首页 > 代码库 > Data Guard启动实时日志应用
Data Guard启动实时日志应用
1. REDO数据实时应用
启动实时应用的优势在于,REDO数据不需要等待归档完成,接收到即可被应用,这样执行角色切换时,操作能够执行得更快,因为日志是被即时应用的。
要启动实时应用也简单,前提是Standby数据库端配置了Standby Redologs。
物理Standby要启用实时应用,要在启动REDO应用的语句后附加USING CURRENT LOGFIE子句,例如:
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE ;
2. 启动实时应用redo日志操作
2.1添加standby redo log
首先查询当前redo log的大小、位置;Standby redo的大小要和redo 的一致
primary>col status format ‘a10‘ primary>select group#,thread#,archived,status, bytes/1024/1024 from v$log; GROUP# THREAD# ARCHIVED STATUS BYTES/1024/1024 ---------- ---------- --------- ---------- --------------- 1 1 YES INACTIVE 50 2 1 NO CURRENT 50 3 1 YES INACTIVE 50 primary>col member format ‘a35‘; primary>select group#,type, member from v$logfile; GROUP# TYPE MEMBER ---------- --------------------- ----------------------------------- 1 ONLINE /u01/app/oradata/ora234/redo01.log 2 ONLINE /u01/app/oradata/ora234/redo02.log 3 ONLINE /u01/app/oradata/ora234/redo03.log
添加standby redo 操作;主库/备库都操作;
主库操作原因;当发生故障;主备库发生切换;减少切换过程操作
主库操作 primary> ALTER DATABASE ADD STANDBY LOGFILE GROUP 4 (‘/home/oracle/oradata/redolog/std_redo04.log‘) size 50M; Database altered. primary> ALTER DATABASE ADD STANDBY LOGFILE GROUP 5 (‘/home/oracle/oradata/redolog/std_redo05.log‘) size 50M; Database altered. primary> ALTER DATABASE ADD STANDBY LOGFILE GROUP 6 (‘/home/oracle/oradata/redolog/std_redo06.log‘) size 50M; Database altered. primary> ALTER DATABASE ADD STANDBY LOGFILE GROUP 7 (‘/home/oracle/oradata/redolog/std_redo07.log‘) size 50M; Database altered. 备库操作 standby> ALTER DATABASE ADD STANDBY LOGFILE GROUP 4 (‘/home/oracle/oradata/redolog/std_redo04.log‘) size 50M; Database altered. standby> ALTER DATABASE ADD STANDBY LOGFILE GROUP 5 (‘/home/oracle/oradata/redolog/std_redo05.log‘) size 50M; Database altered. standby> ALTER DATABASE ADD STANDBY LOGFILE GROUP 6 (‘/home/oracle/oradata/redolog/std_redo06.log‘) size 50M; Database altered. standby> ALTER DATABASE ADD STANDBY LOGFILE GROUP 7 (‘/home/oracle/oradata/redolog/std_redo07.log‘) size 50M; Database altered.
2.2修改主备库参数;
启动实时应用日志;需采用lgwr模式;即应用redolog。不再是archivelog
primary>alter system set LOG_ARCHIVE_DEST_2=‘SERVICE=tns_standby LGWR VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=db_standby‘ ; System altered. standby>alter system set log_archive_dest_2=‘SERVICE=tns_primary LGWR VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=db_primary‘; System altered.
2.3启用实时StandBy端redo应用
StandBy>alter database recover managed standby database using current logfile disconnect from session; 取消实时应用:alter database recover managed standby database cancel;
2.4验证结果
primary>truncate table t; Table truncated. primary>insert into t values (1000); 1 row created. primary>commit; Commit complete. standby>select * from t; no rows selected standby>select * from t; ID ---------- 1000
Data Guard启动实时日志应用
声明:以上内容来自用户投稿及互联网公开渠道收集整理发布,本网站不拥有所有权,未作人工编辑处理,也不承担相关法律责任,若内容有误或涉及侵权可进行投诉: 投诉/举报 工作人员会在5个工作日内联系你,一经查实,本站将立刻删除涉嫌侵权内容。