我有一个存储过程，我写了一段时间，以帮助生成一个XML文件，用于与外部资源共享数据。基本上，最终用户将数据转储到名为DataSharing的表中，然后当我们执行Query时，它将返回一个XML文档，其中包含DataSharing中指定的必需字段。现在这个程序确实运行良好，但它非常慢。当我通过SSMS运行并设置“显示实际执行计划”时，94％的查询将花费在索引假脱机（急切线轴）上。经过研究，看起来我应该重新编写查询以更好地执行。
由于数据列我永远不知道它们是什么，我必须做独特的数据透视才能生成我的数据。
以下是程序：
CREATE PROCEDURE [dbo].[sp_HPSDDataSharing]
-- Add the parameters for the stored procedure here
@fileName varchar(MAX), @StartDate datetime, @EndDate datetime
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
DECLARE @sqlCommand varchar(MAX), @listStr VARCHAR(MAX)
SELECT @listStr =
COALESCE(@listStr +',' ,'') + '[' + [ColumnName] + ']'
FROM [FCPP_HPSD].[dbo].[DataSharing]
WHERE FileName = @fileName
DECLARE @Result XML
SET @sqlCommand = 'Select * From ( SELECT
[DatapointDate]
,dp.ColumnName
,[DataPointValue]
FROM [FCPP_HPSD].[dbo].[vw_DataCollection] DC
JOIN [FCPP_HPSD].[dbo].[Datasharing] dp
ON DC.DataPointID = DP.DatapointID
WHERE
[DatapointDate] >= ''' + CONVERT(varchar(MAX), @StartDate) + '''
and [DatapointDate] < ''' + CONVERT(varchar(MAX), @EndDate) + '''
and dc.DataPointID in (SELECT [DatapointID] FROM [FCPP_HPSD].[dbo].[DataSharing] Where FileName = ''' + @fileName + ''')
) AS source
PIVOT
(
SUM(DataPointValue)
FOR ColumnName IN ('+ @listStr +')
) as pvt
ORDER BY DatapointDate
FOR XML Path(''' + 'DataRow' + '''), ROOT;'
Print @sqlCommand
EXEC (@sqlCommand)
END
GO
完全执行的查询如下所示：
SELECT *
FROM (SELECT [datapointdate],
dp.columnname,
[datapointvalue]
FROM [FCPP_HPSD].[dbo].[vw_datacollection] DC
JOIN [FCPP_HPSD].[dbo].[datasharing] dp
ON DC.datapointid = DP.datapointid
WHERE [datapointdate] >= 'Jul 15 2013 12:00AM'
AND [datapointdate] < 'Jul 22 2013 12:00AM'
AND dc.datapointid IN (SELECT [datapointid]
FROM [FCPP_HPSD].[dbo].[datasharing]
WHERE filename = 'fdrD3')) AS source
PIVOT ( Sum(datapointvalue)
FOR columnname IN ([fdrD3_kWh_A],
[fdrD3_kWh_B],
[fdrD3_kWh_C],
[fdrD3_kWh],
[fdrD3_I_A],
[fdrD3_I_B],
[fdrD3_I_C],
[fdrD3_I_N],
[fdrD3_V_A],
[fdrD3_V_B],
[fdrD3_V_C],
[fdrD3_V_A-B],
[fdrD3_V_B-C],
[fdrD3_kV_C-A],
[fdrD3_kW],
[fdrD3_kVA],
[fdrD3_kVAr],
[fdrD3_kW_A],
[fdrD3_kW_B],
[fdrD3_kW_C],
[fdrD3_kVA_A],
[fdrD3_kVA_B],
[fdrD3_kVA_C],
[fdrD3_kVAr_A],
[fdrD3_kVAr_B],
[fdrD3_kVAr_C],
[fdrD3_F],
[fdrD3_Iang_A],
[fdrD3_Iang_B],
[fdrD3_Iang_C],
[fdrD3_Iang_N],
[fdrD3_Vang_A],
[fdrD3_Vang_B],
[fdrD3_Vang_C],
[fdrD3_Vang_A-B],
[fdrD3_Vang_B-C],
[fdrD3_Vang_C-A],
[fdrD3_PF_A],
[fdrD3_PF_B],
[fdrD3_PF_C],
[fdrD3_PF],
[fdrD3_Pst_V_A],
[fdrD3_Pst_V_B],
[fdrD3_Pst_V_C],
[fdrD3_Plt_V_A],
[fdrD3_Plt_V_B],
[fdrD3_Plt_V_C],
[fdrD3_Vdev_A],
[fdrD3_Vdev_B],
[fdrD3_Vdev_C],
[fdrD3_Fdev],
[fdrD3_THD_I_A],
[fdrD3_THD_I_B],
[fdrD3_THD_I_C],
[fdrD3_THD_I_N],
[fdrD3_THD_V_A],
[fdrD3_THD_V_B],
[fdrD3_THD_V_C]) ) AS pvt
