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10G中Sqlplus的prelim选项

作者：OoNiceDream【转载时请务必以超链接形式标明文章原始出处和作者信息】
链接：http://www.dbaroad.me/archives/2009/02/10g-sqlplus-prelim.html

10G中，当数据库无法连接，又需要做SYSTEM DUMP时，可以尝试使用sqlplus的prelim选项

使用方法如下：

[/home/ora10g]$ export ORACLE_SID=EMREP
[/home/ora10g]$ sqlplus -prelim / as sysdba
 
SQL*Plus: Release 10.2.0.1.0 - Production on Tue Feb 17 14:24:51 2009
 
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
 
SQL>show user
USER is "SYS"
SQL> conn / as sysdba
Prelim connection established
SQL>

显示用户为”SYS”，当用”conn / as sysdba”时会告知Prelim的连接已建立，但其实是不能进行查询操作的：

SQL> select * from v$version;
select * from v$version
*
ERROR at line 1:
ORA-01012: not logged on
 
 
SQL> select * from dual;
select * from dual
*
ERROR at line 1:
ORA-01012: not logged on

不过此时可以采用oradebug工具做system dump或hanganalyze:

SQL> oradebug setmypid
Statement processed.
SQL> oradebug unlimit
Statement processed.
SQL> oradebug dump systemstate 10
Statement processed.
SQL> oradebug tracefile_name
/oradata/app/oracle/admin/EMREP/udump/emrep_ora_15603.trc
SQL> 
SQL> !
[/home/ora10g]$ ls -l /oradata/app/oracle/admin/EMREP/udump/emrep_ora_15603.trc
-rw-r-----   1 ora10g     dba        2855859 Feb 17 14:46 /oradata/app/oracle/admin/EMREP/udump/emrep_ora_15603.trc
[/home/ora10g]$ 
[/home/ora10g]$ ps -ef|grep LOCAL=YES
  ora10g 18273 17628  0 14:53:24 pts/td    0:00 grep LOCAL=YES
  ora10g 15603 15365  0 14:25:12 ?         0:00 oracleEMREP (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
[/home/ora10g]$