ROW_NUMBER() OVER 因大型查询而超时。最佳解决方案？

Question

我正在尝试修复在数据库上运行大型查询的应用程序（不是我自己的）中的错误。这会在部署时导致 504 网关超时。当我在 MSSMS 中运行查询时，它只会永远执行而不返回任何结果：

SELECT * 
FROM   (SELECT Row_number() 
                 OVER ( 
                   ORDER BY [TABLE_ONE].[MET_uid] ) 
                      AS RowNum, 
               (SELECT Count(1) 
                FROM   TABLE_ONE 
                       LEFT OUTER JOIN TABLE_TWO 
                                    ON TABLE_ONE.SCC_uid = 
                                       TABLE_TWO.SCC_uid 
                WHERE  ( [TABLE_ONE].[ANOTHER_DATE] <= 
                         '30 November 2020' ) 
                       AND ( [TABLE_ONE].[SOME_DATE] >= 
                             '30 November 2020' ) 
                       AND ( [TABLE_TWO].[ANOTHER_DATE] <= 
                             '30 November 2020' ) 
                       AND ( [TABLE_TWO].[SOME_DATE] >= 
                             '30 November 2020' )) 
                      AS 
               TotalRows, 
               [TABLE_ONE].[MET_uid] 
                      AS TABLE_ONE_MET_UID, 
               [TABLE_ONE].[MET_type_uid] 
                      AS TABLE_ONE_MET_TYPE_UID, 
               [TABLE_ONE].[IIC] 
                      AS 
               TABLE_ONE_IIC, 
               [TABLE_ONE].[LCD] 
                      AS 
               TABLE_ONE_LCD, 
               [TABLE_ONE].[ANOTHER_DATE] 
                      AS TABLE_ONE_ANOTHER_DATE, 
               [TABLE_ONE].[SOME_DATE] 
                      AS TABLE_ONE_SOME_DATE, 
               [TABLE_ONE].[SOME_DATEd] 
                      AS TABLE_ONE_SOME_DATED, 
               [TABLE_ONE].[LED] 
                      AS TABLE_ONE_LED, 
               [TABLE_ONE].[LED_U_UID] 
                      AS 
               TABLE_ONE_LED_U_UID, 
               [TABLE_ONE].[P_UID] 
                      AS TABLE_ONE_P_UID, 
               [TABLE_ONE].[FM_UID] 
                      AS TABLE_ONE_FM_UID, 
               [TABLE_ONE].[D_LEN] 
                      AS TABLE_ONE_D_LEN, 
               [TABLE_ONE].[D_AR] 
                      AS TABLE_ONE_D_AR, 
               [TABLE_ONE].[ETI] 
                      AS TABLE_ONE_ETI, 
               [TABLE_ONE].[NT] 
                      AS TABLE_ONE_NT, 
               [TABLE_ONE].[BLT] 
                      AS TABLE_ONE_BLT, 
               [TABLE_ONE].[BLK] 
                      AS TABLE_ONE_BLK, 
               [TABLE_ONE].[BLU] 
                      AS TABLE_ONE_BLU, 
               [TABLE_ONE].[trcn] 
                      AS TABLE_ONE_TRCN, 
               [TABLE_ONE].[SCC_uid] 
                      AS TABLE_ONE_SCC_UID, 
               [TABLE_TWO].[F_uid] 
                      AS TABLE_TWO_F_UID, 
               [TABLE_TWO].[RDT_UID] 
                      AS TABLE_TWO_RDT_UID, 
               [TABLE_TWO].[SCC_code] 
                      AS TABLE_TWO_SCC_CODE, 
               [TABLE_TWO].[SCC_name] 
                      AS TABLE_TWO_SCC_NAME, 
               [TABLE_TWO].[SCC_type_uid] 
                      AS TABLE_TWO_SCC_TYPE_UID, 
               [TABLE_TWO].[SCC_length] 
                      AS TABLE_TWO_SCC_LENGTH, 
               [TABLE_TWO].[SPDT] 
                      AS TABLE_TWO_SPDT, 
               [TABLE_TWO].[SNC] 
                      AS TABLE_TWO_SNC, 
               [TABLE_TWO].[SNJT_uid] 
                      AS 
               TABLE_TWO_SNJT_UID, 
               [TABLE_TWO].[SN_name] 
                      AS TABLE_TWO_SN_NAME, 
               [TABLE_TWO].[ENC] 
                      AS TABLE_TWO_ENC, 
               [TABLE_TWO].[ENCT_JT_uid] 
                      AS 
               TABLE_TWO_ENCT_JT_UID, 
               [TABLE_TWO].[ENCT_name] 
                      AS TABLE_TWO_ENCT_NAME, 
               [TABLE_TWO].[NTT_uid] 
                      AS TABLE_TWO_NTT_UID, 
               [TABLE_TWO].[RG_uid] 
                      AS TABLE_TWO_RG_UID, 
               [TABLE_TWO].[AR_uid] 
                      AS TABLE_TWO_AR_UID, 
