id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 36263 DB connection is not recreated after it closed due to time out. Sivakajan Sivaparan "**Issue Faced**: When executing a query after a database connectivity loss (lasting more than 6 minutes), Django is unable to recreate a new connection automatically. This issue persists even when using `connection.cursor()`, saving a model instance (`model.save()`), or explicitly calling `connection.ensure_connection()`. However, if the connection is explicitly closed using `connection.close()`, Django successfully establishes a new connection to the database. {{{ The above exception was the direct cause of the following exception: Traceback (most recent call last): File ""/home/ubuntu/environment/db_tester/my_tester/views.py"", line 20, in insert_model new_model.save() File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 892, in save self.save_base( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 998, in save_base updated = self._save_table( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 1161, in _save_table results = self._do_insert( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 1202, in _do_insert return manager._insert( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/manager.py"", line 87, in manager_method return getattr(self.get_queryset(), name)(*args, **kwargs) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/query.py"", line 1847, in _insert return query.get_compiler(using=using).execute_sql(returning_fields) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/sql/compiler.py"", line 1836, in execute_sql cursor.execute(sql, params) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 122, in execute return super().execute(sql, params) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 79, in execute return self._execute_with_wrappers( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 92, in _execute_with_wrappers return executor(sql, params, many, context) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 100, in _execute with self.db.wrap_database_errors: File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/utils.py"", line 91, in __exit__ raise dj_exc_value.with_traceback(traceback) from exc_value File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 105, in _execute return self.cursor.execute(sql, params) django.db.utils.OperationalError: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. [2025-03-18 11:34:35] ERROR my_tester.views: Database connection failed on 11:34:35 Traceback (most recent call last): File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/base/base.py"", line 298, in _cursor return self._prepare_cursor(self.create_cursor(name)) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/utils/asyncio.py"", line 26, in inner return func(*args, **kwargs) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/postgresql/base.py"", line 429, in create_cursor cursor = self.connection.cursor() psycopg2.InterfaceError: connection already closed }}} Even if it says, `connection already closed`, I can not create a new healthy connection. If I call close() function and continue, it create a new connection form `connection.cursor()`. **Recreate the Issue**: {{{ from django.db import connection from django.db.utils import OperationalError from my_tester.models import SimpleModel import time import logging logger = logging.getLogger(__name__) def insert_model(request): logger.info(f""======== Function triggered on:{time.strftime('%H:%M:%S')} "") model_name_suffix = int(round(time.time() * 1000)) query = ""INSERT INTO my_tester_simplemodel (model_name, model_description) VALUES (%s, %s);"" for _ in range(200): try: check_connection(_) new_model = SimpleModel(model_name=f""model_{model_name_suffix}_{_}"", model_description=""model_description"") new_model.save() check_connection(_) logger.info(f""Inserted: model_{model_name_suffix}_{_} on {time.strftime('%H:%M:%S')}"") time.sleep(10) except Exception as e: logger.error(f""Database connection failed on {time.strftime('%H:%M:%S')}"", exc_info=True) # connection.close() time.sleep(10) logger.info(f""+++++++++ Function end on:{time.strftime('%H:%M:%S')}"") return ""Models added successfully"" def check_connection(iterr): try: if connection.connection is not None: logger.info(f""Database connection is established {iterr} on {time.strftime('%H:%M:%S')}"") else: logger.info(f""Database connection is not established {iterr} on {time.strftime('%H:%M:%S')}"") except: logger.error(f""Connection checker {iterr} error on {time.strftime('%H:%M:%S')}"") }}} In the above code set, I am sending a number of queries in a 10sec time interval. While the queries getting execute, I stop the connection between the Django app and the DB.( I created the application in the cloud9 instance and DB in the AWS RDS, both with the same security group. I can change the inbound rules of the SG and control the connectivity). When stop the connection, the app will wait for nearly 6mins( maybe the default idle session time). After that interval, it will throws the exception as I given above. It continuously throws the exception every 10 sec. Then I enable the connection, still the django/ensure_connection is not creating a fresh connection at all. {{{ [2025-03-18 08:28:59] INFO my_tester.views: ======== Function triggered on:08:28:59 [2025-03-18 08:28:59] INFO my_tester.views: Database connection is not established 0 on 08:28:59 [2025-03-18 08:28:59] INFO my_tester.views: Database connection is established 0 on 08:28:59 [2025-03-18 08:28:59] INFO my_tester.views: Inserted: model_1742286539377_0 on 08:28:59 [2025-03-18 08:29:09] INFO my_tester.views: Database connection is established 1 on 08:29:09 [2025-03-18 08:29:09] INFO my_tester.views: Database connection is established 1 on 08:29:09 [2025-03-18 08:29:09] INFO my_tester.views: Inserted: model_1742286539377_1 