How to solve problem “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.”

How to solve problem “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.”

Reason: 

Usually do not close its associated connection when use a DataReader.

Three ways to solve:

1 SqlDataReader sdr = sCmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);

2 Explicitly close the connection

sc.Close();

3 Using block

using (SqlConnection sc = new SqlConnection(connString))

{

SqlCommand sCmd = new SqlCommand("SELECT * FROM Shippers", sc);

sc.Open();

Console.WriteLine("Conns opened " + i.ToString());

SqlDataReader sdr = sCmd.ExecuteReader();

sdr.Close();

}