Oracle 11g rac + Dataguard 环境调整 redo log 大小

睿思达DBA_WGX2025-01-05 12:59

Oracle 11g rac + Dataguard 环境调整 redo log 大小

目录

一、问题的产生

客户的生产库为 Oracle 11g rac双节点集群，并且配置有Dataguard，近期业务出现卡顿，检查发现日志文件异常，系统一共配置6组redo log（1号线程与2号线程各3组，每个日志文件的大小为100MB）与8组standby log（1号线程与2号线程各4组）。

1、查看日志文件、日志组信息

（1）日志文件信息

sql 复制代码 
SQL> select * from v$logfile;

    GROUP# STATUS  TYPE MEMBER   IS_
-----------------------------------------------------------------------------------
	 1	   ONLINE  +DATA/hisdb/onlinelog/redo01.log  NO
	 2	   ONLINE  +DATA/hisdb/onlinelog/redo02.log  NO
	 4	   ONLINE  +DATA/hisdb/onlinelog/redo04.log  NO
	 5	   ONLINE  +DATA/hisdb/onlinelog/redo05.log  NO
	 6	   ONLINE  +DATA/hisdb/onlinelog/redo06.log  NO
	 3	   ONLINE  +DATA/hisdb/onlinelog/redo03.log  NO
	 7	   STANDBY  +DATA/hisdb/onlinelog/group_7.446.1121009477   NO
	 8	   STANDBY  +DATA/hisdb/onlinelog/group_8.447.1121009483   NO
	 9	   STANDBY  +DATA/hisdb/onlinelog/group_9.448.1121009489   NO
	10	   STANDBY  +DATA/hisdb/onlinelog/group_10.449.1121009493  NO
	11	   STANDBY  +DATA/hisdb/onlinelog/group_11.450.1121009499  NO
	12	   STANDBY  +DATA/hisdb/onlinelog/group_12.451.1121009507  NO
	13	   STANDBY  +DATA/hisdb/onlinelog/group_13.452.1121009507  NO
	14	   STANDBY  +DATA/hisdb/onlinelog/group_14.453.1121009507  NO
14 rows selected.

（2）日志组信息

sql 复制代码 
SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS  FIRST_CHANGE# FIRST_TIME
------------- ---------------------- ---------- ---------- ---------- ---------- --- ----------
	 1	    2	  114460	100	     1 YES ACTIVE    9057709636 03-JAN-25
	 2	    2	  114461	100	     1 YES ACTIVE    9057751045 03-JAN-25
	 3	    2	  114462	100	     1 NO  CURRENT   9057800557 03-JAN-25
	 4	    1	  324121	100	     1 YES ACTIVE    9057794541 03-JAN-25
	 5	    1	  324122	100	     1 NO  CURRENT   9057807196 03-JAN-25
	 6	    1	  324120	100	     1 YES ACTIVE   9057790272 03-JAN-25
6 rows selected.

（3）standby log信息

sql 复制代码 
SQL> select group#,thread#,round(bytes/1024/1024,2) size_mb,status from v$standby_log;

    GROUP#    THREAD#	 SIZE_MB STATUS
---------- ---------- ---------- ----------
	 7	    1	     100 UNASSIGNED
	 8	    1	     100 UNASSIGNED
	 9	    1	     100 UNASSIGNED
	10	    1	     100 UNASSIGNED
	11	    2	     100 UNASSIGNED
	12	    2	     100 UNASSIGNED
	13	    2	     100 UNASSIGNED
	14	    2	     100 UNASSIGNED
8 rows selected.
2、日志切换较快出现的问题

