1. A method of managing a datastore storing one or more tiered data structures, comprising: at a memory controller with one or more processors, wherein the memory controller is operatively coupled with the datastore: detecting a request to perform an update operation of a first data object in a tiered data structure of the one or more tiered data structures stored in the datastore, the request includes first key information corresponding to the first data object and a new value for the first data object; locating the first data object using a key-map to map the first key information to a location of the first data object in the datastore; identifying a sequence number associated with the first data object; in accordance with a first determination that the sequence number associated with the first data object is greater than a first boundary sequence number corresponding to a first snapshot of the tiered data structure: replacing the first data object in the tiered data structure with a modified first data object including the first key information and the new value; and assigning the modified first object a unique sequence number; and in accordance with a second determination that the sequence number associated with the first data object is less than or equal to the first boundary sequence number corresponding to the first snapshot of the tiered data structure: while maintaining the first data object in the tiered data structure, inserting a second data object into the tiered data structure, the second data object including the first key information and the new value; and assigning the second data object the unique sequence number.