oracle 中如何定位重要(消耗资源多)的SQL ??请问有什么命令可以??、
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SELECT sql_text,buffer_gets,disk_reads FROM v$sql
ORDER BY buffer_gets,disk_reads DESC)
WHERE ROWNUM<=10;
select substr(to_char(s.pct, '99.00'), 2) || '%' load,
s.executions executes,
p.sql_text
from (select address,
disk_reads,
executions,
pct,
rank() over(order by disk_reads desc) ranking
from (select address,
disk_reads,
executions,
100 * ratio_to_report(disk_reads) over() pct
from sys.v_$sql
where command_type != 47)
where disk_reads > 50 * executions) s,
sys.v_$sqltext p
where s.ranking <= 5
and p.address = s.address
order by 1, s.address, p.piece;
-- 逻辑读多的SQL
select *
from (select buffer_gets, sql_text
from v$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;
-- 游标的观察
set pages 300;
select sum(a.value), b.name
from v$sesstat a, v$statname b
where a.statistic# = b.statistic#
and b.name = 'opened cursors current'
group by b.name;
select count(0) from v$open_cursor;
select user_name, sql_text, count(0)
from v$open_cursor
group by user_name, sql_text
having count(0) > 30;
--查看当前用户&username执行的SQL
select sql_text
from v$sqltext_with_newlines
where (hash_value, address) in
(select sql_hash_value, sql_address
from v$session
where username = '&username')
order by address, piece;