上周，在公司中心范围内进行了一次技术分享，主要阐述一下Datagurd技术的使用范围，其中涉及一些Flashback技术的应用：我们主要利用Flashback闪回特性进行应用人员的误操作，进行恢复。
实际操作流程如下：
主库：Travelskydba
备库：Travelskydba_std
主库：
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON
--------- ------------------------------ -------------------- ---------------- --- ------------------
Travelskydba Travelskydba READ WRITE PRIMARY YES NO
备库：
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON
--------- ------------------------------ -------------------- ---------------- --- ------------------
Travelskydba Travelskydba_std MOUNTED PHYSICAL STANDBY YES YES
SQL> show parameter db_flashback_retention_target
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_flashback_retention_target integer 1440
主库执行事务：
SQL> create user albert identified by albert;
User created.
SQL> grant connect,resource to albert;
Grant succeeded.
SQL> conn albert/albert
Connected.
SQL> create table Travelskydba (id1 number,id2 number,id3 number);
Table created.
SQL> insert into Travelskydba values(1,2,3);
1 row created.
SQL> insert into Travelskydba values(4,5,6);
1 row created.
SQL> commit;
Commit complete.
主库：
SQL> select * from albert.Travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
4 5 6
SQL> conn / as sysdba
Connected.
SQL> select current_scn from v$database;
CURRENT_SCN
-----------
20619438
--开启实时应用的备库已经完成redo应用，数据已经保持与主库同步了：
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON
--------- ------------------------------ -------------------- ---------------- --- ------------------
Travelskydba Travelskydba_std READ ONLY WITH APPLY PHYSICAL STANDBY YES YES
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
4 5 6
有时我们接收到应用人员的电话，数据误删除了，或者对数据的调研不足，导致实时应用的数据当做历史数据删除掉了，请求DBA需要进行数据恢复，此时我们可以利用DataGuard 备库已经开启的flashback特性进行数据恢复。
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON
--------- ------------------------------ -------------------- ---------------- --- ------------------
Travelskydba Travelskydba_std READ ONLY WITH APPLY PHYSICAL STANDBY YES YES
SQL> select OLDEST_FLASHBACK_SCN,to_char(OLDEST_FLASHBACK_TIME,'yyyymmdd hh24:mi:ss') time,RETENTION_TARGET,FLASHBACK_SIZE,ESTIMATED_FLASHBACK_SIZE from v$flashback_database_log;
OLDEST_FLASHBACK_SCN TIME RETENTION_TARGET FLASHBACK_SIZE ESTIMATED_FLASHBACK_SIZE
-------------------- ----------------- ---------------- -------------- ------------------------
20611974 20200325 12:16:12 1440 629145600 1323294720
如果数据量较少，主库可以利用DBLINK 进行数据恢复：
SQL> show user
USER is "ALBERT"
SQL> insert into travelskydba select * from albert.travelskydba@TRAVELSKYDBA_LINK where id1=1;
1 row created.
SQL> commit;
Commit complete.
SQL> select * from travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
4 5 6
--数据恢复后，备库可以继续进行实时应用
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup;
ORACLE instance started.
Total System Global Area 4108759040 bytes
Fixed Size 2259680 bytes
Variable Size 1543505184 bytes
Database Buffers 2550136832 bytes
Redo Buffers 12857344 bytes
Database mounted.
Database opened.
--备库：
SQL> set linesize 200
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in ('LNS','RFS','MRP0') and THREAD# <> 0
2 /
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
MRP0 APPLYING_LOG N/A 1 6942 1 5 5
SQL> /
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
MRP0 APPLYING_LOG N/A 1 6942 1 5 5
RFS CLOSING UNKNOWN 1 6944 1 0 0
RFS OPENING UNKNOWN 1 6943 0 0 0
RFS OPENING UNKNOWN 1 6942 0 0 0
RFS OPENING UNKNOWN 1 6946 0 0 0
RFS OPENING UNKNOWN 1 6948 0 0 0
6 rows selected.
