查看Oracle最耗时的SQL

2019/07/23 15:00
阅读数 331

查看Oracle最耗时的SQL

有很多种方法可以用来找出哪些SQL语句需要优化,但是很久以来,最简单的方法都是分析保存在V$SQL视图中的缓存的SQL信息。通过V$SQL视图,可以确定具有高消耗时间、CUP和IO读取的SQL语句。

1.查看总消耗时间最多的前10条SQL语句
 select *
from (select v.sql_id,
v.child_number,
v.sql_text,
last_load_time,
v.PARSING_USER_ID,
ROUND(v.ELAPSED_TIME / 1000000 / (CASE
               WHEN (EXECUTIONS = 0 OR NVL(EXECUTIONS, 1 ) = 1) THEN
                1
               ELSE
                EXECUTIONS
             END),
             2) "执行时间'S'",
 v.SQL_FULLTEXT,
v.cpu_time,
v.disk_reads,
rank() over(order by v.elapsed_time desc) elapsed_rank
from v$sql v  ) a
where elapsed_rank <= 100  and   last_load_time > to_char(sysdate - 1/24, 'YYYY-MM-DD/HH:MI:SS')    order by "执行时间'S'" desc

查询最近一小时内最慢的SQL:

select executions, cpu_time/1e6 as cpu_sec, elapsed_time/1e6 as elapsed_sec, round(elapsed_time/sqrt(executions)) as important, v.* 
from v$sql v 
where executions > 10 and last_load_time > to_char(sysdate - 1/24, 'YYYY-MM-DD/HH:MI:SS')  
order by important desc

2.查看CPU消耗时间最多的前10条SQL语句
select *
from (select v.sql_id,
v.child_number,
v.sql_text,
v.elapsed_time,
v.cpu_time,
v.disk_reads,
rank() over(order by v.cpu_time desc) elapsed_rank
from v$sql v) a
where elapsed_rank <= 10;

3.查看消耗磁盘读取最多的前10条SQL语句
select *
from (select v.sql_id,
v.child_number,
v.sql_text,
v.elapsed_time,
v.cpu_time,
v.disk_reads,
rank() over(order by v.disk_reads desc) elapsed_rank
from v$sql v) a
where elapsed_rank <= 10;

 

 

 

一、查询执行最慢的sql

select  *
  from ( select sa.SQL_TEXT,
         sa.SQL_FULLTEXT,
         sa.EXECUTIONS "执行次数" ,
         round(sa.ELAPSED_TIME / 1000000, 2) "总执行时间" ,
         round(sa.ELAPSED_TIME / 1000000 / sa.EXECUTIONS, 2) "平均执行时间" ,
         sa.COMMAND_TYPE,
         sa.PARSING_USER_ID "用户ID" ,
         u.username "用户名" ,
         sa.HASH_VALUE
      from v$sqlarea sa
      left join all_users u
       on sa.PARSING_USER_ID = u.user_id
      where sa.EXECUTIONS > 0
      order by (sa.ELAPSED_TIME / sa.EXECUTIONS) desc )
  where rownum <= 50;
 
         s.EXECUTIONS "执行次数" ,
         s.PARSING_USER_ID "用户名" ,
         rank() over( order by EXECUTIONS  desc ) EXEC_RANK
      from v$sql s
      left join all_users u
       on u.USER_ID = s.PARSING_USER_ID) t
  where exec_rank <= 100;
 
二、查询次数最多的 sql
 
select  *
  from ( select s.SQL_TEXT,
         s.EXECUTIONS "执行次数" ,
         s.PARSING_USER_ID "用户名" ,
         rank() over( order by EXECUTIONS  desc ) EXEC_RANK
      from v$sql s
      left join all_users u
       on u.USER_ID = s.PARSING_USER_ID) t
  where exec_rank <= 100;

展开阅读全文
打赏
0
0 收藏
分享
加载中
更多评论
打赏
0 评论
0 收藏
0
分享
返回顶部
顶部