This looks like an in-memory log-structured merge tree [0]. (Albeit based on sorted runs rather than trees, as in the more recent variations of the idea) [0]

This looks like an in-memory log-structured merge tree [0]. (Albeit based on sorted runs rather than trees, as in the more recent variations of the idea) [0] https://www.cs.umb.edu/~poneil/lsmtree.pdf https://www.cs.umb.edu/~poneil/lsmtree.pdf