一朋友公司环境，因测试库、生产库错连，造成大批量数据丢失，通过Oracle数据库回收站方式已找回绝大部分数据，还有部分数据丢失， 查看dg备端，发现备端归档都在，但没有应用到数据库里。 可通过指定时间方式，先恢复数据库到删除之前的节点。 参考命令如下： ``` #示例为19c dg #因操作不当，误删除了一个pdb，根据删除时间，通过备端进行恢复 2021-07-22T15:55:44.291222+08:00 drop pluggable database testpdb including datafiles 2021-07-22T15:55:55.145297+08:00 Deleted file /u01/app/oracle/oradata/MYDB19C/testpdb/testpdb_user01.dbf 2021-07-22T15:55:56.436102+08:00 Deleted file /u01/app/oracle/oradata/MYDB19C/testpdb/testpdb_temp01.dbf #dg备端为mount状态，通过rman恢复 RMAN> recover database until time "to_date('2021-07-22 15:51:00','YYYY-MM-DD HH24:MI:SS')"; Starting recover at 22-JUL-21 using target database control file instead of recovery catalog allocated channel: ORA_DISK_1 channel ORA_DISK_1: SID=35 device type=DISK starting media recovery archived log for thread 1 with sequence 153 is already on disk as file /arch/1_153_1029107282.arc archived log for thread 1 with sequence 154 is already on disk as file /arch/1_154_1029107282.arc archived log for thread 1 with sequence 155 is already on disk as file /arch/1_155_1029107282.arc archived log for thread 1 with sequence 156 is already on disk as file /arch/1_156_1029107282.arc archived log for thread 1 with sequence 157 is already on disk as file /arch/1_157_1029107282.arc archived log for thread 1 with sequence 158 is already on disk as file /arch/1_158_1029107282.arc archived log for thread 1 with sequence 159 is already on disk as file /arch/1_159_1029107282.arc archived log for thread 1 with sequence 160 is already on disk as file /arch/1_160_1029107282.arc archived log for thread 1 with sequence 161 is already on disk as file /arch/1_161_1029107282.arc archived log for thread 1 with sequence 162 is already on disk as file /arch/1_162_1029107282.arc archived log for thread 1 with sequence 163 is already on disk as file /arch/1_163_1029107282.arc archived log for thread 1 with sequence 164 is already on disk as file /arch/1_164_1029107282.arc archived log file name=/arch/1_153_1029107282.arc thread=1 sequence=153 archived log file name=/arch/1_154_1029107282.arc thread=1 sequence=154 archived log file name=/arch/1_155_1029107282.arc thread=1 sequence=155 archived log file name=/arch/1_156_1029107282.arc thread=1 sequence=156 archived log file name=/arch/1_157_1029107282.arc thread=1 sequence=157 archived log file name=/arch/1_158_1029107282.arc thread=1 sequence=158 archived log file name=/arch/1_159_1029107282.arc thread=1 sequence=159 archived log file name=/arch/1_160_1029107282.arc thread=1 sequence=160 archived log file name=/arch/1_161_1029107282.arc thread=1 sequence=161 archived log file name=/arch/1_162_1029107282.arc thread=1 sequence=162 archived log file name=/arch/1_163_1029107282.arc thread=1 sequence=163 archived log file name=/arch/1_164_1029107282.arc thread=1 sequence=164 media recovery complete, elapsed time: 00:02:16 Finished recover at 22-JUL-21 ``` 检查备端情况 ``` sql --打开数据库 SQL> alter database open; Database altered. SQL> show pdbs CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 3 TESTPDB MOUNTED 4 MYPDB MOUNTED --如果开启recover，后续就删除了testpdb SQL> alter database recover managed standby database using current logfile disconnect from session; Database altered. SQL> show pdbs CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 4 MYPDB MOUNTED ``` 另，注意，Oracle19c 在mount数据库时，dg备端会自动开启recover模式，应用归档日志。 alert日志参考： ``` ARCc started with pid=64, OS id=88513 2021-07-22T16:10:49.636837+08:00 MRP0 (PID:88499): Managed Standby Recovery starting Real Time Apply 2021-07-22T16:10:49.672074+08:00 ARCd started with pid=65, OS id=88518 2021-07-22T16:10:49.672676+08:00 Starting background process ARCe 2021-07-22T16:10:51.903729+08:00 max_pdb is 8 2021-07-22T16:10:55.411248+08:00 Starting background process ARCf 2021-07-22T16:10:55.420715+08:00 ARCe started with pid=66, OS id=88524 2021-07-22T16:10:57.850452+08:00 Starting background process ARCg 2021-07-22T16:10:57.967273+08:00 ARCf started with pid=67, OS id=88528 2021-07-22T16:11:01.664535+08:00 stopping change tracking 2021-07-22T16:11:01.682638+08:00 MRP0 (PID:88499): Media Recovery Log /arch/1_151_1029107282.arc 2021-07-22T16:11:02.562368+08:00 Completed: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT NODELAY 2021-07-22T16:11:03.176818+08:00 ARCg started with pid=68, OS id=88532 2021-07-22T16:11:03.177282+08:00 ```