Data Guard出现gap sequence修复

发表于 2011 年 7 月 5 日 由 惜分飞

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标题：Data Guard出现gap sequence修复

作者：惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

一、出现gap sequence现象
备库

Fetching gap sequence in thread 1, gap sequence 710-716
Tue May 31 15:02:38 2011
FAL[client]: Failed to request gap sequence 
 GAP - thread 1 sequence 710-716
 DBID 3240478808 branch 746916894
FAL[client]: All defined FAL servers have been attempted.
-------------------------------------------------------------
Check that the CONTROL_FILE_RECORD_KEEP_TIME initialization
parameter is defined to a value that is sufficiently large
enough to maintain adequate log switch information to resolve
archivelog gaps.
-------------------------------------------------------------

主库

Tue May 31 13:50:47 2011
FAL[server]: Fail to queue the whole FAL gap
 GAP - thread 1 sequence 710-716
 DBID 3240478808 branch 746916894

二、修复操作
1、查询备库的scn

SQL> SELECT CURRENT_SCN FROM V$DATABASE;
CURRENT_SCN
-----------
    1154337
--在出现意外datafile header scn不一致的时候,需要根据提示归档日志,找出最小scn

2、确定主库是否添加数据文件

SQL> select FILE#,name from v$datafile where CREATION_CHANGE#> =1154337;
no rows selected

确定主库在这个scn之后是否有添加数据文件，如果添加文件，需要手工在备库添加

3、备库停止日志应用

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

4、主库增量备份并传输到备库上
主库进行增量备份

RMAN> BACKUP INCREMENTAL FROM SCN  1154337 DATABASE 
FORMAT '/home/oracle/xff_%U' tag 'XIFENFEI';
[oracle@localhost ~]$ scp xff* 192.168.1.30:/home/oracle/rman

说明：主库之前必须要做过rman的全备（没有全备的库，基于scn的增量备份也能够成功）

5、备库上进行恢复

RMAN> CATALOG START WITH '/home/oracle/rman';
RMAN> RECOVER DATABASE NOREDO;

说明：CATALOG START WITH是10g及其以后版本中才存在功能，没有该功能可以采用catalog或者复制主库的控制文件，rman备份放置和主库备份时相同目录实现。

6、主库上创建standby controlfile文件并传输到备库

RMAN> BACKUP CURRENT CONTROLFILE FOR STANDBY 
FORMAT '/home/oracle/xff_ctl.bck';
[oracle@localhost ~]$ scp xff_ctl.bck 192.168.1.30:/home/oracle/rman

创建standby controlfile两步可以需要根据实际情况考虑,大多数情况下不需要

7、备库恢复控制文件

RMAN> shutdown;
RMAN> STARTUP NOMOUNT;
RMAN> RESTORE STANDBY CONTROLFILE FROM '/home/oracle/rman/xff_ctl.bck';
RMAN> alter database mount;

8、清空备库日志组

SQL> ALTER DATABASE CLEAR LOGFILE GROUP 1; 
注：如果采用了standby log模式，不需要清空，如果清空会出现
SQL> ALTER DATABASE CLEAR LOGFILE GROUP 1;
ALTER DATABASE CLEAR LOGFILE GROUP 1
*
ERROR at line 1:
ORA-19527: physical standby redo log must be renamed
ORA-00312: online log 1 thread 1: '/u01/oradata/xienfei/redo01.log'

说明：如果没有采用standby log模式，有几组需要清空几组

9、备库重设flashback

SQL> ALTER DATABASE FLASHBACK OFF; 
SQL> ALTER DATABASE FLASHBACK ON;

10、备库重新接收并应用日志

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

三、修复成功标志
1、sql中操作
在主库中执行alter system switch logfile;
分别主备库中执行select max(sequence#) from v$archived_log;如果一致标示修复成功

2、通过alert文件
主库

PING[ARC0]: Error 3113 when pinging standby xff.
Tue May 31 14:11:51 2011
Thread 1 advanced to log sequence 719
  Current log# 3 seq# 719 mem# 0: /u01/oradata/xienfei/redo03.log
Tue May 31 14:20:05 2011
Thread 1 advanced to log sequence 720
  Current log# 1 seq# 720 mem# 0: /u01/oradata/xienfei/redo01.log
Tue May 31 14:20:16 2011
ARC0: Standby redo logfile selected for thread 1 sequence 719 for destination LOG_ARCHIVE_DEST_2

备库

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION
Tue May 31 15:30:37 2011
Attempt to start background Managed Standby Recovery process (xff)
MRP0 started with pid=18, OS id=14704
Tue May 31 15:30:37 2011
MRP0: Background Managed Standby Recovery process started (xff)
Managed Standby Recovery not using Real Time Apply
 parallel recovery started with 2 processes
Media Recovery Log /u01/archive/1_718_746916894.arc
Tue May 31 15:30:43 2011
Completed: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION
Tue May 31 15:30:52 2011
RFS[1]: Successfully opened standby log 4: '/u01/oradata/xienfei/s_redo1.log'
Media Recovery Log /u01/archive/1_719_746916894.arc
Media Recovery Waiting for thread 1 sequence 720
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《Data Guard出现gap sequence修复》有 2 条评论

