Oracle Automated segment Management ASSM notes

CREATE tablespace Demo
DataFile ' J:\app\wufan\oradata\orcl\demo01.dbf '
SIZE 50M
EXTENT MANAGEMENT Local--must be managed locally
SEGMENT SPACE MANAGEMENT AUTO; --ASSM Management of the logo
CREATE TABLE Demotab (x number)
Tablespace Demo
STORAGE (INITIAL K);

Sql> Show User
USER is "SCOTT"
Sql> SELECT T.table_name,
2 T.initial_extent,
3 T.next_extent,
4 T.pct_free,
5 t.pct_used
6 from User_tables t
7 WHERE t.table_name = ' demotab ';
table_name initial_extent next_extent Pct_free pct_used
------------------------------ -------------- ----------- ---------- ----------
Demotab 1024000 10
Sql> set Serveroutput on
sql> exec scott.show_space (' Demotab ', ' auto ', ' T ', ' Y ');
Total Blocks ......... ............ 0
Total Bytes ......... ............. 0
Unused Blocks ......... ........... 0
Unused Bytes ......... ............ 0
Last used Ext FileId ......... ..... 0
Last used Ext blockid ......... ..... 0
Last used Block ......... .......... 0
*************************************************
The segment is analyzed
0%--25% free space blocks .... ..... 0
0%---25% free space bytes ...... 0
25%---50% free space blocks ..... 0
25%--50% free space bytes .... ..... 0
50%---75% free space blocks ..... 0
50%--75% free space bytes .... ..... 0
75%--100% free space blocks ..... 0
75%---100% free space bytes ..... 0
Unused Blocks ......... ........... 0
Unused Bytes ......... ............ 0
Total Blocks ......... ............ 0
Total bytes ......... ............. 0
PL/SQL procedure successfully completed.
Sql> SELECT t.segment_name, t.extent_id, t.block_id
2 from Dba_extents t
3 WHERE t.segment_name = ' demotab ';
No rows selected
Sql>

The experiment just confirms that 11g creates a table, but produces a table definition that does not allocate any space

Attached Show_space Process Code, think this code is very useful, write down to mark:

CREATE OR REPLACE PROCEDURE show_space (p_segname_1 in varchar2, p_space in varchar                                        2 Default ' MANUAL ', p_type_1 in varchar2 default ' TABLE ', p_analyzed in varchar2 default ' N ', p_owner_1 in varchar2 default   USER) as P_segname VARCHAR2 (100);   P_type VARCHAR2 (10);   P_owner VARCHAR2 (30);   L_unformatted_blocks number;   L_unformatted_bytes number;   L_fs1_blocks number;   L_fs1_bytes number;   L_fs2_blocks number;   L_fs2_bytes number;   L_fs3_blocks number;   L_fs3_bytes number;   L_fs4_blocks number;   L_fs4_bytes number;   L_full_blocks number;   L_full_bytes number;   L_free_blks number;   L_total_blocks number;   L_total_bytes number; L_unused_blocks number;   L_unused_bytes number;   L_lastusedextfileid number;   L_lastusedextblockid number;   L_last_used_block number; PROCEDURE p (P_label in varchar2, p_num in number) is BEGIN dbms_output.put_line (Rpad (P_label, +, '. ') | | p_nu   m); END;          BEGIN P_segname: = UPPER (p_segname_1);   --Rainy changed P_owner: = UPPER (p_owner_1);   P_type: = P_type_1; IF (p_type_1 = ' I ' OR p_type_1 = ' i ') then--rainy changed p   _type: = ' INDEX ';   END IF; IF (p_type_1 = ' t ' OR p_type_1 = ' t ') then--rainy changed p   _type: = ' TABLE ';   END IF; IF (p_type_1 = ' C ' OR p_type_1 = ' C ') then--rainy changed p   _type: = ' CLUSTER ';   END IF;                 Dbms_space.unused_space (Segment_owner = P_owner,           Segment_name = p_segname, Segment_type = P_type,                            Total_blocks = l_total_blocks, total_bytes = L_total_bytes,                            Unused_blocks = l_unused_blocks, unused_bytes = L_unused_bytes, last_used_extent_file_id = L_lastusedextfileid, last_used_extent_block_id = L_lastu   Sedextblockid, last_used_block = L_last_used_block); IF p_space = ' MANUAL ' OR (p_space <> ' auto ' and p_space <> ' auto ') then Dbms_space.free_blocks (segment  _owner = P_owner, segment_name = P_segname, Segment_type = p_type, freelist_group_id = 0, free_blks = L_free      _blks);   P (' Free Blocks ', l_free_blks); ENDIF;   P (' Total Blocks ', l_total_blocks);   P (' Total Bytes ', l_total_bytes);   P (' Unused Blocks ', l_unused_blocks);   P (' Unused Bytes ', l_unused_bytes);   P (' last used Ext FileId ', L_lastusedextfileid);   P (' last used Ext blockid ', l_lastusedextblockid);   P (' Last used Block ', l_last_used_block);                              /*if the segment is analyzed */IF p_analyzed = ' Y ' then dbms_space.space_usage (Segment_owner = P_owner,                              Segment_name = p_segname, Segment_type = P_type, Unformatted_blocks = l_unformatted_blocks, unformatted_bytes = L_u  Nformatted_bytes, fs1_blocks = l_fs1_blocks, fs1_bytes = L_fs1_bytes, fs2_blocks = l_fs2_blocks, fs2_bytes = L_f               S2_bytes, fs3_blocks = L_fs3_blocks,               Fs3_bytes = l_fs3_bytes, fs4_blocks = L_fs4_blocks,                              Fs4_bytes = l_fs4_bytes, full_blocks = L_full_blocks,      Full_bytes = l_full_bytes);      Dbms_output.put_line (Rpad (', 50, ' * '));      Dbms_output.put_line (' The segment is analyzed ');      P (' 0%-25% free space blocks ', l_fs1_blocks);      P (' 0%-25% free Space bytes ', l_fs1_bytes);      P (' 25%-50% free space blocks ', l_fs2_blocks);      P (' 25%-50% free Space bytes ', l_fs2_bytes);      P (' 50%-75% free space blocks ', l_fs3_blocks);      P (' 50%-75% free Space bytes ', l_fs3_bytes);      P (' 75%-100% free space blocks ', l_fs4_blocks);      P (' 75%-100% free Space bytes ', l_fs4_bytes);      P (' Unused Blocks ', l_unformatted_blocks);      P (' Unused Bytes ', l_unformatted_bytes);      P (' Total Blocks ', l_full_blocks);  P (' Total bytes ', l_full_bytes); END IF; END;

Oracle Automated segment Management ASSM notes