A database that resides in RAM. An entire database is copied from storage to main memory and remains there for processing. Today's computers support terabytes of RAM, and because RAM is considerably faster than storage, complex decision support queries are satisfied more rapidly with in-memory databases. However, memory can fail due to power outages and component breakdown; therefore, snapshots are taken periodically and saved to permanent storage. See
SAP HANA and
RAM disk.
In Time, It May All Merge
At some point in the future, perhaps 10 or 20 years from now, RAM and storage may merge into one "memory/storage" pool (see
future memory chips).