Pool slot chart is misleading when deferred tasks don't consume slots #55734
Description
Apache Airflow version
3.0.6
If "Other Airflow 2 version" selected, which one?
No response
What happened?
The pool slots chart is currently misleading when deferred tasks are configured not to consume pool slots.
- When deferred tasks are not consuming pool slots, the chart still shows them, making it look like the pool usage is 129 with 128 available.
- When deferred tasks are consuming pool slots, the chart shows 127 used + 1 deferred, which makes sense in that context
This creates confusion because it looks like the chart is "double-counting" or incorrectly showing available slots, even though the numbers are technically correct. As a user, I would need to know both:
- Total possible slots
- How deferred tasks are being treated (counted vs not counted)
What you think should happen instead?
The chart should only show deferred tasks if they are actively consuming a pool slot. Otherwise, it creates a misleading impression of slot usage.
Update the chart logic to:
- Only show deferred tasks if they are actively consuming a pool slot
- Optionally clarify total slots vs available slots.
How to reproduce
- Configure a deployment with a pool size of 128 slots (using the default pool is fine)
- Run a dag with a deferred task. HITL example is easiest.
- View the pool slot chart.
- With deferred tasks not consuming slots, the chart shows 128 ✓ + 1 (appears as 129)
- With deferred tasks consuming slots the chart shows 127 ✓ + 1 which is expected
Operating System
macos
Versions of Apache Airflow Providers
No response
Deployment
Other
Deployment details
Using Breeze locally on my Mac, via the v3.1.0-test branch
Anything else?
No response
Are you willing to submit PR?
- Yes I am willing to submit a PR!
Code of Conduct
- I agree to follow this project's Code of Conduct