## 18.3. Installing Additional Supplied Modules

PostgreSQL comes with a set of additional server extensions, or modules. On Linux, these extensions are provided in the `postgrespro-contrib` package. On Windows, these extensions are installed together with the server components.

Once you have the binary files installed, you have to enable additional extensions in the database in order to use them. In most cases, you only need to issue the CREATE EXTENSION command. However, some extensions also require shared libraries to be preloaded on server startup. If you want to use such extensions, you need to configure parameter

    shared_preload_libraries = 'lib1, lib2, lib3'

in the `postgresql.conf` file of your PostgreSQL database instance and restart the server before executing the `CREATE EXTENSION` statement.

For the exact installation and configuration instructions for each particular extension, see the corresponding documentation under Appendix F.

To get the list of extensions available in your PostgreSQL installation, you can view the `pg_available_extensions` system catalog.