停用DG可在主库运行
DGMGRL> EDIT DATABASE o19 SET STATE='TRANSPORT-OFF';
观察alert日志发现
2023-01-12T13:54:56.882778+08:00 ALTER SYSTEM SET log_archive_dest_state_2='RESET' SCOPE=BOTH;
恢复可运行:
DGMGRL> EDIT DATABASE o19 SET STATE='TRANSPORT-ON';
2. 更改保护模式本例中原来的保护模式是最高性能,现改为最大可用。必须先把到备库的异步传输改为同步:
DGMGRL> EDIT DATABASE 'o19dg' SET PROPERTY 'LogXptMode'='SYNC'; Property "LogXptMode" updated
然后更改保护模式:
DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXAVAILABILITY; Succeeded.
观察结果可得:
DGMGRL> show configuration; Configuration - o19 Protection Mode: MaxAvailability --已改为最大可用 Members: o19 - Primary database o19dg - Physical standby database Fast-Start Failover: Disabled Configuration Status: SUCCESS (status updated 18 seconds ago)
特别注意,主库此时的同步设置不会自动改为同步
DGMGRL> show database verbose o19; Database - o19 Role: PRIMARY Intended State: TRANSPORT-ON Instance(s): o19 Properties: DGConnectIdentifier = 'o19' ObserverConnectIdentifier = '' FastStartFailoverTarget = '' PreferredObserverHosts = '' LogShipping = 'ON' RedoRoutes = '' LogXptMode = 'ASYNC' --此时还是异步
也需要显式地配置为同步:
DGMGRL> EDIT DATABASE 'o19' SET PROPERTY 'LogXptMode'='SYNC'; Property "LogXptMode" updated
