--找出需要大量緩衝讀取（邏輯讀）操作的查詢 TOP 100：
select
buffer_gets,sql_text
from (select sql_text,buffer_gets,
dense_rank() over
(order by buffer_gets desc) buffer_gets_rank
from v$sql)
where buffer_gets_rank<=100
and sql_text like '%DM_WMG%';
 

--消耗DISK 讀取最多的sql TOP 100：
select
disk_reads,sql_text
from (select sql_text,disk_reads,
dense_rank() over
(order by disk_reads desc) disk_reads_rank
from v$sql)
where disk_reads_rank <=100
and sql_text like '%DM_WMG%';
 
--列出使用頻率最高的10個查詢：
select
sql_text,executions
from (select sql_text,executions,
rank() over
(order by executions desc) exec_rank
from v$sql)
where exec_rank <=10;
 
--從V$SQLAREA中查詢最佔用資源的查詢
select
b.username username,a.disk_reads reads,
a.executions exec,a.disk_reads/decode(a.executions,0,1,a.executions) rds_exec_ratio,
a.sql_text Statement
from v$sqlarea a,dba_users b
where a.parsing_user_id=b.user_id
and a.disk_reads > 100000
order by a.disk_reads desc;