将GetResponseStream写入文件需要很长时间

Question

我制作了一个SSRS批量报告器，它使用HTTPWebRequest和HTTPWebResponse查询来自SSRS的报告，以获得流并将其保存为文件。

然而，客户抱怨说这花了很长时间。我已经测试过了，这个函数需要+- 15.5秒。如果我在GetResponseStream和文件写入器之间插入一个断点，在进入下一部分之前等待大约3秒，那么总时间会减少4秒吗？

有谁能解释一下这一点，或者给出一些建议，让它更快一点？

这是函数：

 Public Function ExportReport(ByVal QueryStringParameters As String, ByVal FileName As String) As String
    Dim PDFName As String = ReportFolderPath & FileName & ".pdf"
    'Create a http request or connecting to the report server.
    Dim ReportHTTPRequest As HttpWebRequest = Nothing
    'Create a http response to catch the data stream returned from the http request.
    Dim ReportHTTPResponse As HttpWebResponse = Nothing
    'Create a stream to read the binary data from the http reponse.
    Dim ReportStream As Stream = Nothing
    Dim ReportFileStream As FileStream = Nothing
    'Create an array of bytes to get the binary data from the stream.
    Dim ReportBytes As Byte()
    Dim ReportBuffer As Integer = 204800
    Dim ReportBytesRead As Integer = 0


    'Create a webrequest to get the report with all the report parameters included.
    ReportHTTPRequest = WebRequest.Create(ReportServerURL & QueryStringParameters)
    ReportHTTPRequest.Credentials = CredentialCache.DefaultCredentials
    'Get the response from the request.

    ReportHTTPResponse = ReportHTTPRequest.GetResponse()

    'Read the binary stream from the http response.
    ReportStream = ReportHTTPResponse.GetResponseStream()

    ReportBytes = New Byte(ReportBuffer) {}
    ReportBytesRead = ReportStream.Read(ReportBytes, 0, ReportBuffer)
    ReportFileStream = New FileStream(PDFName, FileMode.Create)
    Do While ReportStream.CanRead And ReportBytesRead > 0
        ReportFileStream.Write(ReportBytes, 0, ReportBytesRead)
        ReportBytesRead = ReportStream.Read(ReportBytes, 0, ReportBuffer)
    Loop

    ReportHTTPResponse.Close()
    ReportStream.Close()
    ReportFileStream.Close()

    Return PDFName
End Function

Answer 1

一个对我有效的神奇方法，尝试使用32768的缓冲区大小