--主库：
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in ('LNS','RFS','MRP0') and THREAD# <> 0;
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
LNS WRITING LNS 1 6950 5 0 0
SQL> /
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
LNS WRITING LNS 1 6950 6 0 0
SQL> /
/
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
LNS WRITING LNS 1 6950 7 0 0
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /oracle/archive_Travelskydba/Traveskydba
Oldest online log sequence 6948
Next log sequence to archive 6950
Current log sequence 6950
上述情形适用于误删除数据量较小的情况，如果遇到误删除的数据较多，利用DB_LINK的方式效率相对是比较低下的，我们需要将备库打开至read write mode，将数据导入导出，从而达到进行数据恢复的目的
--备库：
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON
--------- ------------------------------ -------------------- ---------------- --- ------------------
Travelskydba Travelskydba_std READ ONLY WITH APPLY PHYSICAL STANDBY YES YES
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
主库误删除用户：
SQL> drop user albert cascade;
User dropped.
备库：
SQL> select * from albert.travelskydba;
select * from albert.travelskydba
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> alter database recover managed standby database cancel;
Database altered.
SQL> create restore point tra guarantee flashback database; --创建resotre point
Restore point created.
SQL> flashback database to scn 20668180;
Flashback complete.
SQL> ALTER DATABASE ACTIVATE STANDBY DATABASE;--将备库打开至可读可写状态
Database altered.
SQL> alter database open;
Database altered.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON
--------- ------------------------------ -------------------- ---------------- --- ------------------
Travelskydba Travelskydba_std READ WRITE PRIMARY YES YES
SQL> select * from albert.travelskydba; --数据恢复完成，将此用户导出，导入恢复至主库
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
SQL> create directory tra_dir as '/home/ora11g/';
Directory created.
SQL>
SQL> grant read,write,execute on directory tra_dir to public;
Grant succeeded.
[ora11g@albert ]$ expdp schemas=ALBERT directory=tra_dir dumpfile=albert_dmp.20200325 logfile=expdp_20200325.log
Export: Release 11.2.0.4.0 - Production on Wed Mar 25 09:59:48 2020
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
Username: / as sysdba
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Starting "SYS"."SYS_EXPORT_SCHEMA_01": /******** AS SYSDBA schemas=ALBERT directory=tra_dir dumpfile=albert_dmp.20200325 logfile=expdp_20200325.log
Estimate in progress using BLOCKS method...
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 64 KB
Processing object type SCHEMA_EXPORT/USER
Processing object type SCHEMA_EXPORT/SYSTEM_GRANT
Processing object type SCHEMA_EXPORT/ROLE_GRANT
Processing object type SCHEMA_EXPORT/DEFAULT_ROLE
Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
. . exported "ALBERT"."TRAVELSKYDBA" 5.812 KB 1 rows
Master table "SYS"."SYS_EXPORT_SCHEMA_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SYS.SYS_EXPORT_SCHEMA_01 is:
/home/ora11g/albert_dmp.20200325
Job "SYS"."SYS_EXPORT_SCHEMA_01" successfully completed at Wed Mar 25 10:00:08 2020 elapsed 0 00:00:17
[ora11g@albert ~]$ scp albert_dmp.20200325 ******:/home/ora11g
The authenticity of host '*******' can't be established.
RSA key fingerprint is 45:b9:52:12:86:55:8d:e5:33:8b:b8:59:02:68:81:ff.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '******' (RSA) to the list of known hosts.
ora11g@******'s password:
albert_dmp.20200325 100% 180KB 180.0KB/s 00:00
--导入主库：
SQL> create directory tra_dir as '/home/ora11g/';
Directory created.
SQL> grant read,write,execute on directory tra_dir to public;
Grant succeeded.
