oracle查看執行最慢與查詢次數最多的sql語句及其執行速度很慢的問題分析

在ORACLE數據庫應用調優中，一個SQL的執行次數/頻率也是常常需要關注的，因為某個SQL執行太頻繁，要么是由於應用設計有缺陷，需要在業務邏輯上做出優化處理，要么是業務特殊性所導致。如果執行頻繁的SQL，往往容易遭遇一些並發性的問題。 那么如何查看ORACLE數據庫某個SQL的執行頻率/次數呢？ 下面來看看完整的示例代碼。

 

一、查詢執行最慢的sql

select *
 from (select sa.SQL_TEXT,
        sa.SQL_FULLTEXT,
        sa.EXECUTIONS "執行次數",
        round(sa.ELAPSED_TIME / 1000000, 2) "總執行時間",
        round(sa.ELAPSED_TIME / 1000000 / sa.EXECUTIONS, 2) "平均執行時間",
        sa.COMMAND_TYPE,
        sa.PARSING_USER_ID "用戶ID",
        u.username "用戶名",
        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、查詢次數最多的 sql

select *
 from (select s.SQL_TEXT,
        s.EXECUTIONS "執行次數",
        s.PARSING_USER_ID "用戶名",
        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查詢SQL語句執行的耗時

select a.sql_text SQL語句,
       b.etime 執行耗時,
       c.user_id 用戶ID,
       c.SAMPLE_TIME 執行時間,
       c.INSTANCE_NUMBER 實例數,
       u.username 用戶名, a.sql_id SQL編號
  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：定位系統里面哪些SQL腳本存在TABLE ACCESS FULL行為

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';