I like "Architecture of a Database System" by Stonebraker, Hamilton, and Hellerstein (http://db.cs.berkeley.edu/papers/fntdb07-architecture.pdf) for an overview and then "Transaction Processing: Concepts and Techniques" by Gray and Reuter (https://www.amazon.com/Transaction-Processing-Concepts-Techn...) for the storage-side of things. Granted these are a little old (especially G&R) so extra thought must be given for modern hardware (memory, CPU performance, processor counts, network, disks, etc) as well as distributed processing, replication, and consensus.

This book is more about different types of tradeoffs you can make in terms of your system design. I'd recommend looking at grad databases courses instead, e.g:

- http://db.cs.cmu.edu/courses/ - http://daslab.seas.harvard.edu/classes/cs165/ - http://daslab.seas.harvard.edu/classes/cs265/

I really wish this class (or the Harvard class referenced below) were offered as a MOOC w/ some certification. I rarely find classes around OS/databases offered as MOOCs, which is a pity because those are the things I'd love to spend time on.

Part of the problem is that doing a decent MOOC takes a TON of preparation and effort, much more so than a regular class. The professor who runs the class (Stratos Idreos) has a billion things that he's working on, so turning it unto a MOOC would require some outside support, probably. That said, releasing the videos might be a possibility, I'll ask and see. I believe Andy Pavlo's class has videos online already.

The other part is that in the Harvard classes specifically, the class discussion is a huge part of the class.

This course does, has lectures on youtube http://15721.courses.cs.cmu.edu/spring2017/

I have a copy of https://www.amazon.com/gp/product/0130402648 and while I don't think it'll win any "best textbook ever" awards it presents all the basic concepts in a straightforward if somewhat simple way.

I also looking for info on this.

I will be very happy in how build a sqlite-like DB engine.

All the answer so far is "read the sqlite code". As if everyone know low-level C or DB design!