RE: Which rollback segment is currently active?

David  

This query will show sessions using rollback segments:  

select  s.username,  s.sid,       rn.name,     rs.extents


               ,rs.status,  t.used_ublk,  t.used_urec

               ,do.object_name

        from    v$transaction   t


               ,v$session       s

               ,v$rollname      rn

               ,v$rollstat      rs

               ,v$locked_object lo

               ,dba_objects     do

        where  t.addr        = s.taddr
        and    t.xidusn      = rn.usn
        and    rn.usn        = rs.usn
        and    t.xidusn      = lo.xidusn(+)
        and    do.object_id  = lo.object_id;
 

If you offline a rollback segment that a transaction is using, Oracle puts it in "offline pending" status.

   Bigger question: What are you trying to do? Do you feel you have too many rollback segments? Usually I create a new rollback segment and put it online before I take one offline.

   If you remove a rollback segment, remember to change init.ora. When you start up again, if Oracle can't find a rollback segment listed in init.ora, it won't start.

Dennis Williams
DBA, 40%OCP
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, February 04, 2003 5:24 PM To: Multiple recipients of list ORACLE-L

I have three rollback segments which all show ONLINE. I want to drop one of them but I need to know which one should I drop. How do I find out which one is good to drop?

SVRMGR> select segment_name,owner,tablespace_name,status from dba_rollback_segs;

SEGMENT_NAME                   OWNER  TABLESPACE_NAME                STATUS

------------------------------ ------ ------------------------------ -------

RBS01                          PUBLIC RBS                            ONLINE

RBS02                          PUBLIC RBS                            ONLINE

RBS04                          PUBLIC RBS                            ONLINE

Thanks,
David

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM

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