[20221014]数据文件2的小疑问.txt

--//查看v$dbfile 视图,发现一点点奇怪的地方,一般数据文件2都是对应sysaux表空间数据文件.
--//不知道从怎么版本开始,oracle的数据文件2不是sysaux表空间数据文件.感觉出现PDB开始.

1.环境:
SYS@192.168.100.235:1521/orcl> @ prxx
==============================
PORT_STRING                   : x86_64/Linux 2.4.xx
VERSION                       : 19.0.0.0.0
BANNER                        : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
BANNER_FULL                   : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
BANNER_LEGACY                 : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
CON_ID                        : 0
PL/SQL procedure successfully completed.

SYS@192.168.100.235:1521/orcl> column name format a70
SYS@192.168.100.235:1521/orcl> select * from v$dbfile order by 1;
     FILE# NAME                                                                       CON_ID
---------- ---------------------------------------------------------------------- ----------
         1 /u02/app/oracle/oradata/orcl/datafile/ORCL/system01.dbf                         0
         2 /u02/app/oracle/oradata/orcl/datafile/ORCL/lis_max_data.dbf                     0
         3 /u02/app/oracle/oradata/orcl/datafile/ORCL/sysaux01.dbf                         0
         4 /u02/app/oracle/oradata/orcl/datafile/ORCL/undotbs01.dbf                        0
         5 /u02/app/oracle/oradata/orcl/datafile/ORCL/lis_data.dbf                         0
         7 /u02/app/oracle/oradata/orcl/datafile/ORCL/users01.dbf                          0
         8 /u02/app/oracle/oradata/orcl/datafile/ORCL/lis_max_data01.dbf                   0
         9 /u02/app/oracle/oradata/orcl/datafile/ORCL/lis_data02.dbf                       0
        10 /u02/app/oracle/oradata/orcl/datafile/ORCL/lis_max_data02.dbf                   0
        11 /u02/app/oracle/oradata/orcl/datafile/ORCL/lis_max_data03.dbf                   0
10 rows selected.
--//一般以前建立数据库数据文件2都是属于sysaux表空间,而这里建立的数据文件对应应用软件的数据文件.

# ls -li sys* lis_max_data.dbf
52690971 -rw-r-----. 1 oracle oinstall 34359730176 Oct 14 08:37 lis_max_data.dbf
52690958 -rw-r-----. 1 oracle oinstall  3292536832 Oct 14 08:36 sysaux01.dbf
52690957 -rw-r-----. 1 oracle oinstall  1048584192 Oct 14 08:33 system01.dbf
--//从I节点建立的顺序看system01.dbf,sysaux01.dbf,lis_max_data.dbf.

--//查看另外数据库也是一样的情况:
SYS@192.168.100.141:1521/dyhis> column name format a70
SYS@192.168.100.141:1521/dyhis> select * from v$dbfile order by 1;
     FILE# NAME                                                                       CON_ID
---------- ---------------------------------------------------------------------- ----------
         1 +DATA/DYHIS/DATAFILE/system.279.1065727197                                      0
         2 +DATA/DYHIS/DATAFILE/users.283.1065727203                                       0
         3 +DATA/DYHIS/DATAFILE/sysaux.269.1065727197                                      0
         4 +DATA/DYHIS/DATAFILE/undotbs1.282.1065727201                                    0
         5 +DATA/DYHIS/DATAFILE/undotbs2.263.1065727197                                    0
...
15 rows selected.

2.为什么呢?
--//oracle为什么出现这样的情况或者设计呢?难道可以使应用软件的数据文件近可能在磁盘内圈吗?那位给出合理的解析.