               [TABLE_TWO].[division_uid] 
                      AS TABLE_TWO_DIVISION_UID, 
               [TABLE_TWO].[DST_uid] 
                      AS TABLE_TWO_DST_UID, 
               [TABLE_TWO].[SVV_AR_uid] 
                      AS TABLE_TWO_SVV_AR_UID, 
               [TABLE_TWO].[RTF] 
                      AS TABLE_TWO_RTF, 
               [TABLE_TWO].[CL_UID] 
                      AS TABLE_TWO_CL_UID, 
               [TABLE_TWO].[MH_uid] 
                      AS 
               TABLE_TWO_MH_UID, 
               [TABLE_TWO].[ENV_uid] 
                      AS TABLE_TWO_ENV_UID, 
               [TABLE_TWO].[ONR_uid] 
                      AS TABLE_TWO_ONR_UID, 
               [TABLE_TWO].[AG_uid] 
                      AS TABLE_TWO_AG_UID, 
               [TABLE_TWO].[ANOTHER_DATE] 
                      AS TABLE_TWO_ANOTHER_DATE, 
               [TABLE_TWO].[SOME_DATE] 
                      AS TABLE_TWO_SOME_DATE, 
               [TABLE_TWO].[DPT_code] 
                      AS TABLE_TWO_DPT_CODE, 
               [TABLE_TWO].[NMT_code] 
                      AS TABLE_TWO_NMT_CODE, 
               [TABLE_TWO].[RW_code] 
                      AS 
               TABLE_TWO_RW_CODE, 
               [TABLE_TWO].[SLVL_uid] 
                      AS TABLE_TWO_SLVL_UID, 
               [TABLE_TWO].[FTG_code] 
                      AS TABLE_TWO_FTG_CODE, 
               [TABLE_TWO].[FT_uid] 
                      AS 
               TABLE_TWO_FT_UID, 
               [TABLE_TWO].[FO_uid] 
                      AS TABLE_TWO_FO_UID, 
               [TABLE_TWO].[DC] 
                      AS TABLE_TWO_DC, 
               [TABLE_TWO].[SVV_uid] 
                      AS TABLE_TWO_SVV_UID, 
               [TABLE_TWO].[SCC_length_status] 
                      AS 
               TABLE_TWO_SCC_LENGTH_STATUS, 
               [TABLE_TWO].[SVV] 
                      AS TABLE_TWO_SVV, 
               [TABLE_TWO].[MAX] 
                      AS TABLE_TWO_MAX, 
               [TABLE_TWO].[SQN] 
                      AS TABLE_TWO_SQN, 
               [TABLE_TWO].[DRT] 
                      AS TABLE_TWO_DRT, 
               [TABLE_TWO].[cwxsp] 
                      AS TABLE_TWO_CWXSP, 
               [TABLE_TWO].[offcwxsp] 
                      AS TABLE_TWO_OFFCWXSP, 
               [TABLE_TWO].[ukpms_MHH_uid] 
                      AS 
               TABLE_TWO_UKPMS_MHH_UID, 
               [TABLE_TWO].[fway_MHH_uid] 
                      AS 
               TABLE_TWO_FWAY_MHH_UID, 
               [TABLE_TWO].[SMH_uid] 
                      AS 
               TABLE_TWO_SMH_UID, 
               [TABLE_TWO].[SMP_ROU_uid] 
                      AS 
               TABLE_TWO_SMP_ROU_UID, 
               [TABLE_TWO].[SMP_dot_CLK_uid] 
                      AS 
               TABLE_TWO_SMP_DOT_CLK_UID, 
               [TABLE_TWO].[LCT_uid] 
                      AS TABLE_TWO_LCT_UID, 
               [TABLE_TWO].[LH] 
                      AS TABLE_TWO_LH, 
               [TABLE_TWO].[programmed_date] 
                      AS TABLE_TWO_PROGRAMMED_DATE, 
               [TABLE_TWO].[LCD_uid] 
                      AS TABLE_TWO_LCD_UID, 
               [TABLE_TWO].[CW] 
                      AS TABLE_TWO_CW, 
               [TABLE_TWO].[lca_occ_LCT_uid] 
                      AS 
               TABLE_TWO_LCA_OCC_LCT_UID, 
               [TABLE_TWO].[SG] 
                      AS TABLE_TWO_SG, 
               [TABLE_TWO].[SGG] 
                      AS TABLE_TWO_SGG 
        FROM   TABLE_ONE 
               LEFT OUTER JOIN TABLE_TWO 
                            ON TABLE_ONE.SCC_uid = 
                               TABLE_TWO.SCC_uid 
        WHERE  ( [TABLE_ONE].[ANOTHER_DATE] <= '30 November 2020' ) 
               AND ( [TABLE_ONE].[SOME_DATE] >= '30 November 2020' ) 
               AND ( [TABLE_TWO].[ANOTHER_DATE] <= '30 November 2020' ) 
               AND ( [TABLE_TWO].[SOME_DATE] >= '30 November 2020' )) AS 
       RowConstrainedResult 
WHERE  rownum >= 0 
       AND rownum < 24 
ORDER  BY rownum 

