tst> create database link tst_link connect to u1 identified by u1 using 'tst';

Database link created.

tst> select sid, process, spid from v$session s, v$process p where p.addr=s.paddr and sid=userenv('sid');

       SID PROCESS                  SPID
---------- ------------------------ ------------------------
       349 264:2068                 21714

tst> select s.sid, s.process, p.spid, rs.sid, rs.process, rs.username
  2  from v$session s, v$process p, v$session@tst_link rs
  3  where p.addr=s.paddr and s.sid=userenv('sid')
  4  and rs.process=p.spid;

       SID PROCESS                  SPID                            SID PROCESS                  USERNAME
---------- ------------------------ ------------------------ ---------- ------------------------ -------------------------
       349 264:2068                 21714                           123 21714                    U1

tst> select sql_text from v$sql where sql_id=(select prev_sql_id from v$session where sid=123);

SQL_TEXT
-----------------------------------------------------------------
SELECT "SID","USERNAME","PROCESS" FROM "V$SESSION" "RS"

tst> drop database link tst_link;

Database link dropped.