Note that the pictures in the post seem to be binary trees, rather than B-Trees. The latter is what postgres actually uses. For indexes in database systems b-tr

Note that the pictures in the post seem to be binary trees, rather than B-Trees. The latter is what postgres actually uses. For indexes in database systems b-trees usually are vastly preferable, because they're far less deep, and the lookups for the next tree level are usually more expensive. That's especially true for disk resident cases, but it's also true in memory resident cases (locking overhead, more cache misses).