ORDER BY datapointdate
FOR xml path('DataRow'), root;
因此当前程序目前需要35-65秒才能运行。当我处理超时时，我真的需要看到加速这个过程。如果有人能帮助我，我可以做些什么来帮助加快速度并摆脱在Index Spool（热切换线轴）上花费这么多时间，我将不胜感激。
编辑1：
我添加了SQL Fiddle，所以希望这会有所帮助。
答案 0 :(得分：0)
这是您的枢轴解开 - 看看它是否运行得更快（我敢打赌它主要是因为CTE的优化），如果确实如此，那么你可以重新编写你的生成器来创建一个看起来像这样的查询：
WITH datelist
(
SELECT datapointid, filename, datapointvalue
FROM [FCPP_HPSD].[dbo].[datasharing]
WHERE datapointdate >= @StartDate AND datapointdate < @EndDate AND filename = @filename
)
SELECT
SUM( j1.datepointvalue) as sum_fdrD3_kWh_A
SUM( j2.datepointvalue) as sum_fdrD3_kWh_B
SUM( j3.datepointvalue) as sum_fdrD3_kWh_C
SUM( j4.datepointvalue) as sum_fdrD3_kWh
SUM( j5.datepointvalue) as sum_fdrD3_I_A
SUM( j6.datepointvalue) as sum_fdrD3_I_B
SUM( j7.datepointvalue) as sum_fdrD3_I_C
SUM( j8.datepointvalue) as sum_fdrD3_I_N
SUM( j9.datepointvalue) as sum_fdrD3_V_A
SUM(j10.datepointvalue) as sum_fdrD3_V_B
SUM(j12.datepointvalue) as sum_fdrD3_V_C
SUM(j13.datepointvalue) as sum_fdrD3_V_A_B
SUM(j14.datepointvalue) as sum_fdrD3_V_B_C
SUM(j15.datepointvalue) as sum_fdrD3_kV_C_A
SUM(j16.datepointvalue) as sum_fdrD3_kW
SUM(j17.datepointvalue) as sum_fdrD3_kVA
SUM(j18.datepointvalue) as sum_fdrD3_kVAr
SUM(j19.datepointvalue) as sum_fdrD3_kW_A
SUM(j20.datepointvalue) as sum_fdrD3_kW_B
SUM(j21.datepointvalue) as sum_fdrD3_kW_C
SUM(j22.datepointvalue) as sum_fdrD3_kVA_A
SUM(j23.datepointvalue) as sum_fdrD3_kVA_B
SUM(j24.datepointvalue) as sum_fdrD3_kVA_C
SUM(j25.datepointvalue) as sum_fdrD3_kVAr_A
SUM(j26.datepointvalue) as sum_fdrD3_kVAr_B
SUM(j27.datepointvalue) as sum_fdrD3_kVAr_C
SUM(j28.datepointvalue) as sum_fdrD3_F
SUM(j29.datepointvalue) as sum_fdrD3_Iang_A
SUM(j20.datepointvalue) as sum_fdrD3_Iang_B
SUM(j31.datepointvalue) as sum_fdrD3_Iang_C
SUM(j32.datepointvalue) as sum_fdrD3_Iang_N
SUM(j33.datepointvalue) as sum_fdrD3_Vang_A
SUM(j34.datepointvalue) as sum_fdrD3_Vang_B
SUM(j35.datepointvalue) as sum_fdrD3_Vang_C
SUM(j36.datepointvalue) as sum_fdrD3_Vang_A_B
SUM(j37.datepointvalue) as sum_fdrD3_Vang_B_C
SUM(j38.datepointvalue) as sum_fdrD3_Vang_C_A
SUM(j39.datepointvalue) as sum_fdrD3_PF_A
SUM(j40.datepointvalue) as sum_fdrD3_PF_B
SUM(j41.datepointvalue) as sum_fdrD3_PF_C
SUM(j42.datepointvalue) as sum_fdrD3_PF
SUM(j43.datepointvalue) as sum_fdrD3_Pst_V_A
SUM(j44.datepointvalue) as sum_fdrD3_Pst_V_B
SUM(j45.datepointvalue) as sum_fdrD3_Pst_V_C
SUM(j46.datepointvalue) as sum_fdrD3_Plt_V_A
SUM(j47.datepointvalue) as sum_fdrD3_Plt_V_B
SUM(j48.datepointvalue) as sum_fdrD3_Plt_V_C
SUM(j49.datepointvalue) as sum_fdrD3_Vdev_A
SUM(j50.datepointvalue) as sum_fdrD3_Vdev_B
SUM(j51.datepointvalue) as sum_fdrD3_Vdev_C
SUM(j52.datepointvalue) as sum_fdrD3_Fdev