频繁的日志切换会增加CPU和I/O负载，因为每次切换都需要更新控制文件和数据字典，并且产生新的归档。

日志组循环写满以后，LGWR进程要覆盖先前的日志文件，如果未完成归档会导致无法切换，出现等待，数据库将陷于停顿状态，直到要覆盖的日志文件完成归档。

在生产环境中，设置一个相对合理的redo log大小是十分重要的，可以提升数据库的整体性能，减轻系统I/O负担，数据库恢复时间合理。

理想性状态下，平均一个小时切换2-4次较为合理。

使用以下脚本可以查看日志每小时切换次数，平均每小时2-4次合适，也就是15-30分钟切一次日志。

sql 复制代码 
set linesize 120
set pagesize 100
column  day     format a15              heading 'Day'
column  d_0     format a3               heading '00'
column  d_1     format a3               heading '01'
column  d_2     format a3               heading '02'
column  d_3     format a3               heading '03'
column  d_4     format a3               heading '04'
column  d_5     format a3               heading '05'
column  d_6     format a3               heading '06'
column  d_7     format a3               heading '07'
column  d_8     format a3               heading '08'
column  d_9     format a3               heading '09'
column  d_10    format a3               heading '10'
column  d_11    format a3               heading '11'
column  d_12    format a3               heading '12'
column  d_13    format a3               heading '13'
column  d_14    format a3               heading '14'
column  d_15    format a3               heading '15'
column  d_16    format a3               heading '16'
column  d_17    format a3               heading '17'
column  d_18    format a3               heading '18'
column  d_19    format a3               heading '19'
column  d_20    format a3               heading '20'
column  d_21    format a3               heading '21'
column  d_22    format a3               heading '22'
column  d_23    format a3               heading '23'
select
        substr(to_char(FIRST_TIME,'YYYY/MM/DD,DY'),1,15) day,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'00',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'00',1,0))) d_0,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'01',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'01',1,0))) d_1,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'02',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'02',1,0))) d_2,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'03',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'03',1,0))) d_3,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'04',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'04',1,0))) d_4,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'05',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'05',1,0))) d_5,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'06',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'06',1,0))) d_6,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'07',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'07',1,0))) d_7,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'08',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'08',1,0))) d_8,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'09',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'09',1,0))) d_9,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'10',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'10',1,0))) d_10,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'11',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'11',1,0))) d_11,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'12',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'12',1,0))) d_12,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'13',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'13',1,0))) d_13,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'14',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'14',1,0))) d_14,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'15',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'15',1,0))) d_15,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'16',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'16',1,0))) d_16,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'17',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'17',1,0))) d_17,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'18',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'18',1,0))) d_18,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'19',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'19',1,0))) d_19,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'20',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'20',1,0))) d_20,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'21',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'21',1,0))) d_21,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'22',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'22',1,0))) d_22,
        decode(sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'23',1,0)),0,'-',sum(decode(substr(to_char(FIRST_TIME,'HH24'),1,2),'23',1,0))) d_23
from
        gv$log_history where first_time> sysdate-60
group by
        substr(to_char(FIRST_TIME,'YYYY/MM/DD,DY'),1,15)
order by
        substr(to_char(FIRST_TIME,'YYYY/MM/DD,DY'),1,15) desc;
        
-- 运行结果如下：
Day	00  01	02  03	04  05	06  07	08  09	10  11	12  13	14  15	16  17	18  19	20  21	22  23
------- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---
2025/01/02,THU	-   -	-   -	-   -	1   -	-   -	-   -	-   -	5   -	-   -	-   -	-   -	1   -
2025/01/01,WED	-   -	-   -	1   -	-   -	-   -	-   -	-   -	-   -	-   2	-   1	1   1	-   -
2024/12/31,TUE	-   -	-   -	-   -	-   -	-   -	-   -	-   -	-   -	1   -	-   -	-   -	-   -
2024/12/30,MON	-   -	-   -	-   -	-   -	-   -	-   -	-   -	-   -	-   -	-   -	-   4	2   -

经过分析日志的切换频率，拟把日志文件大小扩容为1024MB，操作步骤如下：

二、 确认 DG 同步是否正常

1、检查数据库角色
sql 复制代码 
--主库
SQL> select db_unique_name, open_mode, switchover_status, database_role from v$database;