[ora11g@vm-kvm17146-ora ~]$ impdp schemas=ALBERT directory=tra_dir dumpfile=albert_dmp.20200325 logfile=impdp_20200325.log
Import: Release 11.2.0.4.0 - Production on Wed Mar 25 20:28:48 2020
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
Username: / as sysdba
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Master table "SYS"."SYS_IMPORT_SCHEMA_01" successfully loaded/unloaded
Starting "SYS"."SYS_IMPORT_SCHEMA_01": /******** AS SYSDBA schemas=ALBERT directory=tra_dir dumpfile=albert_dmp.20200325 logfile=impdp_20200325.log
Processing object type SCHEMA_EXPORT/USER
Processing object type SCHEMA_EXPORT/SYSTEM_GRANT
Processing object type SCHEMA_EXPORT/ROLE_GRANT
Processing object type SCHEMA_EXPORT/DEFAULT_ROLE
Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
. . imported "ALBERT"."TRAVELSKYDBA" 5.812 KB 1 rows
Job "SYS"."SYS_IMPORT_SCHEMA_01" successfully completed at Wed Mar 25 20:28:59 2020 elapsed 0 00:00:04
主库数据恢复：
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
主库数据已经恢复，但是我们现在要继续处理备库，让备库继续进行实时应用
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL>
SQL>
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 4108759040 bytes
Fixed Size 2259680 bytes
Variable Size 1577059616 bytes
Database Buffers 2516582400 bytes
Redo Buffers 12857344 bytes
Database mounted.
SQL> flashback database to restore point tra; --闪回至restore point
Flashback complete.
SQL> alter database convert to physical standby; 更新control_file，database_role为physical standby
Database altered.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON
--------- ------------------------------ -------------------- ---------------- --- ------------------
Travelskydba Travelskydba_std MOUNTED PHYSICAL STANDBY YES YES
SQL> alter database recover managed standby database using current logfile disconnect from session;
Database altered.
主库：
SQL> set linesize 200
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in('LNS','RFS','MRP0') and thread# <>0;
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
LNS WRITING LNS 1 6972 90 0 0
SQL> alter system switch logfile;
System altered.
SQL> set linesize 200
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in('LNS','RFS','MRP0') and thread# <>0
2 ;
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
LNS WRITING LNS 1 6973 4 0 0
备库：
SQL> set linesize 200
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in('LNS','RFS','MRP0') and thread# <>0;
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
RFS IDLE LGWR 1 6973 8 0 0
MRP0 APPLYING_LOG N/A 1 6973 8 5 5
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
我们还可以利用Oracle snapshot方式进行备库的read write模式打开
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba READ WRITE PRIMARY YES NO 20755536
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
--备库：
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std READ ONLY WITH APPLY PHYSICAL STANDBY YES YES 20755688
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
--主库误删除数据：
SQL> drop user albert cascade;
User dropped.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba READ WRITE PRIMARY YES NO 20755761
--备库：
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std READ ONLY WITH APPLY PHYSICAL STANDBY YES YES 20755770
SQL> select * from albert.travelskydba;
select * from albert.travelskydba
*
ERROR at line 1:
ORA-00942: table or view does not exist
准备恢复数据：
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 4108759040 bytes
Fixed Size 2259680 bytes
Variable Size 1577059616 bytes
Database Buffers 2516582400 bytes
Redo Buffers 12857344 bytes
Database mounted.
SQL> show parameter broker
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
dg_broker_config_file1 string /oracle/oradata_Travelskydba/Travelskydba/dataguardconfig/dg_config0
1.ora
dg_broker_config_file2 string /oracle/oradata_Travelskydba/Travelskydba/dataguardconfig/dg_config0
2.ora
dg_broker_start boolean TRUE
SQL> alter system set dg_broker_start=false;
System altered.
SQL> alter database recover managed standby database cancel;
Database altered.
SQL> flashback database to scn 20755688;
Flashback complete.
SQL> alter database open;
Database altered.
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 4108759040 bytes
Fixed Size 2259680 bytes
Variable Size 1577059616 bytes
Database Buffers 2516582400 bytes
Redo Buffers 12857344 bytes
Database mounted.
