Remaining Time of oracle detection rollback

When oracle detects rollback for the remaining time to operate the oracle database, a large transaction needs to be rolled back, which is very slow. It depends on how long it takes to roll back. Find the following SQL statement on the Internet:

select * from v$transaction;

 

But when I run it, return: ORA-00942: The table or view does not exist. It is like this: the view v $ is not visible under a common user, and the conn/as sysdba is just fine. Execute the return statement again: you can find a segment under the unselected row to see how long it will take to roll back.

when transaction will finish rollback----------------------------------------------------------------------------------- Script:  rolling_back.sql-- Purpose: to predict when transactions will finish rolling back-- For: 9.0+---- Copyright:   (c) Ixora Pty Ltd-- Author:  Steve Adams---------------------------------------------------------------------------------@save_sqlplus_settingsset serveroutput onset feedback offpromptprompt Looking for transactions that are rolling back ...promptdeclare  cursor tx isselect  s.username,  t.xidusn,  t.xidslot,  t.xidsqn,  x.ktuxesizfrom  sys.x$ktuxe  x,  sys.v_$transaction  t,  sys.v_$session  swhere  x.inst_id = userenv('Instance') and  x.ktuxesta = 'ACTIVE' and  x.ktuxesiz 1 and  t.xidusn = x.ktuxeusn and  t.xidslot = x.ktuxeslt and  t.xidsqn = x.ktuxesqn and  s.saddr = t.ses_addr;  user_name  varchar2(30);  xid_usnnumber;  xid_slot   number;  xid_sqnnumber;  used_ublk1 number;  used_ublk2 number;begin  open tx;  loopfetch tx into user_name, xid_usn, xid_slot, xid_sqn, used_ublk1;exit when tx%notfound;if tx%rowcount = 1then  sys.dbms_lock.sleep(10);end if;select  sum(ktuxesiz)into  used_ublk2from  sys.x$ktuxewhere  inst_id = userenv('Instance') and  ktuxeusn = xid_usn and  ktuxeslt = xid_slot and  ktuxesqn = xid_sqn and  ktuxesta = 'ACTIVE';if used_ublk2 < used_ublk1then  sys.dbms_output.put_line(user_name ||'''s transaction ' ||xid_usn  || '.' ||xid_slot || '.' ||xid_sqn  ||' will finish rolling back at approximately ' ||to_char(  sysdate + used_ublk2 / (used_ublk1 - used_ublk2) / 6 / 60 / 24,  'HH24:MI:SS DD-MON-YYYY')  );end if;  end loop;  if user_name is null  thensys.dbms_output.put_line('No transactions appear to be rolling back.');  end if;end;/prompt@restore_sqlplus_settings