DG - 将physical standby置于read-only模式

1.备库处于关闭状态

SQL> startup
ORACLE instance started.

Total System Global Area  430075904 bytes
Fixed Size                  2253944 bytes
Variable Size             184552328 bytes
Database Buffers          239075328 bytes
Redo Buffers                4194304 bytes
Database mounted.
Database opened.
SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ ONLY

SQL>

2.备库处于redo apply状态

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
MOUNTED

SQL> alter database recover managed standby database cancel;

Database altered.

SQL> alter database open;

Database altered.

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ ONLY

SQL>