Esta pode ser uma sugestão, de uma das páginas da Web que você listou acima:
Many modules supply new user-defined functions, operators, or types. To make use of one of these modules, after you have installed the code you need to register the new objects in the database system by running the SQL commands in the .sql file supplied by the module. For example,
psql -d dbname -f SHAREDIR/contrib/module.sql