#PDB級閃回（Flashback PDB）
#PDB閃回有幾個基本的前提條件：
1，enable local undo
2，enable archivelog mode
3，enable flashback database;
#停快速故障轉移功能
DGMGRL>?stop observer
DGMGRL>?disable fast_start failover;
#主庫停止日志傳到從庫（可選操作）
SQL>alter system set log_archive_dest_state_2=defer scope=both;? （可選擇）
[oracle@XAG126 ~]$ dgmgrl sys/123456
Connected to "DG126"
Connected as SYSDG.
DGMGRL> show configuration;
Configuration - ADGbroker
? Protection Mode: MaxAvailability
? Members:
? DG125 - Primary database
? ? DG126 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS? (status updated 3 seconds ago)
[oracle@XAG125 ~]$ sqlplus / as sysdba
SQL> select database_role,flashback_on from v$database;
????????????PRIMARY YES
SQL> show parameter db_recovery_file_dest
db_recovery_file_dest ? ? string /u01/app/oracle/fast_recovery_area/ORACLE12CDG
db_recovery_file_dest_size ? ? big integer 8016M
SQL> show parameter flashback
db_flashback_retention_target ? ? integer 1440
SQL>?select flashback_on from v$database;
????????????YES
SQL> show pdbs
2 PDB$SEED ? READ ONLY? NO
3 PDB1 ? READ WRITE NO
1. 在 PDB 級別創(chuàng)建 restore points：
連接到特定的 PDB 然后運行 CREATE RESTORE POINT 命令：
SQL> alter session set container=PDB1;
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi') from dual;
????????????2018-10-04 13:44
SQL> create restore point pdb1_10041344;? ?#正常還原點 （和如下2選1）
SQL> create restore point pdb1_10041344?guarantee flashback database;? #擔保還原點
或
連接到 CDB，并使用 CREATE RESTORE POINT 命令的 FOR PLUGGABLE DATABASE 子句：
SQL> alter session set container=CDB$ROOT;
#正常還原點 （和如下2選1）
SQL> create restore point pdb1_10041344?for pluggable database PDB1;?
SQL> create restore point pdb1_10041344?for pluggable database PDB1 guarantee flashback database;
#第一次測試輸入插入 CDB 及 PDB 都插入測試數(shù)據(jù)
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi') from dual;
? ??????????2018-10-04 13:45
#pdb
#CDB
#第二次測試輸入插入 CDB 及 PDB 都插入測試數(shù)據(jù)
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi') from dual;
????????????2018-10-04 13:50
#PDB
#CDB
##開始還原
#還原到第一次（13:45）插入后，第二次（13:50）插入前時間 即13:47
flashback backup在12.2中有rman和SQL兩種方式閃回， 當使用shared undo里需要使用rman，前提需要在pdb close immediate后創(chuàng)建clean resotre point, 過程中會自動創(chuàng)建輔助實例CDB和PDB PITR；?
使用local undo時,就可以使用SQL命令更佳快速，而且只是pdb 數(shù)據(jù)文件原位置閃回，并應用undo，在做之前創(chuàng)建任意一種restore point都可以，也不需要輔助實例。
SQL> show pdbs;
????????????3 PDB1 ? READ WRITE NO
SQL> shutdown immediate;? or?alter pluggable database PDB1 close;
SQL> show pdbs;
????????????3 PDB1 ? MOUNTED
SQL> FLASHBACK PLUGGABLE DATABASE PDB1 TO TIMESTAMP to_timestamp('2018-10-04 13:47:00','yyyy-mm-dd hh24:mi:ss');
SQL> alter pluggable database PDB1? open resetlogs;
#備庫日誌如下：
#ADG 狀態(tài)如下
DGMGRL> show configuration;
Configuration - ADGbroker
? Protection Mode: MaxAvailability
? Members:
? DG125 - Primary database
? ? DG126 - Physical standby database
? ? ? Error: ORA-16810: multiple errors or warnings detected for the member
Fast-Start Failover: DISABLED
Configuration Status:
ERROR? (status updated 37 seconds ago)
DGMGRL> show database 'DG126' statusreport
STATUS REPORT
? ? ? INSTANCE_NAME? SEVERITY ERROR_TEXT
? ? ? ? ? ? ? ? ? *? ? WARNING ORA-16853: apply lag has exceeded specified threshold
? ? ? ? ? ? ? ? ? *? ? ? ERROR ORA-16766: Redo Apply is stopped
#主庫狀態(tài)如下
DGMGRL> show database 'DG125';
Database - DG125
? Role:? ? ? ? ? ? ? PRIMARY
? Intended State:? ? TRANSPORT-ON
? Instance(s):
? ? DG
Database Status:
SUCCESS
但是備庫存在錯誤
DGMGRL> show database 'DG126';
Database - DG126
? Role:? ? ? ? ? ? ? PHYSICAL STANDBY
? Intended State:? ? APPLY-ON
? Transport Lag:? ? ? 0 seconds (computed 0 seconds ago)
? Apply Lag:? ? ? ? ? 7 minutes 28 seconds (computed 0 seconds ago)
? Average Apply Rate: 5.00 KByte/s
? Real Time Query:? ? OFF
? Instance(s):
? ? DG
? Database Error(s):
? ? ORA-16766: Redo Apply is stopped
? Database Warning(s):
? ? ORA-16853: apply lag has exceeded specified threshold
Database Status:
ERROR
?#alert log of the standby dataset we can find following errors
---------------------------------------------------------------------
2018-10-04T13:59:55.300500+08:00
(3):Recovery of pluggable database PDB1 aborted due to pluggable database open resetlog marker.
