django-traceback-in-sql 0.2.2

Contextmanager for annotation the relevant stack trace to SQL queries as a comment

django-traceback-in-sql

Annotates the stacktrace into the SQL query as a comment at runtime. Helpful for tracking down where queries are ran from within code, for example for analysing query counts in unit tests when trying to prevent N+1s.

Compatibility

• Python 3.9–3.13
• Django 4.2, 5.2
• SQLite, PostgreSQL, MySQL

Quick Examples

Find N+1 queries in Django unit tests

from django.contrib.auth import get_user_model
from django.test import TestCase
from sql_traceback import sql_traceback


User = get_user_model()


class Test(TestCase):
    def test_something(self):
        with sql_traceback(), self.assertNumQueries(0):
            _ = User.objects.count()

If the assert gets triggered, you will see something like the following output:

E   AssertionError: 1 != 0 : 1 queries executed, 0 expected
E   Captured queries were:
E   1. SELECT COUNT(*) AS `__count` FROM `auth_user`
E   /*
E   STACKTRACE:
E   # /path/to/tests/test_test_test.py:12 in test_something
E   */

In pytest-django tests

The above equivalent would look like so

import pytest
from django.contrib.auth import get_user_model
from sql_traceback import sql_traceback


User = get_user_model()


@pytest.mark.django_db
def test_something(django_assert_num_queries):
    with sql_traceback(), django_assert_num_queries(0):
        _ = User.objects.count()

and when pytest is ran with the -v flag, you will see the following in the output

E               Queries:
E               ========
E
E               SELECT COUNT(*) AS `__count` FROM `auth_user`
E               /*
E               STACKTRACE:
E               # /path/to/tests/tests/test_test_test.py:12 in test_something
E               */

As a context manager

from django.db import connection
from sql_traceback import sql_traceback
from services import get_user_count

with sql_traceback():
    get_user_count()

print(connection.queries[-1]['sql'])

Should print output

SELECT COUNT(*) AS "__count" FROM "auth_user"
/*
STACKTRACE:
# /path/to/project/services.py:5 in get_user_count
*/

As a decorator

from sql_traceback import SqlTraceback

@SqlTraceback()
def get_users():
    return User.objects.filter(is_active=True)

Configuration

Optional settings in your Django settings.py:

SQL_TRACEBACK_ENABLED = True                      # Enable/disable stacktracing (default: True)
SQL_TRACEBACK_MAX_FRAMES = 15                     # Max number of stack frames (default: 15)
SQL_TRACEBACK_FILTER_SITEPACKAGES = True          # Filter out third-party packages (e.g., **django**, requests, pluggy, etc.) (default: True)
SQL_TRACEBACK_FILTER_TESTING_FRAMEWORKS = True    # Filter out pytest/unittest frames (pytest + unittest) (default: True)
SQL_TRACEBACK_FILTER_STDLIB = True                # Filter out Python standard library frames (e.g., threading, contextlib, etc.) (default: True)
SQL_TRACEBACK_MIN_APP_FRAMES = 1                  # Minimum application frames required (default: 1)