3． 对其他用户session设置
    通过DBMS_SYSTEM.SET_EV系统包来实现:

    SQL> desc dbms_system
    ...
    PROCEDURE SET_EV
    Argument Name Type In/Out Default?
    ------------------------------ 
    SI BINARY_INTEGER IN
    SE BINARY_INTEGER IN
    EV BINARY_INTEGER IN
    LE BINARY_INTEGER IN
    NM VARCHAR2 IN

    其中的参数SI、SE来自v$session视图:

    查询获得需要跟踪的session信息:

    SQL> select sid,serial#,username from v$session
    where username is not null;
    SID SERIAL# USERNAME
    ---------- ---------- 
    8 2041 SYS
    9 437 EYGLE

    执行跟踪:

    SQL> exec dbms_system.set_ev(9,437,10046,8,'eygle');
    PL/SQL procedure successfully completed.

    结束跟踪:

    SQL> exec dbms_system.set_ev(9,437,10046,0,'eygle');
    PL/SQL procedure successfully completed.

    (c) 获取跟踪文件
    以上生成的跟踪文件位于user_dump_dest目录中，位置及文件名可以通过以下SQL查询获得:

 SQL> select 2 d.value||'/'||lower(rtrim(i.instance, chr(0)))||'_ora_'||p.spid||'.trc' trace_file_name 3 from
4 ( select p.spid 5 from sys.v$mystat m,sys.v$session s,sys.v$process p
6 where m.statistic# = 1 and s.sid = m.sid and p.addr = s.paddr) p,
7 ( select t.instance from sys.v$thread t,sys.v$parameter v
8 where v.name = 'thread' and
(v.value = 0 or t.thread# = to_number(v.value))) i,
9 ( select value from sys.v$parameter
 where name = 'user_dump_dest') d 10 /

       (d) 读取当前session设置的参数
    当我们通过alter session的方式设置了sql_trace,这个设置是不能通过show parameter的方式得到的,我们需要通过dbms_system.read_ev来获取： 

   SQL> set feedback offSQL> set serveroutput on
    SQL> declare
    2 event_level number;
    3 begin
    4 for event_number in 10000..10999 loop
    5 sys.dbms_system.read_ev(event_number, event_level);
    6 if (event_level > 0) then
    7 sys.dbms_output.put_line(
    8 'Event ' ||
    9 to_char(event_number) ||
    10 ' is set at level ' ||
    11 to_char(event_level)
    12 );
    13 end if;
    14 end loop;
    15 end;
    16 /
    Event 10046 is set at level 1