -- Josh Berkus Red Hat OSAS (any opinions are my own)