SQL Server 通过寻找另一种执行相同类型连接的方法来提高脚本性能

Question

我有一个脚本，它在给定的时间段内只返回有问题的行，并复制任何花费超过 60 秒发送的行。这是通过执行以下连接来实现的：

FROM Table t
INNER JOIN CTE_DayHourMinutes dhm ON
Calculate_Date >= t.[Start Date]
AND 
dhm.Calculate_Date <= t.[End Date]

对于表 t 中与计算日期的 YYYY-MM-DD HH-MM-SS 匹配的每条记录，它连接在一起。唯一的问题是返回 100 条记录需要 10 分钟左右。最终，该脚本将在系统内部使用，该系统可能有数千行甚至数百万行，因为我们将寻求提取三个月的数据。

我还应该提到，我已经测试了脚本的其余部分，并且在运行必要的 CTE 和其他部分时，每个都运行良好并且没有性能问题。唯一的问题是我尝试执行上述连接的方式以及它必须检查的行数，目前这需要太长时间。

因此，我不知道如何以类似的方式实现上述目标，但要提高脚本的性能。

'

DECLARE
    @startDate DateTime 
,   @currentDate DateTime

/* Demo System */    SET @currentDate = '2014-04-26'

SET @startDate = DATEADD(day, -10 , @CurrentDate)

-- Create a list of Days (depending on the month in question)
-------------------------------------------------------------
; WITH CTE_dayList as
(
SELECT @startDate as cal_day
union all
SELECT DATEADD(DAY , 1, d1var.cal_day) as cal_day FROM CTE_daylist d1var 
WHERE  DATEADD(DAY , 1, d1var.cal_day) <= @currentDate 
)

-- Create a list of hours 0 - 23 (24 hours)
-------------------------------------------
, CTE_hourList as
(
SELECT 0  as cal_hour
union all
SELECT h1var.cal_hour + 1 as cal_hour FROM CTE_hourList h1var 
WHERE h1var.cal_hour + 1 <= 23 
)

-- Create a list of minutes 0 - 59 (1 hour)
-------------------------------------------
, CTE_minuteList as
(
SELECT 0  as cal_minute
union all
SELECT m1var.cal_minute + 1 as cal_minute FROM CTE_minuteList m1var 
WHERE m1var.cal_minute + 1 <= 59 
)

-- Create a day , hour and minnute -- cross join the hour and minute onto each day between the two dates.

, CTE_DayHourMinutes as
(
SELECT
    -- cast the cal_day (date) with the hours and minute, to create a date and time.
    CAST(CAST(cal_day AS VARCHAR) + CAST(CAST(cal_hour as VARCHAR) + ':' + CAST(cal_minute AS VARCHAR) AS DATETIME) AS DATETIME) AS Calculate_Date
FROM CTE_dayList  
CROSS JOIN
(SELECT cal_hour , cal_minute FROM CTE_hourList CROSS JOIN CTE_minuteList) DHMList)

-- create transmission end date and time ( required for the join in the main select statement )


, CTE_Text RF as
(
SELECT
        H.ObjectGuid AS Transmission_ID
    ,   CAST(H.[TRDateTime] AS DateTime) AS [Transmission Start Date]
    ,   CAST(DATEADD(second, HT.ElapsedTime, H.TRDateTime) AS DateTime) AS [Transmission End Date]
    ,   HT.[ElapsedTime] AS [Time taken to send]
    ,   HT.GoodPageCount AS Pages
    ,   HT.[ChannelUsed]
FROM [dbo].History AS H (NOLOCK)
LEFT OUTER JOIN [dbo].HistoryTRX AS HT (NOLOCK) ON H.handle = HT.handle

)

