Description
   Loads a shared library file into the PostgreSQL backend's address
   space.  If the file had been loaded previously, it is first
   unloaded.  This command is primarily useful to unload and reload a
   shared library file that has been changed since the backend first
   loaded it.  To make use of the
   shared library, function(s) in it need to be declared using the CREATE FUNCTION command.
  
   The file name is specified in the same way as for shared library
   names in CREATE FUNCTION; in particular, one
   may rely on a search path and automatic addition of the system's standard
   shared library file name extension.  See the
   Programmer's Guide for more detail.