Oracle Database Start And Shutdown

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Content

  • Start and shutdown stages
  • How to Starting Database in different stage
  • Change Database Open Mode status
  • Shutdown Database with command

Start and shutdown stages

Database is startup and shutdown its goes four different stages
 
SHUTDOWN: Database and instance are compleate shutdown they are in rest. In that time no process, no memory is allocated but oracle server porcess  is still up like listener OEM agent. Oracle database instance and oracle database server is different thing. One oracle server can hande many oracle database instance its depents on server(physical server) hardware like HDD,RAM,porcessor.
 
NOMOUNT: In that stage instance has been started and memory is allocated, server backgroud porcess is also started. Its call Nomount mode.
 
MOUNT: In that stage instance is started and the control file is open and read but its contents are not validated. In that time database is not open. Its call Mount mode.
 
OPEN : When database is open mode, control file contents is validated and database is fully ready for service. In that stage database open_mode status is read write.  

How to Starting Database in different stage

You can start database in different stage what are you need.we check out database status using this query.
 
SQL> select open_mode from v$database;

first you login sysdba user from sqlplus open cmd(windows os) or terminal(linux os) and type “sqlplus / sys as sysdba”

NOTE: SQL query is not case sensitive

STARTUP: when your database is compleate shutdown, using startup command you can start database is directly in open mode. Login database as sysdba you see that message “Connected to an idle instance” thats means database instance is compleate shutdown. in that time you cant not run any sql command.

SQL> startup;
SQL> select open_mode from v$database;

NOMOUNT: Database start at nomount mode. In this mode you can run paramiter related sql.

SQL> startup nomount;
SQL> select open_mode from v$database;
SQL> show paramiter sga;

MOUNT : Database start at mount mode. You can run database related query in this mode.

SQL> startup mount;
SQL> select open_mode from v$database;

STARTUP FORCE: If you want to restart database then you use this command. Its shutdown and startup at a time.

SQL> select open_mode from v$database;
SQL> startup force;
SQL> select open_mode from v$database;

Change Database Open Mode status

The ALTER DATABASE command use to move database from one state to another.

NOMOUNT TO MOUNT: If instance started at Nomount Mode you may want to Mount Database.
 
SQL> alter database mount;

MOUNT TO OPEN: If Database already Mounted and you want to open it.

SQL> alter database open;

Shutdown Database with command

You can shutdown database with Different shutdown command. Lets see why you use different shutdown command

SHUTDOWN: The shutdown command is shutdown database. Another name is SHU. shu and shutdown do same work. If nothing is going on and no one is login your database then shutdown command is perfect. If any transaction or any one is still login your database then never shutdown your database until  the transaction is completed and user is logout from database. after press shutdown command database not allow new transaction or new connection.
 
SQL> shu
SQL> shutdown

SHUTDOWN IMMEDIATE: The shutdown immediate command will prevent new logons, roll back any uncommitted transactions, and then bring the database down. Many DBA Like this command.

 

SQL> shutdown immediate;

SHUTDOWN TRANSACTIONAL: Shutdown immediate and shutdown transactional is almost same. Main difference is shutdown transactional wait for active transaction  is completed(commit).

SQL> shutdown transactional;

SHUTDOWN ABORT: Its do work like plug and play. Naturally shutdown abort command not using. Its down database without debate.

SQL> shutdown abort;

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