Managing installed extensions

In the previous two recipes, we showed you how to install external modules in PostgreSQL to augment its capabilities.

In this recipe, we will show you some more capabilities that are offered by the extension infrastructure.

How to do it…

Here are the steps to manage extensions:

1. First, we list all the available extensions:

   postgres=# \x on
   Expanded display is on.
   postgres=# SELECT *
   postgres-# FROM pg_available_extensions
   postgres-# ORDER BY name;
   -[ RECORD 1 ]-----+-----------------------------------
   name              | adminpack
   default_version   | 2.1
   installed_version |
   comment           | administrative functions for PostgreSQL
   (...)
   -[ RECORD 28 ]----+-----------------------------------
   name              | pg_stat_statements
   default_version   | 1.10
   installed_version |
   comment           | track planning and execution statistics of all SQL statements executed
   (...)
   

   In particular, if the dblink extension is...