Celery GroupResult has minimum result latency of 500ms (Fix)

The Fix

pip install celery==4.4.1

Based on closed celery/celery issue #5930 · 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.

Jump to Verify Open PR/Commit

@@ -200,6 +200,7 @@ def _wait_for_pending(self, result,
             result, timeout=timeout,
             on_interval=on_interval, on_message=on_message,
+            **kwargs
         )

repro.py

import time
from flask import Flask
from celery import Celery, group


app = Flask(__name__)
celery = Celery('app', broker='redis://redis:6379/1', backend='redis://redis:6379/2')


@celery.task
def debug():
    return


@app.route('/', methods={'GET', 'POST'})
def hello_world():
    task = group([
        debug.si() for i in range(10)
    ]).apply_async()

    start = time.perf_counter()
    task.get(timeout=5, interval=0.01)
    print('END', (time.perf_counter() - start) * 1000)
    return {}

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==4.4.1\nWhen NOT to use: This fix should not be applied if the `_iter_meta` method is not used in the application.\n\n

Why This Fix Works in Production

Trigger: GroupResult has minimum result latency of 500ms
Mechanism: The `_iter_meta` method did not accept `kwargs`, causing options like `interval` to be ignored
Why the fix works: Fixes the issue by passing `kwargs` to `_iter_meta`, allowing options like `interval` to be recognized. (first fixed release: 4.4.1).

Why This Breaks in Prod

The `_iter_meta` method did not accept `kwargs`, causing options like `interval` to be ignored
Production symptom (often without a traceback): GroupResult has minimum result latency of 500ms

Proof / Evidence

GitHub issue: #5930
Fix PR: https://github.com/celery/celery/pull/5931
First fixed release: 4.4.1
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.57

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“ # Checklist  - [x] I hav”

Issue thread · issue description · source

Failure Signature (Search String)

GroupResult has minimum result latency of 500ms
- [x] I have included all related issues and possible duplicate issues

Copy-friendly signature

signature.txt

Failure Signature
-----------------
GroupResult has minimum result latency of 500ms
- [x] I have included all related issues and possible duplicate issues

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
GroupResult has minimum result latency of 500ms
- [x] I have included all related issues and possible duplicate issues

Minimal Reproduction

repro.py

import time
from flask import Flask
from celery import Celery, group


app = Flask(__name__)
celery = Celery('app', broker='redis://redis:6379/1', backend='redis://redis:6379/2')


@celery.task
def debug():
    return


@app.route('/', methods={'GET', 'POST'})
def hello_world():
    task = group([
        debug.si() for i in range(10)
    ]).apply_async()

    start = time.perf_counter()
    task.get(timeout=5, interval=0.01)
    print('END', (time.perf_counter() - start) * 1000)
    return {}

What Broke

GroupResult had a minimum result latency of 500ms, impacting performance.

Why It Broke

The `_iter_meta` method did not accept `kwargs`, causing options like `interval` to be ignored

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

pip install celery==4.4.1

When NOT to use: This fix should not be applied if the `_iter_meta` method is not used in the application.

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/5931

First fixed release: 4.4.1

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

This fix should not be applied if the `_iter_meta` method is not used in the application.

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
4.4.1	Fixed

Related Issues

No related fixes found.

Cluster: celery:auth Celery hub Celery best practices All hubs All clusters

Related clusters: Configuration error Data consistency Duplicates

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.