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ESP32 · Code review · Building an internal platform with esp32-review from scratch: architecture and decision log

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ESr/esp32-review·posted by huang_ke·6 hours agoDiscussion

Building an internal platform with esp32-review from scratch: architecture and decision log

Some background first. Our setup is esp32-review plus three downstream services, seven figures of daily requests, peaking around nine in the evening.

We also fixed monitoring along the way: replaced average-based alerts with percentiles and split them per endpoint. False alerts dropped by about seventy percent and the on-call rotation visibly cheered up.

Worth noting: the official docs do cover this, just in a very inconspicuous spot. I only found it reading the source comments, where the author explains the reasoning — roughly "so that it degrades into predictable behaviour in extreme cases".

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16 comments

16 comments

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Rran_bo·1 hour ago

I see point 3 differently. The trade-off depends on your read/write ratio: read-heavy with little writing means caching actually widens the inconsistency window.

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Rran_bo·2 days ago

Has anyone run a controlled experiment? I did, reducing it to a single variable, and the difference was 4% — within noise. So I suspect the main cause is something else.

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Ddev_zhouOP·28 minutes ago

Agreeing with the above. One addition: with this option enabled the GC count in your metrics doubles, so adjust the alert threshold at the same time or it will keep firing.

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Rran_bo·2 hours ago

This is not a esp32-review problem, it is a usage problem. The docs say this API is not thread-safe and you must lock around it yourself.

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Kkite·2 days ago

Has anyone run a controlled experiment? I did, reducing it to a single variable, and the difference was 4% — within noise. So I suspect the main cause is something else.

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Sswoole_lee·1 hour ago

A question: what changes in a container with a 512Mi memory limit? That is how we run it in production.

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Ddev_zhou·2 days ago

Saved. I am reworking this area this week — this saves a lot of wrong turns.

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Mmike_xu·1 hour agoedited

There is actually a simpler fix that needs no architecture change: move this check up to the gateway and the problem disappears. The cost is one extra lookup at the gateway.

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Hhuang_ke·yesterday

Thanks for sharing real numbers — far more useful than the articles that only cover concepts.

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Zzhou_yi·just nowedited

We have run this in production for two years without hitting it. That said, we never reached this scale, so our experience is not really evidence here.

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Kkite·just now

Sharing our numbers, 8 cores 16GB, same scenario:

| Concurrency | P50 | P99 |
|---|---|---|
| 200 | 12ms | 88ms |
| 500 | 31ms | 340ms |

P99 clearly collapses at 500 concurrency, which lines up with your knee point.

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Bbob_chen·28 minutes ago

I just read the esp32-review source — the author actually explains the reasoning in a comment, roughly "so that it degrades into predictable behaviour in extreme cases".

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Nnikic·12 minutes ago

One counter-example: below esp32-review 7.4 the semantics of that code are different, so do not copy it verbatim. We got burned in staging and rolled back once.

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Sswoole_lee·just now

This matches what we see in production. We only hit it past 3k QPS; the earlier load tests showed nothing — the test traffic was too clean, with no long-tail requests.

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Ddev_zhou·12 minutes agoedited

Can you give a minimal reproduction? I ran it locally for ten minutes and could not reproduce on macOS with the latest version.

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Sswoole_leeOP·2 days ago

Thanks for sharing real numbers — far more useful than the articles that only cover concepts.

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