 
         # quick check for write query against read-only connection
         if @is_standby and (opts.set? or opts.jsonb_set? or opts.jsonb_merge?)
-            opts.cb("set queries against standby not allowed")
+            opts.cb?("set queries against standby not allowed")
             return
 
         if opts.retry_until_success

                cb       : (err) =>
                    if err
                        dbg("FAILED to connect -- #{err}")
                        opts.cb("database is down (please try later)")
                    else
                        dbg("connected, now doing query")
                        @__do_query(opts)

        # calls the original cb.
        retry_opts.cb = (err) =>
            if err
                orig_cb?(err)
            else
                orig_cb?(args...)

        # OK, now start it attempting.
        misc.retry_until_success(retry_opts)
