Objects with blocks inside undo

I was monitoring some (really) long-running SQLs in my 9.2.0.6 EE bd with the following query :

select b.sid, substr(a.segment_name,1,25) obj_name,   substr(a.partition_name,1,15) partition,    a.segment_type OBJ_TYPE, b.p1 FILE_ID, b.p2 BLOCK_ID, b.p3 BLOCKS,    b.event
  from dba_extents a,

       v$session_wait b

 where b.p2 between a.block_id and (a.block_id + a.blocks)
   and a.file_id =    b.p1
   and b.p1text  like 'file%'
   and (   b.event like '%file%'
        or b.event like 'direct path%');

and in some cases the object being read is one of the _SYSSMUnn$ segments (I am using AUM), what indicates a consistent read, someone in the recent past altered something after the start os the long-run SQL, it is acessing undo, ok. What I want to know, if possible, is :

1. the exact session what made the alter (it is very difficult to find
   (could be anyone)
   
2. what objects (tables, indexes, etc) contains blocks in the undo seg _SYSnn being read : with this I can check the execution log and
   (hopefully) find the culprits.
   

Regards,

 Chiappa Received on Tue Jun 21 2005 - 12:52:12 CDT