DB_UNIQUE_NAME		       OPEN_MODE	    SWITCHOVER_STATUS   DATABASE_ROLE
---------------------------------------------- -------------------- --------------------
HISDB			       READ WRITE	    SESSIONS ACTIVE          PRIMARY

--备库
SQL> select db_unique_name, open_mode, switchover_status, database_role from v$database;

DB_UNIQUE_NAME		       OPEN_MODE	    SWITCHOVER_STATUS   DATABASE_ROLE
---------------------------------------------- -------------------- --------------------
DGHISDB 		       READ ONLY WITH APPLY NOT ALLOWED   PHYSICAL STANDBY
2、查看进程信息

（1）在主库查看LNS进程，此进程负责将主数据库的重做日志条目传输到备用数据库。

sql 复制代码 
SQL> select process, status, sequence# from v$managed_standby;

PROCESS   STATUS	SEQUENCE#
--------- ------------ ----------
ARCH	  CLOSING	   324114
ARCH	  CLOSING	   317879
ARCH	  CLOSING	   324115
ARCH	  CLOSING	   324116
LNS	  WRITING	   324117

（2）在备库查看MRP0进程，此进程负责将接收到的归档日志应用到备用数据库上，以维持与主数据库的同步。MRP进程是DG中的关键组件，它确保备用数据库的数据与主数据库保持一致。

sql 复制代码 
SQL> select process, status, sequence# from v$managed_standby;

PROCESS   STATUS	SEQUENCE#
--------- ------------ ----------
ARCH	  CLOSING	   324117
ARCH	  CLOSING	   114458
ARCH	  CONNECTED		0
ARCH	  CLOSING	   324116
RFS	  IDLE		   324118
RFS	  IDLE			0
RFS	  IDLE			0
RFS	  IDLE			0
MRP0	  APPLYING_LOG	   324118
RFS	  IDLE			0
RFS	  IDLE			0
RFS	  IDLE		   114459
RFS	  IDLE			0

13 rows selected.
3、检查归档是否一致
sql 复制代码 
-- 主库
SQL> select max(sequence#),thread# from v$archived_log where RESETLOGS_CHANGE# = (SELECT RESETLOGS_CHANGE# FROM V$DATABASE_INCARNATION WHERE STATUS = 'CURRENT') GROUP BY THREAD#;

MAX(SEQUENCE#)	  THREAD#
-------------- ----------
	324117		1
	114458		2
	
-- 备库
SQL> select max(sequence#),thread# from v$archived_log where RESETLOGS_CHANGE# = (SELECT RESETLOGS_CHANGE# FROM V$DATABASE_INCARNATION WHERE STATUS = 'CURRENT') GROUP BY THREAD#;

MAX(SEQUENCE#)	  THREAD#
-------------- ----------
	324117		1
	114458		2
4、查看 GAP 是否有延迟

GAP产生的原因是，一般是备库已经长时间未与主库同步，等发现的时候，主库的归档日志已经删除，备库无法再次与主库同步，这时候GAP就产生了。

sql 复制代码 
-- 主库
SQL> select * from v$archive_gap;

no rows selected

SQL> select STATUS, GAP_STATUS from V$ARCHIVE_DEST_STATUS where DEST_ID = 2;

STATUS	  GAP_STATUS
--------- ------------------------
VALID	  NO GAP


-- 备库
SQL> select * from v$archive_gap;

no rows selected

SQL> select STATUS, GAP_STATUS from V$ARCHIVE_DEST_STATUS where DEST_ID = 2;

STATUS	  GAP_STATUS
--------- ------------------------
VALID	  RESOLVABLE GAP

三、在主库上重建 redo log file

1、查看 redo 日志组及大小

（1）查看日志文件

sql 复制代码 
SQL> select * from v$logfile;