SUM(j53.datepointvalue) as sum_fdrD3_THD_I_A
SUM(j54.datepointvalue) as sum_fdrD3_THD_I_B
SUM(j55.datepointvalue) as sum_fdrD3_THD_I_C
SUM(j56.datepointvalue) as sum_fdrD3_THD_I_N
SUM(j57.datepointvalue) as sum_fdrD3_THD_V_A
SUM(j58.datepointvalue) as sum_fdrD3_THD_V_B
SUM(j59.datepointvalue) as sum_fdrD3_THD_V_C
FROM [FCPP_HPSD].[dbo].[vw_datacollection] DC
LEFT JOIN datelist j1 ON DC.datapointid = j1.datapointid AND j1.columnname = 'fdrD3_kWh_A'
LEFT JOIN datelist j2 ON DC.datapointid = j2.datapointid AND j2.columnname = 'fdrD3_kWh_B'
LEFT JOIN datelist j3 ON DC.datapointid = j3.datapointid AND j3.columnname = 'fdrD3_kWh_C'
LEFT JOIN datelist j4 ON DC.datapointid = j4.datapointid AND j4.columnname = 'fdrD3_kWh'
LEFT JOIN datelist j5 ON DC.datapointid = j5.datapointid AND j5.columnname = 'fdrD3_I_A'
LEFT JOIN datelist j6 ON DC.datapointid = j6.datapointid AND j6.columnname = 'fdrD3_I_B'
LEFT JOIN datelist j7 ON DC.datapointid = j7.datapointid AND j7.columnname = 'fdrD3_I_C'
LEFT JOIN datelist j8 ON DC.datapointid = j8.datapointid AND j8.columnname = 'fdrD3_I_N'
LEFT JOIN datelist j9 ON DC.datapointid = j9.datapointid AND j9.columnname = 'fdrD3_V_A'
LEFT JOIN datelist j10 ON DC.datapointid = j10.datapointid AND j10.columnname = 'fdrD3_V_B'
LEFT JOIN datelist j12 ON DC.datapointid = j12.datapointid AND j12.columnname = 'fdrD3_V_C'
LEFT JOIN datelist j13 ON DC.datapointid = j13.datapointid AND j13.columnname = 'fdrD3_V_A-B'
LEFT JOIN datelist j14 ON DC.datapointid = j14.datapointid AND j14.columnname = 'fdrD3_V_B-C'
LEFT JOIN datelist j15 ON DC.datapointid = j15.datapointid AND j15.columnname = 'fdrD3_kV_C-A'
LEFT JOIN datelist j16 ON DC.datapointid = j16.datapointid AND j16.columnname = 'fdrD3_kW'
LEFT JOIN datelist j17 ON DC.datapointid = j17.datapointid AND j17.columnname = 'fdrD3_kVA'
LEFT JOIN datelist j18 ON DC.datapointid = j18.datapointid AND j18.columnname = 'fdrD3_kVAr'
LEFT JOIN datelist j19 ON DC.datapointid = j19.datapointid AND j19.columnname = 'fdrD3_kW_A'
LEFT JOIN datelist j20 ON DC.datapointid = j20.datapointid AND j20.columnname = 'fdrD3_kW_B'
LEFT JOIN datelist j21 ON DC.datapointid = j21.datapointid AND j21.columnname = 'fdrD3_kW_C'
LEFT JOIN datelist j22 ON DC.datapointid = j22.datapointid AND j22.columnname = 'fdrD3_kVA_A'
LEFT JOIN datelist j23 ON DC.datapointid = j23.datapointid AND j23.columnname = 'fdrD3_kVA_B'
LEFT JOIN datelist j24 ON DC.datapointid = j24.datapointid AND j24.columnname = 'fdrD3_kVA_C'
LEFT JOIN datelist j25 ON DC.datapointid = j25.datapointid AND j25.columnname = 'fdrD3_kVAr_A'
LEFT JOIN datelist j26 ON DC.datapointid = j26.datapointid AND j26.columnname = 'fdrD3_kVAr_B'
LEFT JOIN datelist j27 ON DC.datapointid = j27.datapointid AND j27.columnname = 'fdrD3_kVAr_C'
