數據庫訪問與本地文件訪問實測報告

 

一直認爲數據庫訪問比本地文件訪問是要慢很多的，但究竟慢多少卻不清楚。終於忍不住作了下比較測試。

測試環境：OS---Windows 2000 Server        DatabaseServer----SQLServer 2000        程序語言：CSharp

測試方式：從數據庫中讀取參數表/從XML中讀取配置參數等同數量的記錄並實例化對象。

測試程序如下：

 using System;
 using System.Globalization;
 using System.IO;
 using System.Xml.Serialization;
 using System.Xml;
 using System.Data;
 using System.Data.SqlClient;

 public class Demo
 {
  public static void Main()
  {
   System.Console.WriteLine("===== ExecuteXML() =====================================");
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine(ExecuteXML());
   System.Console.WriteLine("========================================================");
   
   System.Console.WriteLine("===== ExecuteSQL() =====================================");
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine(ExecuteSQL());
   System.Console.WriteLine("========================================================/n");

  }

  static double ExecuteSQL()
  {
   string _connString = "server=data-server;user id=sa;password=1234;database=LeadDB;min pool size=4;max pool size=4;packet size=3072";
   SqlCommand cmd = new SqlCommand();
   SqlConnection conn = new SqlConnection(_connString);

   double begin = CultureInfo.InvariantCulture.Calendar.GetMilliseconds(DateTime.Now);
   try {
    conn.Open();

    cmd.Connection = conn;
    cmd.CommandText = "SELECT [CategoryId], [Name] FROM [SYS_Category] WHERE [CategoryType] = 2";

    cmd.CommandType = CommandType.Text;
    SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
    while (rdr.Read())
    {
     new Entity(rdr.GetInt32(0), rdr.GetString(1));
    }
    rdr.Close();
   }catch {
    conn.Close();
    throw;
   }
   begin = CultureInfo.InvariantCulture.Calendar.GetMilliseconds(DateTime.Now) - begin;
   return (begin >= 0)?begin:begin+1000.0;
  }

  static double ExecuteXML()
  {
   double begin = CultureInfo.InvariantCulture.Calendar.GetMilliseconds(DateTime.Now);
   XmlDocument xmlDoc = new XmlDocument();
   xmlDoc.Load( @"F:/LeadBridge/XCERP/Web/OnlineService/SYS_Category_Headship.xml" );
   
   foreach(XmlNode node in xmlDoc.SelectNodes("items/item")){
    new Entity(int.Parse(node.Attributes["id"].Value), node.InnerText);
   }
   begin = CultureInfo.InvariantCulture.Calendar.GetMilliseconds(DateTime.Now) - begin;
   return (begin >= 0)?begin:begin+1000.0;
  }
 }

 public class Entity {
  public Entity(int age, string name){
   this._Age = age;
   this._Name = name;
  }
  private int _Age;
  private string _Name;
  public int Age{
   get{ return _Age; }
   set{ _Age = value; }
  }
  public string Name{
   get{ return _Name; }
   set{ _Name = value; }
  }
 }

執行結果如下：

===== ExecuteXML() =====================================
47
0
0
16
0
0
0
0
16
0
========================================================
===== ExecuteSQL() =====================================
203
0
0
0
0
0
16
0
0
0
========================================================

做過多次測試，基本上是如上數量級別（一個數量級）的差異（第一次執行差異），因此建議，大家對於無需經常修改的數據保存爲本地參數文件形式比直接從數庫讀取效率要高一些。