Enabling WAL in SQLite in Django

Write Ahead Logging (WAL) mode is a mode that enables more concurrent writes in SQLite. I implemented this as I have a local Django app that uses SQLite, and sometimes I would get database locks when to many processes were writing at once.

Here’s how to set it up in Django:

1. Create a new file (e.g., db_signals.py) in one of your apps:

2. Add the following code to set the PRAGMA settings:

from django.db.backends.signals import connection_created
from django.dispatch import receiver

@receiver(connection_created)
def setup_sqlite_pragmas(sender, connection, **kwargs):
    if connection.vendor == 'sqlite':
        cursor = connection.cursor()
        cursor.execute('PRAGMA journal_mode=wal;')
        cursor.execute('PRAGMA busy_timeout=5000;')
        cursor.close()

3. Import this file somewhere in your application to ensure the signal is connected, such as in the ready() method of your app’s AppConfig:

from django.apps import AppConfig

class MyAppConfig(AppConfig):
    name = 'my_app'

    def ready(self):
        import my_app.db_signals

By setting up your database this way, you ensure that these PRAGMA settings are applied every time a new connection to the SQLite database is created, so you won’t need to manually set them each time.

Enjoy!