SELECT 

        Calculate_Date AS [Full Calculated Date]
    ,   CAST(Calculate_Date AS DATE) AS Calculated_Date
    ,   CAST(DATEPART(YYYY , dhm.Calculate_Date) AS VARCHAR ) + '-' + RIGHT('0' + CAST(DATEPART(Month , dhm.Calculate_Date) AS VARCHAR) , 2) AS [Calculated Year-Month]
    ,   CAST(DATEPART(YYYY , dhm.Calculate_Date) AS VARCHAR ) + '-' + RIGHT('0' + CAST(DATEPART(Week , dhm.Calculate_Date) AS VARCHAR) , 2)  AS [Calculated Year-Week]
    ,   CAST(DATEPART(YYYY , dhm.Calculate_Date) AS VARCHAR ) + '-' + RIGHT('0' + CAST(DATEPART(DAY , dhm.Calculate_Date) AS VARCHAR) , 2)   AS [Calculated Year-Day]

    ,   DATEPART(YYYY, dhm.Calculate_Date)                                  AS [Calculated Year]
    ,   RIGHT('0' + CAST(DATEPART(MM, dhm.Calculate_Date) AS VARCHAR) ,2)   AS [Calculated Month]
    ,   DATEPART(Week, dhm.Calculate_Date)                                  AS [Calculated Week]
    ,   DATEPART(DAY, dhm.Calculate_Date)                                   AS [Calculated Day]

   ,    RF.Transmission_ID
   ,    RF.[Transmission Start Date]
   ,    RF.[Transmission End Date]
   ,    RIGHT('0' + CAST(DATEPART(HOUR , RF.[Transmission Start Date]) AS VARCHAR) ,2) + ':' + RIGHT('0' + CAST(DATEPART(Minute , RF.[Transmission Start Date]) AS VARCHAR) ,2) AS [Transmission Start Time]
   ,    RIGHT('0' + CAST(DATEPART(HOUR , RF.[Transmission End Date]) AS VARCHAR) ,2) + ':' + RIGHT('0' + CAST(DATEPART(Minute , RF.[Transmission End Date]) AS VARCHAR) ,2) AS [Transmission End Time]
   ,    RF.[Time taken to send]
   ,    RF.Pages
   ,    RF.[ChannelUsed]

FROM CTE_Text RF
INNER JOIN CTE_DayHourMinutes dhm ON

        -- Join where the calculate_date is between the start and end date of the transmission date.           
           dhm.Calculate_Date >= RF.[Transmission Start Date]
           AND 
           dhm.Calculate_Date <= RF.[Transmission End Date]

Answer 1

我会根据您在上面放置的代码以及对缺少的内容（例如数据类型和表模型、现有索引或 pk 等）的一些猜测来建议以下这些更改。更新/信息会很好。

• 我认为数据类型如下

  • 创建表历史记录(

    ObjectGuid uniqueidentifier
    TRDateTime datetime
    handle bigint
    

  • 历史TRX

    ElapsedTime int
    GoodPageCount int
    ChannelUsed int
    handle bigint
    

• 尽管它不会改善整个查询，但 CTE_DayHourMinutes 这样更快更短：

  ; with CTE_DayHourMinutes(Calculate_Date) as (
  select @startDate
  union all 
  select DATEADD(MINUTE, 1, Calculate_Date) from CTE_DayHourMinutes 
  where Calculate_Date<DATEADD(MINUTE, 60*24-1, @currentDate)
  )
  Select Calculate_Date From  CTE_DayHourMinutes
  Option (MaxRecursion 0)
  

• CTE_Text 射频表扫描

  您应该尽早将 [dbo].History 与 CTE_DayHourMinutes 一起加入，并尝试缩小此 CTE 和历史表的范围。现在您可能正在扫描整个 History 表 + HistoryTRX 的全部或部分

• 左外连接 [dbo].HistoryTRX

  当两个表不匹配时，HT.ElapsedTime 为空。因此 [Transmission End Date] 为空且 dhm.Calculate_Date >= RF.[Transmission Start Date] AND dhm.Calculate_Date

• 尽可能去除演员表和功能

  看起来大部分都不需要。它们还会阻止正确使用索引。

• 查看您的索引

  它们是否正确设置和有用？