Extensions are add-ons that you can install in a PostgreSQL database to extend the functionality beyond the basic offering. You can find a list of PostgreSQL extensions available on the PostgreSQL Extension Network website, http://www.pgxn.org/. The OpenShift PostgreSQL cartridge comes in a bundle with a list of extensions. These extensions are not installed by default but are available to you if you need them. In this recipe, you will learn how to install an extension in your OpenShift PostgreSQL cartridge.
To complete this recipe, you will need an application with the PostgreSQL cartridge. Please refer to the Adding the PostgreSQL cartridge to your application recipe in this chapter to learn how to add the PostgreSQL cartridge to your application.