Connection pooling enables your .NET application to use a connection from a pool of connections that do not need to be restablised each time. Once a connection with a particular connection string has been created it is placed in a pool and an application can reuse that connection without opening a connection all over again. So that when a user requests a connection it is returned from the set of pooled connections rather than a new connection being established. Similarly whenever a connection is closed, it is returned to the pool as opposed to being released.
Note: Connection pooling only works when you use the same connection string each time. If the connection string is different, then a new connection will be opened and hence connection pooling will not be used.
When establishing a connection, one of the parameters which can be modified is if connection pooling is enabled or not. By default all ADO.NET Data Providers automatically have connection pooling enabled. If you explicitly want to enable or disable connection pooling you should set Pooling=true/false in your connection string.
string connectionString = "Server=10.90.1.29;Port=5444;User Id=edb;Password=edb;Database=test;Pooling=false"