查看Oracle最耗时的SQL

查看Oracle最耗时的SQL

2017年09月22日 14:15:36 DS_树苗 阅读数 5053

 

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(selectsa.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

     fromv$sqlarea sa

     leftjoinall_users u

      onsa.PARSING_USER_ID = u.user_id

     wheresa.EXECUTIONS > 0

     orderby(sa.ELAPSED_TIME / sa.EXECUTIONS)desc)

 whererownum <= 50;

 

        s.EXECUTIONS"执行次数",

        s.PARSING_USER_ID"用户名",

        rank() over(orderbyEXECUTIONS desc) EXEC_RANK

     fromv$sql s

     leftjoinall_users u

      onu.USER_ID = s.PARSING_USER_ID) t

 whereexec_rank <= 100;

 

二、查询次数最多的 sql

 

select *

 from(selects.SQL_TEXT,

        s.EXECUTIONS"执行次数",

        s.PARSING_USER_ID"用户名",

        rank() over(orderbyEXECUTIONS desc) EXEC_RANK

     fromv$sql s

     leftjoinall_users u

      onu.USER_ID = s.PARSING_USER_ID) t

 whereexec_rank <= 100;

转载：https://blog.csdn.net/xwnxwn/article/details/78062433