> A btree is a kind of binary tree
By definition a binary tree means there are two children per node.
Binary is the one thing a b-tree is not.
By definition a binary tree means there are two children per node.
Binary is the one thing a b-tree is not.
This difference occurs because a B-tree can have interior nodes that aren't completely full, whereas a binary tree's interior nodes have exactly 2 children.
Seems like it would be extremely odd to have a 2-2 btree, you’d just get a significantly more complicated BST no?
I’d figure you’d want to fill a cacheline with something typical-ish, so probably at least 4 (this way if you have 4 children and 3 keys, the keys are 8 bytes and the child links are straight pointers your node is 56 bytes and you can add some metadata e.g. a bitmap).
Apparently Rust’s BTreeMap is a 6-11 btree but I don’t know how they picked the branching factor.