我们知道,Oracle在启动过程中,需要读取参数文件(pfile/spfile)来创建实例.Oracle在启动过程中,寻找参数文件的顺序为:spfile<sid>.ora,spfile.ora,init<sid>.ora.
而创建实例的过程中,Oracle需要的最少参数为一个,即db_name参数.
我们来看一个测试,启动一个任意设置的实例,本例ORACLE_SID=julia:
[oracle@jumper dbs]$ export ORACLE_SID=julia
[oracle@jumper dbs]$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.4.0 - Production on Mon May 8 11:08:36 2006
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to an idle instance.
SQL> startup nomount;
ORA-01078: failure in processing system parameters
LRM-00109: could not open parameter file '/opt/oracle/product/9.2.0/dbs/initjulia.ora'
Oracle最后检查的文件为initjulia.ora,让我们创建这个文件,然后数据库实例即可创建:
SQL> ! echo "db_name=julia" > /opt/oracle/product/9.2.0/dbs/initjulia.ora
SQL> startup nomount;
ORACLE instance started.
Total System Global Area 97588504 bytes
Fixed Size 451864 bytes
Variable Size 46137344 bytes
Database Buffers 50331648 bytes
Redo Buffers 667648 bytes
我们可以看一下缺省的各类文件的存储地点:
SQL> show parameter dump_dest
NAME TYPE VALUE
------------------------------------ ---------------------- ------------------------------
background_dump_dest string ?/rdbms/log
core_dump_dest string ?/dbs
user_dump_dest string ?/rdbms/log
SQL> show parameter control_files
NAME TYPE VALUE
------------------------------------ ---------------------- ------------------------------
control_files string ?/dbs/cntrl@.dbf
我们顺便看一下缺省的,警报日志中记录的信息:
[oracle@jumper dbs]$ cat $ORACLE_HOME/rdbms/log/alert_julia.log
Mon May 8 11:09:04 2006
Starting ORACLE instance (normal)
Mon May 8 11:09:04 2006
WARNING: EINVAL creating segment of size 0x0000000006400000
fix shm parameters in /etc/system or equivalent
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
SCN scheme 2
Using log_archive_dest parameter default value
LICENSE_MAX_USERS = 0
SYS auditing is disabled
Starting up ORACLE RDBMS Version: 9.2.0.4.0.
System parameters with non-default values:
db_name = julia
PMON started with pid=2
DBW0 started with pid=3
LGWR started with pid=4
CKPT started with pid=5
SMON started with pid=6
RECO started with pid=7