Re: extent size and segment size

From: Kelly Young <young_at_maricopa.edu>
Date: 1997/01/23
Message-ID: <32E7FB5D.2EB8@maricopa.edu>#1/1

Pauro Tanaka wrote:
>
> The size of the initial extent differs from user_segment(view) shows.
> Please tell me why.
>
> SQL> create table a ( a char(1) ) storage ( initial 101k );
>
> [table was created](Japanese local message)
>
> SQL> select * from user_segments;
>
> SEGMENT_NAME
> --------------------------------------------------------------------------------
> SEGMENT_TYPE TABLESPACE_NAME BYTES BLOCKS
> ----------------- ------------------------------ ---------- ----------
> EXTENTS INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE
> ---------- -------------- ----------- ----------- ----------- ------------
> FREELISTS FREELIST_GROUPS
> ---------- ---------------
> A
> TABLE SYOUJIT 122880 30
> 1 106496 8192 1 249 0
> 1 1
>
> Page size is 4K.
> I can understand that 'INITIAL_EXTENT' is changed from 101k to 104k(106496bytes)
> But I can't understand that 'BYTES' shows 122880 bytes ( 120k ).

When Oracle allocates storage for an extent, it allocates in multiples of
5 oracle blocks. Your initial extent equated to 26 oracle blocks 106496 / 4096 = 26. Oracle rounded that to 30 blocks. 30 * 4096 = 122880. Received on Thu Jan 23 1997 - 00:00:00 CST