Database Mode
Purpose
This section tells you about setting the operating mode of the Oracle database.
Prerequisites
The main components of the database and instance are shown in the following graphic:
When an Oracle database is running, it is associated with an instance. The process of associating the database with an instance is called mounting the database. To make the mounted database accessible to authorized users, you must open it.
Process Flow
We strongly recommend you to use BRCONNECT functions to start and stop the database rather than the equivalent SAPDBA ones (if one is available, this is indicated below). The reason is that we are no longer developing the SAPDBA functions, whereas BRCONNECT functions will always be fully up-to-date.
Starting the Database
The following describes how you can start the database:
|
Type |
What happens |
How |
|
No mount |
Database instance is built up Operating system resources are allocated using configuration information stored in the profile init<SID>.ora. |
SAPDBA Startup NOMOUNT |
|
Mount |
Database control files are evaluated. Information about the file structure of the database is read Datafiles and logs are not yet opened. |
SAPDBA Startup MOUNT |
|
Open |
All files in the database system are opened. If required, instance recovery is performed immediately after opening the database. Pending database transactions are ended. |
brconnect -f start SAPDBA Startup normal SAPDBA Startup RESTRICT – this is restricted mode (privileged user access only) for database administration tasks such as reorganization |
Stopping the Database
The following describes how you can stop the database:
|
Type |
What happens |
How |
|
Normal |
No new database logon possible. After all database user have logged off, the database is closed properly: all files are closed, the database is dismounted, and the instance is shut down. The database is consistent after shutdown. |
brconnect -f dbshut SAPDBA Shutdown normal |
|
Immediate |
Only the current commands are executed. PMON ends all sessions and performs a rollback of the open transactions. The database is then closed properly (as for a normal shutdown). The database is consistent after shutdown. DBWR and ARCH might require up to 1 hour post-processing time. |
SAPDBA Shutdown immediate SAPDBA Shutdown immediate force – this forcibly disconnects any SAP users that are still connected |
|
Abort |
Emergency database shutdown Users are not logged off and open transactions are not rolled back. The database is not consistent after shutdown. An instance recovery is automatically performed at the next database startup. |
SAPDBA Shutdown Abort |
See
Startup and Shutdown of the Oracle Database with SAPDBA.