[20171110]_allow_read_only_corruption参数.txt
[20171110]_allow_read_only_corruption参数.txt
--//昨天在修改查询隐含参数脚本时发现一个参数_allow_read_only_corruption,感觉应该可以在异常关闭的情况下以read only打开.
--//自己测试看看.
1.环境:
SYS@book> @ &r/ver1
PORT_STRING VERSION BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
SYS@book> @ &r/hide _allow_read_only_corruption
NAME DESCRIPTION DEFAULT_VALUE SESSION_VALUE SYSTEM_VALUE
--------------------------- ------------------------------------------------ ------------- ------------- ------------
_allow_read_only_corruption allow read-only open even if database is corrupt TRUE FALSE FALSE
2.测试前准备:
SYS@book> create pfile='/tmp/init@.ora' from spfile ;
File created.
--//修改 /tmp/initbook.ora文件,加入如下内容:
*._allow_read_only_corruption=true
--//做一个异常关闭数据库.
SYS@book> shutdown abort ;
ORACLE instance shut down.
SYS@book> startup mount pfile='/tmp/init@.ora'
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
SYS@book> show parameter allow
NAME TYPE VALUE
--------------------------- ------- ------
_allow_read_only_corruption boolean TRUE
--//说明只要配置了参数在参数文件中,隐含参数实际上也可以使用show parameter.但是像前面带2个下划线参数,show parameter还是无
--//法查询.比如:
SYS@book> show parameter __java_pool_size
SYS@book> @ &r/hide __java_pool_size
NAME DESCRIPTION DEFAULT_VALUE SESSION_VALUE SYSTEM_VALUE
----------------- --------------------------------- ------------- ------------- ------------
__java_pool_size Actual size in bytes of java pool FALSE 4194304 4194304
SYS@book> alter database open read only;
alter database open read only
*
ERROR at line 1:
ORA-16005: database requires recovery
--//可以发现不行.也许需要_allow_resetlogs_corruption参数配合.
3.继续测试:
--//修改 /tmp/initbook.ora文件,加入如下内容:
*._allow_resetlogs_corruption=true
SYS@book> @ &r/logfile
GROUP# STATUS TYPE MEMBER IS_ GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME
------ ---------- ---------- -------------------------------- --- ------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ -------------------
1 ONLINE /mnt/ramdisk/book/redo01.log NO 1 1 728 52428800 512 1 NO CURRENT 13277659048 2017-11-09 16:18:09 2.814750E+14
2 ONLINE /mnt/ramdisk/book/redo02.log NO 2 1 726 52428800 512 1 YES INACTIVE 13277630208 2017-11-09 09:54:47 13277632611 2017-11-09 10:18:14
3 ONLINE /mnt/ramdisk/book/redo03.log NO 3 1 727 52428800 512 1 YES INACTIVE 13277632611 2017-11-09 10:18:14 13277659048 2017-11-09 16:18:09
4 STANDBY /mnt/ramdisk/book/redostb01.log NO
5 STANDBY /mnt/ramdisk/book/redostb02.log NO
6 STANDBY /mnt/ramdisk/book/redostb03.log NO
7 STANDBY /mnt/ramdisk/book/redostb04.log NO
7 rows selected.
$ mv /mnt/ramdisk/book/redo01.log /mnt/ramdisk/book/redo01.log_xxx
--//这样避免找到redo文件.或者假象redo01.log文件损坏了.
SYS@book> shutdown abort ;
ORACLE instance shut down.
SYS@book> startup mount pfile='/tmp/init@.ora'
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
SYS@book> @ &r/hide allow_r%corrupt%
NAME DESCRIPTION DEFAULT_VALUE SESSION_VALUE SYSTEM_VALUE
--------------------------- ------------------------------------------------ ------------- ------------- ------------
_allow_read_only_corruption allow read-only open even if database is corrupt FALSE TRUE TRUE
_allow_resetlogs_corruption allow resetlogs even if it will cause corruption FALSE TRUE TRUE
SYS@book> alter database open read only;
alter database open read only
*
ERROR at line 1:
ORA-16005: database requires recovery
$ oerr ora 16005
16005, 00000, "database requires recovery"
// *Cause: The database requires recovery, and therefore cannot be opened for
// read-only access by this instance.
// *Action: Perform the necessary recovery and reopen for read-only access.
