> As I understood it's because we can't move root to another page.
Actually not. Path to node could change completely, For example, for page on
second level path is 0-234 (where 0 is a root page, 234 is a page on second
level). After root split path will be 0-new_page-234.
If algorithm could be able to change root then new path could be looked as
new_root-new_page-234 because old root could be splitted to old_root_page and
new_page.
--
Teodor Sigaev E-mail: teodor@sigaev.ru
WWW: http://www.sigaev.ru/