“…There are key-value stores such as Redis [66], RAMCloud [2], MemepiC [60], [138], Masstree [249], MICA [64], Mercury [250], Citrusleaf/Aerospike [34], Kyoto/Tokyo Cabinet [251], Pilaf [252], document stores such as MongoDB [65], Couchbase [253], graph databases such as Trinity [46], Bitsy [254], RDF databases such as OWLIM [255], WhiteDB [50], etc. There are some systems that are partially in-memory, such as MongoDB [65], MonetDB [256], MDB [257], as they use memory-mapped files to store data such that the data can be accessed as if it was in the memory.…”