B+Tree Growth and Change
The big idea: When a node is full, it splits.
- middle value is propagated upward
If we’re lucky, there’s room for it in the level above
- two new nodes are at same level as original node
Height of tree increases only when the root splits
- A very nice property
- This is what keeps the tree perfectly balanced
Recommended: split only “on the way down”
On deletion: two adjacent nodes recombine if both are < half full