性能：加速应用程序[关闭]

Question

附上，我已经编写了一些代码，进入我们的 SQL 数据库，执行一些查询，然后在 windows 窗体上应用 104 个标签的结果。

I have timed this procedure and it takes about 4 seconds which is way to long because my goal is to have this process done instantly so whenever a new employee is selected, his/her stats are loading as fast as possible.

我的问题：我可以做些什么来实现这个目标？

Dim RESULT1 As Decimal 'declare this as global  
Dim RESULT2 As Decimal 'declare this as global

Private Sub Week(ByVal week As Integer)
    Dim queryString As String = "SELECT " & _  
        "(SELECT CAST(SUM(TARGET_SECONDS) AS DECIMAL)/ CAST(SUM(ROUTE_SECONDS) AS DECIMAL) FROM dbo.APE_BUSDRIVER_MAIN WITH(NOLOCK) WHERE WEEK_TIME = " & week & " AND APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND EMPLOYEE_NAME = '" & cbEmployeeName.Text & "' AND YEAR_TIME = '" & cbYear.Text & "' AND ACTIVE = 1) AS RESULT1," & _
        " (SELECT (SELECT CAST(COUNT(APE_BUSDRIVER_STATUS_OBJID) AS DECIMAL) FROM dbo.APE_BUSDRIVER_MAIN AS RESULT2 WHERE WEEK_TIME = " & week & " AND APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND EMPLOYEE_NAME = '" & cbEmployeeName.Text & "' AND YEAR_TIME = '" & cbYear.Text & "' AND ACTIVE = 1 AND APE_BUSDRIVER_STATUS_OBJID = 1)/(SELECT CAST(COUNT(APE_BUSDRIVER_STATUS_OBJID) AS DECIMAL) FROM dbo.APE_BUSDRIVER_MAIN AS RESULT2 WHERE WEEK_TIME = " & week & " AND APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND EMPLOYEE_NAME = '" & cbEmployeeName.Text & "' AND YEAR_TIME = '" & cbYear.Text & "' AND ACTIVE = 1)) AS RESULT2" & _
        " FROM dbo.APE_BUSDRIVER_MAIN "

    Using connection As New SqlConnection(SQLConnectionStr)
        Dim command As New SqlCommand(queryString, connection)
        connection.Open()

        Dim reader As SqlDataReader = command.ExecuteReader()

        ' Call Read before accessing data. 
        If reader.HasRows Then
            While reader.Read()
                RESULT1 = reader("RESULT1")
                RESULT2 = reader("RESULT2")
            End While
        Else
            RESULT1 = 0
            RESULT2 = 0
        End If
        ' Call Close when done reading.
        reader.Close()
    End Using
End Sub


Private Sub LoadWeeklyStats()

    For i As Integer = 0 To 51
        Week(i + 1)
        Dim LabelWkEff As String = "LblWkEff" + (i + 1).ToString
        Dim myArray1 As Array = Controls.Find(LabelWkEff, False)
        Dim myControl1 As Label = myArray1(0)
        myControl1.Text = RESULT1    


        Dim LabelDeliveryStat As String = "lblDeliveryStat" + (i + 1).ToString
        Dim myArray2 As Array = Controls.Find(LabelDeliveryStat, False)
        Dim myControl2 As Label = myArray2(0)
        myControl2.Text = RESULT2
    Next

End Sub

Answer 1

我看到至少三个明显的大问题，但由于我没有坐在你的办公桌前，所以无法确定哪个是罪魁祸首。

你的 SQL 太可怕了

看看这个查询中表查询的数量就知道了！

SELECT
        (
            SELECT
                    CAST(SUM(TARGET_SECONDS) AS DECIMAL) / CAST(SUM(ROUTE_SECONDS) AS DECIMAL)
            FROM
                    dbo.APE_BUSDRIVER_MAIN WITH(NOLOCK)
            WHERE
                    WEEK_TIME = @week
                AND APE_AREA_OBJID = @areaOBJID
                AND EMPLOYEE_NAME = @EmployeeName
                AND YEAR_TIME = @Year
                AND ACTIVE = 1
        ) AS RESULT1
    ,   (
            SELECT
                    (
                        SELECT
                                CAST(COUNT(APE_BUSDRIVER_STATUS_OBJID) AS DECIMAL)
                        FROM
                                dbo.APE_BUSDRIVER_MAIN AS RESULT2
                        WHERE
                                WEEK_TIME = @week
                            AND APE_AREA_OBJID = @AreaOBJID
                            AND EMPLOYEE_NAME = @EmployeeName
                            AND YEAR_TIME = @Year
                            AND ACTIVE = 1
                            AND APE_BUSDRIVER_STATUS_OBJID = 1
                    ) / (
                        SELECT
                                CAST(COUNT(APE_BUSDRIVER_STATUS_OBJID) AS DECIMAL)
                        FROM
                                dbo.APE_BUSDRIVER_MAIN AS RESULT2
                        WHERE
                                WEEK_TIME = @week
                            AND APE_AREA_OBJID = @AreaOBJID
                            AND EMPLOYEE_NAME = @EmployeeName
                            AND YEAR_TIME = @Year
                            AND ACTIVE = 1
                    )
        ) AS RESULT2
FROM dbo.APE_BUSDRIVER_MAIN

由于问题的严重性，我什至无法开始为您重构它，而且我不知道您的架构，但我不得不猜测这是罪魁祸首之一。如果可能，请将其中的部分或全部缓存在一个表中（如果性能确实是您的主要目标）。

不必要的循环

您要返回多少行？如果你只需要一个，为什么会有多行？这种循环是完全没有必要的，可能会影响你的性能：

    If reader.HasRows Then
        While reader.Read()
            RESULT1 = reader("RESULT1")
            RESULT2 = reader("RESULT2")
        End While
    Else
        RESULT1 = 0
        RESULT2 = 0
    End If

效率低 * 52 + 重绘

尽管上面的代码效率低下，但您调用它 52 次​​strong> 让情况变得更糟！我很惊讶这只需要 4 秒。

For i As Integer = 0 To 51
    Week(i + 1)
    Dim LabelWkEff As String = "LblWkEff" + (i + 1).ToString
    Dim myArray1 As Array = Controls.Find(LabelWkEff, False)
    Dim myControl1 As Label = myArray1(0)
    myControl1.Text = RESULT1    


    Dim LabelDeliveryStat As String = "lblDeliveryStat" + (i + 1).ToString
    Dim myArray2 As Array = Controls.Find(LabelDeliveryStat, False)
    Dim myControl2 As Label = myArray2(0)
    myControl2.Text = RESULT2
Next

除了无效的函数调用之外，您还强制表单重新绘制自身 104 次（一次用于myControl1.Text，再次用于myControl2.Text）。某些 WinForm 控件（面板等）具有您可以设置或调用的属性或方法，以允许您在最后加载带有单个重绘的控件（例如SuspendLayout）。如果这对您不起作用，您可能会发现这篇文章很有帮助：

How do I suspend painting for a control and its children?