Re: spfile

"Howard J. Rogers" <hjr_at_dizwell.com> wrote in message news:418c0fe9$0$32599$afc38c87_at_news.optusnet.com.au...
> Mark D Powell wrote:
>
> > "Howard J. Rogers" <hjr_at_dizwell.com> wrote in message
> > news:<418ad185$0$24942$afc38c87_at_news.optusnet.com.au>...
> >> "Oradba Linux" <techiey2k3_at_comcast.net> wrote in message
> >> news:1bAid.46596$HA.33011_at_attbi_s01...
> >> > Using spfile and old fashioned rollback segments, once a bunch of new
> >> > rollback segments are added how do you update the spfile
> >> > so that they are online next time you recycle the database
> >>
> >>
> >> It ought to be something like
> >>
> >> alter system set rollback_segments='RBS01, RBS02, RBS03, RBS04'
> >> scope=spfile;
> >>
> >> ...ie, just a comma-separated list of segments.
> >>
> >> But it is so long since I used rollback segments rather than undo, I
> >> don't actually have a system I can test that on easily. So it might not
> >> be that at all!
> >>
> >> Just curious: why wouldn't you want to use automatic undo?
> >>
> >> Regards
> >> HJR
> >
> > Here are some reasons why some sites may not have switched to using
> > undo tablespaces instead of manually managed RBS segments:
> >
> > 1- some sites have complained about 1555 errors under auto undo
> > management that did not occur under their manual RBS management.
> > There are apparently times where automatic undo gets very aggressive
> > with releasing segments.
>
> Why not increase UNDO_RETENTION, then?
>
> > 2- under heavy load some sites have complained that new undo segments
> > are allocated consuming the undo tablespace when unused segments were
> > available and should have been reused.
>
> That's what happens when you over-size your undo tablespace, of course.
>
> > 3- You run RAC and do not trust that Oracle has all the kinks worked
> > out of the feature in version 9 or 9.2
>
> You run RAC, but don't trust automatic undo???!!!?
>
> Could I suggest such sites learn about risk management and/or
> prioritisation?
>
> > And the most likely reason sites are not using the feature
> > 4 - traditional RBS management is working well so the DBA has not got
> > around to making the change because there is not real way to test it
> > without actually using it in production due to load differences
> > between test and production.
>
> Grudgingly grant that one. But our OP has obviously not been too afraid to
> implement the spfile... and I remember the init.ora always "worked well".
>
> :-)
>
> > 5- If the DBA is willing to make the change to production, IT
> > management does not want to take what they see as an unnecessary risk.
> > In the past new features often brought new bugs with them and
> > managment does not forget being burned.
>
> I think my point is that as far as anything can be, automatic undo has (by
> 9i Release 2... I willingly admit things were different in release 1) had
> most of its quirks shaken out. I don't keep an eagle-eye on Metalink, so I
> could be wrong. But sticking with manual rollback has the same feel about
> it to me as the die-hard use of dictionary-managed tablespace.
>
> Regards
> HJR
>
>

I find automatic undo to be working just fine, and agree: Don't use the old rollback segments in 9i instances. Received on Sun Nov 07 2004 - 13:49:55 CST