SELECT s.username, s.sid, s.serial#, s.sql_address, 
s.machine, s.program, su.tablespace, su.segtype, su.contents
FROM v$session s, v$sort_usage su
WHERE s.saddr = su.session_addr;

SQL>Alter system kill session 'sid,serial#';

SQL>Alter tablespace TEMP coalesce;

SQL>select ts#, name from sys.ts$ ; 

TS# NAME 
----------------------- 
0 SYSYEM 
1 RBS 
2 USERS 
3* TEMP 
4 TOOLS 
5 INDX 
6 DRSYS

SQL>alter session set events 'immediate trace name DROP_SEGMENTS level 4'