Oracle 19c通过recover standby database from service修复GAP案例
案例介绍
环境介绍
操作系统： Red Hat Enterprise Linux release 8.10 (Ootpa) 数据库版本： Oracle 19.23.0.0.0
上周五，系统管理员需要给Linux升级补丁，UAT环境下的一套DG，数据库没有正常关闭的情况下，操作系统升级补丁后强制reboot了，周一早上处理的过程中遇到下面错误：
备库的告警日志有下面错误信息(GAP sequence提示信息)：
PR00 (PID:145361): FAL: Failed to request gap sequence
PR00 (PID:145361): GAP - thread 1 sequence 94-94
PR00 (PID:145361): DBID 1790039322 branch 1173452819
PR00 (PID:145361): FAL: All defined FAL servers have been attempted
PR00 (PID:145361): -------------------------------------------------------------------------
PR00 (PID:145361): Check that the CONTROL_FILE_RECORD_KEEP_TIME initialization
PR00 (PID:145361): parameter is defined to a value that's sufficiently large
PR00 (PID:145361): enough to maintain adequate log switch information to resolve
PR00 (PID:145361): archived redo log gaps.
PR00 (PID:145361): -------------------------------------------------------------------------
2024-07-22T10:26:06.796447+08:00
主库查询
set linesize 720
col name for a60
col creator for a12
select name,creator,sequence#,applied,completion_time from v$archived_log where sequence#=94;
SQL> set linesize 720
SQL> col name for a60
SQL> col creator for a12
SQL> select name,creator,sequence#,applied,completion_time from v$archived_log where sequence#=94;
NAME CREATOR SEQUENCE# APPLIED COMPLETIO
------------------------------------------------------------ ------------ ---------- --------- ---------
/gspdblog/gspprod_1173452819_1_94.arc ARCH 94 NO 19-JUL-24
SQL>
检查确认主库上的归档日志gspprod_1173452819_1_94.arc已经被删除了。
检查备库最后应用的归档日志信息：
SQL> set pages 1000 lines 1000
SQL> SELECT al.thrd "Thread", almax "Last Seq Received", lhmax "Last Seq Applied"
2 FROM (select thread# thrd, MAX(sequence#) almax
3 FROM v$archived_log
4 WHERE resetlogs_change#=(SELECT resetlogs_change# FROM v$database) GROUP BY thread#) al,
5 (SELECT thread# thrd, MAX(sequence#) lhmax
6 FROM v$log_history
7 WHERE resetlogs_change#=(SELECT resetlogs_change# FROM v$database) GROUP BY thread#) lh
8 WHERE al.thrd = lh.thrd;
Thread Last Seq Received Last Seq Applied
---------- ----------------- ----------------
1 111 93
SQL>
SQL> col client_pid for a10
SQL> select inst_id, thread#, process, pid, status, client_process, client_pid,
2 sequence#, block#, active_agents, known_agents from gv$managed_standby order by thread#, pid;
INST_ID THREAD# PROCESS PID STATUS CLIENT_P CLIENT_PID SEQUENCE# BLOCK# ACTIVE_AGENTS KNOWN_AGENTS
---------- ---------- --------- ------------------------ ------------ -------- ---------- ---------- ---------- ------------- ------------
1 0 DGRD 143439 ALLOCATED N/A N/A 0 0 0 0
1 0 DGRD 143441 ALLOCATED N/A N/A 0 0 0 0
1 0 RFS 147165 IDLE UNKNOWN 148946 0 0 0 0
1 0 RFS 147167 IDLE UNKNOWN 148942 0 0 0 0
1 0 RFS 147169 IDLE UNKNOWN 148944 0 0 0 0
1 1 ARCH 143437 CLOSING ARCH 143437 91 700416 0 0
1 1 ARCH 143443 CLOSING ARCH 143443 92 704512 0 0
1 1 ARCH 143445 CLOSING ARCH 143445 93 696320 0 0
1 1 ARCH 143447 CLOSING ARCH 143447 90 708608 0 0
1 1 MRP0 145359 WAIT_FOR_GAP N/A N/A 94 0 9 9
1 1 RFS 145885 IDLE Archival 148936 0 0 0 0
1 1 RFS 147161 IDLE LGWR 148948 112 321083 0 0
12 rows selected.
SQL>
因为UAT环境没有备份归档日志，而主库上都设置了一个作业清除两天前的归档日志(资源不足，需要定期清理归档日志)，正常情况下，这个作业并不会带来什么问题，而由于上周五升级系统补丁，数据库停了2天，但是这个作业并没有停止(crontab作业)，周一处理的时候，这个作业已经将两天前的归档日志给清理了。导致备用数据库无法获取序列号(SEQUENCE#)为94的归档日志。 此时由于出现归档日志的GAP导致备用数据库无法同步数据，这种情况下， 我们打算用Oracle 18.1提供的新特性来恢复物理备库，如下所示
RMAN> RECOVER STANDBY DATABASE FROM SERVICE primary_connect_identifier;
This command will internally keep track of standby file locations, refresh standby controlfile from primary,
update the new standby controlfile with standby file names, perform incremental backup on primary, transfer
the backup-pieces over network to standby and perform recovery on standby
主要是这种新特性来恢复备用数据库非常方便，一条命令即可搞定，相比之前的增量备份/还原要简单很多。
操作步骤：
取消redo应用(备用数据库)
SQL> alter database recover managed standby database cancel;
Database altered.
