How many rollback segments can a transaction use?

From: michael ngong <mngong_at_yahoo.com>
Date: 9 Jul 2003 06:20:58 -0700
Message-ID: <ecf365d5.0307090520.ff449ae@posting.google.com>

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 Received on Wed Jul 09 2003 - 08:20:58 CDT