The use of connection pooling on certain kinds of applications can definitely degrade the performance. If your application has any of the following characteristics, it is not a suitable candidate for connection pooling:

• If an application restarts many times daily, we should avoid connection pooling because, based on the configuration of the connection pool, it may be populated with connections each time the application is started, which would cause a performance penalty up front.
• If you have single-user applications, such as applications only generating reports (in this type of application, the user only uses the application three to four times daily, for generating reports), then avoid connection pooling. The memory utilization for establishing a database connection three to four times daily is low, compared to the database connection associated with a connection pool. In such cases, configuring a connection pool degrades the overall performance of the application.
• If an application runs only batch jobs, there is no advantage to using connection pooling. Normally, a batch job is run at the end of the day or month or year, during the off hours, when performance is not as much of a concern.