Hi,

You can do the following:

1. Create a table:
create table vj_test(no number, name varchar2(20))
storage(initial 1m next 1m pctincrease 0 minextents 3) ;

2. Issue a select statement from user_segments.

select blocks, bytes, extents from user_segments where
segment_name='VJ_TEST'
SQL> /

BLOCKS BYTES EXTENTS
---------- ---------- ----------
384 3145728 3

3. Analyze the table.
SQL> analyze table vj_test compute statistics ;

4. Insert some records into the table and reanalyze the
table and then query USER_TABLES:

SQL> begin
2 for i in 1..100 loop
3 insert into vj_test values(i,'Name'||i) ;
4 end loop ;
5 end ;
6 /

PL/SQL procedure successfully completed.

SQL> select count(*) from vj_test ;

COUNT(*)
----------
100

SQL> analyze table vj_test compute statistics ;

Table analyzed.

SQL> select blocks, empty_blocks from user_tables where table_name='VJ_TEST' ;

BLOCKS EMPTY_BLOCKS
---------- ------------
1 382

5. Issue the following query:

SQL> select bytes, blocks, extents from user_segments where segment_name='VJ_TEST_NO_PK' ;

BYTES BLOCKS EXTENTS
---------- ---------- ----------
16384 2 1

This shows that for the index Oracle shows the no. of blocks allocated(since it took the default values for the storage parameters).

You can also check the same thing using DBMS_SPACE.UNUSED_SPACE package:

SQL> var total_blocks number ;
SQL> var total_bytes number ;
SQL> var unused_blocks number ;
SQL> var unused_bytes number ;
SQL> var file_id number ;
SQL> var block_id number ;
SQL> var last_used_block number ;

SQL> exec dbms_space.unused_space('SYSTEM','VJ_TEST','TABLE',:total_blocks,:total_bytes,:unused_bloc
ks,:unused_bytes,:file_id,:block_id,:last_used_block) ;


SQL> select :total_blocks, :total_bytes, :unused_blocks, :unused_bytes, :file_id, :block_id, :last_u
sed_block from dual ;

:TOTAL_BLOCKS :TOTAL_BYTES :UNUSED_BLOCKS :UNUSED_BYTES :FILE_ID :BLOCK_ID
------------- ------------ -------------- ------------- ---------- ----------
:LAST_USED_BLOCK
----------------
384 3145728 382 3129344 1 18405
2


HTH.

Vijay.