It's strange to me everyone touts Postgres but when you finally scale to a medium to large architecture HN has a handful of articles on great start-ups (now full fledge companies) switching FROM Postgres to MySQL. It's more efficient, atm, especially when accounting for labor. I wish the HN community would see that.
There are more MySQL experts out there than there are PostgreSQL experts (though the number is still probably under 10,000 worldwide). MySQL replication and scaling is a well understood solution, and thoroughly battle tested. There are dozens of good solutions out there for handling near-instantaneous failovers, using little more than the tools provided by MySQL.
It has a lot of problems, but when you need to scale, you can do so much more affordably with MySQL.
