標籤：
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;用buffer_gets列來替換disk_reads列可以得到佔用最多記憶體的sql語句的相關資訊。V$SQL是記憶體共用SQL地區中已經解析的SQL語句。列出使用頻率最高的5個查詢：select sql_text,executions
from (select sql_text,executions,
rank() over
(order by executions desc) exec_rank
from v$sql)
where exec_rank <=5;消耗磁碟讀取最多的sql top5：
select disk_reads,sql_text
from (select sql_text,disk_reads,
dense_rank() over
(order by disk_reads desc) disk_reads_rank
from v$sql)
where disk_reads_rank <=5;找出需要大量緩衝讀取（邏輯讀）操作的查詢：select buffer_gets,sql_text
from (select sql_text,buffer_gets,
dense_rank() over
(order by buffer_gets desc) buffer_gets_rank
from v$sql)
where buffer_gets_rank<=5;
oracle查詢最佔用資源的查詢
