某客户给sysaux表空间添加了数据文件,但有在操作系统层rm删除了数据文件,更悲催的的是之前归档所在的磁盘损坏,恢复所需要的归档那是没指望了,也一年多没进行
某客户给sysaux表空间添加了数据文件,但有在操作系统层rm 删除了数据文件,更悲催的的是之前归档所在的磁盘损坏,恢复所需要的归档那是没指望了,也一年多没进行过数据库备份了,
现记录恢复过程如下:(虚拟机上重新模拟该恢复过程)
1 数据文件状态如下
SQL> select file#,name,status from v$datafile;
FILE# NAME STATUS
---------- ---------------------------------------- -------
1 /oracle/CRM/ZBCRM/system01.dbf SYSTEM
2 /oracle/CRM/ZBCRM/sysaux01.dbf ONLINE
3 /oracle/CRM/ZBCRM/undotbs01.dbf ONLINE
4 /oracle/CRM/ZBCRM/users01.dbf ONLINE
5 /oracle/CRM/ZBCRM/sysaux02.dbf RECOVER
2 重新生成操作系统层删除的数据文件
SQL> alter database create datafile '/oracle/CRM/ZBCRM/sysaux02.dbf';
Database altered.
注意,香港服务器,当我们用 alter database create datafile 创建数据文件时,数据文件头部scn以及rba.seq号均取自于该数据文件创建时控制文件中记录的scn和rba.seq号.
3 此刻数据文件头部信息如下:
SQL> select hxfil,fhscn,fhrba_seq from x$kcvfh;
HXFIL FHSCN FHRBA_SEQ
---------- ---------------- ----------
1 1047892 18
2 1047892 18
3 1047892 18
4 1047892 18
5 1026926 1
这里可以明确看出5号数据文件恢复需要从seq号为1的归档开始恢复,香港空间,但实际上seq#=1及其之后的归档已经不存在了,虚拟主机,所以如下恢复失败:
SQL> recover datafile 5;
ORA-00283: recovery session canceled due to errors
ORA-01110: data file 5: '/oracle/CRM/ZBCRM/sysaux02.dbf'
ORA-01157: cannot identify/lock data file 5 - see DBWR trace file
ORA-01110: data file 5: '/oracle/CRM/ZBCRM/sysaux02.dbf'
4 用bbed调整5号数据文件如下几个偏移量
ub4 kcvfhcpc @140 ------检查点计数
ub4 kcvfhccc @148 ------总是比检查点计数少1
ub4 kcvcptim @492 ------检查点时间
ub4 kscnbas @484 ------scn的低位
ub2 kscnwrp @488 ------scn的高位
[oracle@oracle ~]$ bbed parfile=bbed.par
Password:
BBED: Release 2.0.0.0.0 - Limited Production on Thu Jul 25 14:26:45 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************

oracle asm指的是“自动存储管理”,是一种卷管理器,可自动管理磁盘组并提供有效的数据冗余功能;它是做为单独的Oracle实例实施和部署。asm的优势:1、配置简单、可最大化推动数据库合并的存储资源利用;2、支持BIGFILE文件等。

方法:1、利用“select*from user_indexes where table_name=表名”语句查询表中索引;2、利用“select*from all_indexes where table_name=表名”语句查询所有索引。

在oracle中,可以利用“TO_SINGLE_BYTE(String)”将全角转换为半角;“TO_SINGLE_BYTE”函数可以将参数中所有多字节字符都替换为等价的单字节字符,只有当数据库字符集同时包含多字节和单字节字符的时候有效。

在Oracle中,可利用lsnrctl命令查询端口号,该命令是Oracle的监听命令;在启动、关闭或重启oracle监听器之前可使用该命令检查oracle监听器的状态,语法为“lsnrctl status”,结果PORT后的内容就是端口号。

在oracle中,可以利用“drop sequence sequence名”来删除sequence;sequence是自动增加数字序列的意思,也就是序列号,序列号自动增加不能重置,因此需要利用drop sequence语句来删除序列。

在oracle中,可以利用“select ... From all_tab_columns where table_name=upper('表名') AND owner=upper('数据库登录用户名');”语句查询数据库表的数据类型。

方法:1、利用“LOWER(字段值)”将字段转为小写,或者利用“UPPER(字段值)”将字段转为大写;2、利用“REGEXP_LIKE(字符串,正则表达式,'i')”,当参数设置为“i”时,说明进行匹配不区分大小写。

方法:1、利用“alter system set sessions=修改后的数值 scope=spfile”语句修改session参数;2、修改参数之后利用“shutdown immediate – startup”语句重启服务器即可生效。


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