A database-backed operating system

Question

Here where I work I am attending a series of lectures about database query optimizers. While the speaker was introducing databases, he made a very insightful comment about a kernel having basically to administer tables of processes, pointers to open files, inodes, etc, and it's therefore basically a POSIX-compliant database engine. Clearly, having read the Bach a long time ago, when I was young and more inexperienced, I never got to analyze the thing from this point of view, but it's fundamentally true.

As you can imagine, it's not easy to google... so I ask: I was wondering if some crazy guy out there designed a (hopefully, just for fun, real fun) userspace POSIX-compliant kernel on top of MySQL...

Edit: please note. I'm not talking about a kernel having a database filesystem. I am talking about a kernel having the whole ring-0 state handled by MySQL.

Edit 2: clarification as it seems I've been misunderstood. I did not look for it to use it in production. I was just wondering if someone did it because he wanted to have fun. The real fun was a reference to the fact that Linux was done "just for fun" as I wrote, but it ended up as a serious product, hence my addition of real to imply total lack of seriousness. There's a bunch of useless projects out there that are made just because they are unusual or crazy enough to be funny just for the idea of it. My question was looking for something developed under this point of view.

Answer 1

I don't know if it's been done, but if so, I wouldn't want to use it. Regardless of how fast it was, I can't believe it would be as fast as a highly-tuned, kernal specific set of data structures. I would think that you'd start throwing out features as quickly as possible from a general purpose DB to get performance and likely still end up with something slower than a purpose-built data structure.