--打开trace文件设置，把sql trace设置为true，就会在udump目录中增加一个trc文件。
alter session set sql_trace=true;
show parameter sql_trace;
（select * from v$parameter where name='sql_trace';）
exec dbms_system.set_sql_trace_in_session(954,7961,true)
exec dbms_system.set_sql_trace_in_session(954,7961,false)
查看位置dump
select d.value||'/'||lower(rtrim(i.instance, chr(0)))||'_ora_'||p.spid||'.trc' trace_file_name
from( select p.spid from sys.v$mystat m,sys.v$session s,sys.v$process p
where m.statistic# = 1 and s.sid = m.sid and p.addr = s.paddr) p,( select t.instance from sys.v$thread t,sys.v$parameter v
where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i,( select value from sys.v$parameter where name = 'user_dump_dest') d
select auditstatus,categoryid,auditlevel
from categoryarticleassign a,category b where b.id=a.categoryid and articleId=20030700400141 and auditstatus>0
参考：
http://www.cnblogs.com/chinhr/archive/2011/11/09/2243306.html
http://www.eygle.com/case/Use.sql_trace.to.Diagnose.database.htm
http://www.eygle.com/case/sql_trace_1.htm
