If you are looking for a database-related blog, SlicingDice's is a good one:
This series of posts below describes in details how they built their database engine from scratch and the data warehouse service.
- https://blog.slicingdice.com/slicingdice-uncovered-part-1-in...
- https://blog.slicingdice.com/slicingdice-uncovered-part-2-s1...
- https://blog.slicingdice.com/slicingdice-uncovered-part-3-s1...
- https://blog.slicingdice.com/slicingdice-uncovered-part-4-in...