An information processing device comprises: a memory comprising a cache for storing information related to an object from a plurality of objects, and a summary structure configured to store a summary for the object; a volume configured to store a merge file including the plurality of objects, and a set of dump-files, each dump-file being associated with a specific cache-dump operation of the cache; and a processor configured to assign, to the cache, a first identifier; perform a cache-dump operation based on generating a dump-file associated with the first identifier and storing the information related to the object from the cache to the generated dump-file; and assign, to the cache, a second identifier, wherein the second identifier is larger than the first identifier.