Re: Rollback segments

Incidentally, you are asking for trouble having rollback segments with only two extents. The chances of them having to acquire more extents is very high (assuming you eventually bring them online).

Rollbacks should have around half a dozen extents to minimise the need to extend dynamically (and don't beleieve the guff you will read -even from Oracle- about them needing 20 extents, because that hasn't been true since Oracle 6 days when transactions couldn't share extents).

Regards
HJR "Howard J. Rogers" <howardjr_at_www.com> wrote in message news:3a5a8f79_at_news.iprimus.com.au...
> For starters, V$ views are only interested in rollback segments which are
> actually on-line.
>
> The fact that a rb segment has been created is irrelevant to the v$... it
> needs to either be brought online manually (alter rollback segment blah
> online) or listed in the init.ora to be brought online at Instance startup
> (rollback_segments=blah,blah2,blah3 etcetcetc).
>
> However, the dba_ views will list any segment that's been created, whether
> online or off.
>
> Regards
> HJR
>
>
> "Boris Arhangelsky" <bor1_at_sprint.ca> wrote in message
> news:b1w66.3475$O8.47467_at_newscontent-01.sprint.ca...
> > Hi folks,
> >
> > I need to know what rollback segments do I have in system.
> >
> > Two different queries(DBA_SEGMENTS and V$ROLLNAME) produce different
> > results;
> >
> > SQL> select substr(segment_name,1,15) name, extents from dba_segments
> > 2 where segment_type='ROLLBACK';
> >
> > NAME EXTENTS
> > --------------- ---------
> > SYSTEM 8
> > RB_TEMP 9
> > RB1 2
> > RB2 2
> > RB3 2
> > RB4 2
> > RB5 2
> > RB6 2
> > RB7 2
> > RB8 2
> > RB9 2
> > RB10 2
> > RB11 2
> > RB12 2
> > RB13 2
> > RB14 2
> > RB15 2
> > RB16 2
> > N1 2
> > AA1 2
> > AAPR1 2
> >
> > NAME EXTENTS
> > --------------- ---------
> > RL1 2
> >
> > 22 rows selected.
> >
> >
> > SQL> SELECT * FROM V$ROLLNAME;
> >
> > USN NAME
> > --------- ------------------------------
> > 0 SYSTEM
> > 2 RB1
> > 3 RB2
> >
> > Two questions:
> > 1. Why it's happening?
> > 2. What is the difference between DBA_SEGMENTS and V$ROLLNAME views?
> >
> > Thank you for cooperation.
> >
> > voronovboris_at_hotmail.com
> >
> > Boris
> >
> >
>
>
Received on Mon Jan 08 2001 - 22:16:13 CST