fix: Return the link to the connection pool after the node execution is completed (#3919)

Author: shaohuzhang1

apps/application/flow/workflow_manage.py

@@ -14,7 +14,7 @@
 from functools import reduce
 from typing import List, Dict
 
-from django.db import close_old_connections
+from django.db import close_old_connections, connection
 from django.db.models import QuerySet
 from django.utils import translation
 from django.utils.translation import get_language
@@ -569,6 +569,8 @@ def hand_event_node_result(self, current_node, node_result_future):
             return None
         finally:
             current_node.node_chunk.end()
+            # 归还链接
+            connection.close()
 
     def run_node_async(self, node):
         future = executor.submit(self.run_node, node)