通過v$sqlarea,v$sql查詢最佔用資源的查詢

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內存的sql語句的相關信息

 

V$SQL是內存共享SQL區域中已經解析的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;

 

消耗磁盤讀取最多的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;