Oracle DB instance startup and shutdown

Distinguishing between databases and instances: an instance refers to a variety of memory structures and service processes, and the database is the storage disk space in the object.

DB Instance Startup:

startup [Nomount | mount | open | force] [RESETRICT] [Pfile=finename]

• Nomount indicates that the startup instance does not load the database
• Mount means launching the instance, loading the database, and keeping the database off state
• Open means launching the instance, loading and opening the database, which defaults to this option
• Force means terminating the instance and restarting the database
• Resetrict to start the database as a restricted session
• Pfile used to specify the text parameter file to use when launching an instance

An ORACLE DB instance must read an initialization parameter file at startup to obtain configuration information about the instance startup. If Pfile is not specified, ORACLE reads the default location of the server initialization parameter file SPFile (typically Init$oracle_sid.ora in the $oralce_home/dbs directory).

To close a DB instance:

Shutdown [Nomal | transactional | immediate | abort]

• Nomal indicates that the database is shut down in a normal manner
• Transactional indicates that the database is closed after all currently active things have been committed
• Immediate means to close the database immediately in the shortest possible time
• Abort means to close the database by terminating

Oracle DB instance startup and shutdown