In this recipe, we will explain how to enable an installed module so that it can be used in a particular database. The additional types, functions, and so on will exist only in those databases where we have carried out this step.
Although most modules require this procedure, there are actually a couple of notable exceptions. For instance, the auto_explain module mentioned earlier, which is shipped together with PostgreSQL, does not create any function, type, or operator. To use it, you must load its object file using the LOAD command. From that moment, all statements longer than a configurable threshold will be logged together with their execution plan. In the rest of this recipe, we will cover all the other modules. They do not require a LOAD statement, because PostgreSQL can automatically load the relevant libraries when they are required.
As mentioned...