calculating segment size issue

From: john kelly <johnt.kelly_at_worldnet.att.net>
Date: Mon, 19 Apr 1999 23:59:27 GMT
Message-ID: <371bc2ea.587244@netnews.worldnet.att.net>

I have a question. I created a rollback segment (called RB1) with the following attributes:

SQL>
SQL> CREATE ROLLBACK SEGMENT RB1 - RB16   2 TABLESPACE ROLLBACK_DATA STORAGE (   3 INITIAL 25 K
  4 NEXT 25 K
  5 MINEXTENTS 24
  6 ) ;

Rollback segment created.

But when I check it's size in the DBA_segment table I get an initial extent of 26624. I was told that it's size is based upon the block size (which is 2048). So if I multiply 25k (initial extent) by block size I get 12.5. If I round this up to 13 and multiply it by 25k I get 26624, Great. But I cant seem to do the same for the bytes size of 737280. Can anyone please explain to me what I am doing wrong.

	thanks 
	John

SQL> select * from dba_segments where segment_type = 'ROLLBACK';

OWNER                          SEGMENT_NAME

SEGMENT_TYPE

TABLESPACE_NAME                HEADER_FILE HEADER_BLOCK     BYTES

BLOCKS EXTENTS INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS
------------------------------ ----------- ------------ ---------
--------- --------- -------------- ----------- ----------- MAX_EXTENTS PCT_INCREASE FREELISTS FREELIST_GROUPS ----------- ------------ --------- ---------------

SYS                            RB1
ROLLBACK
ROLLBACK_DATA                            6            2    737280
360        24          26624       26624          24
        121            0         1               1

Received on Mon Apr 19 1999 - 18:59:27 CDT