What databases are used in large web applications?

Question

Database

Hello.
I'm interested in what databases use for example pinterest, ask.fm, toaster.
Those. sites with a huge amount of data.

Answer 1

pinterest uses mysql, I don't know about the rest of the question.
but in general the question does not make sense, since all sorts of subds are used.

Answer 2

Disqus (comment service) uses PostgreSQL and the load there is about 10 thousand requests per second (I came across an article in English about the backend of this project, but now I can’t find the link)

Answer 3

https://www.insight-it.ru/highload/