MySQL v PostgreSQL: Which have you used and why? 18 years ago
We switched from MySQL to Postgres because MySQL does not scale. MySQL rebuilds all indexes for InnoDB tables (and all other storage engines) on any trivial "alter table" even though InnoDB indexes refer to records using the primary key. So just adding a column to a big table means taking down your database for hours, even though the rebuilt indexes will be exactly the same as before the rebuild. So dumb... We are happy with Postgres.