    GROUP# STATUS  TYPE MEMBER   IS_
-----------------------------------------------------------------------------------
	 1	   ONLINE  +DATA/hisdb/onlinelog/redo01.log  NO
	 2	   ONLINE  +DATA/hisdb/onlinelog/redo02.log  NO
	 4	   ONLINE  +DATA/hisdb/onlinelog/redo04.log  NO
	 5	   ONLINE  +DATA/hisdb/onlinelog/redo05.log  NO
	 6	   ONLINE  +DATA/hisdb/onlinelog/redo06.log  NO
	 3	   ONLINE  +DATA/hisdb/onlinelog/redo03.log  NO
	 7	   STANDBY  +DATA/hisdb/onlinelog/group_7.446.1121009477   NO
	 8	   STANDBY  +DATA/hisdb/onlinelog/group_8.447.1121009483   NO
	 9	   STANDBY  +DATA/hisdb/onlinelog/group_9.448.1121009489   NO
	10	   STANDBY  +DATA/hisdb/onlinelog/group_10.449.1121009493  NO
	11	   STANDBY  +DATA/hisdb/onlinelog/group_11.450.1121009499  NO
	12	   STANDBY  +DATA/hisdb/onlinelog/group_12.451.1121009507  NO
	13	   STANDBY  +DATA/hisdb/onlinelog/group_13.452.1121009507  NO
	14	   STANDBY  +DATA/hisdb/onlinelog/group_14.453.1121009507  NO
14 rows selected.

（2）查看redo log信息

sql 复制代码 
SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS  FIRST_CHANGE# FIRST_TIME
------------- ---------------------- ---------- ---------- ---------- ---------- --- ----------
	 1	    2	  114460	100	     1 YES ACTIVE    9057709636 03-JAN-25
	 2	    2	  114461	100	     1 YES ACTIVE    9057751045 03-JAN-25
	 3	    2	  114462	100	     1 NO  CURRENT   9057800557 03-JAN-25
	 4	    1	  324121	100	     1 YES ACTIVE    9057794541 03-JAN-25
	 5	    1	  324122	100	     1 NO  CURRENT   9057807196 03-JAN-25
	 6	    1	  324120	100	     1 YES ACTIVE   9057790272 03-JAN-25
6 rows selected.

（3）查看standby log信息

sql 复制代码 
SQL> select group#,thread#,round(bytes/1024/1024,2) size_mb,status from v$standby_log;

    GROUP#    THREAD#	 SIZE_MB STATUS
---------- ---------- ---------- ----------
	 7	    1	     100 UNASSIGNED
	 8	    1	     100 UNASSIGNED
	 9	    1	     100 UNASSIGNED
	10	    1	     100 UNASSIGNED
	11	    2	     100 UNASSIGNED
	12	    2	     100 UNASSIGNED
	13	    2	     100 UNASSIGNED
	14	    2	     100 UNASSIGNED
8 rows selected.
2、在主库删除 standby log

删除旧的 standby log（group: 7-14）：

sql 复制代码 
alter database drop logfile group 7;
alter database drop logfile group 8;
alter database drop logfile group 9;
alter database drop logfile group 10;
alter database drop logfile group 11;
alter database drop logfile group 12;
alter database drop logfile group 13;
alter database drop logfile group 14;
3、在主库替换 redo log

步骤1：添加两组临时日志文件：

sql 复制代码 
节点1：
alter database add logfile thread 1 group 14 '+DATA' size 1024M;
alter database add logfile thread 1 group 15 '+DATA' size 1024M;

节点2：
alter database add logfile thread 2 group 16 '+DATA' size 1024M;
alter database add logfile thread 2 group 17 '+DATA' size 1024M;


SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

    GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS	    FIRST_CHANGE# FIRST_TIME
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------
	 1	    2	  114484	100	     1 YES ACTIVE	       9058578050 03-JAN-25
	 2	    2	  114485	100	     1 YES ACTIVE	       9058584300 03-JAN-25
	 3	    2	  114483	100	     1 YES ACTIVE	       9058554867 03-JAN-25
	 4	    1	  324142	100	     1 YES ACTIVE	       9058579106 03-JAN-25
	 5	    1	  324140	100	     1 YES INACTIVE	       9058515833 03-JAN-25
	 6	    1	  324141	100	     1 YES ACTIVE	       9058538032 03-JAN-25
	14	    1	  324143       1024	     1 NO  CURRENT	       9058623959 03-JAN-25
	15	    1	       0       1024	     1 YES UNUSED			0
	16	    2	  114486       1024	     1 NO  CURRENT	       9058621526 03-JAN-25
	17	    2	       0       1024	     1 YES UNUSED			0

10 rows selected.

步骤2：切日志，让旧的日志文件（group: 1-6）组为INACTIVE：

sql 复制代码 
alter system switch logfile;
alter system checkpoint;

select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

    GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS	    FIRST_CHANGE# FIRST_TIME
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------
	 1	    2	  114484	100	     1 YES INACTIVE	       9058578050 03-JAN-25
	 2	    2	  114485	100	     1 YES INACTIVE	       9058584300 03-JAN-25
	 3	    2	  114483	100	     1 YES INACTIVE	       9058554867 03-JAN-25
	 4	    1	  324142	100	     1 YES INACTIVE	       9058579106 03-JAN-25
	 5	    1	  324140	100	     1 YES INACTIVE	       9058515833 03-JAN-25
	 6	    1	  324141	100	     1 YES INACTIVE	       9058538032 03-JAN-25
	14	    1	  324143       1024	     1 YES INACTIVE	       9058623959 03-JAN-25
	15	    1	  324144       1024	     1 NO  CURRENT	       9058634615 03-JAN-25
	16	    2	  114486       1024	     1 NO  CURRENT	       9058621526 03-JAN-25
	17	    2	       0       1024	     1 YES UNUSED			0

10 rows selected.

步骤3：删除1-6组日志文件：

sql 复制代码 
alter database drop logfile group 1;
alter database drop logfile group 2;
alter database drop logfile group 3;
alter database drop logfile group 4;
alter database drop logfile group 5;
alter database drop logfile group 6;

SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

    GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS	    FIRST_CHANGE# FIRST_TIME
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------
	14	    1	  324143       1024	     1 YES INACTIVE	       9058623959 03-JAN-25
	15	    1	  324144       1024	     1 NO  CURRENT	       9058634615 03-JAN-25
	16	    2	  114486       1024	     1 NO  CURRENT	       9058621526 03-JAN-25
	17	    2	       0       1024	     1 YES UNUSED			0

步骤4：添加新的日志文件：

sql 复制代码 
/*
SQL> select * from v$logfile;

    GROUP# STATUS  TYPE MEMBER   IS_
-----------------------------------------------------------------------------------
	 1	   ONLINE   +DATA/hisdb/onlinelog/redo01.log  NO
	 2	   ONLINE   +DATA/hisdb/onlinelog/redo02.log  NO
	 4	   ONLINE   +DATA/hisdb/onlinelog/redo04.log  NO
	 5	   ONLINE   +DATA/hisdb/onlinelog/redo05.log  NO
	 6	   ONLINE   +DATA/hisdb/onlinelog/redo06.log  NO
	 3	   ONLINE   +DATA/hisdb/onlinelog/redo03.log  NO
	 7	   STANDBY  +DATA/hisdb/onlinelog/group_7.446.1121009477   NO
	 8	   STANDBY  +DATA/hisdb/onlinelog/group_8.447.1121009483   NO
	 9	   STANDBY  +DATA/hisdb/onlinelog/group_9.448.1121009489   NO
	10	   STANDBY  +DATA/hisdb/onlinelog/group_10.449.1121009493  NO
	11	   STANDBY  +DATA/hisdb/onlinelog/group_11.450.1121009499  NO
	12	   STANDBY  +DATA/hisdb/onlinelog/group_12.451.1121009507  NO
	13	   STANDBY  +DATA/hisdb/onlinelog/group_13.452.1121009507  NO
	14	   STANDBY  +DATA/hisdb/onlinelog/group_14.453.1121009507  NO
14 rows selected.
*/