//
--//视乎与_allow_resetlogs_corruption无关,取消*._allow_resetlogs_corruption=true设置,重来..
SYS@book> shutdown abort ;
ORACLE instance shut down.
SYS@book> startup mount pfile='/tmp/init@.ora'
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
SYS@book> @ &r/hide allow_r%corrupt%
old 10: and lower(a.ksppinm) like lower('%&1%')
new 10: and lower(a.ksppinm) like lower('%allow_r%corrupt%%')
NAME DESCRIPTION DEFAULT_VALUE SESSION_VALUE SYSTEM_VALUE
--------------------------- ------------------------------------------------ ------------- ------------- -------------
_allow_read_only_corruption allow read-only open even if database is corrupt FALSE TRUE TRUE
_allow_resetlogs_corruption allow resetlogs even if it will cause corruption TRUE FALSE FALSE
SYS@book> recover database until cancel;
ORA-00279: change 13277663682 generated at 11/10/2017 09:14:12 needed for thread 1
ORA-00289: suggestion : /u01/app/oracle/archivelog/book/1_728_896605872.dbf
ORA-00280: change 13277663682 for thread 1 is in sequence #728
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
ORA-00308: cannot open archived log '/u01/app/oracle/archivelog/book/1_728_896605872.dbf'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
ORA-00308: cannot open archived log '/u01/app/oracle/archivelog/book/1_728_896605872.dbf'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/mnt/ramdisk/book/system01.dbf'
SYS@book> alter database open read only;
alter database open read only
*
ERROR at line 1:
ORA-16005: database requires recovery
--//依旧不行.失望!!
4.看看正常关闭数据库丢失某个redo的情况呢?
$ mv /mnt/ramdisk/book/redo01.log_xxx /mnt/ramdisk/book/redo01.log
--//先恢复到正常状态.
SYS@book> shutdown abort ;
ORACLE instance shut down.
SYS@book> startup mount
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
SYS@book> @ &r/hide allow_r%corrupt%
NAME DESCRIPTION DEFAULT_VALUE SESSION_VALUE SYSTEM_VALUE
--------------------------- ------------------------------------------------ ------------- ------------- ------------
_allow_read_only_corruption allow read-only open even if database is corrupt FALSE TRUE TRUE
_allow_resetlogs_corruption allow resetlogs even if it will cause corruption TRUE FALSE FALSE
SYS@book> recover database until cancel;
ORA-00279: change 13277663682 generated at 11/10/2017 09:14:12 needed for thread 1
ORA-00289: suggestion : /u01/app/oracle/archivelog/book/1_728_896605872.dbf
ORA-00280: change 13277663682 for thread 1 is in sequence #728
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
/mnt/ramdisk/book/redo01.log
Log applied.
Media recovery complete.
SYS@book> alter database open ;
alter database open
*
ERROR at line 1:
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
SYS@book> alter database open NORESETLOGS;
Database altered.
--//这种情况下是可以NORESETLOGS打开的,因为redo文件设置回来了.
SYS@book> select open_mode from v$database ;
OPEN_MODE
-----------
READ WRITE
SYS@book> shutdown immediate ;
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@book> startup mount pfile='/tmp/init@.ora'
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
SYS@book> @ &r/logfile
GROUP# STATUS TYPE MEMBER IS_ GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME
------ ------ ---------- -------------------------------- --- ------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ -------------------
1 ONLINE /mnt/ramdisk/book/redo01.log NO 1 1 728 52428800 512 1 YES INACTIVE 13277659048 2017-11-09 16:18:09 13277684336 2017-11-10 09:54:02
2 ONLINE /mnt/ramdisk/book/redo02.log NO 2 1 729 52428800 512 1 NO CURRENT 13277684336 2017-11-10 09:54:02 2.814750E+14
3 ONLINE /mnt/ramdisk/book/redo03.log NO 3 1 727 52428800 512 1 YES INACTIVE 13277632611 2017-11-09 10:18:14 13277659048 2017-11-09 16:18:09
4 STANDBY /mnt/ramdisk/book/redostb01.log NO
5 STANDBY /mnt/ramdisk/book/redostb02.log NO
6 STANDBY /mnt/ramdisk/book/redostb03.log NO
7 STANDBY /mnt/ramdisk/book/redostb04.log NO
7 rows selected.
--//当前是/mnt/ramdisk/book/redo02.log.