LEFT JOIN datelist j28 ON DC.datapointid = j28.datapointid AND j28.columnname = 'fdrD3_F'
LEFT JOIN datelist j29 ON DC.datapointid = j29.datapointid AND j29.columnname = 'fdrD3_Iang_A'
LEFT JOIN datelist j20 ON DC.datapointid = j20.datapointid AND j20.columnname = 'fdrD3_Iang_B'
LEFT JOIN datelist j31 ON DC.datapointid = j31.datapointid AND j31.columnname = 'fdrD3_Iang_C'
LEFT JOIN datelist j32 ON DC.datapointid = j32.datapointid AND j32.columnname = 'fdrD3_Iang_N'
LEFT JOIN datelist j33 ON DC.datapointid = j33.datapointid AND j33.columnname = 'fdrD3_Vang_A'
LEFT JOIN datelist j34 ON DC.datapointid = j34.datapointid AND j34.columnname = 'fdrD3_Vang_B'
LEFT JOIN datelist j35 ON DC.datapointid = j35.datapointid AND j35.columnname = 'fdrD3_Vang_C'
LEFT JOIN datelist j36 ON DC.datapointid = j36.datapointid AND j36.columnname = 'fdrD3_Vang_A-B'
LEFT JOIN datelist j37 ON DC.datapointid = j37.datapointid AND j37.columnname = 'fdrD3_Vang_B-C'
LEFT JOIN datelist j38 ON DC.datapointid = j38.datapointid AND j38.columnname = 'fdrD3_Vang_C-A'
LEFT JOIN datelist j39 ON DC.datapointid = j39.datapointid AND j39.columnname = 'fdrD3_PF_A'
LEFT JOIN datelist j40 ON DC.datapointid = j40.datapointid AND j40.columnname = 'fdrD3_PF_B'
LEFT JOIN datelist j41 ON DC.datapointid = j41.datapointid AND j41.columnname = 'fdrD3_PF_C'
LEFT JOIN datelist j42 ON DC.datapointid = j42.datapointid AND j42.columnname = 'fdrD3_PF'
LEFT JOIN datelist j43 ON DC.datapointid = j43.datapointid AND j43.columnname = 'fdrD3_Pst_V_A'
LEFT JOIN datelist j44 ON DC.datapointid = j44.datapointid AND j44.columnname = 'fdrD3_Pst_V_B'
LEFT JOIN datelist j45 ON DC.datapointid = j45.datapointid AND j45.columnname = 'fdrD3_Pst_V_C'
LEFT JOIN datelist j46 ON DC.datapointid = j46.datapointid AND j46.columnname = 'fdrD3_Plt_V_A'
LEFT JOIN datelist j47 ON DC.datapointid = j47.datapointid AND j47.columnname = 'fdrD3_Plt_V_B'
LEFT JOIN datelist j48 ON DC.datapointid = j48.datapointid AND j48.columnname = 'fdrD3_Plt_V_C'
LEFT JOIN datelist j49 ON DC.datapointid = j49.datapointid AND j49.columnname = 'fdrD3_Vdev_A'
LEFT JOIN datelist j50 ON DC.datapointid = j50.datapointid AND j50.columnname = 'fdrD3_Vdev_B'
LEFT JOIN datelist j51 ON DC.datapointid = j51.datapointid AND j51.columnname = 'fdrD3_Vdev_C'
LEFT JOIN datelist j52 ON DC.datapointid = j52.datapointid AND j52.columnname = 'fdrD3_Fdev'
LEFT JOIN datelist j53 ON DC.datapointid = j53.datapointid AND j53.columnname = 'fdrD3_THD_I_A'
LEFT JOIN datelist j54 ON DC.datapointid = j54.datapointid AND j54.columnname = 'fdrD3_THD_I_B'
LEFT JOIN datelist j55 ON DC.datapointid = j55.datapointid AND j55.columnname = 'fdrD3_THD_I_C'
