Just finished reading DDIA, can't recommend it enough! I learned a lot of new info in every single chapter even for topics I thought I had a firm grasp on. Great job Martin Kleppmann!
I know this sounds like a cliche at this point, but volume 3 of Donald Knuth's "The Art of Computer Programming" goes into more depth on the theory that underpins these algorithms than anything else I've ever seen/read/heard of (in fairness, I haven't read OP's suggestion yet, though).
This is one of the best technology books I've ever read. I spent a few years diving into big data architecture. I thought I had a reasonably good handle on it, then I read this book. So many insights.