将备用数据库启动到MOUNT状态
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 8589932424 bytes
Fixed Size 13932424 bytes
Variable Size 2348810240 bytes
Database Buffers 6207569920 bytes
Redo Buffers 19619840 bytes
Database mounted.
执行下面命令
# 注意，不执行此命令，会遇到RMAN-05150
SQL> recover managed standby database cancel;
Media recovery complete.
SQL>
如果不执行上面命令，在RMAN做recover standby database时会遇到RMAN-05150错误，如下案例所示：
RMAN> recover standby database from service gsp;
Starting recover at 22-JUL-24
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 07/22/2024 10:46:14
RMAN-05150: Managed Recovery Process must be disabled before running RECOVER STANDBY DATABASE.
4: 备库执行修复命令，开始在线刷新备库
RMAN> recover standby database from service gsp;
注意，这里RMAN连接数据库的方式请选择账号密码，不要使用系统认证方式，否则可能会遇到错误案例1.
正常情况下，你会看到类似这样的输出信息
.............................
starting media recovery
media recovery complete, elapsed time: 00:00:00
Finished recover at 22-JUL-24
Finished recover at 22-JUL-24
5：启动数据库恢复同步
在sqlplus中执行下面命令
alter databae open;
alter pluggable database all open;
alter database recover managed standby database using current logfile disconnect;
下面还介绍一下，在操作过程中容易踩到的坑或错误：
错误案例1
使用RMAN恢复备库时，遇到ORA-17629: Cannot connect to the remote database server错误，如下所示
$ rman target /
Recovery Manager: Release 19.0.0.0.0 - Production on Mon Jul 22 10:59:06 2024
Version 19.23.0.0.0
Copyright (c) 1982, 2019, Oracle and/or its affiliates. All rights reserved.
connected to target database: gsp (DBID=1790039322, not open)
RMAN> recover standby database from service gsp;
Starting recover at 22-JUL-24
Oracle instance started
Total System Global Area 8589932424 bytes
Fixed Size 13932424 bytes
Variable Size 2348810240 bytes
Database Buffers 6207569920 bytes
Redo Buffers 19619840 bytes
contents of Memory Script:
{
restore standby controlfile from service 'gsp';
alter database mount standby database;
}
executing Memory Script
Starting restore at 22-JUL-24
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=5 device type=DISK
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 07/22/2024 10:59:33
RMAN-03015: error occurred in stored script Memory Script
ORA-17629: Cannot connect to the remote database server
ORA-17627:
ORA-17629: Cannot connect to the remote database server
RMAN> exit
遇到这个错误，是因为RMAN连接数据库使用操作系统认证，这种方式连接远程数据库(remote database server)就会有问题，应该改成账号密码认证方式连接数据库。 这样就不会遇到这个错误了。
正确方式
rman target sys/user_password
错误方式
rman target /
错误案例2
还原恢复过程遇到下面一系列ORA错误。具体如下所示：
.......................................................................
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 07/22/2024 11:08:40
RMAN-03015: error occurred in stored script Memory Script
ORA-19849: error while reading backup piece from service gsp
ORA-19573: cannot obtain exclusive enqueue for datafile 18
ORA-19890: data file already in use
ORA-45909: restore, recover or block media recovery may be in progress
ORA-19660: some files in the backup set could not be verified
ORA-19661: datafile 18 could not be verified due to corrupt blocks
ORA-19849: error while reading backup piece from service gsp
ORA-19573: cannot obtain exclusive enqueue for datafile 18
ORA-19890: data file already in use
ORA-45909: restore, recover or block media recovery may be in progress
RMAN>
检查备库
select process,status,sequence#,thread# from gv$managed_standby where process like 'MRP%';
SQL> select process,status,sequence#,thread# from gv$managed_standby where process like 'MRP%';
PROCESS STATUS SEQUENCE# THREAD#
--------- ------------ ---------- ----------
MRP0 WAIT_FOR_GAP 94 1
在dgmgr中执行命令
DGMGRL> edit database gspro set state='APPLY-OFF';
Succeeded.
DGMGRL>
重新验证(备用数据库)MRP进程是否已经结束。
SQL> select process,status,sequence#,thread# from gv$managed_standby where process like 'MRP%';
no rows selected
SQL>
如上所示，MRP进程已经不存在了，就可以重新进行还原恢复操作。
参考资料:
ORA-19573 when trying to restore to standby with incremental backup From Primary or During any RMAN restore operation (Doc ID 1646232.1) ORA-17629 with RMAN 'From Service' Command (Doc ID 2960469.1)
