The Fix
pip install celery==4.4.2
Based on closed celery/celery issue #6019 · PR/commit linked
Production note: This usually shows up under retries/timeouts. Treat it as a side-effect risk until you can verify behavior with a canary + real traffic.
@@ -39,7 +39,9 @@ def get_engine(self, dburi, **kwargs):
return engine
else:
- return create_engine(dburi, poolclass=NullPool)
+ kwargs = dict([(k, v) for k, v in kwargs.items() if
+ not k.startswith('pool')])
repro.py
from airflow.models import DagRun
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
e = create_engine({AIRFLOW__CELERY__SQL_ALCHEMY_CONN},connect_args= {'ssl': {'ca': '/path-to-mysql-sslcert/server-ca', 'cert': '/path-to-mysql-sslcert/client-cert', 'key': '/path-to-mysql-sslcert/client-key'}})
s = scoped_session(sessionmaker(autocommit=False, autoflush=False, bind=e))
s.query(DagRun).all()
verify
Re-run the minimal reproduction on your broken version, then apply the fix and re-run.
fix.md
Option A — Upgrade to fixed release\npip install celery==4.4.2\nWhen NOT to use: Do not use this fix if you require pooling parameters to be passed to create_engine().\n\n
Why This Fix Works in Production
- Trigger: OperationalError: (_mysql_exceptions.OperationalError) (1045, "Access denied for user 'airflow'@'10.x.x.xxx' (using password: YES)")
- Mechanism: The create_engine() function was ignoring MySQL SSL parameters due to filtering of kwargs
- Why the fix works: Fixes issue #6019 by allowing the use of MySQL SSL parameters in the create_engine() function. (first fixed release: 4.4.2).
Production impact:
- If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.
Why This Breaks in Prod
- Shows up under Python 2.7 in real deployments (not just unit tests).
- The create_engine() function was ignoring MySQL SSL parameters due to filtering of kwargs
- Surfaces as: OperationalError: (_mysql_exceptions.OperationalError) (1045, "Access denied for user 'airflow'@'10.x.x.xxx' (using password: YES)")
Proof / Evidence
- GitHub issue: #6019
- Fix PR: https://github.com/celery/celery/pull/6020
- First fixed release: 4.4.2
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.75
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.47
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“I am working on a PR for the line I proposed to change.”
“Finished creating the PR. https://github.com/celery/celery/pull/6020”
Failure Signature (Search String)
- OperationalError: (_mysql_exceptions.OperationalError) (1045, "Access denied for user 'airflow'@'10.x.x.xxx' (using password: YES)")
Error Message
Stack trace
error.txt
Error Message
-------------
OperationalError: (_mysql_exceptions.OperationalError) (1045, "Access denied for user 'airflow'@'10.x.x.xxx' (using password: YES)")
Stack trace
error.txt
Error Message
-------------
from airflow.models import DagRun
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
e = create_engine({AIRFLOW__CELERY__SQL_ALCHEMY_CONN},connect_args= {'ssl': {'ca': '/path-to-mysql-sslcert/server-ca', 'cert': '/path-to-mysql-sslcert/client-cert', 'key': '/path-to-mysql-sslcert/client-key'}})
s = scoped_session(sessionmaker(autocommit=False, autoflush=False, bind=e))
s.query(DagRun).all()
Stack trace
error.txt
Error Message
-------------
sqlalchemy.exc.OperationalError: (_mysql_exceptions.OperationalError) (1045, "Access denied for user 'airflow'@'10.xx.xx.xxx' (using password: YES)")
(Background on this error at: http://sqlalche.me/e/e3q8)
Minimal Reproduction
repro.py
from airflow.models import DagRun
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
e = create_engine({AIRFLOW__CELERY__SQL_ALCHEMY_CONN},connect_args= {'ssl': {'ca': '/path-to-mysql-sslcert/server-ca', 'cert': '/path-to-mysql-sslcert/client-cert', 'key': '/path-to-mysql-sslcert/client-key'}})
s = scoped_session(sessionmaker(autocommit=False, autoflush=False, bind=e))
s.query(DagRun).all()
Environment
- Python: 2.7
What Broke
Users were unable to connect to MySQL with SSL parameters, causing connection failures.
Why It Broke
The create_engine() function was ignoring MySQL SSL parameters due to filtering of kwargs
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install celery==4.4.2
When NOT to use: Do not use this fix if you require pooling parameters to be passed to create_engine().
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Fix reference: https://github.com/celery/celery/pull/6020
First fixed release: 4.4.2
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- Do not use this fix if you require pooling parameters to be passed to create_engine().
Verify Fix
verify
Re-run the minimal reproduction on your broken version, then apply the fix and re-run.
Did This Fix Work in Your Case?
Quick signal helps us prioritize which fixes to verify and improve.
Prevention
- Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
- Pin production dependencies and upgrade only with a reproducible test that hits the failing path.
Version Compatibility Table
| Version | Status |
|---|---|
| 4.4.2 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.