Now I know why SYSTEM tablespace comes with dictionary extent manament in a vendor application

It seems the database uses raw devices, and created manually (not using dbca), when the option is not specified explicitly, by default the SYSTEM tablespace is created  as DICTIONARY managed.

It seems quite a few article list disadvantages of DICTIONARY extent management, but don't where it come from.

Below is my testing.

default setting for SYSTEM datafile

-bash-3.2$ cat cre_db.sql

STARTUP NOMOUNT

CREATE DATABASE "RAWDB1"

    MAXLOGFILES 16

    MAXLOGMEMBERS 3

    MAXDATAFILES 100

    MAXINSTANCES 8

    MAXLOGHISTORY 292

DATAFILE '/software/oracle/admin/RAWDB1/conf/RAWDB1_system_raw_1000m' size 900m reuse

sysaux datafile '/software/oracle/admin/RAWDB1/conf/RAWDB1_sysaux_raw_600m'size 560m  reuse

undo tablespace "UNDOTBS1" datafile '/software/oracle/admin/RAWDB1/conf/RAWDB1_undotbs1_raw_500m' size 480m reuse

default temporary tablespace temp tempfile '/software/oracle/admin/RAWDB1/conf/RAWDB1_temp_raw_250m' size 200m reuse

LOGFILE

  GROUP 1 ('/software/oracle/admin/RAWDB1/conf/RAWDB1_redo1_1_raw_120m')  SIZE 50M reuse ,

  GROUP 2 ('/software/oracle/admin/RAWDB1/conf/RAWDB1_redo1_2_raw_120m')  SIZE 50M reuse

user sys identified by "oracle123" user  system identified by "oracle123" ;

 
and
run the $ORACLE_HOME/rdbms/admin/catalog.sql and $ORACLE_HOME/rdbms/admin/catproc.sql.

17:00:32 SYS@RAWDB1> select tablespace_name , extent_management from dba_tablespaces;

TABLESPACE_NAME                EXTENT_MAN

------------------------------ ----------

SYSTEM                         DICTIONARY

UNDOTBS1                       LOCAL

SYSAUX                         LOCAL

TEMP                           LOCAL

4 rows selected.

 

Create non-dictionary extent management for SYSTEM tablespace

-bash-3.2$ cat cre_db_non_dict_system.sql

STARTUP NOMOUNT

CREATE DATABASE "RAWDB1"

    MAXLOGFILES 16

    MAXLOGMEMBERS 3

    MAXDATAFILES 100

    MAXINSTANCES 8

    MAXLOGHISTORY 292

DATAFILE '/software/oracle/admin/RAWDB1/conf/RAWDB1_system_raw_1000m' size 900m reuse extent management local

sysaux datafile '/software/oracle/admin/RAWDB1/conf/RAWDB1_sysaux_raw_600m'size 560m  reuse

undo tablespace "UNDOTBS1" datafile '/software/oracle/admin/RAWDB1/conf/RAWDB1_undotbs1_raw_500m' size 480m reuse

default temporary tablespace temp tempfile '/software/oracle/admin/RAWDB1/conf/RAWDB1_temp_raw_250m' size 200m reuse

LOGFILE

  GROUP 1 ('/software/oracle/admin/RAWDB1/conf/RAWDB1_redo1_1_raw_120m')  SIZE 50M reuse ,

  GROUP 2 ('/software/oracle/admin/RAWDB1/conf/RAWDB1_redo1_2_raw_120m')  SIZE 50M reuse

user sys identified by "oracle123" user  system identified by "oracle123" ;

17:24:40 SYS@RAWDB1> select tablespace_name,  extent_management from dba_tablespaces;

TABLESPACE_NAME                EXTENT_MAN

------------------------------ ----------

SYSTEM                         LOCAL

UNDOTBS1                       LOCAL

SYSAUX                         LOCAL

TEMP                           LOCAL

 

delete file from raw partition

It seems  I was wrong to search above key words from Google.  In the end, I found no simple command to destroy the raw partition.

Maybe some storage related command may work, like dd, format. But I won't bother it.

For command "drop database", in fact it drops nothing to me . below demo is performed with Oracle database 10.2.0.5 running on linux 32bit platform.

16:20:44 SYS@RAWDB1> drop database ;

Database dropped.

Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

Elapsed: 00:00:06.17

16:35:11 @> exit

-bash-3.2$ ps -fu oracle

UID        PID  PPID  C STIME TTY          TIME CMD

oracle    5807 26909  0 Mar25 ?        00:02:53 /software/oracle/product/10.2.0/jdk/bin/java -server -Xmx256M -XX:MaxPermSize=96m -XX:M

oracle    5949     1  0 Mar25 ?        00:00:00 /software/oracle/product/10.2.0/bin/tnslsnr LISTENER -inherit

oracle   22956 22952  0 14:58 ?        00:00:00 sshd: oracle@pts/0

oracle   22965 22956  0 14:58 pts/0    00:00:00 -bash

oracle   23029 23025  0 15:00 ?        00:00:00 sshd: oracle@pts/1

oracle   23040 23029  0 15:00 pts/1    00:00:00 -bash

oracle   24230 22965  0 16:35 pts/0    00:00:00 ps -fu oracle

oracle   26909     1  0 Mar25 ?        00:00:02 /software/oracle/product/10.2.0/perl/bin/perl /software/oracle/product/10.2.0/bin/emwd.

oracle   29695 26909  0 Mar25 ?        00:06:00 /software/oracle/product/10.2.0/bin/emagent

-bash-3.2$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.5.0 - Production on Thu Apr 3 16:35:21 2014

Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.

Connected to an idle instance.

16:35:21 SYS@RAWDB1> startup

ORACLE instance started.

Total System Global Area  901775360 bytes

Fixed Size                  2100424 bytes

Variable Size             226493240 bytes

Database Buffers          666894336 bytes

Redo Buffers                6287360 bytes

Database mounted.

Database opened.