如何查找运行在系统里的“bad sql“语句

select * from (select buffer_gets, sql_text 
from v$sqlarea 
where buffer_gets >500000 
order by buffer_gets desc) where rownum<=30;

select sql_text,executions from 
(select sql_text,executions from v$sqlarea order by executions desc) 
where rownum<81;

select sql_text,disk_reads from 
(select sql_text,disk_reads from v$sqlarea order by disk_reads desc) 
where rownum<21;

select sql_text,sorts from 
(select sql_text,sorts from v$sqlarea order by sorts desc) 
where rownum<21;

set pagesize 600; 
set linesize 120; 
select substr(sql_text,1,80) "sql", 
count(*), sum(executions) "totexecs" 
from v$sqlarea 
where executions < 5 
group by substr(sql_text,1,80) 
having count(*) > 30 
order by 2;

set pages 300; 
select sum(a.value), b.name 
from v$sesstat a, v$statname b 
where a.statistic# = b.statistic# 
and b.name = 'opened cursors current' 
group by b.name; 
select count(0) from v$open_cursor; 
select user_name,sql_text,count(0) from v$open_cursor 
group by user_name,sql_text having count(0)>30;

select sql_text from v$sqltext_with_newlines 
where (hash_value,address) in 
(select sql_hash_value,
sql_address from v$session 
where username='&username') 
order by address,piece