B-Tree

If a tree is not balanced, it is not efficient and it is the same efficient as a linked list in the worst situation for seaching a given key. Self-balance trees include red-black tree, btree and so on...In Linux kernel, the scheduler use red-black tree to pick up the next process to run. B-tree is used in most of the RDBMS. Here is the details of B-Tree.

reference:

https://www.youtube.com/watch?v=C_q5ccN84C8

https://www.cs.usfca.edu/~galles/visualization/BTree.html