Re: Adding rollback

From: Howard J. Rogers <hjr_at_dizwell.com>
Date: Wed, 18 Aug 2004 01:01:20 +1000
Message-ID: <41221dde$0$3928$afc38c87@news.optusnet.com.au>

Daniel Morgan wrote:

> Howard J. Rogers wrote:
> 

>> Daniel Morgan wrote:
>>
>>

>>>bw wrote:
>>>
>>>
>>>>I have inherited a 9.2.0 database where the only rollback segments
>>>>that exist are what was created for SYSTEM.  Can I get away with
>>>>adding the needed rollback segments (RBS01... etc.) to the init.ora,
>>>>creating them in the existing RBS tablespace?  Once this has been
>>>>completed do I then bounce the instance so they are recognized via the
>>>>init.ora?
>>>
>>>SELECT segment_name
>>>FROM dba_undo_extents;
>>>
>>>Unless this query returns no rows I'd suggest you get yourself
>>>current with the 9i and 10g docs.
>>>

>>
>>
>>
>> Now why would you get him to query that view and in that way?
>>
>> For meaningful output, you'd surely want him to select DISTINCT
>> segment_name from dba_undo_extents.
>>
>> But then if you were going to do that, you might as well simply select
>> segment_name from dba_rollback_segs... a view which is just as 'current'
>> in 9i and 10g as any with the buzz-word 'undo' in it.
>>
>> Regards
>> HJR

> 
> Because it was the first query that came to mind that would quickly
> indicate that there were undo segments.

It was a rhetorical question. The point actually was: dba_rollback_segs tells you all you need to know about UNDO segments, too.

In the rush to modernity that is 8i and 9i, let's not throw the 7 and 8.0 babies out with the bathwater.

> No other reason. And it pointed
> the OP to the appropriate data dictionary view.

My point exactly. It's a dictionary view, of course. And it has its uses, obviously. But it's not exactly "appropriate" for finding out which undo segments you have (if any) and what they're called.

Would you query dba_extents to find out the names of the tables that exist in the database?

That's a rhetorical question, too, btw.

Regards
HJR Received on Tue Aug 17 2004 - 10:01:20 CDT