This blog entry will attempt to explain the effect on datasource connection pooling in ColdFusion MX when using unique username and password combinations passed through the CFQuery tag, often a requirement for databases configured for User-based Security. In this case the username/password combination often comes directly from end user logins on the application.

Normal Usage and Starting a Connection Pool
To provide a little background of normal circumstances, most ColdFusion users configure JDBC datasources to use datasource connection pooling by enabling the check box for "Maintain Connections" in the datasource detail page within the ColdFusion Administrator. This page accepts a single username/password combination when setting up the datasource. Connection pooling will cause new database connections created for that datasource to be added to a datasource connection pool for reuse later by another request.