幸福是把温暖的枪

sql调优(摘自javaeye)

-- 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;

-- 排序多的SQL
select sql_text,sorts from
(select sql_text,sorts from v$sqlarea order by sorts desc)
where rownum<21;

--分析的次数太多,执行的次数太少,要用绑变量的方法来写sql
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;

posted on 2006-04-20 13:58 幸福是把温暖的枪 阅读(167) 评论(0)  编辑  收藏 所属分类: oracle


只有注册用户登录后才能发表评论。


网站导航: