SHUTDOWN ABORT
This mode is intended for emergency situations, such as when no other form of shutdown is successful. This mode of shutdown is the fastest. However, a subsequent open of this database may take substantially longer because instance recovery must be performed to make the data files consistent.
SHUTDOWN IMMEDIATE
This mode is typically the fastest next to SHUTDOWN ABORT. Oracle Database terminates any executing SQL statements and disconnects users. Active transactions are terminated and uncommitted changes are rolled back.
SHUTDOWN TRANSACTIONAL
This mode prevents users from starting new transactions, but waits for all current transactions to complete before shutting down. This mode can take a significant amount of time depending on the nature of the current transactions.
SHUTDOWN NORMAL
This is the default mode of shutdown. The database waits for all connected users to disconnect before shutting down.