Why Caching A DataBase Connection Is A Bad Idea

While caching data in the Application or Session object can be a good idea, caching database connections is usually a bad one.  Take for example the Connection object, if you store a connection in a Session object, you no longer have the benefit of connection pooling. Connection pooling is beneficial when connections are shared across multiple clients and resources are in use only as long as they are needed i.e. If the Connection object is stored in the ASP Session object, then a database connection will be created for every user. Similarly, if one Connection object is stored in the Application object and used on all pages, then all pages will contend for use of this connection. This puts unnecessarily high stress on both the Web server and the database.

Instead of caching database connections, create and destroy ADO objects on every ASP page that uses ADO. This is efficient because IIS has database connection pooling built in. More accurately, IIS automatically enables OLEDB and ODBC connection pooling. This ensures that creating and destroying connections on each page will be efficient.

Since connected recordsets store a reference to a database connection, it follows that you should not cache connected recordsets in the Application or Session objects. However, you can safely cache disconnected recordsets, which don't hold a reference to their data connection. To disconnect a recordset, take the following two steps:

Set rs = Server.CreateObject("ADODB.RecordSet")
rs.CursorLocation = adUseClient  ' step 1

' Populate the recordset with data
rs.Open strSQL, strProv

' Now disconnect the recordset from the data provider and data source
rs.ActiveConnection = Nothing    ' step 2