GZipStream解压性能较差

发布于 2024-08-06 12:34:41 字数 1996 浏览 6 评论 0原文

我有一个连接到后端 WAS 服务器的 .NET 2.0 WinForms 应用程序。我正在使用 GZipStream 解码从对服务器进行的 HttpWebRequest 调用返回的数据。返回的数据是压缩的 CSV，Apache 正在对其进行压缩。整个服务器堆栈是Hibernate-->EJB-->Spring-->Apache。

对于小的响应，性能很好（<50ms）。当我收到>150KB的响应时，解压需要超过60秒。大部分时间似乎都花在 GZipStream 构造函数上。

这是显示我从 HttpWebResponse 调用获取响应流的位置的代码：

using (Stream stream = this.Response.GetResponseStream())
{
 if (this.CompressData && this.Response.ContentEncoding == "gzip")
 {
        // Decompress the response
  byte[] b = Decompress(stream);
  this.ResponseBody = encoding.GetString(b);
    }
 else
 {
  // Just read the stream as a string
  using (StreamReader sr = new StreamReader(stream))
  {
   this.ResponseBody = sr.ReadToEnd();
  }
 }
}

编辑 1

根据 Lucero 的评论，我将 Decompress 方法修改为以下内容，但我没有看到任何性能优势在实例化 GZipStream 之前将 ResponseStream 加载到 MemoryStream 中。

private static byte[] Decompress(Stream stream)
{
 using (MemoryStream ms = new MemoryStream())
 {
  byte[] buffer = new byte[4096];
  int read = 0;

  while ((read = stream.Read(buffer, 0, buffer.Length)) > 0)
  {
   ms.Write(buffer, 0, read);
  }

  ms.Seek(0, SeekOrigin.Begin);

  using (GZipStream gzipStream = new GZipStream(ms, CompressionMode.Decompress, false))
  {
   read = 0;
   buffer = new byte[4096];

   using (MemoryStream output = new MemoryStream())
   {
    while ((read = gzipStream.Read(buffer, 0, buffer.Length)) > 0)
    {
     output.Write(buffer, 0, read);
    }

    return output.ToArray();
   }
  }
 }
}

根据上面的代码，任何人都可以看到任何问题吗？这对我来说似乎很基本，但它让我发疯。

编辑2

我使用ANTS Profiler对应用程序进行了分析，在60秒的解压过程中，CPU接近于零，内存使用率没有变化。

编辑 3

实际速度下降似乎是在读取期间

this.Response.GetResponseStream

The entire 60s is spent loading the response stream into the MemoryStream. Once it's there, the call to GZipStream is quick.
Edit 4

我发现使用 HttpWebRequest.AutomaticDecompression 会出现相同的性能问题，因此我将结束这个问题。

原文

I have a .NET 2.0 WinForms app that connects to a backend WAS server. I am using GZipStream to decode data coming back from a HttpWebRequest call made to the server. The data returned is compressed CSV, which Apache is compressing. The entire server stack is Hibernate-->EJB-->Spring-->Apache.

For small responses, the performance is fine (<50ms). When I get a response >150KB, it takes more than 60 seconds to decompress. The majority of the time seems to be spent in the GZipStream constructor.

This is the code showing where I get the response stream from the HttpWebResponse call:

using (Stream stream = this.Response.GetResponseStream())
{
 if (this.CompressData && this.Response.ContentEncoding == "gzip")
 {
        // Decompress the response
  byte[] b = Decompress(stream);
  this.ResponseBody = encoding.GetString(b);
    }
 else
 {
  // Just read the stream as a string
  using (StreamReader sr = new StreamReader(stream))
  {
   this.ResponseBody = sr.ReadToEnd();
  }
 }
}

Edit 1

Based on the comment from Lucero, I modified the Decompress method to the following, but I do not see any performance benefit from loading the ResponseStream into a MemoryStream before instantiating the GZipStream.

private static byte[] Decompress(Stream stream)
{
 using (MemoryStream ms = new MemoryStream())
 {
  byte[] buffer = new byte[4096];
  int read = 0;

  while ((read = stream.Read(buffer, 0, buffer.Length)) > 0)
  {
   ms.Write(buffer, 0, read);
  }

  ms.Seek(0, SeekOrigin.Begin);

  using (GZipStream gzipStream = new GZipStream(ms, CompressionMode.Decompress, false))
  {
   read = 0;
   buffer = new byte[4096];

   using (MemoryStream output = new MemoryStream())
   {
    while ((read = gzipStream.Read(buffer, 0, buffer.Length)) > 0)
    {
     output.Write(buffer, 0, read);
    }

    return output.ToArray();
   }
  }
 }
}

Based on the code above, can anyone see any issues? This seems quite basic to me, but it's driving me nuts.

Edit 2

I profiled the application using ANTS Profiler, and during the 60s of decompression, the CPU is near zero and the memory usage does not change.

Edit 3

The actual slowdown appears to be during the read of