oracle查看执行最慢与查询次数最多的sql语句及其执行速度很慢的问题分析

在ORACLE数据库应用调优中，一个SQL的执行次数/频率也是常常需要关注的，因为某个SQL执行太频繁，要么是由于应用设计有缺陷，需要在业务逻辑上做出优化处理，要么是业务特殊性所导致。如果执行频繁的SQL，往往容易遭遇一些并发性的问题。 那么如何查看ORACLE数据库某个SQL的执行频率/次数呢？ 下面来看看完整的示例代码。

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;

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;

三、Oracle查询SQL语句执行的耗时

select a.sql_text SQL语句,
       b.etime 执行耗时,
       c.user_id 用户ID,
       c.SAMPLE_TIME 执行时间,
       c.INSTANCE_NUMBER 实例数,
       u.username 用户名, a.sql_id SQL编号
  from dba_hist_sqltext a,
       (select sql_id, ELAPSED_TIME_DELTA / 1000000 as etime
          from dba_hist_sqlstat
         where ELAPSED_TIME_DELTA / 1000000 >= 1) b,
       dba_hist_active_sess_history c,
       dba_users u
 where a.sql_id = b.sql_id
   and u.username = 'POADB'
   and c.user_id = u.user_id
   and b.sql_id = c.sql_id
   and a.sql_text like '%insert into TTTTTT %'
 order by  SAMPLE_TIME desc,
  b.etime desc;

四：定位系统里面哪些SQL脚本存在TABLE ACCESS FULL行为

select * from v$sql_plan v
where v.operation = 'TABLE ACCESS'
and v.OPTIONS = 'FULL'
and v.OBJECT_OWNER='POSDB';

select s.SQL_TEXT from v$sqlarea s
where s.SQL_ID = '4dpd97jh2gzsd'
and s.HASH_VALUE = '1613233933'
and s.PLAN_HASH_VALUE = '3592287464';

/*或者*/
select s.SQL_TEXT from v$sqlarea s where s.ADDRESS ='00000000A65D2318';