Database Shutdown Modes

1.shutdown normal

2.shutdown transactional

3.shutdown immediate

4.shutdown abort

1.shutdown normal : This is a graceful shutdown.

Oracle waits until all the users disconnects their sessions explicitly.

No new connections will be allowed.

Dismounts the database, releases the memory to the Operating System by terminating all the mandatory background processes and closes the data files.

Next startup does not require instance recovery.

2.shutdown transactional : This is also a graceful shutdown.

No new connections will be allowed.

Oracle waits until all the ongoing transactions are completed either by commit or rollback.

Dismounts the database and releases the memory and closes the data files.

Next startup do not require instance recovery.

3.shutdown immediate :This is also a graceful shutdown.

Oracle disconnects all the sessions by rolling back any ongoing transactions.

Dismounts the database and releases the memory and close the data files.

4.shutdown abort : This is not a graceful shutdown.

Oracle immediately terminates the instance without closing the data files.

Next startup requires instance recovery which will be carried out by SMON background process.

Note : if shutdown transactional or shutdown immediate is taking more time, we can issue shutdown

abort, then startup, and then shutdown immediate.

Generally, in the industry, we issue shutdown abort in the event of loss of control files,

system.dbf and the loss of full database.

Whenever we issue shutdown or startup, oracle generates SCN(System Change Number) and that SCN, oracle will update to all the data file headers as well as the control file.