加一个大写的A的隐藏属性，可以让文件的access time属性不会变，用来减少磁盘的I/O（access time属性使用stat 命令去查看)
--注意：A属性对于再touch一次这个文件是无效的
=====================================
SQL>conn / as sysdba
spool /u01/chattr.sql
set heading off  
set feedback off
select 'ho chattr +A  '||member from v$logfile
union select 'ho chattr +A  '||name  from v$tempfile
union select 'ho chattr +A  '||name  from v$datafile
union select 'ho chattr +A  '||name  from v$controlfile;
set heading on
set feedback on
spool off

去掉没用的头尾几行
SQL> @/u01/chattr.sql

[root@test1 orcl]# lsattr *
-------A----- app_data.dbf
-------A----- control01.ctl
-------A----- control02.ctl
-------A----- control03.ctl
-------A----- example01.dbf
-------A----- redo01.log
-------A----- redo02.log
-------A----- redo03.log
-------A----- redo04.log
-------A----- sysaux01.dbf
-------A----- system01.dbf
-------A----- temp01.dbf
-------A----- undotbs01.dbf
-------A----- users01.dbf

SQL> startup

[oracle@test1 orcl]$ stat system01.dbf
  File: `system01.dbf'
  Size: 503324672       Blocks: 984024     IO Block: 4096   regular file
Device: 805h/2053d      Inode: 2286198     Links: 1
Access: (0755/-rwxr-xr-x)  Uid: (  500/  oracle)   Gid: (  501/oinstall)
Access: 2012-02-18 15:38:17.000000000 +0800
Modify: 2012-02-18 15:43:44.000000000 +0800
Change: 2012-02-18 15:43:44.000000000 +0800

SQL> shutdown immediate

[oracle@test1 orcl]$ stat system01.dbf
  File: `system01.dbf'
  Size: 503324672       Blocks: 984024     IO Block: 4096   regular file
Device: 805h/2053d      Inode: 2286198     Links: 1
Access: (0755/-rwxr-xr-x)  Uid: (  500/  oracle)   Gid: (  501/oinstall)
Access: 2012-02-18 15:38:17.000000000 +0800----时间与上面的状态相比不变
Modify: 2012-02-18 15:44:54.000000000 +0800
Change: 2012-02-18 15:44:54.000000000 +0800


定期在业务低峰期，用oracle用户对所有的文件，touch一次就可以更新Access time了
SQL>conn / as sysdba
spool /u01/touch.sql
set heading off  
set feedback off
select 'ho touch '||member from v$logfile
union select 'ho touch '||name  from v$tempfile
union select 'ho touch '||name  from v$datafile
union select 'ho touch '||name  from v$controlfile;
set heading on
set feedback on
spool off

去掉没用的头尾几行
SQL> @/u01/touch.sql