SQL>
SQL> alter database convert to snapshot standby;
Database altered.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std MOUNTED SNAPSHOT STANDBY YES YES 0
SQL> alter database open;
Database altered.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std READ WRITE SNAPSHOT STANDBY YES YES 20755867
SQL> select * from albert.travelskydba;
ID1 ID2 ID3
---------- ---------- ----------
1 2 3
[ora11g@albert ~]$ expdp schemas=ALBERT directory=tra_dir dumpfile=albert_dmp.20200326 logfile=expdp_20200326.log
Export: Release 11.2.0.4.0 - Production on Thu Mar 26 01:12:23 2020
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
Username: / as sysdba
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Starting "SYS"."SYS_EXPORT_SCHEMA_01": /******** AS SYSDBA schemas=ALBERT directory=tra_dir dumpfile=albert_dmp.20200326 logfile=expdp_20200326.log
Estimate in progress using BLOCKS method...
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 64 KB
Processing object type SCHEMA_EXPORT/USER
Processing object type SCHEMA_EXPORT/SYSTEM_GRANT
Processing object type SCHEMA_EXPORT/ROLE_GRANT
Processing object type SCHEMA_EXPORT/DEFAULT_ROLE
Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
. . exported "ALBERT"."TRAVELSKYDBA" 5.812 KB 1 rows
Master table "SYS"."SYS_EXPORT_SCHEMA_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SYS.SYS_EXPORT_SCHEMA_01 is:
/home/ora11g/albert_dmp.20200326
Job "SYS"."SYS_EXPORT_SCHEMA_01" successfully completed at Thu Mar 26 01:12:44 2020 elapsed 0 00:00:18
--数据导入过程省略--
--备库恢复至standby模式：
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 4108759040 bytes
Fixed Size 2259680 bytes
Variable Size 1577059616 bytes
Database Buffers 2516582400 bytes
Redo Buffers 12857344 bytes
Database mounted.
SQL> alter database convert to physical standby;
Database altered.
SQL> shutdown immediate;
ORA-01507: database not mounted
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 4108759040 bytes
Fixed Size 2259680 bytes
Variable Size 1577059616 bytes
Database Buffers 2516582400 bytes
Redo Buffers 12857344 bytes
Database mounted.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std MOUNTED PHYSICAL STANDBY YES YES 20755688 --之前闪回的SCN点，flashback database to scn 20755688;
SQL> alter database recover managed standby database using current logfile disconnect from session;
Database altered.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std MOUNTED PHYSICAL STANDBY YES YES 20757332
SQL> /
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std MOUNTED PHYSICAL STANDBY YES YES 20757332
SQL> alter database open;
Database altered.
SQL> select name,DB_UNIQUE_NAME,open_mode,database_role,force_logging,flashback_on,current_scn from v$database;
NAME DB_UNIQUE_NAME OPEN_MODE DATABASE_ROLE FOR FLASHBACK_ON CURRENT_SCN
--------- ------------------------------ -------------------- ---------------- --- ------------------ -----------
Travelskydba Travelskydba_std MOUNTED PHYSICAL STANDBY YES YES 20757498
主库：
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in('LNS','RFS','MRP0') and thread# <>0;
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
LNS WRITING LNS 1 19 206 0 0
SQL>
SQL> alter system switch logfile;
System altered.
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in('LNS','RFS','MRP0') and thread# <>0;
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
LNS WRITING LNS 1 20 6 0 0
备库：
SQL> set linesize 200
SQL> select process,status,client_process,thread#,sequence#,block#,active_agents,known_agents from gv$managed_standby where process in('LNS','RFS','MRP0') and thread# <>0;
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
MRP0 APPLYING_LOG N/A 1 19 142 5 5
RFS IDLE LGWR 1 19 142 0 0
SQL> /
PROCESS STATUS CLIENT_P THREAD# SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
--------- ------------ -------- ---------- ---------- ---------- ------------- ------------
MRP0 APPLYING_LOG N/A 1 20 55 5 5
RFS IDLE LGWR 1 20 55 0 0
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