Understanding how extensions work

Before digging into the extensions available out there, it is a good idea to take a look at how extensions work in the first place. Understanding the inner workings of the extension machinery can be quite beneficial.

Let's take a look at the syntax first:

test=# \h CREATE EXTENSION
Command:   CREATE EXTENSION
Description: Install an extension
Syntax:
CREATE EXTENSION [ IF NOT EXISTS ] extension_name
[ WITH ] [ SCHEMA schema_name ]
[ VERSION version ]
[ FROM old_version ]
[ CASCADE ]

When you want to deploy an extension, simply call the CREATE EXTENSION command. It will check for the extension and load it into your database. Note that the extension will be loaded into a database and not into the entire database instance.

If you are loading an extension, you can decide on the schema you want to use. Many extensions can be relocated so the user has the choice of which schema to use. Then, it is possible to decide on a specific version of the extension. Often, you...