查看历史执行计划

如果要查看过去历史真实的执行计划，而不是使用explain plan命令即时解析，需要查看相关视图。

如果当前执行计划仍然保存在library cache，则可以从v$sql_plan中看到。

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1. SELECT plan_hash_value,
2.        TO_CHAR(RAWTOHEX(child_address)),
          TO_NUMBER(child_number),
          id,
          LPAD(' ', DEPTH) || operation operation,
          options,
          object_owner,
          object_name,
          optimizer,
          cost,
          access_predicates,
          filter_predicates
     FROM V$SQL_PLAN
     where sql_id = 'abcd'
    ORDER BY 1, 3, 2, 4

黄色文字部分为sql_id

如果执行计划已经不在library cache中了，则需要去DBA_HIST_SQL_PLAN中寻找。

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1. set linesize 500

2. set pagesize 500
   col plan_hash_value format 9999999999
   col id format 999999
   col operation format a30
   col options format a15
   col object_owner format a15
   col object_name format a20
   col optimizer format a15
   col cost format 9999999999
   col access_predicates format a15
   col filter_predicates format a15

   SELECT plan_hash_value,
            id,
            LPAD (' ', DEPTH) || operation operation,
            options,
            object_owner,
            object_name,
            optimizer,
            cost,
            access_predicates,
            filter_predicates
      FROM dba_hist_sql_plan
      WHERE sql_id = 'fahv8x6ngrb50'
   ORDER BY plan_hash_value, id;

通常，在AWR中发现的可疑语句可以通过如上方式操作。

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转载于:http://blog.itpub.net/22621861/viewspace-2085396/