Oracle参数文件的本质
Oracle参数文件的本质
环境:
- SQL> select * from v$version where rownum=1;
- BANNER
- ----------------------------------------------------------------
- Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
- SQL> !uname -r
- 2.6.18-308.el5xen
参数文件的根本作用就是“覆盖参数的默认值”,以便刻画出一个最适合自己应用场景的环境
因此参数文件中记录的都是我们调研的,与默认值存在不同
通过删除pfile参数文件中的的参数,可达到恢复参数为其默认值的目的
下面用一个实验来测试一下:
db_recovery_file_dest_size参数的作用是限制闪回恢复区可存放文件总大小
一旦将参数db_recovery_file_dest_size设置为非零值后“很难”恢复为默认值“0”。
这里我们用reset对spfile操作,来恢复为0
- sys@ORCL> show parameter db_recovery_file_dest_size
- NAME TYPE VALUE
- ------------------------------------ ----------- ------------------------------
- db_recovery_file_dest_size big integer 2G
- sys@ORCL> alter system reset db_recovery_file_dest_size scope=spfile sid='*';
- System altered.
- sys@ORCL> shutdown immediate
- Database closed.
- Database dismounted.
- ORACLE instance shut down.
- sys@ORCL> create pfile from spfile;
- 编辑pfile 去掉DB_RECOVERY_FILE_DEST
- SQL> startup pfile='/u01/app/oracle/product/10.2.0/db_1/dbs/initorcl.ora';
- ORACLE instance started.
- Total System Global Area 419430400 bytes
- Fixed Size 1219760 bytes
- Variable Size 146801488 bytes
- Database Buffers 268435456 bytes
- Redo Buffers 2973696 bytes
- Database mounted.
- Database opened.
- SQL> show parameter db_recovery_file_dest_size
- NAME TYPE VALUE
- ------------------------------------ ----------- ------------------------------
- db_recovery_file_dest_size big integer 0
评论暂时关闭