Why DB indexes use balanced trees, not hashtables?
database
Solution
Size, btrees start small and perfectly formed and grow nicely to enormous sizes. Hashes have a fixed size which can be too big (10,000 buckets for 1000 entries) or too small (10,000 buckets for 1,000,000,000 entries) for the amount of data you have.
Problem
Hashtables seem to be preferable in terms of disk access. What is the real reason that indexes usually implemented with a tree? Sorry if it's infantile, but i did not find the straight answer on SO.