Re: Rollback Segments Question

"Tim X" <timx_at_spamto.devnul.com> wrote in message news:873ckssjmb.fsf_at_tiger.rapttech.com.au...
> Sybrand Bakker <gooiditweg_at_nospam.demon.nl> writes:
>
> > On 08 Apr 2003 18:15:12 +1000, Tim X <timx_at_spamto.devnul.com> wrote:
> >
> > >2. According to the Oracle 8i documentation, if you do not include
> > > your rollback segments in the rollback_segment parameter in the
> > > init.ora file, your rollback segments will not be brought back
> > > on-line when you bring your database up and will need to explicitly
> > > be brought on-line with a alter statement. THis is in addition to
> > > the rollback_segments other role relating to public/private rbs and
> > > parallel servers. I have done some experiments with 8i and this
> > > does not seem to be the case. If I don't include the RBS in the
> > > parameter file, they still come up on-line when the db is
> > > started. Again, is this just old documentation left from an earlier
> > > Oracle version, a documentation error or am I missing something?
> >
> > PUBLIC rollback segments come up automatically. PRIVATE rollback
> > segments must be in init.ora or brought up manually. You probably have
> > PUBLIC rollback segments, which you can verify by looking at the owner
> > of the rollback segment
> >
> Ah, yes - that is it. Thanks for the clarification. The manual does
> not specifically say the init.ora parameter needs to be there for
> private rollback segments to be automatically brought up - it just
> says rollback segments. This is what had me a bit confused as I had
> found with public rollback segments they automatically come up with or
> without the init.ora entry.
>

I think Howard has already covered this better than I will, but here goes anyway:

Private rollback segs are private *to the instance*; i.e. they're not shareable across instances in an OPS (7,8,8i) or RAC(9i) configuration.

Not having dealt with OPS/RAC up to now, I have always used private rollback segments, and put them in the init.ora if I want them online at startup. This seems to me to be nothing more than an exercise in scripting correctly.

I'm not suggesting for a moment that Howard (or anyone else) is wrong to create public rollback segments in a non-OPS/RAC environment; just that I've never bothered.

Yes, my create_db statements - up to 8174 now in Prod; (9i is dev only) include creation of a (short-lived) second RBS in the system tablespace prior to creation of the real tablespaces and rollback segs. I accept that this may be unnecessary, but it still works.

And by the way I still drop it rather than offlining it, once the other work is done.

Just my 2c.

Regards,
Paul Received on Wed Apr 09 2003 - 14:52:18 CDT