目录

• 起因
• 原来的处理方式
• 新的方式

private T PostDataViaHttpWebRequest<T>(string baseUrl,
            IReadOnlyDictionary<string, string> headers,
            IReadOnlyDictionary<string, string> urlParas,
            string requestBody=null)
        {
            var resuleJson = string.Empty;
            try
            {
                var apiUrl = baseUrl;

                if (urlParas != null)
                    urlParas.ForEach(p =>
                    {
                        if (apiUrl.IndexOf("{" + p.Key + "}") > -1)
                        {
                            apiUrl = apiUrl.Replace("{" + p.Key + "}", p.Value);
                        }
                        else
                        {
                            apiUrl += string.Format("{0}{1}={2}", apiUrl.Contains("?") ? "&" : "?", p.Key, p.Value);
                        }
                    }
                );
                
                var req = (HttpWebRequest)WebRequest.Create(apiUrl);
                req.Method = "POST";
                req.ContentType = "application/json"; 
                req.ContentLength = 0;

                if (!requestBody.IsNullOrEmpty())
                {
                    using (var postStream = req.GetRequestStream())
                    {
                        var postData = Encoding.ASCII.GetBytes(requestBody);
                        req.ContentLength = postData.Length;
                        postStream.Write(postData, 0, postData.Length);
                    }
                }

                if (headers != null)
                {
                    if (headers.Keys.Any(p => p.ToLower() == "content-type"))
                        req.ContentType = headers.SingleOrDefault(p => p.Key.ToLower() == "content-type").Value;
                    if (headers.Keys.Any(p => p.ToLower() == "accept"))
                        req.Accept = headers.SingleOrDefault(p => p.Key.ToLower() == "accept").Value;
                }

                var response = (HttpWebResponse)req.GetResponse();

                using(Stream stream = response.GetResponseStream())
                {
                    using (StreamReader reader = new StreamReader(stream, Encoding.GetEncoding("UTF-8")))
                    {
                        resuleJson = reader.ReadToEnd();
                    }
                }
            }
            catch (Exception ex)
            {
                return default(T);
            }
            return JsonConvert.DeserializeObject<T>(resuleJson);
        }

private T PostDataViaHttpWebRequest<T>(string baseUrl,
            IReadOnlyDictionary<string, string> headers,
            IReadOnlyDictionary<string, string> urlParas,
            string requestBody=null)
        {
            var resuleJson = string.Empty;
            try
            {
                var apiUrl = baseUrl;

                if (urlParas != null)
                    urlParas.ForEach(p =>
                    {
                        if (apiUrl.IndexOf("{" + p.Key + "}") > -1)
                        {
                            apiUrl = apiUrl.Replace("{" + p.Key + "}", p.Value);
                        }
                        else
                        {
                            apiUrl += string.Format("{0}{1}={2}", apiUrl.Contains("?") ? "&" : "?", p.Key, p.Value);
                        }
                    }
                );
                
                var req = (HttpWebRequest)WebRequest.Create(apiUrl);
                req.Method = "POST";
                req.ContentType = "application/json"; //Defalt

                if (!requestBody.IsNullOrEmpty())
                {
                    using (var postStream = new StreamWriter(req.GetRequestStream()))
                    {
                        postStream.Write(requestBody);
                    }
                }

                if (headers != null)
                {
                    if (headers.Keys.Any(p => p.ToLower() == "content-type"))
                        req.ContentType = headers.SingleOrDefault(p => p.Key.ToLower() == "content-type").Value;
                    if (headers.Keys.Any(p => p.ToLower() == "accept"))
                        req.Accept = headers.SingleOrDefault(p => p.Key.ToLower() == "accept").Value;
                }

                var response = (HttpWebResponse)req.GetResponse();

                using(Stream stream = response.GetResponseStream())
                {
                    using (StreamReader reader = new StreamReader(stream, Encoding.GetEncoding("UTF-8")))
                    {
                        resuleJson = reader.ReadToEnd();
                    }
                }
            }
            catch (Exception ex)
            {
                return default(T);
            }
            return JsonConvert.DeserializeObject<T>(resuleJson);
        }

• C#发送Get、Post请求(带参数)
• C#通过GET/POST方式发送Http请求
• C#调用HTTP POST请求上传图片的示例代码
• C#使用HttpPost请求调用WebService的方法
• C#使用GET、POST请求获取结果
• C#中后台post请求常用的两种方式总结

我运行完全相同的Python函数,一个作为Postgresql PL / Python,另一个作为通常的Python脚本在Postgresql之外运行.

令人惊讶的是,当我使用select * from pymax7(20000);调用Postgresql PL / Python时,它平均花费65秒,而当我调用通常的Python脚本python myscript.py 20000时,它平均需要48秒.计算运行查询和脚本10次的平均值.

是否应该有这样的差异？ Postgresql RDBMS(PL / Python)中的Python如何在性能方面与Python之外的Python进行比较？

我在Ubuntu 12.04 64位上运行Postgresql 9.1和Python 2.7.

Postgresql PL / Python：

CREATE FUNCTION pymax7 (b integer)
  RETURNS float
AS $$   
  a = 0
  for i in range(b):
    for ii in range(b):
      a = (((i+ii)%100)*149819874987) 
  return a
$$LANGUAGE plpythonu;

Python：

import time
import sys

def pymax7 (b):     
    a = 0
    for i in range(b):
        for ii in range(b):
            a = (((i+ii)%100)*149819874987) # keeping Python busy
    return a

def main():    
    numIterations = int(sys.argv[1])        
    start = time.time()
    print pymax7(numIterations)
    end = time.time()
    print "Time elapsed in Python:"
    print str((end - start)*1000) + ' ms'        

if __name__ == "__main__":
    main()

我确实调整了PL / Python测试用例,使用与普通Python测试用例相同的测量技术：

CREATE FUNCTION pymax7a (b integer)
  RETURNS float
AS $$
  import time
  start = time.time()
  a = 0
  for i in range(b):
    for ii in range(b):
      a = (((i+ii)%100)*149819874987)
  end = time.time()
  plpy.info("Time elapsed in Python: " + str((end - start)*1000) + ' ms')
  return a
$$LANGUAGE plpythonu;

这将告诉您是否涉及任何非Python开销. FWIW,对我来说,这个打印和客户端打印的psql与总时间之间的差异始终小于1毫秒.