$ mv /mnt/ramdisk/book/redo02.log /mnt/ramdisk/book/redo02.log_xxx
SYS@book> alter database open read only ;
Database altered.
SYS@book> @ &r/hide allow_r%corrupt%
NAME DESCRIPTION DEFAULT_VALUE SESSION_VALUE SYSTEM_VALUE
--------------------------- ------------------------------------------------ ------------- ------------- ------------
_allow_read_only_corruption allow read-only open even if database is corrupt FALSE TRUE TRUE
_allow_resetlogs_corruption allow resetlogs even if it will cause corruption TRUE FALSE FALSE
--//^_^,这个参数意义不大,要在正常关闭的情况下,redo文件损坏的情况下,可以使用它打开数据库.
5.看看使用正常参数启动情况如何?
SYS@book> shutdown immediate ;
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@book> startup
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 18301
Session ID: 274 Serial number: 3
--//因为/mnt/ramdisk/book/redo02.log文件无法找到,启动失败.修改回来:
$ mv /mnt/ramdisk/book/redo02.log_xxx /mnt/ramdisk/book/redo02.log
SYS@book> startup
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
Database opened.
SYS@book> @ &r/hide allow_r%corrupt%
old 10: and lower(a.ksppinm) like lower('%&1%')
new 10: and lower(a.ksppinm) like lower('%allow_r%corrupt%%')
NAME DESCRIPTION DEFAULT_VALUE SESSION_VALUE SYSTEM_VALUE
--------------------------- ------------------------------------------------ ------------- ------------- ------------
_allow_read_only_corruption allow read-only open even if database is corrupt TRUE FALSE FALSE
_allow_resetlogs_corruption allow resetlogs even if it will cause corruption TRUE FALSE FALSE
总结:
1._allow_read_only_corruption参数意义不大,要在正常关闭的情况下,某个redo文件不存在或者损坏的情况下临时open read only打开.
2.一旦数据库文件头与控制文件当前scn不一致,需要恢复是无法使用它,read only打开的,怪不得很少见人提到这个参数.
--//补充测试redo损坏不是current的情况.
SYS@book> shutdown immediate ;
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@book> startup mount pfile='/tmp/init@.ora'
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
SYS@book> @ &r/logfile
GROUP# STATUS TYPE MEMBER IS_ GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME
------ ---------- ---------- ------------------------------- --- ------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ -------------------
1 ONLINE /mnt/ramdisk/book/redo01.log NO 1 1 728 52428800 512 1 YES INACTIVE 13277659048 2017-11-09 16:18:09 13277684336 2017-11-10 09:54:02
2 ONLINE /mnt/ramdisk/book/redo02.log NO 2 1 729 52428800 512 1 NO CURRENT 13277684336 2017-11-10 09:54:02 2.814750E+14
3 ONLINE /mnt/ramdisk/book/redo03.log NO 3 1 727 52428800 512 1 YES INACTIVE 13277632611 2017-11-09 10:18:14 13277659048 2017-11-09 16:18:09
4 STANDBY /mnt/ramdisk/book/redostb01.log NO
5 STANDBY /mnt/ramdisk/book/redostb02.log NO
6 STANDBY /mnt/ramdisk/book/redostb03.log NO
7 STANDBY /mnt/ramdisk/book/redostb04.log NO
7 rows selected.
$ mv /mnt/ramdisk/book/redo03.log /mnt/ramdisk/book/redo03.log_xxx
SYS@book> alter database open ;
alter database open
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 18497
Session ID: 274 Serial number: 3
--//无法打开数据库.
SYS@book> startup mount pfile='/tmp/init@.ora'
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
SYS@book> alter database open read only ;
Database altered.
--//还原现场:
SYS@book> shutdown immediate ;
Database closed.
Database dismounted.
ORACLE instance shut down.
$ mv /mnt/ramdisk/book/redo03.log_xxx /mnt/ramdisk/book/redo03.log
SYS@book> startup
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
Database opened.
[20171110]_allow_read_only_corruption参数.txt的更多相关文章
- [20180123]测试SQLNET.EXPIRE_TIME参数.txt
[20180123]测试SQLNET.EXPIRE_TIME参数.txt --//曾经写过一篇linux内核网络参数测试tcp_keepalive,链接http://blog.itpub.net/26 ...
