Oracle8(TM) Server Concepts "

When a transaction runs out of space in the current extent and needs
to continue writing, Oracle finds an available extent of the same
rollback segment
"
This I intepret to mean if two transactions are running two rollback
segments are to be used (What my question is about)If there is another
explanation different from the fact that transaction could start and
stop within this interval that should help ....

My version/OS Oracle 8i Hp Unix 9000.
When I run a query for the number of transactions I get 2
select current_utilizations from v$resource_limit where
name='transactions'

RESOURCE_NAME CURRENT_UTILIZATION
------------------------------ -------------------
transactions 2

When I find the change in writes after a period of say 10 minutes I
expect may be two rollback segments to change since two transactions
are active.From my understanding of the DOCS these two transactions
should use two rollback segments.
but five of my rollback segments indicate an increase in the amount of
writes
time:3:50a

select n.name,writes from v$rollstat r,v$rollname n where n.usn=r.usn;
SYSTEM 2580
RBS1 101758434
RBS2 241709876
RBS3 31058582
RBS4 37506164
RBSBIG 62053292
Time 4:10a
select n.name,writes from v$rollstat r,v$rollname n where n.usn=r.usn;
SYSTEM 2580
RBS1 112648128
RBS2 241712898
RBS3 111247476
RBS4 37512038
RBSBIG 62058182

I should be missing something and will greatly appreciate your insight

Michael Tubuo Ngong

Comments inline.

"michael ngong" <mngong (AT) yahoo (DOT) com> wrote



(maybe by the same 2 sessions).

Regards Stephan

michael ngong wrote:

There is an init.ora parameter that controls the number of transactions
per rollback segment. The deault is usually 4 or 5.

A transaction can use one, and only one, rollback segment.

If you have 9i drop rollback and go to undo.
--
Daniel Morgan
http://www.outreach.washington.edu/e...ad/oad_crs.asp
damorgan@x.washington.edu
(replace 'x' with a 'u' to reply)

mngong (AT) yahoo (DOT) com (michael ngong) wrote in message news:<ecf365d5.0307090520.ff449ae (AT) posting (DOT) google.com>...
You are getting two rlbsegs with major activity, which
are used by your two main active transactions. These may generate
some dictionary management transactions (also called recursive SQL)
and a number of other activities which are catered for by the
other small usage of rlbseg that you see. All of these need
to be able to be rolled back, hence the additional usage.
You may also have other jobs going you don't know about?

Cheers
Nuno Souto
wizofoz2k (AT) yahoo (DOT) com.au.nospam

On 9 Jul 2003 16:48:48 -0700, Nuno Souto <wizofoz2k (AT) yahoo (DOT) com.au> wrote:


Nuno's got it in one.

Put it another way: v$transaction only reports *user* transactions, not the
many, many others that might be taking place recursively on the data
dictionary. V$rollstat, however, reports all rollback activity without
distinction.

~QM