on 08:29:09 [2025-03-18 08:29:19] INFO my_tester.views: Database connection is established 2 on 08:29:19 [2025-03-18 08:29:19] INFO my_tester.views: Database connection is established 2 on 08:29:19 [2025-03-18 08:35:09] ERROR my_tester.views: Database connection failed on 08:35:09 [2025-03-18 08:35:19] INFO my_tester.views: Database connection is established 3 on 08:35:19 [2025-03-18 08:37:34] ERROR my_tester.views: Database connection failed on 08:37:34 [2025-03-18 08:37:44] INFO my_tester.views: Database connection is established 4 on 08:37:44 [2025-03-18 08:39:58] ERROR my_tester.views: Database connection failed on 08:39:58 [2025-03-18 08:40:08] INFO my_tester.views: Database connection is established 5 on 08:40:08 [2025-03-18 08:42:21] ERROR my_tester.views: Database connection failed on 08:42:21 [2025-03-18 08:42:31] INFO my_tester.views: Database connection is established 6 on 08:42:31 [2025-03-18 08:44:44] ERROR my_tester.views: Database connection failed on 08:44:44 [2025-03-18 08:44:54] INFO my_tester.views: Database connection is established 7 on 08:44:54 [2025-03-18 08:47:08] ERROR my_tester.views: Database connection failed on 08:47:08 }}} You can see, the `connection.connection` is not None in every iteration. In the middle of the execution, I reconnect the DB also. But no changes at all. When I comment out the `connection.close()` in the code, then execute, {{{ [2025-03-18 15:08:33] INFO my_tester.views: ======== Function triggered on:15:08:33 [2025-03-18 15:08:33] INFO my_tester.views: Database connection is not established 0 on 15:08:33 [2025-03-18 15:08:33] INFO my_tester.views: Database connection is established 0 on 15:08:33 [2025-03-18 15:08:33] INFO my_tester.views: Inserted: model_1742310513542_0 on 15:08:33 [2025-03-18 15:08:43] INFO my_tester.views: Database connection is established 1 on 15:08:43 [2025-03-18 15:08:43] INFO my_tester.views: Database connection is established 1 on 15:08:43 [2025-03-18 15:08:43] INFO my_tester.views: Inserted: model_1742310513542_1 on 15:08:43 [2025-03-18 15:08:53] INFO my_tester.views: Database connection is established 2 on 15:08:53 [2025-03-18 15:14:43] ERROR my_tester.views: Database connection failed on 15:14:43 Traceback (most recent call last): File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 105, in _execute return self.cursor.execute(sql, params) psycopg2.OperationalError: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. The above exception was the direct cause of the following exception: Traceback (most recent call last): File ""/home/ubuntu/environment/db_tester/my_tester/views.py"", line 19, in insert_model new_model.save() File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 892, in save self.save_base( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 998, in save_base updated = self._save_table( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 1161, in _save_table results = self._do_insert( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/base.py"", line 1202, in _do_insert return manager._insert( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/manager.py"", line 87, in manager_method return getattr(self.get_queryset(), name)(*args, **kwargs) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/query.py"", line 1847, in _insert return query.get_compiler(using=using).execute_sql(returning_fields) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/models/sql/compiler.py"", line 1836, in execute_sql cursor.execute(sql, params) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 122, in execute return super().execute(sql, params) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 79, in execute return self._execute_with_wrappers( File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 92, in _execute_with_wrappers return executor(sql, params, many, context) File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 100, in _execute with self.db.wrap_database_errors: File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/utils.py"", line 91, in __exit__ raise dj_exc_value.with_traceback(traceback) from exc_value File ""/home/ubuntu/.local/lib/python3.10/site-packages/django/db/backends/utils.py"", line 105, in _execute return self.cursor.execute(sql, params) django.db.utils.OperationalError: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. [2025-03-18 15:14:53] INFO my_tester.views: Database connection is not established 3 on 15:14:53 [2025-03-18 15:17:17] INFO my_tester.views: Database connection is not established 4 on 15:17:17 [2025-03-18 15:19:40] INFO my_tester.views: Database connection is not established 5 on 15:19:40 [2025-03-18 15:22:04] INFO my_tester.views: Database connection is not established 6 on 15:22:04 [2025-03-18 15:22:23] INFO my_tester.views: Database connection is established 6 on 15:22:23 [2025-03-18 15:22:23] INFO my_tester.views: Inserted: model_1742310513542_6 on 15:22:23 [2025-03-18 15:22:33] INFO my_tester.views: Database connection is established 7 on 15:22:33 [2025-03-18 15:22:33] INFO my_tester.views: Database connection is established 7 on 15:22:33 [2025-03-18 15:22:33] INFO my_tester.views: Inserted: model_1742310513542_7 on 15:22:33 }}} You can see in the command, it says `Database connection is not established 6 on 15:22:04`, which implies `connection.connection` is None that time. **Question:** It says, the connection will be closed if the pipe between the DB and the application closed. But in this scenario, it seems the connection is not closed until we explicitly close the connection. Why that happen? Also, please explain, can CONN_HEALTH_CHECK, CONN_MAX_AGE flags use to solve this type of issues. I tried with these, but no changes regarding of the CONN_HEALTH_CHECK value.(True/False)" Bug closed Database layer (models, ORM) 5.1 Normal invalid DB, Connection-close, ensure_connection Sivakajan Sivaparan Unreviewed 0 0 0 0 0 0