EXTENTS

Question

Hi,
I am using 10g DB.
When I issue:
CREATE TABLE AATEST (A NUMBER) TABLESPACE TEST_TAB STORAGE (INITIAL 20M NEXT 2M PCTINCREASE 0);
and after that:
select segment_name, BYTES/(1024*1024) bytes_Mb from dba_extents where segment_name = 'AATEST';
The result is 20 records of 1Mb each.
I would expect 1 extent of 20Mb.
Anyone?
Thanks
Regards
Stephan

Answer 1

Check the SQL Reference for storage clause parameter use (if any) with storage in locally managed tablespaces.
Many parameters are ignored with the current type of tablespace, but initial value specified hints the number of extents in the initial allocation.
Take a look at the tablespace level, e.g.:
SQL> r
1 select tablespace_name,extent_management em, allocation_type at,
2 initial_Extent/1024 in_kb, next_extent/1024 nxt_kb
3* from dba_tablespaces
TABLESPACE_NAME                EM         AT             IN_KB     NXT_KB
SYSTEM                         LOCAL      SYSTEM            64
UNDOTBS01                      LOCAL      SYSTEM            64
TEMP                           LOCAL      UNIFORM         1024       1024