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Modding · Reading list · Built a visual debugging panel for modding-books over the weekend

57
MOr/modding-books·posted by chen_dev·3 hours agoInternals

Built a visual debugging panel for modding-books over the weekend

Short version: modding-books needs almost no tuning at small and medium scale — the point where it starts to hurt is much further out than most people assume. Full measurements below.

On trade-offs, my view is this: if nobody on the team owns this area long-term, do not introduce a second mechanism. With two coexistence you first have to work out which one is even in play when things break, and that costs far more than the performance you saved.

Keep it and wait for an official fix44%
Switch to a third-party option now28%
Fork and maintain it ourselves17%
Write an adapter layer and wait11%

97 votes total

24 comments

24 comments

M
Kkite·12 minutes 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.

488
Wwinter·yesterday

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.

13
Zzhou_yiOP·5 hours ago

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.

395
Ddev_zhou·2 days 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.

439
Kkernel_panic·12 minutes ago

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

436
Oops_wang·5 hours ago

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

138
Kkernel_panic·just nowedited

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.

41
Ddev_zhou·1 hour 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.

379
Oops_wang·1 hour ago

Worth learning from this debugging approach. We went straight at the logs and took a much longer route.

300
Rrase·5 hours ago

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

1
Rran_bo·5 hours ago

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

86
Aalice_devMod·2 days ago

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.

30
Ddev_zhou·12 minutes ago

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.

29
Oops_wang·2 days ago

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

18
Llinlin·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.

15
Hhuang_ke·5 hours ago

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

351
Ttang_hao·28 minutes ago

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.

89
Rran_bo·2 hours ago

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

5
Cchen_dev·3 minutes agoedited

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

84
Sslow_query·2 days ago

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

231
Sswoole_lee·5 hours ago

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

1
Lli_ming·1 hour agoedited

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

109
Zzhou_yi·just now

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.

1
Zzhu_zong·12 minutes ago

Worth learning from this debugging approach. We went straight at the logs and took a much longer route.

1

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