  1. 惜分飞 说：
    2012 年 4 月 19 日23:17

    今天在帮朋友处理类此问题的时候，基于scn恢复好数据库后，因为备库没有standby redo log file 且没有清理备库的redo log，出现如下错误

    Thu Apr 19 22:01:36 2012
Thread 1 cannot allocate new log, sequence 2031
Private strand flush not complete
  Current log# 1 seq# 2030 mem# 0: /u01/app/oracle/oradata/orcl/redo01.log
Thread 1 advanced to log sequence 2031
  Current log# 2 seq# 2031 mem# 0: /u01/app/oracle/oradata/orcl/redo02.log
Thu Apr 19 22:01:37 2012
Errors in file /u01/app/oracle/admin/orcl/bdump/orcl_lns1_7012.trc:
ORA-00270: error creating archive log 
Thu Apr 19 22:01:37 2012
LGWR: Error 270 closing archivelog file 'standby'
Thu Apr 19 22:01:44 2012
Thread 1 cannot allocate new log, sequence 2032
Private strand flush not complete
  Current log# 2 seq# 2031 mem# 0: /u01/app/oracle/oradata/orcl/redo02.log
Thread 1 advanced to log sequence 2032
  Current log# 3 seq# 2032 mem# 0: /u01/app/oracle/oradata/orcl/redo03.log

    trace文件内容如

    *** 2012-04-19 20:51:47.096 57126 kcrr.c
LNS1: initialized successfully ASYNC=1
Destination is specified with ASYNC=61440
*** 2012-04-19 20:51:48.125 70905 kcrr.c
Sending online log thread 1 seq 2025 [logfile 2] to standby
Opening logfile [logno 2]
LGWR: Archivelog for thread 1 sequence 2025 will NOT be compressed
Redo shipping client performing standby login
*** 2012-04-19 20:51:48.174 64561 kcrr.c
Logged on to standby successfully
Client logon and security negotiation successful!
Destination LOG_ARCHIVE_DEST_2 is in MAXIMUM PERFORMANCE mode
Archiving to destination standby ASYNC blocks=20480
Allocate ASYNC blocks: Previous blocks=0 New blocks=20480
Log file opened [logno 2]
*** 2012-04-19 20:52:03.210
*** 2012-04-19 20:52:03.210 71706 kcrr.c
Detected proper completion of online log
*** 2012-04-19 20:52:03.210 71549 kcrr.c
Detected physical end of file
Online entry still exists for log 2 thr 1 seq 2025. Using it
Closing thread 1 sequence 2025 logno 2 nab 2 los 65825433 nxs 65825440
*** 2012-04-19 20:52:03.219 70905 kcrr.c
Sending online log thread 1 seq 2026 [logfile 3] to standby
Opening logfile [logno 3]
LGWR: Archivelog for thread 1 sequence 2026 will NOT be compressed
Destination LOG_ARCHIVE_DEST_2 is in MAXIMUM PERFORMANCE mode
Archiving to destination standby ASYNC blocks=20480
Log file opened [logno 3]
Attempting to send buffer 0x0x2aad8decb000  start block 2  block count 1
    total size to send 512  blocksize 512
*** 2012-04-19 20:52:11.234 71706 kcrr.c
Detected proper completion of online log
*** 2012-04-19 20:52:11.234 71549 kcrr.c
Detected physical end of file
Attempting to send buffer 0x0x2aad8decb000  start block 3  block count 1
    total size to send 512  blocksize 512
Online entry still exists for log 3 thr 1 seq 2026. Using it
Closing thread 1 sequence 2026 logno 3 nab 4 los 65825440 nxs 65825443

    执行如下命令问题解决

    SQL> select group# from v$log;

    GROUP#
----------
         1
         3
         2

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

Database altered.

SQL> ALTER DATABASE CLEAR LOGFILE GROUP 1;

Database altered.

SQL> ALTER DATABASE CLEAR LOGFILE GROUP 2;    

Database altered.

SQL> ALTER DATABASE CLEAR LOGFILE GROUP 3;

Database altered.

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

Database altered.
  2. 惜分飞 说：
    2012 年 4 月 19 日23:13 
    MRP0: Background Managed Standby Recovery process started (orcl)
Managed Standby Recovery not using Real Time Apply
Media Recovery Waiting for thread 1 sequence 2017
Fetching gap sequence in thread 1, gap sequence 2017-2018
Thu Apr 19 20:37:25 2012
FAL[server]: Fail to queue the whole FAL gap
 GAP - thread 1 sequence 2017-2018
 DBID 1298106628 branch 770325894

    当查询v$datafile scn,database scn,datafile_header.scn发现均不一致,这个时候不能使用CURRENT_SCN来作为scn增量备份的起点，这个时候需要根据缺少日志最下sequence#找出scn,然后作为增量备份的起点.

    找出scn起点

    SQL> select FIRST_CHANGE#  from v$archived_log where SEQUENCE#  =2017;

 FIRST_CHANGE# 
 ------------- 
      65727543

    所以使用gap中提示的sequence#找出起始scn比CURRENT_SCN 更加靠谱(出现scn不一致情况,一般人工不正常干预dg导致

    BACKUP INCREMENTAL FROM SCN 65727543 DATABASE
FORMAT '/home/oracle/xff_%U' tag 'XIFENFEI';