如何查询会话 event

很多时候，我们在数据库中设置了event,如何确认设置的event生效或者如何确认你的库中设置了什么event.下面的文章测试了在11g中比较方便的方法
数据库版本

SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0      Production
TNS for Solaris: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production

设置测试event

SQL> alter session set events '10510 trace name context forever,level 1';

Session altered.

SQL> alter session set events
  2  '10046 trace name context forever,level 4';

Session altered.

SQL> alter system set events '60025 trace name context forever';

System altered.

SQL> alter system set events '10513 trace name context forever,level 2';

System altered.

测试spfile参数中是否有event

SQL> create pfile='/tmp/pfile' from spfile;

File created.

solaris*orcl-/home/oracle$ grep -i event /tmp/pfile
--无记录

SQL> show parameter event;

NAME                                 TYPE        VALUE
------------------------------------ ----------- -----------------
event                                string
xml_db_events                        string      enable

证明设置event不会在spfile中记录

查询会话event

--dbms_system实现
SQL> set serveroutput on size 1000000
SQL> declare
  2  event_level number;
  3  begin
  4  for i in 1..100000 loop
  5  sys.dbms_system.read_ev(i,event_level);
  6  if (event_level > 0) then
  7  dbms_output.put_line('Event '||to_char(i)||' set at level '||
  8  to_char(event_level));
  9  end if;
 10  end loop;
 11  end;
 12  /
Event 10510 set at level 1
Event 10513 set at level 2
Event 60025 set at level 1

PL/SQL procedure successfully completed.

--oradebug实现
SQL> oradebug SETMYPID
Statement processed.
SQL> oradebug eventdump session
10510 trace name context forever,level 1
10513 trace name context forever,level 2
60025 trace name context forever
sql_trace level=4

测试证明使用dbms_system可以捕获到event,oradebug可以捕获到本身会话,还可以通过setospid/setorapid来跟踪其他会话的event设置情况.event 10046对应的本质是sql_trace所以使用dbms_system不能捕获到10046