DataGuard Gap sequence的处理方法

检查数据库服务器，发现磁盘已满，因为前期规划问题，磁盘空间不足，还好该库不影响。

删除归档时，发现删除过多，导致备库归档没有成功应用，就被删除了。

这个操作确实粗心大意，检查备库归档时，发现无法应用，查看日志有如下报错：

Fetching gap sequence in thread 1, gap sequence 42102-42102FAL[client]: All defined FAL servers have been attempted.------------------------------------------------------------Check that the CONTROL_FILE_RECORD_KEEP_TIME initializationparameter is defined to a value that's sufficiently largeenough to maintain adequate log switch information to resolvearchivelog gaps.------------------------------------------------------------

处理方法，在主库查看该归档的SCN发生的序列：

SQL> col first_change# for 999999999999999SQL> select first_change# from v$archived_log where sequence#='42102'  2  ;   FIRST_CHANGE#----------------  11769444390910主库SQL> alter system set log_archive_dest_state_2=defer;备库SQL> alter database managed standby database recovery cancel;

对主库进行增量和控制文件备份：

RMAN> backup incremental from scn 11769444390910 database format '/u01/temp/archivedlog_%U';RMAN> backup current controlfile for standby format '/u01/temp/controlfile.bak';

将文件拷贝到备库后，进行还原

RMAN> shutdown immediateRMAN> startup nomountRMAN> restore standby controlfile from '/u01/temp/controlfile.bak';RMAN> alter database mount;RMAN> recover database noredo;

另外如果未采用的standby log模式，则需要清空备库redo log,有几组清理几组。

SQL> alter database clear logfile group 1;

切换主库日志文件观察主备库日志序列是否一致！

主库：SQL> alter system switch logfile;SQL> select max(sequence#) from v$log_history;MAX(SEQUENCE#)--------------         42141备库：SQL> select max(sequence#) from v$log_history;MAX(SEQUENCE#)--------------         42141

恢复归档应用

主库SQL> alter system set log_archive_dest_state_2=enable;备库SQL> alter database managed standby database recovery disconnect from session;

关注以下几个视图：

v$managed_standbySQL> select process,status,sequence# from v$managed_standby;v$archive_dest_statusSQL> col dest_name for a25SQL> select dest_name,status,recovery_mode from v$archive_dest_status;

启动时观察alert日志发现如下内容

Wed Sep 30 14:27:09 2015
Managed Standby Recovery not using Real Time Apply

表示归档没有实时同步，检查发现备库监听未开启

$ tnsping sss_dgTNS Ping Utility for Linux: Version 11.2.0.3.0 - Production on 30-SEP-2015 14:27:42Copyright (c) 1997, 2011, Oracle.  All rights reserved.Used parameter files:Used TNSNAMES adapter to resolve the aliasAttempting to contact (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=x.x.x.x)(PORT=1521))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=sss)))TNS-12541: TNS:no listene

参考：

http://www.xifenfei.com/2011/07/data-guard%e5%87%ba%e7%8e%b0gap-sequence%e4%bf%ae%e5%a4%8d.html