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
36957	Django psycopg connection pool + fork()	Anna		"Django's PostgreSQL backend stores `psycopg_pool.ConnectionPool` objects in a class-level dict (`DatabaseWrapper._connection_pools`). When gunicorn (or any pre-forking server) forks worker processes, all children inherit references to the same pool objects — and crucially, the same underlying TCP sockets to PostgreSQL. Multiple workers then read/write the same socket concurrently, corrupting the PostgreSQL wire protocol.


**Root cause**

{{{
# django/db/backends/postgresql/base.py
class DatabaseWrapper(BaseDatabaseWrapper):
    _connection_pools = {}   # class-level dict — survives fork()

    @property
    def pool(self):
        if self.alias not in self._connection_pools:
            pool = ConnectionPool(...)
            self._connection_pools.setdefault(self.alias, pool)
        return self._connection_pools[self.alias]
}}}

**Workaround**

{{{
# gunicorn.conf.py
def post_fork(server, worker):
    from django.db.backends.postgresql.base import DatabaseWrapper
    DatabaseWrapper._connection_pools.clear()
}}}

**Suggested fix**
Use `os.register_at_fork(after_in_child=...)` to clear `_connection_pools` in child processes, or check `os.getpid()` in the `pool` property and recreate when it differs from the creating process.

**Tested with**
Django 6.0.2
psycopg 3.2.x – 3.3.2
psycopg-pool 3.2.x – 3.3.0
gunicorn 25.x (--worker-class asgi)
Python 3.12 – 3.14

The minimal reproducible example project is in the attachments

"	Bug	new	Uncategorized	6.0	Normal				Unreviewed	0	0	0	0	0	0