.net connection pooling

问题

I don't get what is the syntax difference between regular connection and connection pool.

When I'm using the using key such as:

using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    command.ExecuteNonQuery();
}

Is this the way to perform a connection pool?

回答1:

You can read about connection pooling here.

Basically as long as the connection string is the same (including case), connections will be taken from the same connection pool.

回答2:

You do not control the connection pool with connections but with the connection string. Most ADO providers use pooling per default.

The using statement is used to call the Dispose method of the object (in this case the connection class). By doing so, the connection is either returned to the pool or being disconnected depending of the connection string configuration.

You should also be aware of that connections are not returned to the pool directly if distributed transactions are being used (TransactionScope in .Net 4). The connections are returned when the transaction have been completed/rolled back.

If you are not using using, you should make sure that you call Connection.Close() as soon as possible. Especially if your application is under some form of load.

回答3:

The management of connection pool is abstracted away from you using SqlConnection like in the above. By default in ADO.NET connection pool is turn on and you can further control that such as turning it off or controlling the pool size in the connection string e.g.

Turn off

Provider=SQLOLEDB;Data Source=localhost;Integrated Security=SSPI;Pooling=false;

or controlling min and max

Provider=SQLOLEDB;Data Source=localhost;Integrated Security=SSPI;Min Pool Size=5; Max Pool Size=20;

More details explanation and way to verify the pool http://www.codeproject.com/KB/dotnet/ADONET_ConnectionPooling.aspx

回答4:

as far as i know,

connection pooling is managed by ado.net client, since making connections to db is costly operation. ado.net makes pool of connections and whenever you need a connection it tries to give it from pool. even if you say to client code to close connection, ado.net hold that connection for later use. you dont manage the pooling

connection pool is told in web.config file of application. when you use using statements , you tell that object should be disposed end of using.

回答5:

Connection Pooling means once the connection object is opened then rather then going and recreating the connection again and again Ado.Net stores or cache the connection object in Pooler. Later if somebody going to opens the connection then it will not go the series of steps it already did , now it simply pic the connection from connection pool where it cached already.

Once we finished operations on database we need to Close the connection then that connection will be returned to the pool and its ready to be reused on the next Open call.

Read more with best example of connection pooling :- http://www.gurujipoint.com/2017/07/what-is-connection-pooling-in-aspnet.html