Out of all the companies Google might be relying on in their back-end, I think Oracle is probably pretty far down the list.

I can’t imagine what part of Google’s history would lead someone to believe there was any third party system in their production stack anywhere.

Now their corporate/finance stack on the other hand... shudder.

Well, google did use a bunch of off the shelf technologies in the early days, but now it is obvious that there is no vendor on earth that could supply the infrastructure to run Gmail.

Didn't they use GNU/Linux form day one on?

Closed-source like Oracle I meant. They've been big boosters of all kinds of open-source stuff like linux, llvm, mysql, ...

Hush, you'll scare the shiny eyed faang wannabies away, they aren't supposed to know this until employed for at least two decades.