The InnoDB transaction model aims combine the best properties of a database with traditional two-phase locking. InnoDB performs locking at the row level and runs queries as nonlocking by default, in the style of Oracle. The lock information in InnoDB is stored space-efficiently so that lock escalation is not needed. Typically, several users are permitted to lock every row in InnoDB tables, or any random subset of the rows, without causing InnoDB memory exhaustion.