Remove the NOTIFY and LISTEN for metric emiter. No sense on using the…

…m now.

Close #3821

pulpcore/tasking/worker.py

@@ -113,8 +113,6 @@ def _signal_handler(self, thesignal, frame):
     def _pg_notify_handler(self, notification):
         if notification.channel == "pulp_worker_wakeup":
             self.wakeup = True
-        elif notification.channel == "pulp_worker_metrics_heartbeat":
-            self.last_metric_heartbeat = datetime.fromisoformat(notification.payload)
         elif self.task and notification.channel == "pulp_worker_cancel":
             if notification.payload == str(self.task.pk):
                 self.cancel_task = True
@@ -453,7 +451,7 @@ def record_unblocked_waiting_tasks_metric(self):
                     unblocked_tasks_stats["longest_unblocked_waiting_time"].seconds
                 )
 
-                self.cursor.execute(f"NOTIFY pulp_worker_metrics_heartbeat, '{str(now)}'")
+                self.last_metric_heartbeat = now
 
     def run(self, burst=False):
         with WorkerDirectory(self.name):
@@ -463,7 +461,6 @@ def run(self, burst=False):
             # Subscribe to pgsql channels
             connection.connection.add_notify_handler(self._pg_notify_handler)
             self.cursor.execute("LISTEN pulp_worker_cancel")
-            self.cursor.execute("LISTEN pulp_worker_metrics_heartbeat")
             if burst:
                 self.handle_available_tasks()
             else:
@@ -476,6 +473,5 @@ def run(self, burst=False):
                         break
                     self.sleep()
                 self.cursor.execute("UNLISTEN pulp_worker_wakeup")
-            self.cursor.execute("UNLISTEN pulp_worker_metrics_heartbeat")
             self.cursor.execute("UNLISTEN pulp_worker_cancel")
             self.shutdown()