Oracle 启动实例所需最小化参数

以下实验过程来自10.2.0.3

引用

SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - Prod
PL/SQL Release 10.2.0.3.0 - Production
CORE    10.2.0.3.0      Production
TNS for Linux: Version 10.2.0.3.0 - Production
NLSRTL Version 10.2.0.3.0 - Production

我们知道Oracle启动实例寻找参数文件的顺序为spfile<sid>.ora,spfile.ora,init<sid>.ora。那么Oracle启动一个实例最小化参数是什么呢？以下就是实验过程。
创建任意名字实例

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[ora10g@mcprod ~]$ export ORACLE_SID=zhoul

启动实例需要参数文件initzhoul.ora

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[ora10g@mcprod ~]$ sqlplus "/as sysdba"

SQL*Plus: Release 10.2.0.3.0 - Production on Sat Jan 9 13:55:35 2010

Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

Connected to an idle instance.

SQL> startup
ORA-01078: failure in processing system parameters
LRM-00109: could not open parameter file '/ora10g/oracle/product/10.2.0/db_1/dbs/initzhoul.ora'
SQL> exit
Disconnected

创建参数文件initzhoul.ora

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[ora10g@mcprod ~]$ touch /ora10g/oracle/product/10.2.0/db_1/dbs/initzhoul.ora

再次尝试启动，提示需要参数db_name

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SQL> startup nomount
ORA-01506: missing or illegal database name

添加db_name至参数文件

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[ora10g@mcprod ~]$ echo "db_name=zhoul">initzhoul.ora

再次尝试启动zhoul实例，启动成功

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SQL> startup nomount
ORACLE instance started.

Total System Global Area  117440512 bytes
Fixed Size                  1260384 bytes
Variable Size              58721440 bytes
Database Buffers           50331648 bytes
Redo Buffers                7127040 bytes

查看数据字典v$parameter,发现启动该实例的只有db_name是非默认，也就是说只要只要设置参数db_name，即可启动数据库实例，其他参数均可采用初始值。

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SQL> select name from v$parameter where isdefault='FALSE';

NAME
--------------------------------------------------------------------------------
db_name

观察alert_zhoul.log，可以看到Oracle在启动实例zhoul中调成了部分初始值。注意到undo retention自动调整被关闭。

引用

SQL> show parameter background_core_dump

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
background_core_dump                 string      partial


[ora10g@mcprod log]$ cat  alert_zhoul.log
Sat Jan  9 13:58:08 2010
Adjusting the default value of parameter parallel_max_servers
from 40 to 25 due to the value of parameter processes (40)
Sat Jan  9 13:58:08 2010
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Sat Jan  9 13:58:19 2010
Adjusting the default value of parameter parallel_max_servers
from 40 to 25 due to the value of parameter processes (40)
Sat Jan  9 13:58:19 2010
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Sat Jan  9 13:59:52 2010
Adjusting the default value of parameter parallel_max_servers
from 40 to 25 due to the value of parameter processes (40)
Sat Jan  9 13:59:52 2010
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Sat Jan  9 14:01:25 2010
Adjusting the default value of parameter parallel_max_servers
from 40 to 25 due to the value of parameter processes (40)
Sat Jan  9 14:01:25 2010
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Shared memory segment for instance monitoring created
Picked latch-free SCN scheme 2
Using LOG_ARCHIVE_DEST_1 parameter default value as /ora10g/oracle/product/10.2.0/db_1/dbs/arch
Autotune of undo retention is turned off.
LICENSE_MAX_USERS = 0
SYS auditing is disabled
ksdpec: called for event 13740 prior to event group initialization
Starting up ORACLE RDBMS Version: 10.2.0.3.0.
System parameters with non-default values:
  db_name                  = zhoul
PMON started with pid=2, OS id=32133
PSP0 started with pid=3, OS id=32135
MMAN started with pid=4, OS id=32137
DBW0 started with pid=5, OS id=32139
LGWR started with pid=6, OS id=32141
CKPT started with pid=7, OS id=32143
SMON started with pid=8, OS id=32145
RECO started with pid=9, OS id=32147
MMON started with pid=10, OS id=32149
MMNL started with pid=11, OS id=32151