Ah, that's helpful, and explains why it exists: "Three novel ideas contribute to the high performance of SplinterDB: the STB-tree, a new compaction policy that

Ah, that's helpful, and explains why it exists: "Three novel ideas contribute to the high performance of SplinterDB: the STB-tree, a new compaction policy that exposes more concurrency, and a concurrent memtable and user-level cache that removes scalability bottlenecks. All three components are designed to enable the CPU to drive high IOPS without wasting cycles." "At the heart of SplinterDB is the STB-tree, a novel data structure that combines ideas from log-structured merge tree and B-trees. The STB-tree adapts the idea of size-tiering (also known as fragmentation) from key-value stores such as Cassandra and PebblesDB and applies them to B-trees to reduce write amplification by reducing the number of times a data item is re-written during compaction."