Question

I am getting this error on my website:

Timeout expired. The timeout period elapsed prior to obtaining a
connection from the pool. This may have occurred because all pooled
connections were in use and max pool size was reached.

Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Timeout expired.
The timeout period elapsed prior to obtaining a connection from the
pool. This may have occurred because all pooled connections were in
use and max pool size was reached.

This is the C# class that is being reused everywhere (I think the leak is here):

public class Generator
{

SqlConnection cn = null; // new SqlConnection(connectionString);

    public SqlConnection Connection {
        get {
            if (cn == null) {
            cn = new SqlConnection("Server=xxxxx,1433;Database=xxxxx;User ID=xxxxx;Password=xxxxx;Trusted_Connection=False;Encrypt=True;");
            }
            if(cn.State != ConnectionState.Open)
                cn.Open();

            return cn;
        }
    }

}

Then in my methods I use it like this:

        var cmd = _generator.Connection.CreateCommand();
        cmd.CommandText = "SELECT * FROM SomeTable";
        var reader = cmd.ExecuteReader();

        while (reader.Read())
        {
            //DO SOMETHING
        }
        reader.Close();

EDIT: In the class of my methods I attempt to share the same SQL connection across multiple methods like this:

private Generator _generator;

public HomeController()
{
    InitializeConnection();
}

private void InitializeConnection()
{
    _generator = new Generator();
}

Can anyone see how I can fix the leak or what is causing my max pool issue?

Answer 1

You need using blocks to make sure the objects are disposed.

using (var cmd = _generator.Connection.CreateCommand()) {
    cmd.CommandText = "SELECT * FROM SomeTable";
    using (var reader = cmd.ExecuteReader()) {

            while (reader.Read())
            {
                //DO SOMETHING
            }
    }
}

I also wouldn’t use a Connection property. It’s better to open and close connections as needed and allow connection pooling to do its job.