alter database add logfile thread 2 group 1 '+DATA/hisdb/onlinelog/redo1.log' size 1024M;
alter database add logfile thread 2 group 2 '+DATA/hisdb/onlinelog/redo2.log' size 1024M;
alter database add logfile thread 2 group 3 '+DATA/hisdb/onlinelog/redo3.log' size 1024M;
alter database add logfile thread 1 group 4 '+DATA/hisdb/onlinelog/redo4.log' size 1024M;
alter database add logfile thread 1 group 5 '+DATA/hisdb/onlinelog/redo5.log' size 1024M;
alter database add logfile thread 1 group 6 '+DATA/hisdb/onlinelog/redo6.log' size 1024M;


SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

    GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS	    FIRST_CHANGE# FIRST_TIME
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------
	 1	    2	       0       1024	     1 YES UNUSED			0
	 2	    2	       0       1024	     1 YES UNUSED			0
	 3	    2	       0       1024	     1 YES UNUSED			0
	 4	    1	       0       1024	     1 YES UNUSED			0
	 5	    1	       0       1024	     1 YES UNUSED			0
	 6	    1	       0       1024	     1 YES UNUSED			0
	14	    1	  324143       1024	     1 YES INACTIVE	       9058623959 03-JAN-25
	15	    1	  324144       1024	     1 NO  CURRENT	       9058634615 03-JAN-25
	16	    2	  114486       1024	     1 NO  CURRENT	       9058621526 03-JAN-25
	17	    2	       0       1024	     1 YES UNUSED			0

10 rows selected.

步骤5：切日志，删除临时添加的日志文件：

sql 复制代码 
alter system switch logfile;
alter system checkpoint;

SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

    GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS	    FIRST_CHANGE# FIRST_TIME
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------
	 1	    2	  114487       1024	     1 NO  CURRENT	       9058754188 03-JAN-25
	 2	    2	       0       1024	     1 YES UNUSED			0
	 3	    2	       0       1024	     1 YES UNUSED			0
	 4	    1	  324145       1024	     1 YES INACTIVE	       9058753823 03-JAN-25
	 5	    1	  324146       1024	     1 NO  CURRENT	       9058759093 03-JAN-25
	 6	    1	       0       1024	     1 YES UNUSED			0
	14	    1	  324143       1024	     1 YES INACTIVE	       9058623959 03-JAN-25
	15	    1	  324144       1024	     1 YES INACTIVE	       9058634615 03-JAN-25
	16	    2	  114486       1024	     1 YES INACTIVE	       9058621526 03-JAN-25
	17	    2	       0       1024	     1 YES UNUSED			0

10 rows selected.


alter database drop logfile group 14;
alter database drop logfile group 15;
alter database drop logfile group 16;
alter database drop logfile group 17;

SQL> select group#,thread#,sequence#,round(bytes/1024/1024,2) size_mb,members,archived,status,first_change#,first_time from v$log;

    GROUP#    THREAD#  SEQUENCE#    SIZE_MB    MEMBERS ARC STATUS	    FIRST_CHANGE# FIRST_TIME
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------
	 1	    2	  114487       1024	     1 NO  CURRENT	       9058754188 03-JAN-25
	 2	    2	       0       1024	     1 YES UNUSED			0
	 3	    2	       0       1024	     1 YES UNUSED			0
	 4	    1	  324145       1024	     1 YES INACTIVE	       9058753823 03-JAN-25
	 5	    1	  324146       1024	     1 NO  CURRENT	       9058759093 03-JAN-25
	 6	    1	       0       1024	     1 YES UNUSED			0

