Sometimes some of the methods you write are slow, but you don't know where the problem is. This is when you need a code analysis tool.
Through this article, you will learn how to run code analysis in Visual Studio, as well as use the Visual Studio Profiler to optimize your programming code.
It is a dynamic program analysis tool to identify performance issues like, memory, complexity of program time, CPU usage, etc.
C# code analyzers
Creating a console application, then create a simple method as show below.
public static void TestWriteFileToDisk(int numberOfRecord)
{
for (int i = 1; i <= numberOfRecord; i++)
{
using (SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["cn"].ConnectionString))
{
if (cn.State == System.Data.ConnectionState.Closed)
cn.Open();
using (SqlCommand cmd = new SqlCommand($"select ProductName from Products where ProductID={i}", cn))
{
using (SqlDataReader reader = cmd.ExecuteReader())
{
if (reader.Read())
System.IO.File.AppendAllText($"{Application.StartupPath}\\data.txt", $"{i}: {reader.GetString(0)}\n");
}
}
}
}
}Modifyding your App.config as shows below.
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
</startup>
<connectionStrings>
<add name="cn" connectionString="Data Source=.;Initial Catalog=Northwind;User ID=sa;Password=123@qaz;" providerName="System.Data.SqlClient"/>
</connectionStrings>
</configuration>I'm using Northwind database to play demo. The TestWriteFileToDisk is a simple method allows you to get data from product table in your Northwind database, then write it to file.
We will observe the code before and after being optimized.
Modifyding your Main method as shown below.
static void Main(string[] args)
{
// Press Ctrl+F5 (or go to Debug > Start Without Debugging) to run your app.
TestWriteFileToDisk(77);
Console.WriteLine("Finished !");
Console.ReadKey();
}How to run code analysis in Visual Studio 2017, 2019
Changing from Debug to Release mode, then select Analyze =>Performance Profiler
Clicking on Performance Wizard, then click the Start button.
Selecting Instrumentation.
Selecting One or more available projects.
Selecting your project, then click Next button.
Finally, Click Finish button.
When you see the word "Finished !" in the app, you turn off the app.
You can see the CPU usage percentage in the graph above is always high.
The AppendAllText method takes 42.73 percent.
Now we will optimize our code as follows.
public static void TestWriteFileToDisk(int numberOfRecord)
{
string connectionString = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;
StringBuilder stringBuilder = new StringBuilder();
for (int i = 1; i <= numberOfRecord; i++)
{
using (SqlConnection cn = new SqlConnection(connectionString))
{
if (cn.State == System.Data.ConnectionState.Closed)
cn.Open();
using (SqlCommand cmd = new SqlCommand($"select ProductName from Products where ProductID={i}", cn))
{
using (SqlDataReader reader = cmd.ExecuteReader())
{
if (reader.Read())
stringBuilder.Append($"{i}: {reader.GetString(0)}\n");
}
}
}
}
System.IO.File.AppendAllText($"{Application.StartupPath}\\data.txt", stringBuilder.ToString());
}Moving the connection string out of the loop, using StringBuilder to concatenate text instead of writing directly to the file. Finally, We will convert the stringBuilder variable to String, then write it to file.
We will continue to reuse Visual Studio Profiler to optimize your code.
As you can see in the graph above, we have reduced the execution time from 1.352 seconds to 0.205 seconds
As you can see, AppendAllText method reduced to 4.84%
We will continue to re-optimize your code as follows.
public static void TestWriteFileToDisk(int numberOfRecord)
{
string connectionString = ConfigurationManager.ConnectionStrings["cn"].ConnectionString;
StringBuilder stringBuilder = new StringBuilder();
for (int i = 1; i <= numberOfRecord; i++)
{
using (SqlConnection cn = new SqlConnection(connectionString))
{
if (cn.State == System.Data.ConnectionState.Closed)
cn.Open();
using (SqlCommand cmd = new SqlCommand($"select ProductName from Products where ProductID={i}", cn))
{
using (SqlDataReader reader = cmd.ExecuteReader())
{
if (reader.Read())
stringBuilder.AppendFormat("{0}: {1}\n", i, reader.GetString(0));
}
}
}
}
System.IO.File.AppendAllText($"{Application.StartupPath}\\data.txt", stringBuilder.ToString());
}Using AppendFormat of StringBuilder instead of Append method.