LEFT JOIN datelist j56 ON DC.datapointid = j56.datapointid AND j56.columnname = 'fdrD3_THD_I_N'
LEFT JOIN datelist j57 ON DC.datapointid = j57.datapointid AND j57.columnname = 'fdrD3_THD_V_A'
LEFT JOIN datelist j58 ON DC.datapointid = j58.datapointid AND j58.columnname = 'fdrD3_THD_V_B'
LEFT JOIN datelist j59 ON DC.datapointid = j59.datapointid AND j59.columnname = 'fdrD3_THD_V_C'
答案 1 :(得分：0)
我已经删除了子查询，我希望这会加快执行速度并且不会产生错误的结果。
SELECT *
FROM (SELECT [datapointdate],
dp.columnname,
[datapointvalue]
FROM [FCPP_HPSD].[dbo].[vw_datacollection] DC
JOIN [FCPP_HPSD].[dbo].[datasharing] dp
ON DC.datapointid = DP.datapointid
WHERE [datapointdate] >= 'Jul 15 2013 12:00AM'
AND [datapointdate] < 'Jul 22 2013 12:00AM'
AND dc.datapointid IN (SELECT [datapointid]
FROM [FCPP_HPSD].[dbo].[datasharing]
WHERE filename = 'fdrD3')) AS source
PIVOT ( Sum(datapointvalue)
FOR columnname IN (select distinct dp.columnname
from [FCPP_HPSD].[dbo].[datasharing] dp ) AS pvt
ORDER BY datapointdate
FOR xml path('DataRow'), root;
修改 如果您想要所选数据，可能需要where子句。它适用于Oracle。 我将子查询重新放回原位并在Pivot中添加了另一个，只是为了简化代码并确保将来也能满足任何新数据。
答案 2 :(得分：0)
从SqlFiddle我建议在DataSharing（FileName，DataPointID）上添加一个额外的索引。但是，从您的评论看来，实际查询似乎只需要6秒钟（这包括将所有547k记录发送到SSMS所需的时间吗？），这样剩下的时间就会被PIVOT吸收并转换为XML？
代码明智我也不是子查询的粉丝，但使用WHERE EXISTS（）结构似乎比直接JOIN imho更安全。然后，优化器也经常意识到这一点，并且已经为我们做了这个。因此，下面的查询计划看起来可能与原始查询计划相同。
Select *
From ( SELECT [DatapointDate]
,dp.ColumnName
,[DataPointValue]
FROM [DataCollection] DC
JOIN [Datasharing] dp
ON DC.DataPointID = DP.DatapointID
WHERE [DatapointDate] >= 'Jul 15 2013 12:00AM'
AND [DatapointDate] < 'Jul 22 2013 12:00AM'
AND EXISTS ( SELECT *
FROM [DataSharing] ds
WHERE ds.[FileName] = 'fdrD3'
AND dc.DataPointID = ds.[DatapointID])
) AS source
PIVOT
(
SUM(DataPointValue)
FOR ColumnName IN ([fdrD3_kWh_A],[fdrD3_kWh_B],[fdrD3_kWh_C],[fdrD3_kWh],[fdrD3_I_A],[fdrD3_I_B],[fdrD3_I_C],[fdrD3_I_N],[fdrD3_V_A],[fdrD3_V_B],[fdrD3_V_C],[fdrD3_V_A-B],[fdrD3_V_B-C],[fdrD3_kV_C-A],[fdrD3_kW],[fdrD3_kVA],[fdrD3_kVAr],[fdrD3_kW_A],[fdrD3_kW_B],[fdrD3_kW_C],[fdrD3_kVA_A],[fdrD3_kVA_B],[fdrD3_kVA_C],[fdrD3_kVAr_A],[fdrD3_kVAr_B],[fdrD3_kVAr_C],[fdrD3_F],[fdrD3_Iang_A],[fdrD3_Iang_B],[fdrD3_Iang_C],[fdrD3_Iang_N],[fdrD3_Vang_A],[fdrD3_Vang_B],[fdrD3_Vang_C],[fdrD3_Vang_A-B],[fdrD3_Vang_B-C],[fdrD3_Vang_C-A],[fdrD3_PF_A],[fdrD3_PF_B],[fdrD3_PF_C],[fdrD3_PF],[fdrD3_Pst_V_A],[fdrD3_Pst_V_B],[fdrD3_Pst_V_C],[fdrD3_Plt_V_A],[fdrD3_Plt_V_B],[fdrD3_Plt_V_C],[fdrD3_Vdev_A],[fdrD3_Vdev_B],[fdrD3_Vdev_C],[fdrD3_Fdev],[fdrD3_THD_I_A],[fdrD3_THD_I_B],[fdrD3_THD_I_C],[fdrD3_THD_I_N],[fdrD3_THD_V_A],[fdrD3_THD_V_B],[fdrD3_THD_V_C])
) as pvt
ORDER BY DatapointDate
FOR XML Path('DataRow'), ROOT
还有一个问题：你真的需要那里的ORDER BY DatapointDate吗？