Oracle慢SQL定位

1. 统计慢查询耗时

select *
 from (select sa.SQL_TEXT "执行 SQL",
        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;

2. 查询执行次数最多的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

3. 查看历史SQL的实际执行计划

-- 1.利用关键常量，模糊查询目标语句的hashCode
select * from v$sql result where result.sql_text like '%ZL0204_03%'

-- 2.根据hashCode查询执行计划
select * from table(dbms_xplan.display_cursor('6d3z1k760s7qp', 0));