Oracle group by 和 OR 查询优化

Question

SELECT BATCH_ID,
  BU_CODE,
  BU_TYPE,
  BATCH_TYPE,
  BATCH_GROUP_ID,
  STATUS,
  UPD_DTIME
FROM BATCH_T
WHERE (BU_CODE, BU_TYPE, BATCH_TYPE, UPD_DTIME) IN
  (SELECT BU_CODE,
    BU_TYPE,
    BATCH_TYPE,
    MAX(UPD_DTIME)
  FROM BATCH_T
  WHERE STATUS = 'CLOSED'
  GROUP BY BU_CODE,
    BU_TYPE,
    BATCH_TYPE
  )
OR UPD_DTIME >= SYSDATE - 5;

就像上面的 Oracle 查询一样，没有 OR 条件它给出了快速响应，但是有 OR 条件它花费了很多时间。能否请您帮助如何提高上述查询的响应时间。

Answer 1

以这样的方式拆分查询，其中应该有 AND 条件以获得如下所示的性能增益。

 SELECT BATCH_ID,
  BU_CODE,
  BU_TYPE,
  BATCH_TYPE,
  BATCH_GROUP_ID,
  STATUS,
  UPD_DTIME
FROM BATCH_T
WHERE UPD_DTIME >= SYSDATE - 5

UNION ALL

SELECT BATCH_ID,
  BU_CODE,
  BU_TYPE,
  BATCH_TYPE,
  BATCH_GROUP_ID,
  STATUS,
  UPD_DTIME
FROM BATCH_T
WHERE (BU_CODE, BU_TYPE, BATCH_TYPE, UPD_DTIME) IN
  (SELECT BU_CODE,
    BU_TYPE,
    BATCH_TYPE,
    MAX(UPD_DTIME)
  FROM BATCH_T
  WHERE STATUS = 'CLOSED'
  GROUP BY BU_CODE,
    BU_TYPE,
    BATCH_TYPE
  ) AND NOT UPD_DTIME >= SYSDATE - 5;

Answer 2

您可以为 UPD_DTIME

创建索引

Answer 3

您想要最后关闭的记录以及最近五天的所有内容。使用 window 个函数！

SELECT b.*
FROM (SELECT b.*,
             ROW_NUMBER() OVER (PARTITION BY BU_CODE, BU_TYPE, BATCH_TYPE, STATUS ORDER BY UPD_DTIME DESC) as seqnum
      FROM BATCH_T b
     ) b
WHERE UPD_DTIME >= SYSDATE - 5 OR
      (STATUS = 'CLOSED' AND seqnum = 1);

这应该比使用 IN/EXISTS 和聚合的任何方法都快。写起来也比较简单

Oracle group by 和 OR 查询优化

Oracle group by and OR query optimization

sql

oracle

oracle12c