ZT]oracle 中如何定位重要(消耗资源多)的SQL
1、查看值得怀疑的SQL

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; 2、查看消耗内存多的sql select b.username, a. buffer_gets, a.executions, a.disk_reads / decode(a.executions, 0, 1, a.executions), a.sql_text SQL from v$sqlarea a, dba_users b where a.parsing_user_id = b.user_id and a.disk_reads > 10000
order by disk_reads desc;
3、查看逻辑读多的SQL

select*
from(select buffer_gets, sql_text
from v$sqlarea
where buffer_gets>500000
order by buffer_gets desc)
where rownum<=30; 4、查看执行次数多的SQL select sql_text, executions from (select sql_text, executions from v$sqlarea order by executions desc) where rownum < 81; 5、查看读硬盘多的SQL select sql_text, disk_reads from(select sql_text, disk_reads from v$sqlarea order by disk_reads desc) where rownum<21; 6、查看排序多的SQL select sql_text, sorts from(select sql_text, sorts from v$sqlarea order by sorts desc) where rownum<21; 7、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 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;