6 rows selected.
4、主库添加 standby log
sql 复制代码 
Alter database add standby logfile thread 1 group 7 '+DATA/hisdb/onlinelog/standby07.log' size 1024m;
Alter database add standby logfile thread 1 group 8 '+DATA/hisdb/onlinelog/standby08.log' size 1024m;
Alter database add standby logfile thread 1 group 9 '+DATA/hisdb/onlinelog/standby09.log' size 1024m;
Alter database add standby logfile thread 1 group 10 '+DATA/hisdb/onlinelog/standby10.log' size 1024m;
Alter database add standby logfile thread 2 group 11 '+DATA/hisdb/onlinelog/standby11.log' size 1024m;
Alter database add standby logfile thread 2 group 12 '+DATA/hisdb/onlinelog/standby12.log' size 1024m;
Alter database add standby logfile thread 2 group 13 '+DATA/hisdb/onlinelog/standby13.log' size 1024m;
Alter database add standby logfile thread 2 group 14 '+DATA/hisdb/onlinelog/standby14.log' size 1024m;

四、在备库上重建 standby log

步骤1：查看 redo 日志组及大小

查看日志文件信息

sql 复制代码 
SQL> select * from v$logfile;

    GROUP# STATUS  TYPE   MEMBER   IS_
------------------------------------------------------------------------
	 1	   ONLINE  /oradata/dghisdb/onlinelog/redo01.log  NO
	 2	   ONLINE  /oradata/dghisdb/onlinelog/redo02.log  NO
	 4	   ONLINE  /oradata/dghisdb/onlinelog/redo04.log  NO
	 5	   ONLINE  /oradata/dghisdb/onlinelog/redo05.log  NO
	 6	   ONLINE  /oradata/dghisdb/onlinelog/redo06.log  NO
	 3	   ONLINE  /oradata/dghisdb/onlinelog/redo03.log  NO
	 7	   STANDBY /oradata/dghisdb/onlinelog/group_7.446.1121009477 NO
	 8	   STANDBY /oradata/dghisdb/onlinelog/group_8.447.1121009483 NO
	 9	   STANDBY /oradata/dghisdb/onlinelog/group_9.448.1121009489 NO
	10	   STANDBY /oradata/dghisdb/onlinelog/group_10.449.1121009493 NO
	11	   STANDBY /oradata/dghisdb/onlinelog/group_11.450.1121009499 NO
	12	   STANDBY /oradata/dghisdb/onlinelog/group_12.451.1121009507 NO
	13	   STANDBY /oradata/dghisdb/onlinelog/group_13.452.1121009507 NO
	14	   STANDBY /oradata/dghisdb/onlinelog/group_14.453.1121009507 NO

14 rows selected.


SQL> select group#,thread#,round(bytes/1024/1024,2) size_mb,status from v$standby_log;

    GROUP#    THREAD#	 SIZE_MB STATUS
---------- ---------- ---------- ----------
	 7	    1	     100 UNASSIGNED
	 8	    1	     100 UNASSIGNED
	 9	    1	     100 UNASSIGNED
	10	    1	     100 UNASSIGNED
	11	    2	     100 UNASSIGNED
	12	    2	     100 UNASSIGNED
	13	    2	     100 UNASSIGNED
	14	    2	     100 UNASSIGNED

8 rows selected.
步骤2：备库取消日志应用
sql 复制代码 
alter database recover managed standby database cancel;
步骤3：修改日志管理模式为手动
sql 复制代码 
SQL> alter system set standby_file_management='manual';

SQL> show parameter standby_file_management

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
standby_file_management              string      manual
步骤4：删除备库 standby log

（1）添加两组临时standby log file：

sql 复制代码 
alter database add standby logfile group 15 '/oradata/dghisdb/onlinelog/stlog15.log' size 1024m reuse;
alter database add standby logfile group 16 '/oradata/dghisdb/onlinelog/stlog16.log' size 1024m reuse;

（2）在主库切日志，将active状态切到临时文件上，将所有旧的standby log的status刷到UNASSIGNED：

sql 复制代码 
SQL> alter system switch logfile;
--备库查看
SQL> select group#,thread#,round(bytes/1024/1024,2) size_mb,status from v$standby_log;

（3）删除旧的standby log file：

sql 复制代码 
alter database drop logfile group 7;
alter database drop logfile group 8;
alter database drop logfile group 9;
alter database drop logfile group 10;
alter database drop logfile group 11;
alter database drop logfile group 12;
alter database drop logfile group 13;
alter database drop logfile group 14;
步骤5：备库新建 standby log

重新添加standby log，大小为1024m，group: 7-14：

sql 复制代码 
alter database add standby logfile group 7 '/oradata/dghisdb/onlinelog/standby07.log' size 1024m reuse;
alter database add standby logfile group 8 '/oradata/dghisdb/onlinelog/standby08.log' size 1024m reuse;
alter database add standby logfile group 9 '/oradata/dghisdb/onlinelog/standby09.log' size 1024m reuse;
alter database add standby logfile group 10 '/oradata/dghisdb/onlinelog/standby10.log' size 1024m reuse;
alter database add standby logfile group 11 '/oradata/dghisdb/onlinelog/standby11.log' size 1024m reuse;
alter database add standby logfile group 12 '/oradata/dghisdb/onlinelog/standby12.log' size 1024m reuse;
alter database add standby logfile group 13 '/oradata/dghisdb/onlinelog/standby13.log' size 1024m reuse;
alter database add standby logfile group 14 '/oradata/dghisdb/onlinelog/standby14.log' size 1024m reuse;
步骤6：主库切日志，将临时standby logfile切到UNASSIGNED状态，然后删除：
sql 复制代码 
alter database drop logfile group 15;
alter database drop logfile group 16;

说明：关于备库的 redo log 处理

通常情况下，备库为只读模式，不对数据库进行修改，不会启用redo log files。

另外，由于 DG 备库处于只读模式，因此，不对备库的 redo log 做任何操作。

步骤7：打开实时应用日志和自动日志管理

完成以上操作后，dg 环境的redo logfile和standby logfile就算更新完成了，接下来只需要恢复数据同步即可。

sql 复制代码 
alter database recover managed standby database using current logfile disconnect;

alter system set standby_file_management='AUTO';
步骤8：重新启动备库，查看数据同步情况
sql 复制代码 
SQL> select process ,status , sequence# from v$managed_standby;

PROCESS   STATUS	SEQUENCE#
--------- ------------ ----------
ARCH	  CLOSING	   324152
ARCH	  CONNECTED		0
ARCH	  CONNECTED		0
ARCH	  CLOSING	   114489
RFS	  IDLE			0
RFS	  IDLE			0
RFS	  IDLE		   114490
RFS	  IDLE			0
RFS	  IDLE		   324153
RFS	  IDLE			0
MRP0	  APPLYING_LOG	   324153

11 rows selected.

SQL> select group#,thread#,sequence#,archived,status from v$standby_log;

    GROUP#    THREAD#  SEQUENCE# ARC STATUS
---------- ---------- ---------- --- ----------
	 7	    2	  114490 YES ACTIVE
	 8	    2	       0 NO  UNASSIGNED
	 9	    1	  324153 YES ACTIVE
	10	    1	       0 NO  UNASSIGNED
	11	    0	       0 YES UNASSIGNED
	12	    0	       0 YES UNASSIGNED
	13	    0	       0 YES UNASSIGNED
	14	    0	       0 YES UNASSIGNED

8 rows selected.
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