Re: table size not true with dba_segments??

On Mar 27, 12:48 pm, "Andrea" <netsecur..._at_tiscali.it> wrote:
> hi,
> i've a oracle 9i db and after run dbms_stats i find a table size with
> this command:
>
> select bytes,initial_extent,next_extent,extents from dba_segments
> where segment_name='TRANSIT' and OWNER='SACT';
>
> the ouput is this:
>
> BYTES INITIAL_EXTENT NEXT_EXTENT EXTENTS
> ---------- --------------
> ----------- ----------
> 756678656 67502080 377524224 7
>
> so, there is something wrong :-?
>
> if next_extent is about 377Mb and the extents allocated is 7, it
> should be more then 756Mb (BYTES). Like 67Mb + 377Mb *6 , (initial +
> 6 extents)
> Instead, why i've gather this result?
>
> how i estimate table size?
>
> thanks a lot
>
> andrew

Nothing wrong, apart from the fact you should realize (or look up in the documentation) the size of the next_extent is the size which will actually be allocated, when the next_extent is created. So next extent in dba_segments = the result of next_extent in dba_tables + pctincrease in dba_tables. If you look in dba_extents, you will see bytes in dba_extents adds up to bytes in dba_segments (it better would, as dba_segments is based on dba_extents). So apart from the usual not reading the documentation and jumping to usenet right away, there is nothing wrong.

--
Sybrand Bakker
Senior Oracle DBA