foo=# create function pllua_init() returns void language pllua_ng as $$
print('foobar')
$$;
CREATE FUNCTION
Time: 3.495 ms
foo=# alter database foo set pllua_ng.on_init = 'spi.execute([[ select pllua_init() ]])';
ALTER DATABASE
Time: 10.375 ms
foo=# \q
$ /opt/postgres-10.1/bin/psql foo
psql (10.1)
Type "help" for help.
foo=# do language plluau_ng $$ print('foobar') $$;
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
Time: 152.826 ms
?!>