(3):To continue recovery, restore all data files for this PDB to checkpoint SCN lower than 2820243, or timestamp before 10/04/2018 13:47:02, and restart recovery
MRP0: Background Media Recovery terminated with error 39874
2018-10-04T13:59:55.301469+08:00
Errors in file /u01/app/oracle/diag/rdbms/dg126/DG/trace/DG_pr00_1448.trc:
ORA-39874: Pluggable Database PDB1 recovery halted
ORA-39873: Restore all data files to a checkpoint SCN lower than 2820243.
Managed Standby Recovery not using Real Time Apply
Recovery interrupted!
Recovered data files to a consistent state at change 2822396
2018-10-04T13:59:55.425604+08:00
Errors in file /u01/app/oracle/diag/rdbms/dg126/DG/trace/DG_pr00_1448.trc:
ORA-39874: Pluggable Database PDB1 recovery halted
ORA-39873: Restore all data files to a checkpoint SCN lower than 2820243.
2018-10-04T13:59:55.526502+08:00
MRP0: Background Media Recovery process shutdown (DG)
---------------------------------------------------------------------------------------------
On the primary PDB, we can can query the current INCARNATION_SCN in the v$pdb_incarnation view. And we can remark that the current SCN is the same that the one specified in the standby alert log?2820243
SQL> show con_name
CON_NAME
------------------------------
PDB1
SQL> select status,INCARNATION_SCN from v$pdb_incarnation;
STATUS ? ? ? INCARNATION_SCN
--------------------- ---------------
CURRENT ? ? ? 2820243
PARENT ? ? ? 2756861
PARENT ? ? ? 2756236
PARENT ? ? ? 2741913
PARENT ? ? ? 2741034
PARENT ? ? ? 1408558
#And then as specified in the alert log we have to flashback the standby pdb to a SCN lower than 2820243
First let’s stop the redo apply on the standby
DGMGRL> edit database 'DG126' set state='APPLY-OFF';
#備庫
And then let’s flashback to 2820241( i.e 2820243-2 ) for example
Let’s shutdown the standby container and startup it in a mount state
SQL> select name,open_mode from v$pdbs;
PDB$SEED????????????????READ ONLY
PDB1????????????????????????????READ ONLY
PDB8????????????????????????????READ ONLY
SQL> show pdbs
2 PDB$SEED ? READ ONLY? NO
3 PDB1 ? READ ONLY? NO
4 PDB8 ? READ ONLY? NO
SQL> shutdown immediate;
SQL> startup mount;
SQL>?flashback pluggable database PDB1 to SCN 2820241;
#啟用備庫應用
DGMGRL> edit database 'DG126' set state='APPLY-ON';
#檢查ADG狀態(tài)
DGMGRL> show configuration
Configuration - ADGbroker
? Protection Mode: MaxAvailability
? Members:
? DG125 - Primary database
? ? DG126 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS? (status updated 4 seconds ago)
#OPEN DB
SQL> alter database open;
Database altered.
SQL> show pdbs;
? ? CON_ID CON_NAME ? OPEN MODE? RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED ? READ ONLY? NO
3 PDB1 ? READ ONLY? NO
4 PDB8 ? READ ONLY? NO
#還原到還原點(restore point)?pdb1_10041344?
