[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

  1. [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 ...

  2. [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 ...

  3. 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. ...

  4. [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 ...

  5. [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? --// ...

  6. 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 ...

  7. [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.--// ...

  8. (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 ...

  9. 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

  1. 转载 Python 正则表达式入门(初级篇)

    Python 正则表达式入门(初级篇) 本文主要为没有使用正则表达式经验的新手入门所写.转载请写明出处 引子 首先说 正则表达式是什么? 正则表达式,又称正规表示式.正规表示法.正规表达式.规则表达式 ...

  2. table滑块

    我们做table时,常常想做一个滑块的移动效果,来让app显得更加生动,原理很简单,废话不说,直接上code public class AnimationActivity extends AppCom ...

  3. SpringBoot初体验及原理解析

    一.前言 ​ 上篇文章,我们聊到了SpringBoot得以实现的幕后推手,这次我们来用SpringBoot开始HelloWorld之旅.SpringBoot是Spring框架对“约定大于配置(Conv ...

  4. GO入门——7. 并发

    1 并发 1.1 goroutine Goroutine 奉行通过通信来共享内存,而不是共享内存来通信 goroutine 只是由官方实现的超级"线程池"而已. 每个实例 4-5K ...

  5. Python基础之带你快速掌握列表的常用方法

    append 前面说过列表是一种 内容可改变的 对象. append方法就会改变列表的内容,在后面添加一个元素 比如 a = [1, 2, 3.14, 'hello'] # append 之后,a就变 ...

  6. Hadoop项目实战-用户行为分析之编码实践

    1.概述 本课程的视频教程地址:<用户行为分析之编码实践> 本课程以用户行为分析案例为基础,带着大家去完成对各个KPI的编码工作,以及应用调度工作,让大家通过本课程掌握Hadoop项目的编 ...

  7. Jackson序列化LocalDate与Springboot集成

    前言 Java8的date API一经推出便广受好评,今日也准备用一用,然后就用出问题了.基本用法见https://www.cnblogs.com/woshimrf/p/java8-date-api. ...

  8. EOS1.1版本新特性介绍

    EOSIO/eos 目前在github的项目活跃度方面排名第一,release版本更新的速度让人应接不暇.今天EOS的大版本1.1发布,我也有幸参与了贡献,本篇文章重点介绍1.1版本的重大功能升级. ...

  9. SpringMVC之文件上传异常处理

    一般情况下,对上传的文件会进行大小的限制.如果超过指定大小时会抛出异常,一般会对异常进行捕获并友好的显示出来.以下用SpringMVC之文件上传进行完善. 首先配置CommonsMultipartRe ...

  10. 《剑指offer》内容总结

    (1)剑指Offer——Trie树(字典树) Trie树 Trie树,即字典树,又称单词查找树或键树,是一种树形结构,是一种哈希树的变种.典型应用是统计和排序大量的字符串(但不仅限于字符串),所以经常 ...