It's just the column of the row being updated. Your few-byte transaction is
thus going to occupy an entire 8192 bytes of a rollback segment (ie, a
transaction always occupies an entire rollback block, however small it is in
itself).
Regards
HJR
"Jeremy Russell" <jeremy.russell-NOTMYREALADDRESS_at_usa.net> wrote in message
news:3d39010b.50393862_at_usenet.plus.net...
> OK, maybe it's too early in the morning, and maybe I'm just dumb, but
> what - in detail - is written to a rollback segment in Oracle 8i? I
> understand that a rollback segment records undo info for a transaction
> (used Oracle long enough for that level of comprehension at least!),
> but it was my understanding that the entire block would be written out
> for potential read consistency, recovery, rollback purposes.
>
> However, I have a feeling that may not be true.
>
> If I issue
>
> UPDATE emp SET ename='RUSSELL' where empno=7369;
>
> does the entire block where this employee resides get written, is it
> the entire row or is it just the changed column?
>
> If there's a link somewhere (technet or otherwise) that explains this,
> please let me have that, rather than taking up newsgroup bandwidth.
>
> TIA
>
> Jeremy Russell
Received on Sat Jul 20 2002 - 02:38:17 CDT
