If I wrote something in plperlu, when would that module be reloaded? Every time the function ran? The first time it ran? Does the Perl DLL get unloaded if it hasn\'t been
I think the module will be loaded once for each server process (i.e. new session / connection) on the first use of that language within that session.
You can preload them to avoid any delay on first use, per the manual for shared_preload_libraries and local_preload_libraries.
Old PostgreSQL versions just had a single preload_libraries
setting; see the manual for your version if you're on something very old.