is_valid_utf8_4postgres.sql

// from https://stackoverflow.com/a/45537886/8591480
CREATE FUNCTION is_valid_utf8(bytea) RETURNS boolean
   LANGUAGE plpgsql AS
$$BEGIN
   PERFORM convert_from($1, 'UTF8');
   RETURN TRUE;
EXCEPTION
   WHEN character_not_in_repertoire THEN
      RAISE WARNING '%', SQLERRM;
      RETURN FALSE;
END;$$;