Performance counters in SqlClient
Applies to: 
.NET Framework 
.NET Core
.NET Standard
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.
| Performance counter | Description |
|---|---|
HardConnectsPerSecond |
The number of connections per second that are being made to a database server. |
HardDisconnectsPerSecond |
The number of disconnects per second that are being made to a database server. |
NumberOfActiveConnectionPoolGroups |
The number of unique connection pool groups that are active. This counter is controlled by the number of unique connection strings that are found in the AppDomain. |
NumberOfActiveConnectionPools |
The total number of connection pools. |
NumberOfActiveConnections |
The number of active connections that are currently in use. Note: This performance counter is not enabled by default. To enable this performance counter, see Activate off-by-default counters. |
NumberOfFreeConnections |
The number of connections available for use in the connection pools. Note: This performance counter is not enabled by default. To enable this performance counter, see Activate off-by-default counters. |
NumberOfInactiveConnectionPoolGroups |
The number of unique connection pool groups that are marked for pruning. This counter is controlled by the number of unique connection strings that are found in the AppDomain. |
NumberOfInactiveConnectionPools |
The number of inactive connection pools that have not had any recent activity and are waiting to be disposed. |
NumberOfNonPooledConnections |
The number of active connections that are not pooled. |
NumberOfPooledConnections |
The number of active connections that are being managed by the connection pooling infrastructure. |
NumberOfReclaimedConnections |
The number of connections that have been reclaimed through garbage collection where Close or Dispose was not called by the application. Note Not explicitly closing or disposing connections hurts performance. |
NumberOfStasisConnections |
The number of connections currently awaiting completion of an action and which are therefore unavailable for use by your application. |
SoftConnectsPerSecond |
The number of active connections being pulled from the connection pool. Note: This performance counter is not enabled by default. To enable this performance counter, see Activate off-by-default counters. |
SoftDisconnectsPerSecond |
The number of active connections that are being returned to the connection pool. Note: This performance counter is not enabled by default. To enable this performance counter, see Activate off-by-default counters. |
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.
Note
This example uses the sample AdventureWorks database. The connection strings provided in the sample code assume that the database is installed and available on the local computer, and that you have created logins that match those supplied in the connection strings. You may need to enable SQL Server logins if your server is configured using the default security settings which allow only Windows Authentication. Modify the connection strings as necessary to suit your environment.
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>;";
}
}
}