Oracle 性能调优答案

【问题标题】：Oracle performance TuningOracle 性能调优
【发布时间】：2016-06-25 11:27:57
【问题描述】：

我有以下 oracle 查询。运行需要很长时间。您能否建议对此查询进行一些性能调整。

select ss.registration_id as REGISTRATION_ID,
       ss.batch_id as BATCH_ID
  from submtd_srvc PARTITION(SUBMTD_SRVC_821370) ss,
       (select a.exceptn_criteria_val,
               a.exceptn_criteria_rtrn_val 
          from EXCEPTN_CRITERIA a,
               EXCEPTN_EXPRESSION b
          where a.EXCEPTN_EXPRESSION_ID = b.EXCEPTN_EXPRESSION_ID
            and b.EXCEPTN_EXPRESSION_NAME = 'NC_CUSTOM_REV_CAT'
            and b.IS_CURRENT_INDCTR = 1
            and a.IS_CURRENT_INDCTR = 1) sub_query
  where ss.REVENUE_CD = sub_query.exceptn_criteria_val
    and ss.batch_id =  821370
    and exists (select 'x'
                  from submtd_srvc PARTITION(SUBMTD_SRVC_821370) ss2,
                       (select a.exceptn_criteria_val,
                               a.exceptn_criteria_rtrn_val 
                          from EXCEPTN_CRITERIA a,
                               EXCEPTN_EXPRESSION b
                          where a.EXCEPTN_EXPRESSION_ID = b.EXCEPTN_EXPRESSION_ID
                            and b.EXCEPTN_EXPRESSION_NAME = 'NC_CUSTOM_REV_CAT'
                            and b.IS_CURRENT_INDCTR = 1
                            and a.IS_CURRENT_INDCTR = 1) sub_query2
                  where ss2.REVENUE_CD = sub_query2.exceptn_criteria_val
                    and ss2.registration_id = ss.registration_id
                    and ss2.batch_id = ss.batch_id
                    and ss2.batch_id = 821370
                    and sub_query2.exceptn_criteria_rtrn_val <> sub_query.exceptn_criteria_rtrn_val)
  Order By Ss.Registration_Id,
           ss.batch_id;

【问题讨论】：

如果你能发布你的解释计划以及你的表和索引的结构将会很有用
我个人会去掉exists 子句并使用join。在我的情况下，它工作得更快。除此之外，请查看说明计划并找到您在哪里进行全表扫描。如果可能的话，在它们上创建索引。
发布查询通常没有足够的信息； here你可能会发现一些你应该发布的提示。

标签： oracle performance oracle11g

【解决方案1】：

如果我理解正确，您可以使用相关子查询来查找具有多个不同 exceptn_criteria_rtrn_val 值的行。如果我是对的，最好使用解析函数：

select vw.registration_id as REGISTRATION_ID, vw.batch_id as BATCH_ID
from
 (select ss.registration_id as REGISTRATION_ID, ss.batch_id as BATCH_ID
        ,count(distinct sub_query.exceptn_criteria_rtrn_val) over(partition by ss.registration_id, ss.batch_id) as cnt
    from submtd_srvc PARTITION(SUBMTD_SRVC_821370) ss,
         (select a.exceptn_criteria_val, a.exceptn_criteria_rtrn_val
            from EXCEPTN_CRITERIA a, EXCEPTN_EXPRESSION b
           where a.EXCEPTN_EXPRESSION_ID = b.EXCEPTN_EXPRESSION_ID
             and b.EXCEPTN_EXPRESSION_NAME = 'NC_CUSTOM_REV_CAT'
             and b.IS_CURRENT_INDCTR = 1
             and a.IS_CURRENT_INDCTR = 1) sub_query
   where ss.REVENUE_CD = sub_query.exceptn_criteria_val
     and ss.batch_id = 821370) vw
where cnt > 1
Order By vw.Registration_Id, vw.batch_id;

【讨论】：

【解决方案2】：

您可以将EXISTS 替换为GROUP BY 和HAVING：

SELECT ss.registration_id,
       ss.batch_id
FROM   submtd_srvc PARTITION(SUBMTD_SRVC_821370) ss
       INNER JOIN
       EXCEPTN_CRITERIA a
       ON ( ss.REVENUE_CD = a.exceptn_criteria_val )
       INNER JOIN
       EXCEPTN_EXPRESSION b
       ON ( a.EXCEPTN_EXPRESSION_ID = b.EXCEPTN_EXPRESSION_ID )
WHERE  b.EXCEPTN_EXPRESSION_NAME = 'NC_CUSTOM_REV_CAT'
AND    b.IS_CURRENT_INDCTR = 1
AND    a.IS_CURRENT_INDCTR = 1
AND    ss.batch_id =  821370
GROUP BY
       ss.Registration_Id,
       ss.batch_id
HAVING COUNT( DISTINCT a.exceptn_criteria_rtrn_val ) = 1
ORDER BY
       ss.Registration_Id,
       ss.batch_id;

我还去掉了所有子查询，并使用 ANSI 标准联接而不是旧的 Oracle 联接。

【讨论】：