django.db.utils.OperationalError: server closed the connection unexpectedly

Question

Not able to solve what is the error.

django.db.utils.OperationalError: server closed the connection unexpectedly
    This probably means the server terminated abnormally
    before or while processing the request.

I keep on getting the Trace when i run any of the command below

python manage.py makemigrations
python manage.py runserver

Unhandled exception in thread started by <function wrapper at     0x0000000003DAC4A8>
Traceback (most recent call last): File "C:\Python27\lib\site-packages\django\utils\autoreload.py", line 226, in wrapper fn(*args, **kwargs)
    File "C:\Python27\lib\site packages\django\core\management\commands\runserver.py", line 124, in inner_run
    self.check_migrations()
  File "C:\Python27\lib\site-packages\django\core\management\base.py", line 437, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
    File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 20, in __init__
    self.loader = MigrationLoader(self.connection)
    File "C:\Python27\lib\site-packages\django\db\migrations\loader.py", line 52, in __init__
    self.build_graph()
    File "C:\Python27\lib\site-packages\django\db\migrations\loader.py", line 203, in build_graph
    self.applied_migrations = recorder.applied_migrations()
    File "C:\Python27\lib\site-packages\django\db\migrations\recorder.py", line 65, in applied_migrations
    self.ensure_schema()
    File "C:\Python27\lib\site-packages\django\db\migrations\recorder.py", line 52, in ensure_schema
    if self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor()):
    File "C:\Python27\lib\site-packages\django\db\backends\base\base.py", line 231, in cursor
    cursor = self.make_debug_cursor(self._cursor())
    File "C:\Python27\lib\site-packages\django\db\backends\base\base.py", line 204, in _cursor
    self.ensure_connection()
    File "C:\Python27\lib\site-packages\django\db\backends\base\base.py", line 199, in ensure_connection
    self.connect()
    File "C:\Python27\lib\site-packages\django\db\utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
    File "C:\Python27\lib\site-packages\django\db\backends\base\base.py", line 199, in ensure_connection
    self.connect()
    File "C:\Python27\lib\site-packages\django\db\backends\base\base.py", line 171, in connect
    self.connection = self.get_new_connection(conn_params)
    File "C:\Python27\lib\site-packages\django\db\backends\postgresql\base.py", line 176, in get_new_connection
    connection = Database.connect(**conn_params)
    File "C:\Python27\lib\site-packages\psycopg2\__init__.py", line 164, in connect
    conn = _connect(dsn, connection_factory=connection_factory, async=async)
django.db.utils.OperationalError: server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.

Thanks in advance.

DATABASES = { 'default': { 'ENGINE': 'django.db.backends.postgresql_psycopg2', 'NAME': 'dab_name', 'USER': 'my_user_name', 'PASSWORD': 'my_password', 'HOST': 'ec2-54-225-242.compute-1.amazonaws.com', 'PORT': '5432', } } — Arnold Laishram, Nov 17 '16 at 04:39
This error seems also to occur when having long running tasks (4h) with DB operations at the beginning at and the end. Any idea how to overcome this? — Matthias Lohr, Dec 19 '20 at 10:49

azalea · Answer 1 · 2017-07-17T15:52:59.337

1

This usually means that your PostgreSQL server is not running properly. You may want to restart it by

Linux

sudo /etc/init.d/postgresql restart

Windows

sc stop postgresql
sc start postgresql

Mac OS X

How to start PostgreSQL server on Mac OS X?

If restart fixes it, note that the root cause of the previous server failure still needs investigation.

edited Jul 17 '17 at 15:52

answered Jul 17 '17 at 15:44

azalea

11,402
3
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score 0 · Answer 2 · answered Dec 03 '20 at 14:47

0

I solved this problem uninstalling and installing postgresql again.

On Mac

Uninstall:

brew uninstall --force postgres

Install:

brew install postgres

PS: Change commands for Linux or Windows.

After, run makemigrations and migrate.

answered Dec 03 '20 at 14:47

André Henrique Mendes

477
6
11

score 0 · Answer 3 · answered Mar 18 '21 at 16:02

Happens when a process forks and connection established in parent process don't work in child processes.

I was using huggingface/tokenizers and BERT to get sentence embeddings and then inserting those into a Postgres database. The database connection was getting established first and then the tokenizer was forking which resulted in the same django.db.utils.OperationalError.

I solved it by disabling TOKENIZER_PARALLELISM. Though for your issue, upgrading to a higher version of Django might help as mentioned here.

django.db.utils.OperationalError: server closed the connection unexpectedly

3 Answers3