--CPU高的SQL
select sql_text from v$sql order by cpu_time desc
--逻辑读多的SQL：
select * from (select buffer_gets, sql_text
from v$sqlarea
where buffer_gets > 500000
order by buffer_gets desc) where rownum<=30;
--执行次数多的SQL ：
select sql_text,executions from
(select sql_text,executions from v$sqlarea order by executions desc)
where rownum<81;
--读硬盘多的SQL ：
select sql_text,disk_reads from
(select sql_text,disk_reads from v$sqlarea order by disk_reads desc)
where rownum<21;