Performance counters in SqlClient

Applies to: .NET Framework .NET Core .NET Standard

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You can use Microsoft.Data.SqlClient performance counters to monitor the status of your application and the connection resources that it uses. Performance counters can be monitored by using Windows Performance Monitor or can be accessed programmatically using the PerformanceCounter class in the System.Diagnostics namespace.

Available performance counters

Currently there are 14 different performance counters available for Microsoft.Data.SqlClient as described in the following table.

Activate off-by-default counters

The performance counters NumberOfFreeConnections, NumberOfActiveConnections, SoftDisconnectsPerSecond, and SoftConnectsPerSecond are off by default. Add the following information to the application's configuration file to enable them:

<system.diagnostics>  
  <switches>  
    <add name="ConnectionPoolPerformanceCounterDetail" value="4"/>  
    <!-- A value of 4 corresponds to System.Diagnostics.TraceLevel.Verbose -->
  </switches>  
</system.diagnostics>  

Retrieve performance counter values

The following console application shows how to retrieve performance counter values in your application. Connections must be open and active for information to be returned for all of the Microsoft SqlClient Data Provider for SQL Server performance counters.

Example

using System;
using Microsoft.Data.SqlClient;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace PerformanceCounterTest
{
    class Program
    {
        PerformanceCounter[] PerfCounters = new PerformanceCounter[10];
        SqlConnection connection = new SqlConnection();

        static void Main()
        {
            Program prog = new Program();
            // Open a connection and create the performance counters.  
            prog.connection.ConnectionString =
               GetIntegratedSecurityConnectionString();
            prog.SetUpPerformanceCounters();
            Console.WriteLine("Available Performance Counters:");

            // Create the connections and display the results.  
            prog.CreateConnections();
            Console.WriteLine("Press Enter to finish.");
            Console.ReadLine();
        }

        private void CreateConnections()
        {
            // List the Performance counters.  
            WritePerformanceCounters();

            // Create 4 connections and display counter information.  
            SqlConnection connection1 = new SqlConnection(
                  GetIntegratedSecurityConnectionString());
            connection1.Open();
            Console.WriteLine("Opened the 1st Connection:");
            WritePerformanceCounters();

            SqlConnection connection2 = new SqlConnection(
                  GetSqlConnectionStringDifferent());
            connection2.Open();
            Console.WriteLine("Opened the 2nd Connection:");
            WritePerformanceCounters();

            SqlConnection connection3 = new SqlConnection(
                  GetSqlConnectionString());
            connection3.Open();
            Console.WriteLine("Opened the 3rd Connection:");
            WritePerformanceCounters();

            SqlConnection connection4 = new SqlConnection(
                  GetSqlConnectionString());
            connection4.Open();
            Console.WriteLine("Opened the 4th Connection:");
            WritePerformanceCounters();

            connection1.Close();
            Console.WriteLine("Closed the 1st Connection:");
            WritePerformanceCounters();

            connection2.Close();
            Console.WriteLine("Closed the 2nd Connection:");
            WritePerformanceCounters();

            connection3.Close();
            Console.WriteLine("Closed the 3rd Connection:");
            WritePerformanceCounters();

            connection4.Close();
            Console.WriteLine("Closed the 4th Connection:");
            WritePerformanceCounters();
        }

        private enum ADO_Net_Performance_Counters
        {
            NumberOfActiveConnectionPools,
            NumberOfReclaimedConnections,
            HardConnectsPerSecond,
            HardDisconnectsPerSecond,
            NumberOfActiveConnectionPoolGroups,
            NumberOfInactiveConnectionPoolGroups,
            NumberOfInactiveConnectionPools,
            NumberOfNonPooledConnections,
            NumberOfPooledConnections,
            NumberOfStasisConnections
            // The following performance counters are more expensive to track.  
            // Enable ConnectionPoolPerformanceCounterDetail in your config file.  
            //     SoftConnectsPerSecond  
            //     SoftDisconnectsPerSecond  
            //     NumberOfActiveConnections  
            //     NumberOfFreeConnections  
        }

        private void SetUpPerformanceCounters()
        {
            connection.Close();
            this.PerfCounters = new PerformanceCounter[10];
            string instanceName = GetInstanceName();
            Type apc = typeof(ADO_Net_Performance_Counters);
            int i = 0;
            foreach (string s in Enum.GetNames(apc))
            {
                this.PerfCounters[i] = new PerformanceCounter();
                this.PerfCounters[i].CategoryName = ".NET Data Provider for SqlServer";
                this.PerfCounters[i].CounterName = s;
                this.PerfCounters[i].InstanceName = instanceName;
                i++;
            }
        }

        [DllImport("kernel32.dll", SetLastError = true)]
        static extern int GetCurrentProcessId();

        private string GetInstanceName()
        {
            //This works for Winforms apps.  
            string instanceName =
                System.Reflection.Assembly.GetEntryAssembly().GetName().Name;

            // Must replace special characters like (, ), #, /, \\  
            string instanceName2 =
                AppDomain.CurrentDomain.FriendlyName.ToString().Replace('(', '[')
                .Replace(')', ']').Replace('#', '_').Replace('/', '_').Replace('\\', '_');

            // For ASP.NET applications your instanceName will be your CurrentDomain's
            // FriendlyName. Replace the line above that sets the instanceName with this:  
            // instanceName = AppDomain.CurrentDomain.FriendlyName.ToString().Replace('(','[')  
            // .Replace(')',']').Replace('#','_').Replace('/','_').Replace('\\','_');  

            string pid = GetCurrentProcessId().ToString();
            instanceName = instanceName + "[" + pid + "]";
            Console.WriteLine("Instance Name: {0}", instanceName);
            Console.WriteLine("---------------------------");
            return instanceName;
        }

        private void WritePerformanceCounters()
        {
            Console.WriteLine("---------------------------");
            foreach (PerformanceCounter p in this.PerfCounters)
            {
                Console.WriteLine("{0} = {1}", p.CounterName, p.NextValue());
            }
            Console.WriteLine("---------------------------");
        }

        private static string GetIntegratedSecurityConnectionString()
        {
            // To avoid storing the connection string in your code,  
            // you can retrieve it from a configuration file.  
            return @"Data Source=.;Integrated Security=True;" +
              "Initial Catalog=AdventureWorks";
        }
        private static string GetSqlConnectionString()
        {
            // To avoid storing the connection string in your code,  
            // you can retrieve it from a configuration file.  
            return @"Data Source=.;User Id=<myUserID>;Password=<myPassword>;" +
              "Initial Catalog=AdventureWorks";
        }

        private static string GetSqlConnectionStringDifferent()
        {
            // To avoid storing the connection string in your code,  
            // you can retrieve it from a configuration file.  
            return @"Initial Catalog=AdventureWorks;Data Source=.;" +
              "User Id=<myUserID>;Password=<myPassword>;";
        }
    }
}

See also

• Event counters in SqlClient
• Connecting to a data source
• Runtime profiling
• Introduction to monitoring performance thresholds
• Microsoft ADO.NET for SQL Server