- [20170927]hugepages与内核参数nr_overcommit_hugepages.txt
[20170927]hugepages与内核参数nr_overcommit_hugepages.txt /proc/sys/vm/nr_overcommit_hugepages specifies h ...
- Revit通过API创建共享参数
Revit共享参数是通过创建一个.txt类型的文件来保存相关信息,一旦与项目保存完毕之后,共享参数也就变成了项目参数(项目参数无法通过API创建),项目参数是保存在Revit项目里面的,所以此时这个. ...
- [20181109]12cR2 的pre_page_sga参数
[20181109]12cR2 的pre_page_sga参数.txt --//12CR2改变了参数pre_page_sga设置为True.设置为true有好处也有缺点.--//先看看官方的定义:ht ...
- [20170927]关于hugepages.txt
[20170927]关于hugepages.txt --//今天测试hugepages与内核参数nr_overcommit_hugepages,才发现HugePages_Surp表示什么? --// ...
- jmeter压测--从文本中读取参数
由于之前从数据库获取查询结果作为请求的入参(使用场景:测试一个接口并发处理数据的能力,并且每次请求传入的参数都要不同.),会一定程度上造成对数据库的压测,在没有完全搞清楚多线程之间参数的传递之前,我们 ...
- [20191220]关于共享内存段相关问题.txt
[20191220]关于共享内存段相关问题.txt --//我一直很好奇如果设置内核参数kernel.shmmax = 68719476736足够大,为什么我的测试实例还是建立3个共享内存段.--// ...
- （一）在Windows下编译扩展OpenCV 3.1.0 + opencv_contrib 及一些问题
一.准备工作: 1.下载OpenCV安装包:https://github.com/opencv/opencv 安装过程实际上就是解压过程,安装完成后得到(这里修改了文件名): 2.下载opencv_c ...
- AS3和js相互通信要点分析
目标:在html页面里可以使用事件来影响到swf文件的内容,swf文件也可以影响html里js代码的内容 一.新建flash文件,用Flash CC试用版新建一个TextArea.fla的源文件,不添 ...
随机推荐
- 2-4 完整Todolist案例
在2-3 的基础上继续,综合前面的Todolist编写一个完整的案例,实现基本的输入内容,添加内容,点击删除内容 稍微讲解54行代码 splice()的用法
- EF code first,set composite primary key 复合key问题
环境: EF core 2.0 Net core 2.0 错误: 因实体定义了多个key,打开数据库时程序报以下错误 An unhandled exception occurred while pro ...
- 当x，y和theta都是向量的时候如何计算损失
function J = computeCost(X, y, theta) %COMPUTECOST Compute cost for linear regression % J = COMPUTEC ...
- 搜索核心原理之网页和查询的相关性——TF-IDF
1.相关性的演进: i.单文本词频TF(Term Frequency) 用关键词的出现的次数除以文章的总次数,做归一化处理得到TF,来屏蔽文章长度对用关键词出现次数来衡量 ...
- 04-TypeScript中的方法新功能（上）
在TypeScript中,提供了一些函数的新功能,能够简化JavaScript中的一些比较复杂代码才能实现的一些能力. 在C#后端语言中,能够对方法传递的参数指定params关键字,也就是可以传递任意 ...
- C# sqlhelper 2
using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Secu ...
- AD预测论文研读系列2
EARLY PREDICTION OF ALZHEIMER'S DISEASE DEMENTIA BASED ON BASELINE HIPPOCAMPAL MRI AND 1-YEAR FOLLOW ...
- 牛刀小试MySQL--基于GTID的replication
实验环境:两个MySQL实例 IP地址:10.0.0.201 端口:3306 (MySQL的Master) IP地址:10.0.0.201 端口:3307 (MySQL的Slave) 需要的参数 se ...
- mysql查看执行sql语句的记录日志
开启日志模式 -- 1.设置 -- SET GLOBAL log_output = 'TABLE';SET GLOBAL general_log = 'ON'; //日志开启 -- SET GLOB ...
- ECharts图表实战经验1：如何设置图表同序列不同数据点的独立颜色值
最近有不少朋友在追问这样一个问题:我单序列的柱状图,我想让每一个根柱子的颜色都不一样,应该如何做? 针对这个问题,其实我只想说你压根没有认真看完或者查找ECharts官方的示例,官方能够找到的示例有: ...