Re: Second RBS in system tablespace

"Hillman, Alex" wrote:
>
> Also you need rollback segment in system when creating database if your
> rollback tablespace is LMT.
>
> Alex Hillman
>
> -----Original Message-----
> [mailto:danisment.unal_at_unal-bilisim.com]
> Sent: Wednesday, July 11, 2001 4:44 PM
> To: Multiple recipients of list ORACLE-L
>
> Hello,
>
> SYSTEM rbs is reserved actions against the SYSTEM tablespace.
>
> There are some mis-conceptions against this issue.
>
> Actions against the SYSTEM tablespace can use non-SYSTEM rbs, too.
>
> For example, Recursive transactions,in other words: Oracle kernel
> transactions
> by SYS users, do not always have to use SYSTEM rbs.
>
> SYSTEM rbs is the last statation if there is no available slot in rbs in
> which
> current user transaction is assigned. So, Oracle kernel does not have to
> compete with user transactions.
>
> hope this helps...
>
> Kevin Lange wrote:
>
> > As a guess I would think it was because the system tablespace is so active
> > with all the queries against the catalog.
> >
> > -----Original Message-----
> > Sent: Wednesday, July 11, 2001 12:03 PM
> > To: Multiple recipients of list ORACLE-L
> >
> > Hi Everybody
> >
> > I'm running 8.1.7 and i just read that i should have a second rollback
> > segment in the system tablespace.
> > Can someone tell me why this is and how big should i create it?
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > --
> > Author: hp
> > INET: hp_at_lechateau.ca
> >

Well, in fact the second rollback segment in SYSTEM is a bootstrap rollback segment. The problem is that if you only have the SYSTEM tablespace (created by CREATE DATABASE) you cannot use it for DML on tables in other tablespaces. There used to be a time (not so distant) when you could not even use it to create rollback segments in another tablespace, so the only way to proceed was to create this bootstrap rollback segment RS0 (as small as possible), to put it online, then to create a number of rollback segments in tablespace RBS (familiar to anybody who has used Oracle prior to 9i), put them online, put RS0 offline (drop it if you want), and proceed.   Since now (read 8i) you can use SYSTEM to create rollback segments in RBS, RS0 is no longer necessary, but many people still create it (it doesn't hurt).
Note that it is still true that you cannot insert into a table in a tablespace other than SYSTEM if you only have the rollback segment SYSTEM online (I have just experienced it on 8.1.7).

-- 
Regards,

Stephane Faroult
Oriole Corporation
Voice:  +44  (0) 7050-696-269 
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Stephane Faroult
  INET: sfaroult_at_oriole.com

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