Database connection release problems

Database connection release problems

" Timeout expired. Timeout period has expired, but has yet to get a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached. "

A look is the database connection pool is full, it should be no reason for the release of the open, but I have to use the Connection object using timely released, how will this happen? It took a long time and finally to reason, so write down the record it.

Extended Tips:

- connections SQL database query the database directly executable :() 
the SELECT  [ dec ] .client_net_address,
 [ des ] . [ Program_name ] ,
 [ des ] . [ Host_name ] ,
 the Count ( [ dec ] .session_id) AS the connection_count
 the FROM SYS .dm_exec_sessions the AS  [ des ] 
the INNER  the JOIN sys.dm_exec_connections the AS  [ On Dec ] 
the ON  [ des ].session_id = [dec].session_id
GROUP BY [dec].client_net_address,
[des].[program_name],
[des].[host_name]
ORDER BY [des].[program_name],
[dec].[client_net_address]

 

Item code:

//创建连接对象的工厂类
public class ConnectionFactory
{
　　private static readonly string connString = ConfigurationManager.ConnectionStrings["SQLServerDatabase"].ConnectionString;
　　public static IDbConnection CreateConnection()
　　{
　　　　IDbConnection conn = new SqlConnection(connString);
　　　　conn.Open();
　　　　return conn;
　　}
}
//UserInfoDAL类
public class UserInfoDAL:IDAL.IUserInfoDAL
{
　　private IDbConnection _conn;
　　public IDbConnection Conn
　　{
　　　　get
　　　　{
　　　　　　//工厂实例化一个连接对象
　　　　　　return _conn = ConnectionFactory.CreateConnection();
　　　　}
　　}
　　//根据id获取entity
　　public UserInfo GetEntity(string id)
　　{
　　　　using (Conn)
　　　　{
　　　　　　string query = "select * from UserInfo where UserInfo_id = @UserInfo_id";
　　　　　　//使用dapper
　　　　　　return userInfo = Conn.Query<UserInfo>(query, new { UserInfo_id = id }).SingleOrDefault();
　　　　}
　　}
}

 

 

Code is basically a form of the above, it seems there is nothing wrong with it. Here's to debug it.
First create a unit test:

[TestMethod]
public void TestConnectionCount()
{
    SQLServerDAL.UserInfoDAL userInfoDAL = new SQLServerDAL.UserInfoDAL();
    Model.UserInfo userInfo = userInfoDAL.GetEntity("3");
    userInfo = userInfoDAL.GetEntity("3");
    userInfo = userInfoDAL.GetEntity("3");
    userInfo = userInfoDAL.GetEntity("3");
}

　　

 

The reason is because the discovery of improper use get, they simply do not get the current solutions:

public class UserInfoDAL:IDAL.IUserInfoDAL
{
    public IDbConnection Conn;
    public UserInfo GetEntity(string id)
    {
        using (Conn=ConnectionFactory.CreateConnection())
        {
        string query = "select * from UserInfo where UserInfo_id = @UserInfo_id";
        return Conn.Query<UserInfo>(query, new { UserInfo_id = id }).SingleOrDefault();
        }
    }
}