Except the person to whom I replied said to use traditional SQL databases:
> Traditional SQL databases end up being many times simpler in practice, and because of their inherent scaling limitations, much easier to manage. And most importantly: their implementations aren't buggy.
They are NOT using stock-standard MySQL and haven't done so for many years. If you are big enough to make your own programming languages the normal rules do not apply.
And if you ask the Youtube team for a recommendation for your project, they will not point you to MySQL.
i haven't touched mysql in years but quite frankly, 99% of websites out there (blog/cms) will run fairly fine on a Mysql database. as for the other 1%, they would be big enough to pick the right db of their choice as the time comes. so there is no need to tell everyone you should be using this or that.
this is kind of like telling everyone that they should ALL be using emacs, when vim/nano is still sufficient for the job.
I honestly don't see a single reason why MySQL should be used over PostgreSQL for anything, thus my sweeping statement. I could be wrong but I don't think so.
MySQL? Nobody, and I mean NOBOBY is saying you should use MySQL. All of the things you mention is trivial using a decent SQL solution like PostgreSQL.