Databases Reference
In-Depth Information
For the prior command to work, you need either an
spfile
or
init.ora
file in the
ORACLE_HOME/dbs
directory.
See the section “Step 2: Configure the Initialization File,” earlier in this chapter, for details.
■
stopping and restarting your database in quick succession is known colloquially in the Dba world as bouncing
your database.
Note
When your instance starts successfully, you should see messages from Oracle indicating that the system global
area (SGA) has been allocated. The database is mounted and then opened:
ORACLE instance started.
Total System Global Area 313159680 bytes
Fixed Size 2259912 bytes
Variable Size 230687800 bytes
Database Buffers 75497472 bytes
Redo Buffers 4714496 bytes
Database mounted.
Database opened.
From the prior output the database startup operation goes through three distinct phases in opening an Oracle
database:
1.
Starting the instance
2.
Mounting the database
3.
Opening the database
You can step through these one at a time when you start your database. First, start the Oracle instance (background
processes and memory structures):
SQL> startup nomount;
Next, mount the database. At this point, Oracle reads the control files:
SQL> alter database mount;
Finally, open the data files and online redo log files:
SQL> alter database open;
This startup process is depicted graphically in Figure
2-2
.
