Wheels 2.x > 4.x Performance Comparison

[chapmandu]

Hi Team,

I have done a preliminary port of my application from 2.5 > 4.0.3. I am just wanting to know if there has been any performance comparisons or load testing done between the two versions. My initial test run is showing a considerably slower test suite execution.

Wheels 2.5 (RocketUnit)
Finished Tue Jun 16 2026 10:05:50 (Took 274 Seconds)

Wheels 4.0.3 (RocketUnit)
The full run took 1599 seconds (~27 minutes) — 1574 pass / 5 skip / 0 fail, finished at 08:03:19 yesterday.

Thanks for all your hard work on wheels framework. 💪

Regards,
Adam

[wheels-bot]

Wheels Bot — Triage

Classified as bug (performance regression). The report is framed as a question, but it carries a clear measured regression: the same RocketUnit suite runs in 274s on 2.5 vs 1599s on 4.0.3 — roughly a 6x slowdown on a like-for-like runner. "What happened / what I expected" are both present, which is the bug shape.

Suspected layer

`controller` — see `.ai/wheels/controllers/` for canonical patterns. The dominant cost in a 1574-test RocketUnit run is per-request lifecycle overhead, which compounds across every test. That's exactly where the framework's recent perf work landed (`ef02be9`: cold-start warm-up, O(1) protected-method gate, schema cache, debug-bar slimming). The ORM/`model` layer (finder + schema-cache overhead) is a plausible secondary contributor and should be profiled alongside.

Fix sketch

No single file is implicated yet — this needs profiling before a fix can be scoped. Propose-fix should first reproduce against a representative request path and identify which per-request hotspots regressed (debug-bar rendering in `testing`, the protected-method gate in `$callAction`, schema lookups, cold-start warm-up). Several of these were already addressed in `ef02be9`, which post-dates 4.0.3 — so part of the remedy may be "confirm the next release includes these fixes" rather than new code. Likely touch points are the request-dispatch/controller lifecycle and model schema-cache paths.

Confidence: `low`

The report has no profiling or operation-level isolation, the slowdown could span multiple layers, and the symptom is environment-/suite-dependent — so the fix shape isn't derivable from the issue body, and low intentionally does not auto-trigger a fix PR.

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