#主庫
SQL> show pdbs;
????????????3 PDB1 ? READ WRITE NO
SQL> shutdown immediate; or alter pluggable database PDB1 close;
SQL> show pdbs;
????????????3 PDB1 ? MOUNTED
SQL> FLASHBACK PLUGGABLE DATABASE PDB1?TO RESTORE POINT pdb1_10041344;
SQL> alter pluggable database PDB1 open resetlogs;
#檢查CDB數(shù)據(jù)未見回滾，但是PDB 數(shù)據(jù)回滾到 pdb1_10041344 點時刻
#ADG 狀態(tài)如下
DGMGRL> show configuration;
Configuration - ADGbroker
? Protection Mode: MaxAvailability
? Members:
? DG125 - Primary database
? ? DG126 - Physical standby database
? ? ? Error: ORA-16810: multiple errors or warnings detected for the member
Fast-Start Failover: DISABLED
Configuration Status:
ERROR? (status updated 37 seconds ago)
DGMGRL> show database 'DG126' statusreport
STATUS REPORT
? ? ? INSTANCE_NAME? SEVERITY ERROR_TEXT
? ? ? ? ? ? ? ? ? *? ? WARNING ORA-16853: apply lag has exceeded specified threshold
? ? ? ? ? ? ? ? ? *? ? ? ERROR ORA-16766: Redo Apply is stopped
#主庫狀態(tài)如下
DGMGRL> show database 'DG125';
Database - DG125
? Role:? ? ? ? ? ? ? PRIMARY
? Intended State:? ? TRANSPORT-ON
? Instance(s):
? ? DG
Database Status:
SUCCESS
但是備庫存在錯誤
DGMGRL> show database 'DG126';
Database - DG126
? Role:? ? ? ? ? ? ? PHYSICAL STANDBY
? Intended State:? ? APPLY-ON
? Transport Lag:? ? ? 0 seconds (computed 0 seconds ago)
? Apply Lag:? ? ? ? ? 7 minutes 28 seconds (computed 0 seconds ago)
? Average Apply Rate: 5.00 KByte/s
? Real Time Query:? ? OFF
? Instance(s):
? ? DG
? Database Error(s):
? ? ORA-16766: Redo Apply is stopped
? Database Warning(s):
? ? ORA-16853: apply lag has exceeded specified threshold
Database Status:
ERROR
#alert log of the standby dataset we can find following errors
---------------------------------------------------------------------
2018-10-04T14:34:03.978752+08:00
Errors in file /u01/app/oracle/diag/rdbms/dg126/DG/trace/DG_pr00_2701.trc:
ORA-39874: Pluggable Database PDB1 recovery halted
ORA-39873: Restore all data files to a checkpoint SCN lower than 2820013.
Managed Standby Recovery not using Real Time Apply
Recovery interrupted!
Recovered data files to a consistent state at change 2828721
2018-10-04T14:34:04.096906+08:00
Errors in file /u01/app/oracle/diag/rdbms/dg126/DG/trace/DG_pr00_2701.trc:
ORA-39874: Pluggable Database PDB1 recovery halted
ORA-39873: Restore all data files to a checkpoint SCN lower than 2820013.
2018-10-04T14:34:04.197542+08:00
MRP0: Background Media Recovery process shutdown (DG)
#On the primary PDB, we can can query the current INCARNATION_SCN in the v$pdb_incarnation view. And we can remark that the current SCN is the same that the one specified in the standby alert log 2820013
SQL> show con_name
CON_NAME
------------------------------
PDB1
SQL> select status,INCARNATION_SCN from v$pdb_incarnation;
STATUS ? ? ? INCARNATION_SCN
--------------------- ---------------
CURRENT ? ? ? 2820013
PARENT ? ? ? 2756861
PARENT ? ? ? 2756236
PARENT ? ? ? 2741913
PARENT ? ? ? 2741034
PARENT ? ? ? 1408558
ORPHAN ? ? ? 2820243
7 rows selected.
#And then as specified in the alert log we have to flashback the standby pdb to a SCN lower than 2820013
First let’s stop the redo apply on the standby
DGMGRL> edit database 'DG126' set state='APPLY-OFF';
#備庫
And then let’s flashback to 2820011( i.e 2820013-2 ) for example
Let’s shutdown the standby container and startup it in a mount state
SQL> show pdbs
2 PDB$SEED ? READ ONLY? NO
3 PDB1? READ ONLY? NO
4 PDB8? READ ONLY? NO
SQL> shutdown immediate;
SQL> startup mount;
SQL> flashback pluggable database PDB1 to SCN 2820011;
#啟用備庫應用
DGMGRL> edit database 'DG126' set state='APPLY-ON';
#檢查ADG狀態(tài)
DGMGRL> show configuration
Configuration - ADGbroker
? Protection Mode: MaxAvailability
? Members:
? DG125 - Primary database
? ? DG126 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS? (status updated 4 seconds ago)
#OPEN DB
SQL> alter database open;
Database altered.
SQL> show pdbs;
? ? CON_ID CON_NAME ? OPEN MODE? RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED ? READ ONLY? NO
3 PDB1? READ ONLY? NO
4 PDB8? READ ONLY? NO
#啟動快速故障轉移功能
DGMGRL>?enable fast_start failover;
DGMGRL>?start observer
參考?http://blog.dbi-services.com/oracle-12-2-dataguard-pdb-flashback-on-the-primary/