我在不使用 ROW_NUMBERS() OVER 的情况下简化了查询，并且查询执行得相当快，没有问题。这是修改后的查询：

SELECT dbo.TABLE_ONE.*, 
       dbo.TABLE_TWO.* 
FROM   dbo.TABLE_ONE 
       INNER JOIN dbo.TABLE_TWO 
               ON dbo.TABLE_ONE.SCC_uid = 
                  dbo.TABLE_TWO.SCC_uid 
WHERE  ( dbo.TABLE_ONE.ANOTHER_DATE <= 
         CONVERT(DATETIME, '2020-11-30 00:00:00' 
                , 
                102) ) 
       AND ( dbo.TABLE_ONE.SOME_DATE >= 
             CONVERT(DATETIME, '2020-11-30 00:00:00', 
                 102) ) 
       AND ( dbo.TABLE_TWO.ANOTHER_DATE <= 
             CONVERT(DATETIME, '2020-11-30 00:00:00', 
                 102) ) 
       AND ( dbo.TABLE_TWO.SOME_DATE >= 
             CONVERT(DATETIME, '2020-11-30 00:00:00', 
             102) ) 

在应用程序中，在超时之前，它似乎检索了 160 万条记录，而简化查询只有 72k，不知道为什么会这样。

知道如何解决这个问题吗？

Answer 1

首先，将查询表述为 CTE：

WITH cs as (
      SELECT ca.*, sa.*. -- you may need to adjust the columns so there are no duplicates
      FROM  dbo.RM_COMMON_ATTRIBUTES ca INNER JOIN
            dbo.SECTION_ATTRIBUTES sa
            ON ca.SECTION_UID = sa.SECTION_UID
      WHERE ca.START_DATE <= '2020-11-30' AND
            ca.END_DATE >= '2020-11-30' AND 
            sa.START_DATE <= '2020-11-30' AND
            sa.END_DATE >= '2020-11-30'
     )

那么，有几件事可能会影响性能：

• 结果集的大小。
• 行号。
• 返回所有行，而不仅仅是第一行。

要消除第三种可能性，只需检查它的运行速度：

select count(*)
from cs;

您只需执行以下操作即可检查第一个：

select *
from cs;

然后你可以添加row_number():

SELECT cs.*, 
       ROW_NUMBER OVER (  ORDER BY [ITEM_UID] ) AS RowNum
FROM cs;