A method is provided for a key-value (KV) store database management system (DBMS) to provide a KV store to an application. The method includes providing a first low-level KV store and a top-level KV store. The first low-level KV store includes a root node and leaf nodes. The top-level KV store includes a leaf node pointing to the first low-level KV store. The leaf node in the top-level KV store includes a minimum key in the first low-level KV store and a pointer to the root node of the first low-level KV store. The method further includes determining a key-value insertion to the KV store would increase a number of keys in the first low-level KV store over an upper threshold and, in response to said determining, creating a second low-level KV store. The method additionally includes determining if a total number of keys in the first low-level store and the second low-level store is less than a lower threshold from key-value deletions and, when the total number of keys in the first low-level store and the second low-level store is less than the lower threshold, merging the first and the second low-level stores.