Oracle重建控制文件的实例教程
前言
控制文件（control file）是一个相当小的文件（最多能增长到64M左右），其中包含Oracle需要的其他文件的一个目录。参数文件告知实例控制文件的位置，控制文件则告知示例数据库和在线重做日志文件的位置。控制文件还告知了Oracle其他一些事情，如已发生检查点的有关信息、数据库名（必须和db_name参数匹配）、创建数据库的时间戳、归档重做日志的历史（有时这会让控制文件变大）、RMAN信息等。
环境：OEL 5.7 + Oracle 10.2.0.5
背景：在Oracle的运维过程中，时常会遇到一些场景是需要重建控制文件才可以解决的。本文的场景可以通过复制控制文件到新路径，运行一段时间后，再用老的控制文件启动数据库重现。
1.当前故障现象
在使用旧的控制文件启动数据库时，报错ORA-01122、ORA-01110、ORA-01207:
SQL> shutdown abort ORACLE instance shut down. SQL> startup ORACLE instance started. Total System Global Area 599785472 bytes Fixed Size 2098112 bytes Variable Size 218106944 bytes Database Buffers 373293056 bytes Redo Buffers 6287360 bytes Database mounted. ORA-01122: database file 1 failed verification check ORA-01110: data file 1: '/oradata/cxywdb/system01.dbf' ORA-01207: file is more recent than control file - old control file
2.分析故障原因
根据报错信息查找MOS文档:
ORA-1122, ORA-1110, ORA-1207 while open the database after crash (文档 ID 283927.1)
延伸思考一下，为什么会这样？
主要错误是ORA-01207，利用oerr工具看到Oralce对这个错误的详细描述是：
01207, 00000, "file is more recent than control file - old control file"
// *Cause: The control file change sequence number in the data file is
// greater than the number in the control file. This implies that
// the wrong control file is being used. Note that repeatedly causing
// this error can make it stop happening without correcting the real
// problem. Every attempt to open the database will advance the
// control file change sequence number until it is great enough.
// *Action: Use the current control file or do backup control file recovery to
// make the control file current. Be sure to follow all restrictions
// on doing a backup control file recovery.
一般遇到这种情况，当前的控制文件肯定是找不到了。那么就得考虑重建控制文件来解决，MOS给出的建议也是重建控制文件。
3.重建控制文件
重建控制文件的核心步骤：
3.1 备份控制文件到trace
startup mount alter database backup controlfile to trace; oradebug setmypid oradebug tracefile_name
3.2 启动数据库到nomount状态
shutdown abort startup nomount;
3.3 确认重建控制文件的语句
vi control.sql CREATE CONTROLFILE REUSE DATABASE "CXYWDB" NORESETLOGS FORCE LOGGING ARCHIVELOG MAXLOGFILES 16 MAXLOGMEMBERS 3 MAXDATAFILES 100 MAXINSTANCES 8 MAXLOGHISTORY 292 LOGFILE GROUP 5 '/oradata2/cxywdb/redo11.log' SIZE 50M, GROUP 6 '/oradata2/cxywdb/redo12.log' SIZE 50M, GROUP 7 '/oradata2/cxywdb/redo13.log' SIZE 50M -- STANDBY LOGFILE DATAFILE '/oradata/cxywdb/system01.dbf', '/oradata/cxywdb/undotbs01.dbf', '/oradata/cxywdb/sysaux01.dbf', '/oradata/cxywdb/users01.dbf', '/oradata/cxywdb/alfred01.dbf', '/oradata/cxywdb/alfred02.dbf', '/oradata/cxywdb/alfred03.dbf', '/oradata/cxywdb/alfred04.dbf', '/oradata/cxywdb/alfred05.dbf', '/oradata/cxywdb/dbs_i_alfred01.dbf' CHARACTER SET ZHS16GBK ;
3.4 恢复并打开数据库
SQL> recover database; Media recovery complete. SQL> alter database open; Database altered.
附：实际解决过程如下：
SQL> shutdown abort ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 599785472 bytes Fixed Size 2098112 bytes Variable Size 218106944 bytes Database Buffers 373293056 bytes Redo Buffers 6287360 bytes Database mounted. SQL> alter database backup controlfile to trace; Database altered. SQL> oradebug setmypid Statement processed. SQL> oradebug tracefile_name /s01/oracle/admin/cxywdb/udump/cxywdb_ora_3983.trc SQL> shutdown abort ORACLE instance shut down. SQL> startup nomount; ORACLE instance started. Total System Global Area 599785472 bytes Fixed Size 2098112 bytes Variable Size 218106944 bytes Database Buffers 373293056 bytes Redo Buffers 6287360 bytes SQL> @control Control file created. SQL> select status from v$instance; STATUS ------------ MOUNTED SQL> recover database; Media recovery complete. SQL> alter database open; Database altered.
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