莱斯ATC笔记4

摘要：

oracle；

1、模拟故障：

[root@host3 fdp1]# mount /dev/sda2 /home/oracle/oradata/fdp1
#  ps -ef | grep oracle   //查看oracle进程运行正常
$sqlplus / as sysdba
SQL> SELECT host_name FROM V$INSTANCE;
HOST_NAME
--------------------------------------------------------------------------------
host3.a28.com
SQL> SELECT DBMS_METADATA.GET_DDL('TABLE','NCHAR_TST') FROM DUAL;
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-01116: error in opening database file 1
ORA-01110: data file 1: '/home/oracle/oradata/fdp1/system01.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3

*：这种情况下SMP监控FDP1-DB状态OK，而且还是主态。

查询当前用户
SQL> SELECT USER FROM DUAL;
SQL> show user;

在Oracle中切换账户可以通过ALTER SESSION和CONNECT语句来实现。ALTER SESSION语句可以在不断开会话的情况下切换账户（需要具有ALTER SESSION系统权限），而CONNECT语句将会话断开并重新连接到新账户。

SQL> SELECT username FROM dba_users;
SQL> connect PLAN/ca2804
Connected.
SQL> select t.table_name from user_tables t;
SQL> SELECT table_name, tablespace_name FROM user_tables WHERE table_name = 'T_CPDLCTIMER';
SQL> SELECT OWNER FROM DBA_TABLES WHERE TABLE_NAME='T_CPDLCTIMER';