Use dbms_space.free_blocks and dbms_space.unused_space : dbms_space « System Packages « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. System Packages
3. dbms_space

SQL> set echo on
SQL>
SQL> create table t ( x int, y char(1000) default 'x' );

Table created.

SQL>
SQL> create or replace procedure measure_usage
  2  as
  3      l_free_blks                 number;
  4      l_total_blocks              number;
  5      l_total_bytes               number;
  6      l_unused_blocks             number;
  7      l_unused_bytes              number;
  8      l_LastUsedExtFileId         number;
  9      l_LastUsedExtBlockId        number;
 10      l_LAST_USED_BLOCK           number;
 11
 12      procedure get_data
 13      is
 14      begin
 15          dbms_space.free_blocks
 16          ( segment_owner     =>  USER,
 17            segment_name      => 'T',
 18            segment_type      => 'TABLE',
 19            FREELIST_group_id => 0,
 20            free_blks         => l_free_blks );
 21
 22          dbms_space.unused_space
 23          ( segment_owner     => USER,
 24            segment_name      => 'T',
 25            segment_type      => 'TABLE',
 26            total_blocks      => l_total_blocks,
 27            total_bytes       => l_total_bytes,
 28            unused_blocks     => l_unused_blocks,
 29            unused_bytes      => l_unused_bytes,
 30            LAST_USED_EXTENT_FILE_ID => l_LastUsedExtFileId,
 31            LAST_USED_EXTENT_BLOCK_ID => l_LastUsedExtBlockId,
 32            LAST_USED_BLOCK => l_last_used_block ) ;
 33
 34
 35          dbms_output.put_line( L_free_blks || ' on FREELIST, ' ||
 36                                to_number(l_total_blocks-l_unused_blocks-1 ) ||
 37                                ' used by table' );
 38      end;
 39  begin
 40      for i in 0 .. 10
 41      loop
 42          dbms_output.put( 'insert ' || to_char(i,'00') || ' ' );
 43          get_data;
 44          insert into t (x) values ( i );
 45          commit ;
 46      end loop;
 47
 48
 49      for i in 0 .. 10
 50      loop
 51          dbms_output.put( 'update ' || to_char(i,'00') || ' ' );
 52          get_data;
 53          update t set y = null where x = i;
 54          commit;
 55      end loop;
 56  end;
 57  /

Procedure created.

SQL>
SQL> exec measure_usage
insert  00 0 on FREELIST, 0 used by table
insert  01 1 on FREELIST, 1 used by table
insert  02 1 on FREELIST, 1 used by table
insert  03 1 on FREELIST, 1 used by table
insert  04 1 on FREELIST, 1 used by table
insert  05 1 on FREELIST, 1 used by table
insert  06 1 on FREELIST, 1 used by table
insert  07 1 on FREELIST, 1 used by table
insert  08 1 on FREELIST, 2 used by table
insert  09 1 on FREELIST, 2 used by table
insert  10 1 on FREELIST, 2 used by table
update  00 1 on FREELIST, 2 used by table
update  01 1 on FREELIST, 2 used by table
update  02 1 on FREELIST, 2 used by table
update  03 1 on FREELIST, 2 used by table
update  04 2 on FREELIST, 2 used by table
update  05 2 on FREELIST, 2 used by table
update  06 2 on FREELIST, 2 used by table
update  07 2 on FREELIST, 2 used by table
update  08 2 on FREELIST, 2 used by table
update  09 2 on FREELIST, 2 used by table
update  10 2 on FREELIST, 2 used by table

PL/SQL procedure successfully completed.

SQL>
SQL> drop table t;

Table dropped.