我們知道,Oracle在啟動過程中,需要讀取參數文件(pfile/spfile)來創建實例.Oracle在啟動過程中,尋找參數文件的順序為:

spfile<sid>.ora,spfile.ora,init<sid>.ora.

而創建實例的過程中,Oracle需要的最少參數為一個,即db_name參數.

我們來看一個測試,啟動一個任意設置的實例,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 2006Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.Connected to an idle instance.SQL> startup nomount;ORA-01078: failure in processing system parametersLRM-00109: could not open parameter file '/opt/oracle/product/9.2.0/dbs/initjulia.ora'

Oracle最后檢查的文件為initjulia.ora,讓我們創建這個文件,然后數據庫實例即可創建:

SQL> ! echo 'db_name=julia' > /opt/oracle/product/9.2.0/dbs/initjulia.oraSQL> startup nomount;ORACLE instance started.Total System Global Area 97588504 bytesFixed Size 451864 bytesVariable Size 46137344 bytesDatabase Buffers 50331648 bytesRedo Buffers 667648 bytes

我們可以看一下缺省的各類文件的存儲地點:

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

我們順便看一下缺省的,警報日志中記錄的信息:

oracle@jumper dbs]$ cat $ORACLE_HOME/rdbms/log/alert_julia.logMon May 8 11:09:04 2006Starting ORACLE instance (normal)Mon May 8 11:09:04 2006WARNING: EINVAL creating segment of size 0x0000000006400000fix shm parameters in /etc/system or equivalentLICENSE_MAX_SESSION = 0LICENSE_SESSIONS_WARNING = 0SCN scheme 2Using log_archive_dest parameter default valueLICENSE_MAX_USERS = 0SYS auditing is disabledStarting up ORACLE RDBMS Version: 9.2.0.4.0.System parameters with non-default values: db_name= juliaPMON started with pid=2DBW0 started with pid=3LGWR started with pid=4CKPT started with pid=5SMON started with pid=6RECO started with pid=7